Pub Date : 2019-06-25DOI: 10.2174/2210681208666180125143258
S. Swain, P. K. Sahu, B. R. Jena, S. Beg, S. M. Babu
Irbesartan is an anti-hypertensive BCS class II drug exhibiting poor aqueous solubility, which makes it highly challenging for delivery through the oral route. Based on this fact, a self-microemulsifying drug delivery system (SMEDDS) was designed and characterized for augmenting the aqueous solubility and dissolution rate of irbesartan. Several blends of oil (Capmul MCM EP), surfactant (Tween 80) and co-surfactant (PEG 600) were screened from the preliminary solubility and pseudo-ternary phase diagram studies. Systematic optimization of the SMEDDS was carried out using 3-factor 3-level Box-Behnken design. The optimized formulation was identified by numerical optimization technique, which revealed faster emulsification time, high percent transmittance and drug content, lower globule size < 100 nm, zeta potential and excellent thermodynamic stability. The optimal formulation unveiled more than 93.3% drug release in vitro within 60 minutes, while the pure drug exhibited only 20% drug release, respectively. Ex vivo permeability and in situ intestinal absorption of drugs was improved nearly 2 to 3- fold by the optimal SMEDDS formulation against the pure drug alone (p < 0.001). Overall, the proposed SMEDDS formulation of irbesartan exhibited a superior biopharmaceutical performance.
{"title":"Formulation Development, Statistical Optimization and Characterization of the Self-Microemulsifying Drug Delivery System (SMEDDS) of Irbesartan","authors":"S. Swain, P. K. Sahu, B. R. Jena, S. Beg, S. M. Babu","doi":"10.2174/2210681208666180125143258","DOIUrl":"https://doi.org/10.2174/2210681208666180125143258","url":null,"abstract":"\u0000\u0000 Irbesartan is an anti-hypertensive BCS class II drug exhibiting poor aqueous\u0000solubility, which makes it highly challenging for delivery through the oral route. Based on this fact, a\u0000self-microemulsifying drug delivery system (SMEDDS) was designed and characterized for augmenting\u0000the aqueous solubility and dissolution rate of irbesartan.\u0000\u0000\u0000\u0000Several blends of oil (Capmul MCM EP), surfactant (Tween 80) and co-surfactant (PEG 600)\u0000were screened from the preliminary solubility and pseudo-ternary phase diagram studies. Systematic optimization\u0000of the SMEDDS was carried out using 3-factor 3-level Box-Behnken design.\u0000\u0000\u0000\u0000The optimized formulation was identified by numerical optimization technique, which revealed\u0000faster emulsification time, high percent transmittance and drug content, lower globule size < 100 nm,\u0000zeta potential and excellent thermodynamic stability. The optimal formulation unveiled more than\u000093.3% drug release in vitro within 60 minutes, while the pure drug exhibited only 20% drug release, respectively.\u0000\u0000\u0000\u0000Ex vivo permeability and in situ intestinal absorption of drugs was improved nearly 2 to 3-\u0000fold by the optimal SMEDDS formulation against the pure drug alone (p < 0.001). Overall, the proposed\u0000SMEDDS formulation of irbesartan exhibited a superior biopharmaceutical performance.\u0000","PeriodicalId":18979,"journal":{"name":"Nanoscience & Nanotechnology-Asia","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73344159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-25DOI: 10.2174/2210681208666180329152523
M. Sabet, M. Mohammadi, Fatemeh Googhari
Due to unique chemical and physical properties and potential application in many fields, nanostructured materials have attracted many attentions. Cadmium sulfide (CdS) is a semiconductor that has a wide band gap of 2.42 eV at room temperature and can be served in solar cells and photoluminescence devices. Cadmium sulfide (CdS) is a kind of attractive semiconductor material, and it is now widely used for optoelectronic applications. CdS nano and microstructures can be synthesized via different chemical methods such as microwave-solvothermal synthesis, surfactant-ligand coassisting solvothermal method and hydrothermal route. Also different morphologies of this semiconductor such as dendrites, nanorods, sphere-like, flakes, nanowires, flower-like shape triangular and hexagonal plates, were synthesized. To synthesis of the nanocomposite, a simple co-precipitation method was served. In briefly, 0.1 g of Pb(NO3)2 was dissolved in the distilled water (Solution 1). Also different aqueous solutions were made from dissolving different mole ratio of Cd(NO3)2.6H2O respect to the lead source in the water (Solution 2). Two solutions were mixed together under vigorous stirring and then S2- solution (0.02 g thiourea in the water) was added to the Pb2+/Cd2+ solution. After that 0.1 g of CTAB as surfactant was added to the final solution. Finally to the synthesis of both sulfide and oxide nanostructures, NaOH solution was added to the prepared solution to obtain pH= 10. Distilled water and absolute ethanol were used to wash the obtained precipitate and then it dried at 80 °C for 8 h. From the XRD pattern it was found that the peaks placed at 24.9°, 27°, 44.1°, 48°, 52°, 54°, 57.8°, 66.8°, 71.2° are associated to CdS compound with hexagonal phase (JCPDS=00-001-0780) that belong to (100), (002), (110), (103), (112), (201), (202), (203), (211) Miller indices respectively. The Other peaks belong to PbS with hexagonal phase (JCPDS=01-078-1897), and CdO with cubic phase (JCPDS=00-001-1049). From SEM images, it was found by choosing the mole ratio to 1:1, very small and uniform particles were achieved. By increasing Pb2+/Cd2+ mole ratio to 1:2, very tiny particles aggregated together were achieved. The results showed that the product can adsorb extra 80% of heavy metal ions from the water. So it can be said that the nanocomposite can be used in the water treatment due to its high photocatalytic and surface adsorption activities. In other words, it can remove heavy metals from the water and also decompose organic pollutions.
纳米结构材料由于其独特的化学和物理性质以及在许多领域的潜在应用，引起了人们的广泛关注。硫化镉(cd)是一种在室温下具有2.42 eV宽禁带隙的半导体材料，可用于太阳能电池和光致发光器件。硫化镉(cd)是一种极具吸引力的半导体材料，目前已广泛应用于光电子领域。采用微波-溶剂热法、表面活性剂-配体助溶法、溶剂热法和水热法等不同的化学方法可以合成CdS的纳米结构和微观结构。此外，还合成了这种半导体的不同形态，如枝晶、纳米棒、球形、薄片、纳米线、花状三角形和六角形板。采用一种简单的共沉淀法合成了纳米复合材料。简单地说，将0.1 g的Pb(NO3)2溶解在蒸馏水(溶液1)中，并将Cd(NO3)2.6H2O相对于铅源(溶液2)的不同摩尔比溶解成不同的水溶液。两种溶液在剧烈搅拌下混合，然后将S2-溶液(水中含有0.02 g硫脲)加入到Pb2+/Cd2+溶液中。在最终溶液中加入0.1 g CTAB保证剂。最后在制备好的溶液中加入NaOH溶液，得到pH= 10，以合成硫化物和氧化结构。用蒸馏水和无水乙醇洗涤所得沉淀物，80℃干燥8 h。XRD谱图表明，在24.9°、27°、44.1°、48°、52°、54°、57.8°、66.8°、71.2°处的峰为六方相CdS化合物(JCPDS=00-001-0780)，分别属于米勒指数(100)、(002)、(110)、(103)、(112)、(201)、(202)、(203)、(211)。其他峰属于六方相的PbS (JCPDS=01-078-1897)和立方相的CdO (JCPDS=00-001-1049)。从SEM图像中可以发现，选择摩尔比为1:1时，可以得到非常小而均匀的颗粒。通过将Pb2+/Cd2+的摩尔比增加到1:2，可以得到非常微小的颗粒聚集在一起。结果表明，该产品可额外吸附水中80%的重金属离子。因此，纳米复合材料具有较高的光催化活性和表面吸附活性，可用于水处理。换句话说，它可以去除水中的重金属，也可以分解有机污染物。
{"title":"Prominent Visible Light Photocatalytic and Water Purification Activity of PbS/CdS/CdO Nanocomposite Synthesized via Simple Co-Precipitation Method","authors":"M. Sabet, M. Mohammadi, Fatemeh Googhari","doi":"10.2174/2210681208666180329152523","DOIUrl":"https://doi.org/10.2174/2210681208666180329152523","url":null,"abstract":"\u0000\u0000Due to unique chemical and physical properties and potential application in\u0000many fields, nanostructured materials have attracted many attentions. Cadmium sulfide (CdS) is a semiconductor\u0000that has a wide band gap of 2.42 eV at room temperature and can be served in solar cells\u0000and photoluminescence devices. Cadmium sulfide (CdS) is a kind of attractive semiconductor material,\u0000and it is now widely used for optoelectronic applications. CdS nano and microstructures can be synthesized\u0000via different chemical methods such as microwave-solvothermal synthesis, surfactant-ligand coassisting\u0000solvothermal method and hydrothermal route. Also different morphologies of this semiconductor\u0000such as dendrites, nanorods, sphere-like, flakes, nanowires, flower-like shape triangular and\u0000hexagonal plates, were synthesized.\u0000\u0000\u0000\u0000To synthesis of the nanocomposite, a simple co-precipitation method was served. In briefly,\u00000.1 g of Pb(NO3)2 was dissolved in the distilled water (Solution 1). Also different aqueous solutions\u0000were made from dissolving different mole ratio of Cd(NO3)2.6H2O respect to the lead source in the\u0000water (Solution 2). Two solutions were mixed together under vigorous stirring and then S2- solution\u0000(0.02 g thiourea in the water) was added to the Pb2+/Cd2+ solution. After that 0.1 g of CTAB as\u0000surfactant was added to the final solution. Finally to the synthesis of both sulfide and oxide\u0000nanostructures, NaOH solution was added to the prepared solution to obtain pH= 10. Distilled water\u0000and absolute ethanol were used to wash the obtained precipitate and then it dried at 80 °C for 8 h.\u0000\u0000\u0000\u0000From the XRD pattern it was found that the peaks placed at 24.9°, 27°, 44.1°, 48°, 52°, 54°,\u000057.8°, 66.8°, 71.2° are associated to CdS compound with hexagonal phase (JCPDS=00-001-0780) that\u0000belong to (100), (002), (110), (103), (112), (201), (202), (203), (211) Miller indices respectively. The\u0000Other peaks belong to PbS with hexagonal phase (JCPDS=01-078-1897), and CdO with cubic phase\u0000(JCPDS=00-001-1049). From SEM images, it was found by choosing the mole ratio to 1:1, very small\u0000and uniform particles were achieved. By increasing Pb2+/Cd2+ mole ratio to 1:2, very tiny particles aggregated\u0000together were achieved.\u0000\u0000\u0000\u0000The results showed that the product can adsorb extra 80% of heavy metal ions from the\u0000water. So it can be said that the nanocomposite can be used in the water treatment due to its high photocatalytic\u0000and surface adsorption activities. In other words, it can remove heavy metals from the water\u0000and also decompose organic pollutions.\u0000","PeriodicalId":18979,"journal":{"name":"Nanoscience & Nanotechnology-Asia","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87175838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-25DOI: 10.2174/2210681208666180813123035
Somrita Ghosh, A. Acharyya
Excess noise characteristics of Multiple Quantum Barrier (MQB) nanoscale avalanche photodiodes (APDs) based on Si~3C-SiC heterostructures have been studied in this part of the paper. The multiplication gain and Excess Noise Factor (ENF) of the MQB APDs have been calculated by varying the number of Quantum Barriers (QBs). The numerically calculated ENF values of MQB APDs have been compared with the ENF of Si flat conventional APDs of similar dimensions and it is observed that the use of QBs leads to significant reduction in ENF of the APDs under similar biasing and illumination conditions. Results: The enhanced ratio of hole to electron ionization rates in MQB structures as compared to the bulk Si APD structure has been found to be the primary cause of improvement in the noise performance of the MQB nano-APDs. Finally, the numerically calculated ENF of Si flat APD has been compared with the experimentally measured ENF of a commercially available Si APD and those are found to be in good agreement; this comparison validates the simulation methodology adopted by the authors in this paper.
{"title":"Multiple Quantum Barrier Nano-avalanche Photodiodes - Part II: Excess Noise Characteristics","authors":"Somrita Ghosh, A. Acharyya","doi":"10.2174/2210681208666180813123035","DOIUrl":"https://doi.org/10.2174/2210681208666180813123035","url":null,"abstract":"\u0000\u0000Excess noise characteristics of Multiple Quantum Barrier (MQB) nanoscale\u0000avalanche photodiodes (APDs) based on Si~3C-SiC heterostructures have been studied in\u0000this part of the paper. The multiplication gain and Excess Noise Factor (ENF) of the MQB APDs\u0000have been calculated by varying the number of Quantum Barriers (QBs).\u0000\u0000\u0000\u0000 The numerically calculated ENF values of MQB APDs have been compared with the\u0000ENF of Si flat conventional APDs of similar dimensions and it is observed that the use of QBs leads\u0000to significant reduction in ENF of the APDs under similar biasing and illumination conditions.\u0000Results: The enhanced ratio of hole to electron ionization rates in MQB structures as compared to\u0000the bulk Si APD structure has been found to be the primary cause of improvement in the noise performance\u0000of the MQB nano-APDs.\u0000\u0000\u0000\u0000Finally, the numerically calculated ENF of Si flat APD has been compared with the experimentally\u0000measured ENF of a commercially available Si APD and those are found to be in good agreement;\u0000this comparison validates the simulation methodology adopted by the authors in this paper.\u0000","PeriodicalId":18979,"journal":{"name":"Nanoscience & Nanotechnology-Asia","volume":"1952 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91231452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-25DOI: 10.2174/2210681208666180813123550
Somrita Ghosh, A. Acharyya
The spectral response of Multiple Quantum Barrier (MQB) nano-scale avalanche photodiodes (APDs) based on Si~3C-SiC material system shows considerable responsivity of the device within a very wide wavelength range which includes some portion of Ultra- Violet (UV) spectrum (200- 90 nm), visible spectrum (390-770 nm), near-infrared (700-1400 nm), short-wavelength infrared (1400-3000 nm) and mid-infrared (3000-4000 nm) wavelengths. It has already been concluded from preceding studies that Si~3C-SiC MQB APDs shows better spectral response and excess noise characteristics as compared to equivalent conventional APDs based on Si. Moreover, the superiority of the illumination through p+-side (ITPS) structure has been observed among two probable optical illumination configurations such as illumination through n+- side (ITNS) and illumination through p+-side (ITPS) structures. In this paper, the time and frequency responses of Si~3C-SiC MQB APDs have been investigated. A very narrow rectangular pulse of pulse-width of 0.4 ps has been used as the input optical pulse having 850 nm wavelength incident on the p+-side of the MQB APD structures (i.e. ITPS is considered here) and corresponding current responses have been calculated by using a rigorous simulation method developed by the authors; finally the frequency responses of the devices are obtained via the Fourier transform of the corresponding pulse current responses in time domain. The width of the current responses are limited to 4.7 and 3.1 ps in Si nano-APD and Si~3C-SiC MQB (consisting of five quantum barriers) nano-APD respectively for the input optical pulse of width 0.4 ps of 850 nm wavelength. On the other hand, the 3 dB upper cut-off frequencies of the above-mentioned diodes are obtained to be 68.63 and 82.64 GHz respectively. Simulation results show that MQB nano-APDs possess significantly faster time response and wider frequency response as compared to the flat Si nano-APDs under similar operating conditions.
{"title":"Multiple Quantum Barrier Nano-avalanche Photodiodes - Part I: Spectral Response","authors":"Somrita Ghosh, A. Acharyya","doi":"10.2174/2210681208666180813123550","DOIUrl":"https://doi.org/10.2174/2210681208666180813123550","url":null,"abstract":"\u0000\u0000The spectral response of Multiple Quantum Barrier (MQB) nano-scale\u0000avalanche photodiodes (APDs) based on Si~3C-SiC material system shows considerable responsivity\u0000of the device within a very wide wavelength range which includes some portion of Ultra-\u0000Violet (UV) spectrum (200- 90 nm), visible spectrum (390-770 nm), near-infrared (700-1400 nm),\u0000short-wavelength infrared (1400-3000 nm) and mid-infrared (3000-4000 nm) wavelengths. It has\u0000already been concluded from preceding studies that Si~3C-SiC MQB APDs shows better spectral\u0000response and excess noise characteristics as compared to equivalent conventional APDs based on\u0000Si. Moreover, the superiority of the illumination through p+-side (ITPS) structure has been observed\u0000among two probable optical illumination configurations such as illumination through n+-\u0000side (ITNS) and illumination through p+-side (ITPS) structures.\u0000\u0000\u0000\u0000In this paper, the time and frequency responses of Si~3C-SiC MQB APDs have been investigated.\u0000A very narrow rectangular pulse of pulse-width of 0.4 ps has been used as the input optical\u0000pulse having 850 nm wavelength incident on the p+-side of the MQB APD structures (i.e. ITPS\u0000is considered here) and corresponding current responses have been calculated by using a rigorous\u0000simulation method developed by the authors; finally the frequency responses of the devices are obtained\u0000via the Fourier transform of the corresponding pulse current responses in time domain.\u0000\u0000\u0000\u0000The width of the current responses are limited to 4.7 and 3.1 ps in Si nano-APD and\u0000Si~3C-SiC MQB (consisting of five quantum barriers) nano-APD respectively for the input optical\u0000pulse of width 0.4 ps of 850 nm wavelength. On the other hand, the 3 dB upper cut-off frequencies\u0000of the above-mentioned diodes are obtained to be 68.63 and 82.64 GHz respectively.\u0000\u0000\u0000\u0000Simulation results show that MQB nano-APDs possess significantly faster time response\u0000and wider frequency response as compared to the flat Si nano-APDs under similar operating\u0000conditions.\u0000","PeriodicalId":18979,"journal":{"name":"Nanoscience & Nanotechnology-Asia","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91255082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-25DOI: 10.2174/2210681208666180321143945
A. Hasani
Laser ablation method has high-yield and pure SWCNHs. On the other hand, arc discharge methods have low-cost production of SWCNHs. However, these techniques have more desirable features, they need special expertness to use high power laser or high current discharge that either of them produces very high temperature. As for the researches, the temperatures of these techniques are higher than 4727°C to vaporize the graphite. So, to become aware of the advantages of SWCNHs, it is necessary to find a new way to synthesize SWCNHs at a lower temperature. In other words, reaction field can be expandable at a moderate temperature. This paper reports a new way to synthesize SWCNHs at an extremely reduced temperature. According to this study, the role of N2 is the protection of the copper holder supporting the graphite rod by increasing heat transfer from the holder. After the current of 70 A was supplied to the system, the temperature of graphite rod was raised to 1600°C. It is obvious that this temperature is somehow higher than the melting point of palladium, 1555°C, and much lower than graphite melting point, 3497°C. Based on the results, there are transitional precursors simultaneous with the SWCNHs. This composition can be created by distortion of the primary SWCNTs at the higher temperature. Subsequently, each SWCNTs have a tendency to be broken into individual horns. With increasing the concentration of the free horns, bud-like SWCNHs can be produced. Moreover, there are individual horns almost separated from the mass of single wall carbon nanohorns. This structure is not common in SWCNHs synthesized by the usual method such as arc discharge or laser ablation. Through these regular techniques, SWCNHs are synthesized as cumulative particles with diameters about 30-150 nm. A simple heating is needed for SWCNTs transformation to SWCNHs with the presence of palladium as catalyst. The well-thought-out mechanism for this transformation is that SWCNTs were initially changed to highly curled shape, and after that were formed into small independent horns. The other rout to synthesize SWCNHs is the pyrolysis of palm olein at 950°C with the assistance of zinc nitrate and ferrocene. Palm olein was used as a promising, bio-renewable and inexpensive carbon source for the production of carbon nanohorns.
{"title":"Using Low Temperature, Cost-effective and Green Methods to Carbon Nanohorn Synthesis","authors":"A. Hasani","doi":"10.2174/2210681208666180321143945","DOIUrl":"https://doi.org/10.2174/2210681208666180321143945","url":null,"abstract":"\u0000\u0000Laser ablation method has high-yield and pure SWCNHs. On the other hand,\u0000arc discharge methods have low-cost production of SWCNHs. However, these techniques have more\u0000desirable features, they need special expertness to use high power laser or high current discharge that\u0000either of them produces very high temperature. As for the researches, the temperatures of these techniques\u0000are higher than 4727°C to vaporize the graphite. So, to become aware of the advantages of\u0000SWCNHs, it is necessary to find a new way to synthesize SWCNHs at a lower temperature. In other\u0000words, reaction field can be expandable at a moderate temperature. This paper reports a new way to\u0000synthesize SWCNHs at an extremely reduced temperature.\u0000\u0000\u0000\u0000 According to this study, the role of N2 is the protection of the copper holder supporting the\u0000graphite rod by increasing heat transfer from the holder. After the current of 70 A was supplied to the\u0000system, the temperature of graphite rod was raised to 1600°C. It is obvious that this temperature is\u0000somehow higher than the melting point of palladium, 1555°C, and much lower than graphite melting\u0000point, 3497°C.\u0000\u0000\u0000\u0000Based on the results, there are transitional precursors simultaneous with the SWCNHs. This\u0000composition can be created by distortion of the primary SWCNTs at the higher temperature. Subsequently,\u0000each SWCNTs have a tendency to be broken into individual horns. With increasing the concentration\u0000of the free horns, bud-like SWCNHs can be produced. Moreover, there are individual horns almost\u0000separated from the mass of single wall carbon nanohorns. This structure is not common in\u0000SWCNHs synthesized by the usual method such as arc discharge or laser ablation. Through these regular\u0000techniques, SWCNHs are synthesized as cumulative particles with diameters about 30-150 nm.\u0000\u0000\u0000\u0000A simple heating is needed for SWCNTs transformation to SWCNHs with the presence of\u0000palladium as catalyst. The well-thought-out mechanism for this transformation is that SWCNTs were\u0000initially changed to highly curled shape, and after that were formed into small independent horns. The\u0000other rout to synthesize SWCNHs is the pyrolysis of palm olein at 950°C with the assistance of zinc nitrate\u0000and ferrocene. Palm olein was used as a promising, bio-renewable and inexpensive carbon source\u0000for the production of carbon nanohorns.\u0000","PeriodicalId":18979,"journal":{"name":"Nanoscience & Nanotechnology-Asia","volume":"67 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88832701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-25DOI: 10.2174/2210681208666180507101809
N. A. Wibowo, Cahya Handoyo, L. R. Sasongko
Even applying thermal pulse has been succeeded to reduce the coercivity through randomization the magnetization in such a way stimulate the magnetic reversion, the efficiency of magnetic switching field consumption in writing process still turns out to be an exciting research field to implement the HAMR technology. One of the remarkable geometric properties of HAMR storage media that can be correlated to the writing field reduction issue is the nano-dot thickness. Furthermore, thermal fluctuation causes the magnetization switching process to be probabilistic. This magnetic switching probability determines the magnitude of the writing field. This paper aims to investigate the impact of changes in media thickness on the magnetization process in particular at high temperatures numerically. Nano-dot was modeled as a parallelepiped with uniaxial anisotropy which was regarded as a magnetically isolated system where no disturbance field of neighboring nano-dots. Simulation arrangements were implemented to evaluate the two viewpoints in the current heat-assisted magnetic recording, either coercivity, as well as writing field consume. Coercivity was gauged by inducing a magnetic field which linearly increased up to 2 Tesla for 2.5 ns at thermal equilibrium to the surrounding. In evaluating writing field consume, thermal field pulse which just below the Curie temperature was generated while the magnetic field inducing the nano-dot. These schemes investigations were based on the Landau-Lifshift- Gilbert equation which accommodates the fluctuation-dissipation theorem in calculating thermal fluctuation effect. Also, temperature dependent material parameters such as magnetic saturation, magnetic anisotropy, and exchange interaction, were taken into account. At room temperature, the coercive and nucleation fields are highly sensitive to the nano-dot thickness. Under thermal assistance, the writing field for 10 nm and 100 nm of the chosen thicknesses are 0.110 T and 0.125 T respectively. These writing grades are significantly lower than the coercivity of the media. For both thicknesses, zero field magnetization reversal phenomena are observed as indicated by the existences of the switching probabilities at H = 0. This numerical study showed that using the heating assistance close to the Curie point, nanodots with the chosen thicknesses and magnetic parameters were probably to be magnetized even no driven magnetic field. Along with this result, magnetic field induction which required to utterly magnetizing was only in the sub-Tesla - about a tenth of the coercive field. During magnetization processes under thermal assistance, randomization of magnetic moments initiated the switching dynamic before the domain wall was nucleated and propagated to reach a single magnetized domain.
{"title":"Thermally Activated Magnetic Switching Mode for Various Thicknesses of Perpendicularly Ferromagnetic Nano-dot","authors":"N. A. Wibowo, Cahya Handoyo, L. R. Sasongko","doi":"10.2174/2210681208666180507101809","DOIUrl":"https://doi.org/10.2174/2210681208666180507101809","url":null,"abstract":"\u0000\u0000Even applying thermal pulse has been succeeded to reduce the coercivity through\u0000randomization the magnetization in such a way stimulate the magnetic reversion, the efficiency of magnetic\u0000switching field consumption in writing process still turns out to be an exciting research field to implement\u0000the HAMR technology. One of the remarkable geometric properties of HAMR storage media that can be\u0000correlated to the writing field reduction issue is the nano-dot thickness. Furthermore, thermal fluctuation\u0000causes the magnetization switching process to be probabilistic. This magnetic switching probability determines\u0000the magnitude of the writing field. This paper aims to investigate the impact of changes in media\u0000thickness on the magnetization process in particular at high temperatures numerically.\u0000\u0000\u0000\u0000Nano-dot was modeled as a parallelepiped with uniaxial anisotropy which was regarded as a\u0000magnetically isolated system where no disturbance field of neighboring nano-dots. Simulation arrangements\u0000were implemented to evaluate the two viewpoints in the current heat-assisted magnetic recording,\u0000either coercivity, as well as writing field consume. Coercivity was gauged by inducing a magnetic field\u0000which linearly increased up to 2 Tesla for 2.5 ns at thermal equilibrium to the surrounding. In evaluating\u0000writing field consume, thermal field pulse which just below the Curie temperature was generated while the\u0000magnetic field inducing the nano-dot. These schemes investigations were based on the Landau-Lifshift-\u0000Gilbert equation which accommodates the fluctuation-dissipation theorem in calculating thermal fluctuation\u0000effect. Also, temperature dependent material parameters such as magnetic saturation, magnetic anisotropy,\u0000and exchange interaction, were taken into account.\u0000\u0000\u0000\u0000At room temperature, the coercive and nucleation fields are highly sensitive to the nano-dot thickness.\u0000Under thermal assistance, the writing field for 10 nm and 100 nm of the chosen thicknesses are 0.110\u0000T and 0.125 T respectively. These writing grades are significantly lower than the coercivity of the media.\u0000For both thicknesses, zero field magnetization reversal phenomena are observed as indicated by the existences\u0000of the switching probabilities at H = 0.\u0000\u0000\u0000\u0000This numerical study showed that using the heating assistance close to the Curie point, nanodots\u0000with the chosen thicknesses and magnetic parameters were probably to be magnetized even no driven\u0000magnetic field. Along with this result, magnetic field induction which required to utterly magnetizing was\u0000only in the sub-Tesla - about a tenth of the coercive field. During magnetization processes under thermal\u0000assistance, randomization of magnetic moments initiated the switching dynamic before the domain wall\u0000was nucleated and propagated to reach a single magnetized domain.\u0000","PeriodicalId":18979,"journal":{"name":"Nanoscience & Nanotechnology-Asia","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90212561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-25DOI: 10.2174/2210681207666171107142451
M. E. Haghiri, N. Soltani, E. Saion, A. Izanloo, G. Bahmanrokh, M. Askari
Development of novel materials represents a new and fast evolving application of research in physics and medicine. The area of nanomaterial research has presented interesting physical and chemical properties that cannot be obtained from their macroscopic counterparts.This study has attempted to attain well-dispersed nanoparticles by variation of polymer concentration.In order to obtain the calcium borate nanoparticles, polyvinyl pyrrolidone has been used as a capping agent and the preparation method was performed via simple co-precipitation technique followed by heating treatment. In absence of polymer, the heating process causes un-controlled growth of particles with more flocculation and the nanoplate-shaped particles with mean size of 16.0 ×30.0 nm was formed. The introduction of polymer concentration of 1 wt% was conducted to the formation of spherical shaped nanoparticles with sufficiently narrow size distribution and small average size of 5.5 nm and 13.0 nm for the initial precipitation and heating process, respectively. Moreover, the synthesized calcium borate nanoparticles showed good luminescence properties with a simple glow curve dominating at 150°C.This curve was utilized to derive trapping parameters including the activation energy, order of kinetic and frequency factor.The well-dispersed calcium borate nanoparticles have been prepared successfully by introduction of sufficient concentration of polymer.
{"title":"Fabrication and Radiation Dose Properties of Well-dispersed Calcium Borate Nanoparticles","authors":"M. E. Haghiri, N. Soltani, E. Saion, A. Izanloo, G. Bahmanrokh, M. Askari","doi":"10.2174/2210681207666171107142451","DOIUrl":"https://doi.org/10.2174/2210681207666171107142451","url":null,"abstract":"Development of novel materials represents a new and fast evolving application of research in physics and medicine. The area of nanomaterial research has presented interesting physical and chemical properties that cannot be obtained from their macroscopic counterparts.This study has attempted to attain well-dispersed nanoparticles by variation of polymer concentration.In order to obtain the calcium borate nanoparticles, polyvinyl pyrrolidone has been used as a capping agent and the preparation method was performed via simple co-precipitation technique followed by heating treatment. In absence of polymer, the heating process causes un-controlled growth of particles with more flocculation and the nanoplate-shaped particles with mean size of 16.0 ×30.0 nm was formed. The introduction of polymer concentration of 1 wt% was conducted to the formation of spherical shaped nanoparticles with sufficiently narrow size distribution and small average size of 5.5 nm and 13.0 nm for the initial precipitation and heating process, respectively. Moreover, the synthesized calcium borate nanoparticles showed good luminescence properties with a simple glow curve dominating at 150°C.This curve was utilized to derive trapping parameters including the activation energy, order of kinetic and frequency factor.The well-dispersed calcium borate nanoparticles have been prepared successfully by introduction of sufficient concentration of polymer.","PeriodicalId":18979,"journal":{"name":"Nanoscience & Nanotechnology-Asia","volume":"60 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85351987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-25DOI: 10.2174/2210681208666180813122145
Hind Jaafar, A. Aouaj, A. Bouziane, B. Iñíguez
A novel Dual Material Gate Graded Channel and Dual Oxide Thickness Cylindrical Gate (DMG-GC-DOT) MOSFET is presented in this paper. Analytical model of drain current is developed using a quasi-two-dimensional cylindrical form of the Poisson equation and is expressed as a function of the surface potential, which is calculated using the expressions of the current density. Comparison of the analytical results with 3D numerical simulations using Silvaco Atlas - TCAD software presents a good agreement from subthreshold to strong inversion regime and for different bias voltages. Two oxide thicknesses with different permittivity can effectively improve the subthreshold current of DMG-GC-DOT MOSFET.
{"title":"An Analytical Drain Current Model for Dual-material Gate Graded - channel and Dual-oxide Thickness Cylindrical Gate (DMG-GC-DOT) MOSFET","authors":"Hind Jaafar, A. Aouaj, A. Bouziane, B. Iñíguez","doi":"10.2174/2210681208666180813122145","DOIUrl":"https://doi.org/10.2174/2210681208666180813122145","url":null,"abstract":"\u0000\u0000A novel Dual Material Gate Graded Channel and Dual Oxide Thickness Cylindrical\u0000Gate (DMG-GC-DOT) MOSFET is presented in this paper.\u0000\u0000\u0000\u0000Analytical model of drain current is developed using a quasi-two-dimensional cylindrical\u0000form of the Poisson equation and is expressed as a function of the surface potential, which is calculated\u0000using the expressions of the current density.\u0000\u0000\u0000\u0000Comparison of the analytical results with 3D numerical simulations using Silvaco Atlas -\u0000TCAD software presents a good agreement from subthreshold to strong inversion regime and for different\u0000bias voltages.\u0000\u0000\u0000\u0000Two oxide thicknesses with different permittivity can effectively improve the subthreshold\u0000current of DMG-GC-DOT MOSFET.\u0000","PeriodicalId":18979,"journal":{"name":"Nanoscience & Nanotechnology-Asia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86520919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-25DOI: 10.2174/2210681208666180403113546
L. Zejun, W. Yan, Liang Qiyang, J. Xia, Jian Li, Yong Huang
The study area is located in the Hebei province Luanxian section along the Luanhe River. The right of Luanhe River is arranged with 3 monitoring sections and is laid with 5 wells in the A-A section and B-B section and 1 well on the floodplain (inside the dike), the distance from the river level is about 10m. The distance between the 4 wells outside the dike is 20m, 50m, 200m and 1500m respectively. 2 wells are arranged on the C-C section, so there are 13 observation wells in the study area. 3# wells and 11# wells have used existing monitoring wells, so 11 wells have been set up actually. The monitoring wells are designed to monitor groundwater level, groundwater quality and isotope analysis. In the upstream of Luanhe’s A-A section of the No. 4 well near the edge of the woods and downstream of the B-B section of the No. 8 well near the edge of farmland (wheat), each point of soil is sampled to determine the content of nitrate nitrogen and 15N isotope ratio in soil profile. The depth of soil is sampled from surface to groundwater level, the total depth is about 2.5m. Taking about 1kg soil samples at 20cm every time from the ground surface and collect and seal in plastic bags and number. The sampling time was November 2015, March 2016, May 2016 and July 2016, taking 4 times. The analysis showed that higher nitrate content in soil is within 0-60cm, and is same as the depth of fertilizing the crops (including animal manure), so when estimating the proportion of groundwater in nitrate, nitrate content in 0-60cm is assumed as the initial value; which is close to the underground water level in the soil and is regarded as the final value of 60cm, that is, the final value of nitrate into the groundwater, which can estimate the soil nitrate into groundwater ratio. The sources of nitrate in groundwater are complex and related to many factors, such as river water, soil and so on. According to the content of nitrogen and oxygen isotopes, it determines the main source of nitrate nitrogen:soil and Luanhe River. The results showed that the ratio of nitrate to groundwater in the forest soil was 20%~80.8%, and the average value was 56.3%. The proportion of nitrate in the soil in the wheat field was 6.8%~98.2%, with an average value of 48.3%. Nitrate nitrogen from water in proportion of large changes with the seasons, the upper reaches of the Luanhe River (near No. 2 wells) for 0~19.6%; the Luanhe River (near No. 7 wells) for 0~31.5%.
{"title":"Source Analysis of Nitrate Nitrogen in Groundwater Based on Different Modes of Land use","authors":"L. Zejun, W. Yan, Liang Qiyang, J. Xia, Jian Li, Yong Huang","doi":"10.2174/2210681208666180403113546","DOIUrl":"https://doi.org/10.2174/2210681208666180403113546","url":null,"abstract":"\u0000\u0000The study area is located in the Hebei province Luanxian section along the\u0000Luanhe River. The right of Luanhe River is arranged with 3 monitoring sections and is laid with 5\u0000wells in the A-A section and B-B section and 1 well on the floodplain (inside the dike), the distance\u0000from the river level is about 10m. The distance between the 4 wells outside the dike is 20m, 50m,\u0000200m and 1500m respectively. 2 wells are arranged on the C-C section, so there are 13 observation\u0000wells in the study area. 3# wells and 11# wells have used existing monitoring wells, so 11 wells have\u0000been set up actually. The monitoring wells are designed to monitor groundwater level, groundwater\u0000quality and isotope analysis.\u0000\u0000\u0000\u0000In the upstream of Luanhe’s A-A section of the No. 4 well near the edge of the woods and\u0000downstream of the B-B section of the No. 8 well near the edge of farmland (wheat), each point of soil\u0000is sampled to determine the content of nitrate nitrogen and 15N isotope ratio in soil profile. The depth\u0000of soil is sampled from surface to groundwater level, the total depth is about 2.5m. Taking about 1kg\u0000soil samples at 20cm every time from the ground surface and collect and seal in plastic bags and number.\u0000The sampling time was November 2015, March 2016, May 2016 and July 2016, taking 4 times.\u0000\u0000\u0000\u0000The analysis showed that higher nitrate content in soil is within 0-60cm, and is same as the\u0000depth of fertilizing the crops (including animal manure), so when estimating the proportion of\u0000groundwater in nitrate, nitrate content in 0-60cm is assumed as the initial value; which is close to the\u0000underground water level in the soil and is regarded as the final value of 60cm, that is, the final value of\u0000nitrate into the groundwater, which can estimate the soil nitrate into groundwater ratio.\u0000\u0000\u0000\u0000 The sources of nitrate in groundwater are complex and related to many factors, such as\u0000river water, soil and so on. According to the content of nitrogen and oxygen isotopes, it determines the\u0000main source of nitrate nitrogen:soil and Luanhe River. The results showed that the ratio of nitrate to\u0000groundwater in the forest soil was 20%~80.8%, and the average value was 56.3%. The proportion of\u0000nitrate in the soil in the wheat field was 6.8%~98.2%, with an average value of 48.3%. Nitrate nitrogen\u0000from water in proportion of large changes with the seasons, the upper reaches of the Luanhe River\u0000(near No. 2 wells) for 0~19.6%; the Luanhe River (near No. 7 wells) for 0~31.5%.\u0000","PeriodicalId":18979,"journal":{"name":"Nanoscience & Nanotechnology-Asia","volume":"71 4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75863226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-05-31DOI: 10.2174/2210681208666180321144536
Babita Sarangi, U. Jana, N. Palei, Guru Prasad, P. K. Manna
The therapeutic efficacy of perorally administered drug is often concealed by their poor oral bioavailability (BA) and low metabolic stability in the gastrointestinal tract (GIT). Most of the newly discovered drug molecules are of high molecular weight and belong to biopharmaceutical classification system (BCS) – II. Poor aqueous solubility and high membrane permeability characteristics of BCS – II drugs limit BA after oral administration. Recently, lipid-based drug delivery (LBDD) systems have gained much importance due to their ability to improve the solubility and BA of poorly soluble drugs. Oral delivery of drugs incorporated in solid lipid nanoparticles (SLNs) has gained considerable interest since the last two decades. SLNs have advantages above the others, as compared to polymer toxicity which is low, as inexpensive excipients and organic solvents are not used. SLNs offer the possibility to develop new therapeutics due to their unique size-dependent properties. An attempt to incorporate drugs into SLNs offers a new prototype in drug delivery system which can be utilized for drug targeting to specific tissue. This review presents elaborate information of SLNs with their aim, advantages, challenges and limitations, the principle of formulation, routes of administration and their biodistribution. It also describes the gastrointestinal absorption and the factors affecting absorption of SLNs from GIT along with its application.
{"title":"Solid Lipid Nanoparticles: A Potential Approach for Drug Delivery System","authors":"Babita Sarangi, U. Jana, N. Palei, Guru Prasad, P. K. Manna","doi":"10.2174/2210681208666180321144536","DOIUrl":"https://doi.org/10.2174/2210681208666180321144536","url":null,"abstract":"\u0000\u0000The therapeutic efficacy of perorally administered drug is often concealed by their poor oral\u0000bioavailability (BA) and low metabolic stability in the gastrointestinal tract (GIT). Most of the newly\u0000discovered drug molecules are of high molecular weight and belong to biopharmaceutical classification\u0000system (BCS) – II. Poor aqueous solubility and high membrane permeability characteristics of BCS –\u0000II drugs limit BA after oral administration. Recently, lipid-based drug delivery (LBDD) systems have\u0000gained much importance due to their ability to improve the solubility and BA of poorly soluble drugs.\u0000Oral delivery of drugs incorporated in solid lipid nanoparticles (SLNs) has gained considerable interest\u0000since the last two decades. SLNs have advantages above the others, as compared to polymer toxicity\u0000which is low, as inexpensive excipients and organic solvents are not used. SLNs offer the possibility to\u0000develop new therapeutics due to their unique size-dependent properties. An attempt to incorporate\u0000drugs into SLNs offers a new prototype in drug delivery system which can be utilized for drug targeting\u0000to specific tissue. This review presents elaborate information of SLNs with their aim, advantages,\u0000challenges and limitations, the principle of formulation, routes of administration and their biodistribution.\u0000It also describes the gastrointestinal absorption and the factors affecting absorption of SLNs from\u0000GIT along with its application.\u0000","PeriodicalId":18979,"journal":{"name":"Nanoscience & Nanotechnology-Asia","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74623519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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