Pub Date : 2015-06-14DOI: 10.1080/23311940.2015.1055623
Sarita Sharma, R. Kundu, Anupinder Singh, S. Murugavel, R. Punia, N. Kishore
Abstract The structural, morphology, optical, electrical, and magnetic properties of Zn0.7MnxNi0.3−xO (x = 0.05, 0.1, 0.15, 0.2) nanoparticles synthesized by sol–gel technique have been systematically investigated by using X-ray diffractometer (XRD), scanning electron microscope (SEM), UV–vis-NIR spectrophotometer, impedance analyzer, and vibration sample magnetometer (VSM). XRD patterns reveal that all samples have hexagonal wurtzite structure along with secondary phases such as NiO and ZnMnO3. The average crystalline size increases with the increase in the Mn concentration in the host matrix. Diffuse reflectance studies (DRS) show an increment in optical band gap with increasing Mn content. AC conductivity of present samples has been studied as a function of frequency (100 Hz–10 MHz) of the applied AC signal in the temperature range of 323–463 K. The results showed that AC conductivity increases with an increase in frequency and temperature. The frequency exponent shows that small polaron conduction mechanism is the most favorable for all samples. The value of AC conductivity is observed to decrease with an increase in the Mn dopant concentration in the Zn0.7MnxNi0.3−xO system. At room temperature, magnetic characterization of the samples indicates the presence of both paramagnetic and ferromagnetic behavior. Magnetic saturation decreases with the increase in the Mn concentration in the host lattice.
{"title":"Structural, optical, electrical, and magnetic properties of Zn0.7MnxNi0.3−xO nanoparticles synthesized by sol–gel technique","authors":"Sarita Sharma, R. Kundu, Anupinder Singh, S. Murugavel, R. Punia, N. Kishore","doi":"10.1080/23311940.2015.1055623","DOIUrl":"https://doi.org/10.1080/23311940.2015.1055623","url":null,"abstract":"Abstract The structural, morphology, optical, electrical, and magnetic properties of Zn0.7MnxNi0.3−xO (x = 0.05, 0.1, 0.15, 0.2) nanoparticles synthesized by sol–gel technique have been systematically investigated by using X-ray diffractometer (XRD), scanning electron microscope (SEM), UV–vis-NIR spectrophotometer, impedance analyzer, and vibration sample magnetometer (VSM). XRD patterns reveal that all samples have hexagonal wurtzite structure along with secondary phases such as NiO and ZnMnO3. The average crystalline size increases with the increase in the Mn concentration in the host matrix. Diffuse reflectance studies (DRS) show an increment in optical band gap with increasing Mn content. AC conductivity of present samples has been studied as a function of frequency (100 Hz–10 MHz) of the applied AC signal in the temperature range of 323–463 K. The results showed that AC conductivity increases with an increase in frequency and temperature. The frequency exponent shows that small polaron conduction mechanism is the most favorable for all samples. The value of AC conductivity is observed to decrease with an increase in the Mn dopant concentration in the Zn0.7MnxNi0.3−xO system. At room temperature, magnetic characterization of the samples indicates the presence of both paramagnetic and ferromagnetic behavior. Magnetic saturation decreases with the increase in the Mn concentration in the host lattice.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2015.1055623","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60084497","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 : 2015-05-22DOI: 10.1080/23311940.2015.1050080
A. Amoddeo
Abstract The urokinase plasminogen activator (uPA) is a proteolytic enzyme, which over expression by cancer cells is recognized as promoting tumour growth and proliferation. In the early stage of formation, cancer cells grow in the avascular phase and oxygen supply come from surrounding healthy tissue. Using parameters estimated from in vivo experiments on human tumours, we simulate the effects of hypoxic conditions on cancer cell interacting with the uPA system, in the avascular phase. The resulting system of six-coupled partial differential equations is solved over one-dimensional domain implementing an adaptive grid technique, using the finite element method. Our results predict that changes of both diffusion and uptake/decay coefficients for oxygen, because of possible microenvironment changes of cancer cells, induce variations of the invasion velocity, with crowding effects during cell growth and proliferation.
{"title":"Moving mesh partial differential equations modelling to describe oxygen induced effects on avascular tumour growth","authors":"A. Amoddeo","doi":"10.1080/23311940.2015.1050080","DOIUrl":"https://doi.org/10.1080/23311940.2015.1050080","url":null,"abstract":"Abstract The urokinase plasminogen activator (uPA) is a proteolytic enzyme, which over expression by cancer cells is recognized as promoting tumour growth and proliferation. In the early stage of formation, cancer cells grow in the avascular phase and oxygen supply come from surrounding healthy tissue. Using parameters estimated from in vivo experiments on human tumours, we simulate the effects of hypoxic conditions on cancer cell interacting with the uPA system, in the avascular phase. The resulting system of six-coupled partial differential equations is solved over one-dimensional domain implementing an adaptive grid technique, using the finite element method. Our results predict that changes of both diffusion and uptake/decay coefficients for oxygen, because of possible microenvironment changes of cancer cells, induce variations of the invasion velocity, with crowding effects during cell growth and proliferation.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2015.1050080","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60084456","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 : 2015-04-17DOI: 10.1080/23311940.2015.1029845
Tommi Tenkanen
In a theory containing scalar fields, a generic consequence is a formation of scalar condensates during cosmic inflation. The displacement of scalar fields out from their vacuum values sets specific initial conditions for post-inflationary dynamics and may lead to significant observational ramifications. In this work, we investigate how these initial conditions affect the generation of dark matter in the class of portal scenarios where the standard model fields feel new physics only through Higgs-mediated couplings. As a representative example, we will consider a symmetric scalar singlet coupled to Higgs via . This simple extension has interesting consequences as the singlet constitutes a dark matter candidate originating from non-thermal production of singlet particles out from a singlet condensate, leading to a novel interplay between inflationary dynamics and dark matter properties.
{"title":"Cosmic inflation constrains scalar dark matter1","authors":"Tommi Tenkanen","doi":"10.1080/23311940.2015.1029845","DOIUrl":"https://doi.org/10.1080/23311940.2015.1029845","url":null,"abstract":"In a theory containing scalar fields, a generic consequence is a formation of scalar condensates during cosmic inflation. The displacement of scalar fields out from their vacuum values sets specific initial conditions for post-inflationary dynamics and may lead to significant observational ramifications. In this work, we investigate how these initial conditions affect the generation of dark matter in the class of portal scenarios where the standard model fields feel new physics only through Higgs-mediated couplings. As a representative example, we will consider a symmetric scalar singlet coupled to Higgs via . This simple extension has interesting consequences as the singlet constitutes a dark matter candidate originating from non-thermal production of singlet particles out from a singlet condensate, leading to a novel interplay between inflationary dynamics and dark matter properties.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2015.1029845","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60084379","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 : 2015-03-13DOI: 10.1080/23311940.2015.1027556
K. Vieira
Every year there are two or more solar eclipses on Earth (and also two or more lunar ones). Yet it is a lifetime experience when it happens in the place, area, or country we live in. In a few days, people in Svalbard (Norway) and the Faroe Islands (Denmark) will see a total eclipse while the rest of Europe, northern and eastern Asia, and northern and western Africa will observe a partial occultation of the Sun by the moon (the northern the location the larger and longer the eclipse). The next solar eclipse visible in Europe will be in 2026.
{"title":"The 20 March 2015 solar eclipse in Europe","authors":"K. Vieira","doi":"10.1080/23311940.2015.1027556","DOIUrl":"https://doi.org/10.1080/23311940.2015.1027556","url":null,"abstract":"Every year there are two or more solar eclipses on Earth (and also two or more lunar ones). Yet it is a lifetime experience when it happens in the place, area, or country we live in. In a few days, people in Svalbard (Norway) and the Faroe Islands (Denmark) will see a total eclipse while the rest of Europe, northern and eastern Asia, and northern and western Africa will observe a partial occultation of the Sun by the moon (the northern the location the larger and longer the eclipse). The next solar eclipse visible in Europe will be in 2026.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2015.1027556","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60084345","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 : 2015-01-25DOI: 10.1080/23311940.2015.1047559
S. Y. Ayazi, S. Firouzabadi
This article will review Inert Triplet Model (ITM) which provide candidate for dark matter (DM) particles. Then, we study possible decays of Higgs boson to DM candidate and apply current experimental data for invisible Higgs decay to constrain parameter space of ITM. We also consider indirect search for DM and use FermiLAT data to put constraints on parameter space. Ultimately, we compare this limit with constraints provided by LUX experiment for low mass DM and invisible Higgs decay.
{"title":"Footprint of triplet scalar dark matter in direct, indirect search and invisible Higgs decay","authors":"S. Y. Ayazi, S. Firouzabadi","doi":"10.1080/23311940.2015.1047559","DOIUrl":"https://doi.org/10.1080/23311940.2015.1047559","url":null,"abstract":"This article will review Inert Triplet Model (ITM) which provide candidate for dark matter (DM) particles. Then, we study possible decays of Higgs boson to DM candidate and apply current experimental data for invisible Higgs decay to constrain parameter space of ITM. We also consider indirect search for DM and use FermiLAT data to put constraints on parameter space. Ultimately, we compare this limit with constraints provided by LUX experiment for low mass DM and invisible Higgs decay.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2015.1047559","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60084394","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 : 2014-11-24DOI: 10.1080/23311940.2014.979604
M. Ghahremani, L. H. Bennett, E. Della Torre, M. Ovichi, Arthur Nwokoye
Abstract The adiabatic temperature change (ΔTad) during the magnetization process of polycrystalline gadolinium and Ni51Mn33.4In15.6 Heusler alloy is directly measured near the Curie temperature. The cooling factor (CF) is introduced as the area under the curve of adiabatic temperature change versus ambient temperature. The CF provides more representative measure of cooling performance in the operational temperature range. Selecting different temperature abscissas qualitatively changes the interpretation of the cooling performance of a magnetocaloric material. In particular, plotting ΔTad versus initial temperature gives a measurably different CF compared to that given by plotting ΔTad versus average temperature.
{"title":"Cooling factor for magnetic refrigeration systems","authors":"M. Ghahremani, L. H. Bennett, E. Della Torre, M. Ovichi, Arthur Nwokoye","doi":"10.1080/23311940.2014.979604","DOIUrl":"https://doi.org/10.1080/23311940.2014.979604","url":null,"abstract":"Abstract The adiabatic temperature change (ΔTad) during the magnetization process of polycrystalline gadolinium and Ni51Mn33.4In15.6 Heusler alloy is directly measured near the Curie temperature. The cooling factor (CF) is introduced as the area under the curve of adiabatic temperature change versus ambient temperature. The CF provides more representative measure of cooling performance in the operational temperature range. Selecting different temperature abscissas qualitatively changes the interpretation of the cooling performance of a magnetocaloric material. In particular, plotting ΔTad versus initial temperature gives a measurably different CF compared to that given by plotting ΔTad versus average temperature.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2014.979604","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60084294","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 : 2012-02-20DOI: 10.1080/23311940.2017.1303931
S. Lapinova, A. Saichev
Abstract Comparative statistical properties of Parkinson, Garman-Klass, Roger-Satchell and bridge oscillation estimators are discussed. Point and interval estimations, related with mentioned estimators are considered.
{"title":"Comparative statistics of Garman-Klass, Parkinson, Roger-Satchell and bridge estimators","authors":"S. Lapinova, A. Saichev","doi":"10.1080/23311940.2017.1303931","DOIUrl":"https://doi.org/10.1080/23311940.2017.1303931","url":null,"abstract":"Abstract Comparative statistical properties of Parkinson, Garman-Klass, Roger-Satchell and bridge oscillation estimators are discussed. Point and interval estimations, related with mentioned estimators are considered.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2017.1303931","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60084824","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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