Mikhail B. Smirnov, D. Pankin, E. Roginski, A. Povolotckaia
Changes in the structure and lattice dynamics of the moganite during crystal expansion were studiedusing ab initio calculations within the framework of density functional theory. The results obtained shed light onmany anomalies in the temperature behavior of this crystal, such as the presence of a phase transition, soft modecondensation, elastic anomalies and negative thermal expansion. Comparison of the structural and dynamicproperties of moganite and quartz opens up new possibilities for their identification in natural samples of mixedcomposition.
{"title":"Theoretical study of structural phase transition and soft mode behavior in moganite","authors":"Mikhail B. Smirnov, D. Pankin, E. Roginski, A. Povolotckaia","doi":"10.23647/ca.md20231228","DOIUrl":"https://doi.org/10.23647/ca.md20231228","url":null,"abstract":"Changes in the structure and lattice dynamics of the moganite during crystal expansion were studiedusing ab initio calculations within the framework of density functional theory. The results obtained shed light onmany anomalies in the temperature behavior of this crystal, such as the presence of a phase transition, soft modecondensation, elastic anomalies and negative thermal expansion. Comparison of the structural and dynamicproperties of moganite and quartz opens up new possibilities for their identification in natural samples of mixedcomposition.","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139792480","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}
Mikhail B. Smirnov, D. Pankin, E. Roginski, A. Povolotckaia
Changes in the structure and lattice dynamics of the moganite during crystal expansion were studiedusing ab initio calculations within the framework of density functional theory. The results obtained shed light onmany anomalies in the temperature behavior of this crystal, such as the presence of a phase transition, soft modecondensation, elastic anomalies and negative thermal expansion. Comparison of the structural and dynamicproperties of moganite and quartz opens up new possibilities for their identification in natural samples of mixedcomposition.
{"title":"Theoretical study of structural phase transition and soft mode behavior in moganite","authors":"Mikhail B. Smirnov, D. Pankin, E. Roginski, A. Povolotckaia","doi":"10.23647/ca.md20231228","DOIUrl":"https://doi.org/10.23647/ca.md20231228","url":null,"abstract":"Changes in the structure and lattice dynamics of the moganite during crystal expansion were studiedusing ab initio calculations within the framework of density functional theory. The results obtained shed light onmany anomalies in the temperature behavior of this crystal, such as the presence of a phase transition, soft modecondensation, elastic anomalies and negative thermal expansion. Comparison of the structural and dynamicproperties of moganite and quartz opens up new possibilities for their identification in natural samples of mixedcomposition.","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139852134","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}
A pure mechanical approach is proposed to gain a more penetrating insight into the physical meaning of the body’s weight, in deducing its notion just from the Newton’s equation for the body moving along the gravitational field. In that view, the body is weighty when its acceleration along the g-field is other than g. The approach was used for to account the occurrence of the gaseous matter weight that was regarded by us as some sort of experimentum crucis capable of estimating its validity. According to the results obtained, the body’s weight is a physical reality fundamentally different from the force of gravity, and represents the inevitable factor assuring the fulfilment of the momentum conservation law in the body – Earth system.
为了更深入地了解物体重量的物理意义，我们提出了一种纯粹的力学方法，即仅仅从牛顿关于沿引力场运动的物体的方程中推导出物体重量的概念。根据这一观点，当物体沿重力场的加速度小于 g 时，它就是有重量的。我们使用这种方法来解释气态物质重量的发生，并将其视为某种能够估计其有效性的十字架实验。根据所获得的结果，人体重量是与重力有本质区别的物理现实，是确保在人体-地球系统中实现动量守恒定律的必然因素。
{"title":"What is the weight: how and why it occursfor gaseous matter","authors":"Mikhail B. Smirnov, Andrey Mirgorodsky","doi":"10.23647/ca.md20231226","DOIUrl":"https://doi.org/10.23647/ca.md20231226","url":null,"abstract":"A pure mechanical approach is proposed to gain a more penetrating insight into the physical meaning of the body’s weight, in deducing its notion just from the Newton’s equation for the body moving along the gravitational field. In that view, the body is weighty when its acceleration along the g-field is other than g. The approach was used for to account the occurrence of the gaseous matter weight that was regarded by us as some sort of experimentum crucis capable of estimating its validity. According to the results obtained, the body’s weight is a physical reality fundamentally different from the force of gravity, and represents the inevitable factor assuring the fulfilment of the momentum conservation law in the body – Earth system.","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139865586","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}
A pure mechanical approach is proposed to gain a more penetrating insight into the physical meaning of the body’s weight, in deducing its notion just from the Newton’s equation for the body moving along the gravitational field. In that view, the body is weighty when its acceleration along the g-field is other than g. The approach was used for to account the occurrence of the gaseous matter weight that was regarded by us as some sort of experimentum crucis capable of estimating its validity. According to the results obtained, the body’s weight is a physical reality fundamentally different from the force of gravity, and represents the inevitable factor assuring the fulfilment of the momentum conservation law in the body – Earth system.
为了更深入地了解物体重量的物理意义，我们提出了一种纯粹的力学方法，即仅仅从牛顿关于沿引力场运动的物体的方程中推导出物体重量的概念。根据这一观点，当物体沿重力场的加速度小于 g 时，它就是有重量的。我们使用这种方法来解释气态物质重量的发生，并将其视为某种能够估计其有效性的十字架实验。根据所获得的结果，人体重量是与重力有本质区别的物理现实，是确保在人体-地球系统中实现动量守恒定律的必然因素。
{"title":"What is the weight: how and why it occursfor gaseous matter","authors":"Mikhail B. Smirnov, Andrey Mirgorodsky","doi":"10.23647/ca.md20231226","DOIUrl":"https://doi.org/10.23647/ca.md20231226","url":null,"abstract":"A pure mechanical approach is proposed to gain a more penetrating insight into the physical meaning of the body’s weight, in deducing its notion just from the Newton’s equation for the body moving along the gravitational field. In that view, the body is weighty when its acceleration along the g-field is other than g. The approach was used for to account the occurrence of the gaseous matter weight that was regarded by us as some sort of experimentum crucis capable of estimating its validity. According to the results obtained, the body’s weight is a physical reality fundamentally different from the force of gravity, and represents the inevitable factor assuring the fulfilment of the momentum conservation law in the body – Earth system.","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139805742","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}
El Hadji Keita, M. Dia, F. Mbaye, C. Sow, C. Sene, B. Mbow
In this work, we develop methods to determine the characteristic electrical parameters of a photovoltaic cell such as the photocurrent density (Jph), the saturation current density (J0), the short-circuit current density (Jsc), the open-circuit voltage (Voc), the maximum power density point (Jm , Vm), the fill factor (FF) and the electrical conversion efficiency (etaC) according to the irradiance spectrum. The real solar cell model is considered for the determination of these various parameters. This model takes into account the effect of shunt and series resistances (parasitic resistances). Notions of semiconductor physics, continuity equation of charge carriers combined to optoelectronic and geometrical properties of the materials, numerical resolution method to solve implicit equations based on characteristic equation of a photodiode, are notions mainly exploited to determine electrical parameters of the real solar cell. The results are applied to the heterostructures ZnO(n+)/CdS(n)/CuInS2(p)/ CuInSe2(p+) named CIS and ZnO(n+)/CdS(n)/CuInSe2(p)/CuInS2(p+) named CISE to evaluate their performances according to the considered parameters. The results obtained for each structure, photocurrent density ~ 17 mA.cm-2 (CIS) and 31 mA.cm-2 (CISE), short-circuit current density ~ 16.79 - 17 mA.cm-2 (CIS) and 30.62 - 31 mA.cm-2 (CISE), open-circuit voltage ~ 0.76 V (CIS) and 0.52 V (CISE), fill factor ~ 0.648 - 0.745 (CIS) and 0.545 - 0.677 (CISE), maximum power density ~ 8.28 - 9.69 mW.cm-2 (CIS) and 8.72 - 11.02 mW.cm-2 (CISE), saturation current ~ 4.117×10-8 mA.cm-2 (CIS) and 1.169×10-3 mA.cm-2 (CISE), are in the same magnitude order as the values published in the literature. We obtain under AM 1.5 solar spectrum and taken into account the parasitic resistances, a theoretical conversion efficiency ranging from 9.93% to 11.62% for the model CIS and from 10.46% to 13.22% for the model CISE. Thus, these results allow to validate the various models established to model the phenomena studied.
{"title":"Real Solar Cell and Determination Methods of Electrical Parameters","authors":"El Hadji Keita, M. Dia, F. Mbaye, C. Sow, C. Sene, B. Mbow","doi":"10.23647/ca.md20230106","DOIUrl":"https://doi.org/10.23647/ca.md20230106","url":null,"abstract":"In this work, we develop methods to determine the characteristic electrical parameters of a photovoltaic cell such as the photocurrent density (Jph), the saturation current density (J0), the short-circuit current density (Jsc), the open-circuit voltage (Voc), the maximum power density point (Jm , Vm), the fill factor (FF) and the electrical conversion efficiency (etaC) according to the irradiance spectrum. The real solar cell model is considered for the determination of these various parameters. This model takes into account the effect of shunt and series resistances (parasitic resistances). Notions of semiconductor physics, continuity equation of charge carriers combined to optoelectronic and geometrical properties of the materials, numerical resolution method to solve implicit equations based on characteristic equation of a photodiode, are notions mainly exploited to determine electrical parameters of the real solar cell. The results are applied to the heterostructures ZnO(n+)/CdS(n)/CuInS2(p)/ CuInSe2(p+) named CIS and ZnO(n+)/CdS(n)/CuInSe2(p)/CuInS2(p+) named CISE to evaluate their performances according to the considered parameters. The results obtained for each structure, photocurrent density ~ 17 mA.cm-2 (CIS) and 31 mA.cm-2 (CISE), short-circuit current density ~ 16.79 - 17 mA.cm-2 (CIS) and 30.62 - 31 mA.cm-2 (CISE), open-circuit voltage ~ 0.76 V (CIS) and 0.52 V (CISE), fill factor ~ 0.648 - 0.745 (CIS) and 0.545 - 0.677 (CISE), maximum power density ~ 8.28 - 9.69 mW.cm-2 (CIS) and 8.72 - 11.02 mW.cm-2 (CISE), saturation current ~ 4.117×10-8 mA.cm-2 (CIS) and 1.169×10-3 mA.cm-2 (CISE), are in the same magnitude order as the values published in the literature. We obtain under AM 1.5 solar spectrum and taken into account the parasitic resistances, a theoretical conversion efficiency ranging from 9.93% to 11.62% for the model CIS and from 10.46% to 13.22% for the model CISE. Thus, these results allow to validate the various models established to model the phenomena studied.","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80224608","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}
This “opinion article” presents the “dialogue”, namely the series of questions addressed to chatGPT and its outputs, on the question of citation index and other metrics associated with scientific publication. The AI is asked to explain basic quantities (citation index, impact factor of journals, h-index, etc) and through different questions, to give outputs on different important problems, mainly related with citation index and its biases. The AI clearly expresses that the citation index alone should not be used for evaluation purposes, and is led to predict that in certain situations a high quality scientific article would be with a low citation index. The AI also replies that the citation index depends on several factors in a complex way, and is probably not defined in an unambiguous way from a mathematical point of view, but it appears unable to explain evolutions in the field of informetrics that occurred following issues with citation index. The article concludes that the citation index is irrelevant as it is not normalized and strongly depends on the publishing journal and databases, and that it is potentially dangerous for science.
{"title":"A critical view on citation index a discussion with ChatGPT","authors":"Pierre Saint-Gregoire","doi":"10.23647/ca.md20230123","DOIUrl":"https://doi.org/10.23647/ca.md20230123","url":null,"abstract":"This “opinion article” presents the “dialogue”, namely the series of questions addressed to chatGPT and its outputs, on the question of citation index and other metrics associated with scientific publication. The AI is asked to explain basic quantities (citation index, impact factor of journals, h-index, etc) and through different questions, to give outputs on different important problems, mainly related with citation index and its biases. The AI clearly expresses that the citation index alone should not be used for evaluation purposes, and is led to predict that in certain situations a high quality scientific article would be with a low citation index. The AI also replies that the citation index depends on several factors in a complex way, and is probably not defined in an unambiguous way from a mathematical point of view, but it appears unable to explain evolutions in the field of informetrics that occurred following issues with citation index. The article concludes that the citation index is irrelevant as it is not normalized and strongly depends on the publishing journal and databases, and that it is potentially dangerous for science.","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90723171","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}
S. Ait Ahmed, Y. Gagou, B. Jonckheere, R. Bouzerar
Electric trains are powered by a current distribution device which depends on several parameters. The research works presented in this paper are located upstream of two types of important applications in the railway field: the electrical supply of trains involving the sliding or stationary pantograph/catenary contact and the famous problem of shunting of trains involving the wheel/rail rolling contact. These cannot be assumed without energy loss. In the case of train navigation, electric current can be transmitted by spots established between sources and the carbon strip. The quality of the pantograph/catenary contact obeys very strict specifications to ensure its maintenance, for permanent current connection. However mechanical aging of the contact and/or infrastructures, alteration of electrical contacts due to electrical arcing, the wear of collection strips during sliding, aging of the materials, are limiting effect for current flow. In this paper we will explicitly describe all the elements necessary to supply trains with electric current.
{"title":"Electrical capturing system for train supplying and involving parameters","authors":"S. Ait Ahmed, Y. Gagou, B. Jonckheere, R. Bouzerar","doi":"10.23647/ca.md20221127","DOIUrl":"https://doi.org/10.23647/ca.md20221127","url":null,"abstract":"Electric trains are powered by a current distribution device which depends on several parameters. The research works presented in this paper are located upstream of two types of important applications in the railway field: the electrical supply of trains involving the sliding or stationary pantograph/catenary contact and the famous problem of shunting of trains involving the wheel/rail rolling contact. These cannot be assumed without energy loss. In the case of train navigation, electric current can be transmitted by spots established between sources and the carbon strip. The quality of the pantograph/catenary contact obeys very strict specifications to ensure its maintenance, for permanent current connection. However mechanical aging of the contact and/or infrastructures, alteration of electrical contacts due to electrical arcing, the wear of collection strips during sliding, aging of the materials, are limiting effect for current flow. In this paper we will explicitly describe all the elements necessary to supply trains with electric current.","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80925126","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}
Y. Almadori, E. Alibert, J. Barbat, R. Jelinek, G. Prévôt, R. Aznar, V. Brois, J. Bantignies, L. Alvarez
Here, we report the development of a homemade experimental setup to perform under vacuum an in situ study of the physical properties of bundles of single-walled carbon nanotubes intercalated with rubidium ions using electrical conductivity, X-ray absorption and Raman measurements. This set-up was successfully used at the SAMBA beamline at the Soleil synchrotron. The electrical resistance displays an important drop with the stoichiometry (intercalation time). The Raman radial breathing modes and the G-band of the nanotubes clearly indicate an important electron transfer. The G-band behaviour features a transition from semiconducting to metallic nanotubes, confirmed by the electrical resistance measurements as a function of the temperature after rubidium intercalation. This set-up can be used for the study of any type of extremely air sensitive materials.
{"title":"Development of a home-made experimental set-up for in situ coupling under vacuum of conductivity measurements, x-ray absorption and Raman Spectroscopies on bundles of single-walled carbon nanotubes intercalated with alkali metals","authors":"Y. Almadori, E. Alibert, J. Barbat, R. Jelinek, G. Prévôt, R. Aznar, V. Brois, J. Bantignies, L. Alvarez","doi":"10.23647/ca.md20220604","DOIUrl":"https://doi.org/10.23647/ca.md20220604","url":null,"abstract":"Here, we report the development of a homemade experimental setup to perform under vacuum an in situ study of the physical properties of bundles of single-walled carbon nanotubes intercalated with rubidium ions using electrical conductivity, X-ray absorption and Raman measurements. This set-up was successfully used at the SAMBA beamline at the Soleil synchrotron. The electrical resistance displays an important drop with the stoichiometry (intercalation time). The Raman radial breathing modes and the G-band of the nanotubes clearly indicate an important electron transfer. The G-band behaviour features a transition from semiconducting to metallic nanotubes, confirmed by the electrical resistance measurements as a function of the temperature after rubidium intercalation. This set-up can be used for the study of any type of extremely air sensitive materials.","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88010938","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}
B.A.B. Alawad, H. Abdelbagi, T. Ntsoane, T. Hlatshwayo
Zirconium carbide (ZrC) samples were prepared by spark plasma sintering (SPS), at temperatures of 1700 °C, 1900 °C and 2100 °C, all at pressure of 50 megapascal (MPa). The density of ZrC ceramic pellets was measured using a Micromeritics AccuPyc II 1340 Helium Pycnometer. The density of ZrC ceramic pellets was found to increase from (6.51 ± 0.032) g/cm3 to (6.66 ± 0.039) g/cm3 and (6.70 ± 0.017) g/cm3 when the temperature of the SPS was increased from 1700 oC to 1900 oC and 2100 oC respectively. Moreover, the hardness of ZrC ceramic pellets were measured using Rockwell hardness test. The hardness of ZrC ceramic pellets increased from (7.4 ± 0.83) to (17.0 ± 0.073) and (18.4± 0.05) gigapascals (GPa) at temperatures of 1700 oC, 1900 oC and 2100 oC respectively. X-ray diffraction shows the absence of spurious phases or impurity. XRD results showed that, all prepared ZrC samples has the same preferred orientation of the planes (i.e., 200). Furthermore, the average grain size of ZrC was calculated using Sherrers’s equation. The average grain size of the pure ZrC powder increased from 67.46 nm to 72 nm, 79 nm and 83 nm when the ZrC powder was sinteried at temperatures of 1700 oC, 1900 oC and 2100 oC respectively. The differences in the average grain size between the prepared samples leads to show different surface morphologies that monitored by scanning electron microscopy (SEM).
采用火花等离子烧结(SPS)技术，在温度为1700℃、1900℃和2100℃，压力为50兆帕斯卡(MPa)的条件下制备了碳化锆(ZrC)样品。采用Micromeritics AccuPyc II 1340型氦气浓度计测定ZrC陶瓷球的密度。当SPS温度从1700℃增加到1900℃和2100℃时，ZrC陶瓷球团的密度分别从(6.51±0.032)g/cm3增加到(6.66±0.039)g/cm3和(6.70±0.017)g/cm3。采用洛氏硬度试验测定了ZrC陶瓷球团的硬度。在1700℃、1900℃和2100℃温度下，ZrC陶瓷球团的硬度分别从(7.4±0.83)提高到(17.0±0.073)和(18.4±0.05)吉帕斯卡(GPa)。x射线衍射显示没有假相或杂质。XRD结果表明，所有制备的ZrC样品具有相同的平面优选取向(均为200)。利用Sherrers方程计算ZrC的平均晶粒尺寸。在1700℃、1900℃和2100℃的烧结温度下，纯ZrC粉末的平均晶粒尺寸分别从67.46 nm增加到72 nm、79 nm和83 nm。在扫描电子显微镜(SEM)下，制备样品的平均晶粒尺寸的差异导致其表面形貌的不同。
{"title":"Microstructure of zirconium carbide ceramics synthesized by spark plasma sintering","authors":"B.A.B. Alawad, H. Abdelbagi, T. Ntsoane, T. Hlatshwayo","doi":"10.23647/ca.md20220408","DOIUrl":"https://doi.org/10.23647/ca.md20220408","url":null,"abstract":"Zirconium carbide (ZrC) samples were prepared by spark plasma sintering (SPS), at temperatures of 1700 °C, 1900 °C and 2100 °C, all at pressure of 50 megapascal (MPa). The density of ZrC ceramic pellets was measured using a Micromeritics AccuPyc II 1340 Helium Pycnometer. The density of ZrC ceramic pellets was found to increase from (6.51 ± 0.032) g/cm3 to (6.66 ± 0.039) g/cm3 and (6.70 ± 0.017) g/cm3 when the temperature of the SPS was increased from 1700 oC to 1900 oC and 2100 oC respectively. Moreover, the hardness of ZrC ceramic pellets were measured using Rockwell hardness test. The hardness of ZrC ceramic pellets increased from (7.4 ± 0.83) to (17.0 ± 0.073) and (18.4± 0.05) gigapascals (GPa) at temperatures of 1700 oC, 1900 oC and 2100 oC respectively. X-ray diffraction shows the absence of spurious phases or impurity. XRD results showed that, all prepared ZrC samples has the same preferred orientation of the planes (i.e., 200). Furthermore, the average grain size of ZrC was calculated using Sherrers’s equation. The average grain size of the pure ZrC powder increased from 67.46 nm to 72 nm, 79 nm and 83 nm when the ZrC powder was sinteried at temperatures of 1700 oC, 1900 oC and 2100 oC respectively. The differences in the average grain size between the prepared samples leads to show different surface morphologies that monitored by scanning electron microscopy (SEM).","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79592679","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}
In this work, we comprehensively explore the spectral and photophysical properties of a coumarin-based dye (1) in neat solvents. The modulation of stokes shifts, emission quantum yields (ФF) and excited-state lifetimes of 1by local environment (polarity, polarizability, viscosity and hydrogen bonding) signifies the formation of intramolecular charge state (ICT) from the amino group to the coumarin moiety. Collectively, in the more viscous polar solvents the rotation of the amino group is restricted, exponentially decreasing the non-radiative rate constants (knr). Keywords :#SPECTROPHYSICS #INTERMOLECULAR_CHARGE_TRANSFER #NON-RADIATIVE_RATE_CONSTANT #EXCITED-STATE_LIFETIME #LOCAL_ENVIRONMENT.
{"title":"Spectrophysics of Coumarin-Based Chromophore","authors":"Faisal Rasool, Amir Sohail","doi":"10.23647/ca.md20220327","DOIUrl":"https://doi.org/10.23647/ca.md20220327","url":null,"abstract":"In this work, we comprehensively explore the spectral and photophysical properties of a coumarin-based dye (1) in neat solvents. The modulation of stokes shifts, emission quantum yields (ФF) and excited-state lifetimes of 1by local environment (polarity, polarizability, viscosity and hydrogen bonding) signifies the formation of intramolecular charge state (ICT) from the amino group to the coumarin moiety. Collectively, in the more viscous polar solvents the rotation of the amino group is restricted, exponentially decreasing the non-radiative rate constants (knr). Keywords :#SPECTROPHYSICS #INTERMOLECULAR_CHARGE_TRANSFER #NON-RADIATIVE_RATE_CONSTANT #EXCITED-STATE_LIFETIME #LOCAL_ENVIRONMENT.","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80394603","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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