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Chinese Physics B 2016年第5期25卷 246-252页

作者： Kulwinder Kaur Ranjan Kumar Department of Physics Panjab University

We study the effect of pressure on electronic and thermoelectric properties of Mg_2Si using the density functional theory and Boltzmann transport equations. The variation of lattice constant, band gap, bulk modulus with pressure is also analyzed. Further, the thermoelectric properties（Seebeck coefficient, electrical conductivity, electronic thermal conductivity） have been studied as a function of temperature and pressure up to 1200 K. The results show that Mg_2Si is an n-type semiconductor with a band gap of 0.21 eV. The negative value of the Seebeck coefficient at all pressures indicates that the conduction is due to electrons. With the increase in pressure, the Seebeck coefficient decreases and electrical conductivity increases. It is also seen that, there is practically no effect of pressure on the electronic contribution of thermal *** paper describes the calculation of the lattice thermal conductivity and figure of merit of Mg_2Si at zero pressure. The maximum value of figure of merit is attained 1.83 × 10^（-3） at 1000 K. The obtained results are in good agreement with the available experimental and theoretical results.

关键词： semiconductors effects of pressure electric and thermal conductivity density functional theory

Effect of doping of different rare earth（europium,gadolinium,dysprosium and neodymium） metal ions on structural,optical and photocatalytic properties of LaFeO3 perovskites

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Journal of Rare Earths 2019年第12期37卷 1279-1287页

作者： Manisha Dhiman Sonal Singhal Department of Chemistry Panjab University

Different rare earth substituted perovskites LaRExFe1-xO3(where RE=Eu3+,Gd3+,Dy3+,Nd3+and x=0.02,0.04,0.06,0.08,0.1)with orthorhombic structure and narrow band gaps were successfully fabricated via sol-gel autocombustion *** the substituted perovskites are found to exhibit excellent photocatalytic activity towards the oxidative degradation of dye *** excellent increase in the rate constant values of pure perovskite(LaFeO3)photocatalytic reactions is observed with the substitution of rare earth metal *** results are obtained for LaNd0.1Fe0.9O3 which exhibits around 7 times increase in the rate constant values for degradation reaction of SO(1.76×10-1 min-1)and RBY(1.69×10-1 min-1)dyes.

关键词： Rare earth substitution Perovskites Sol-gel autocombustion Structural properties Photocatalysis

Enhancement of figure of merit（ZT） by doping Bi in Mg2Si for energy harvesting applications

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Progress in Natural Science:Materials International 2016年第6期26卷 533-539页

作者： Kulwinder Kaur Ranjan Kumar Department of Physics Panjab University

Magnesium Silicide is one of the interesting thermoelectric materials known for relative abundance of its constituents, thermal stability, non-toxicity and environmental friendly nature. In this paper we have theoretically studied Bi doped Mg2Si. The electronic structure calculations predict non-existence of the energy gap for Mg2Si1-xBixwith（0.125≤ x≤0.5）. It has been found that the system with x=0.125 exhibits highest Seebeck coefficient and electrical conductivity. Due to low thermal conductivity at x=0.125, Mg2Si0.875Bi0.125attained maximum value of dimensionless figure of merit 0.67 at 1200 K. With increase in concentration of Bi,the value of figure of merit decreases.

关键词： Electrical transport properties Thermoelectric properties Carrier concentration Density functional theory Lattice thermal conductivity Electronic structure

Thermally and Optical-Induced Effect on Optical and Electrical Parameters of Ag-Doped CdSe Thin Films

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Acta Metallurgica Sinica(English Letters) 2015年第5期28卷 591-599页

作者： Jagdish Kaur S.K.Tripathi Department of Physics Panjab University

Thin films of Ag-doped CdSe are deposited on the glass substrates by thermal evaporation technique using inert gas condensation method. The elemental composition of the prepared thin film is confirmed by EDX spectra. SEM analysis reveals the uniform distribution of the grains over the substrate. TEM analysis reveals the spherical nature of nanoparticles having size in the range of 25-30 nm. X-ray diffraction study indicates an increase in the grain size after thermal annealing and the decrease in the grain size after light soaking treatment. Transmittance spectra are found to decrease with corre- sponding red shift after annealing and light soaking of as-deposited thin films. The value of the band gap is found to decreases and refractive index increases, after annealing and light soaking treatment. The dispersion of refractive index is described using the Wemple-DiDomenico single oscillator model and the effects of the annealing and the light soaking on the dispersion parameters are studied. The dark conductivity is found to change from 2.24 × 10^-8 to 1.54 × 10^-7 and 1.45 ×10^-9 Ω-1 cm-1 after annealing and light soaking of thin films, respectively. Hall effect measurement reveals n-type behavior of as-deposited, annealed and light-soaked thin films.

关键词： CdSe Thin film Surface treatment Electrical properties

Controlling Diffusion by Varying Width of Layers in Nano Channel

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Nano-Micro Letters 2012年第3期4卷 154-157页

作者： Ishu Goyal Sunita Srivastava K.Tankeshwar Department of Physics Panjab University Computer Centre Panjab University

Diffusive dynamics of fluid forming layers of high and low density regions in a nanochannel has been *** coefficient in direction parallel and perpendicular to the confining wall has been found to show behaviour which is not observed in micro channel or bulk *** behaviour of diffusion is found to be controlled by the width of layers formed in nanochannel due to wall and particle *** is an important result as width of layers and hence flow of fluid inside nano pores/tube can be controlled by an external source.

关键词： Nanochannel Layer Diffusion

Integrated approach of heavy metal pollution indices and complexity quantification using chemometric models in the Sirsa Basin, Nalagarh valley, Himachal Pradesh, India

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Chinese Journal Of Geochemistry 2015年第4期34卷 620-633页

作者： Rajkumar Herojeet Madhuri S.Rishi Naval Kishore Department of Environment Studies Panjab University Department of Geology (CAS) Panjab University

Chemometric techniques and pollution assessment indices were applied to determine the source and intensity of pollution in the Sirsa River, Himachal Pradesh,India. Results show EC, Cr, Fe, Mn, and Ni were above the permissible limit as per the Bureau of Indian *** heavy metal pollution index(HPI) and contamination index(Cd) provided contrasting outcome and poor correlation was observed. A heavy metal evaluation index(HEI)method was developed using a multiple of the mean and correlation coefficient values to provide an alternative pollution classification. The criteria of HEI adopted for reclassification of HPI and Cdproduced comparable results; 40 % samples were labeled as low contamination,50 % as medium contamination, and 10 % as high contamination for all indices. Principal component analysis along with cluster analysis was used to identify the main factors responsible for degradation of water quality,namely discharge of industrial effluent, river bed mining,agricultural runoff, and minor natural or geogenic *** methods and chemometric study proposed here can be used as effective tools to gather information about water quality and water resource management.

关键词：化学计量学污染指数评价指标重金属印度盆地模型锡

Interconnects for nanoscale MOSFET technology:a review

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Journal of Semiconductors 2013年第6期34卷 157-164页

作者： Amit Chaudhry UIET Panjab University

In this paper,a review of Cu/low-k,carbon nanotube（CNT）,graphene nanoribbon（GNR）and optical based interconnect technologies has been done,Interconnect models,challenges and solutions have also been *** all the four technologies,CNT interconnects satisfy most of the challenges and they are most suited for nanometer scale technologies,despite some minor *** is concluded that beyond 32nm technology,a paradigm shift in the interconnect material is required as Cu/low-k interconnects are approaching fundamental limits.

关键词： Cu/low-k 3D integration electromigration CNTs graphene interconnects comparisons

Contributions of type II and Ib/c supernovae to Galactic chemical evolution

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Research in Astronomy and Astrophysics 2014年第6期14卷 693-704页

作者： Sandeep Sahijpal Department of Physics Panjab University

Type II and Ib/c supernovae （SNe II and Ib/c） have made major stellar nu- cleosynthetic contributions to the inventories of stable nuclides during chemical evolu- tion of the Galaxy. A case study is performed here with the help of recently developed numerical simulations of Galactic chemical evolution in the solar neighborhood to un- derstand the contributions of SNe II and Ib/c by comparing the stellar nucleosynthetic yields obtained by two leading groups in this field. These stellar nucleosynthetic yields differ in terms of their treatment of stellar evolution and nucleosynthesis. The formu- lation describing Galactic chemical evolution is developed with the recently revised solar metallicity of -0.014. Furthermore, the recent nucleosynthetic yields of stellar models based on the revised solar metallicity are also used. The analysis suggests that it could be difficult to explain, in a self-consistent manner, the various features asso- ciated with the elemental evolutionary trends over Galactic timescales by any single adopted stellar nucleosynthetic model that incorporates SNe II and Ib/c.

关键词： Sun: abundances - stars: evolution - stars: supernovae - Galaxy:abundance - Galaxy: formation - Galaxy: evolution - nucleosynthesis

Influence of selenium induced oxidative stress on spermatogenesis and lactate dehydrogenase-X in mice testis

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Asian Journal of Andrology 2004年第3期6卷 227-232页

作者： Parminder Kaur M.P.Bansal Department of Biophysics Panjab UniversityChandigarh-160014IndiaDepartment of BiophysicsPanjab UniversityChandigarh-160014India

Aim: To evaluate the effect of oxidative stress on the spermatogenesis and lactate dehydrogenase-X (LDH-X) activity in mouse testis. Methods: For creating different levels of oxidative stress in mice, three selenium (Se) level diets were fed in separate groups for 8 weeks. Group 1 animals were fed yeast-based Se-deficient (0.02 ppm) diet. Group 2 and Group 3 animals were fed with the same diet supplemented with 0.2 ppm and 1 ppm Se as sodium selenite, respectively. After 8 weeks, biochemical and histopathological observations of the testis were carried out. LDH-X levels in the testis were analyzed by western immunoblot and ELISA. Results: A significant decrease in testis Se level was observed in Group 1 animals, whereas it was enhanced in Group 3 as compared to Group 2. The glutathione peroxidase (GSH-Px) activity was significantly reduced in both the liver and testis in Group 1, but not in Group 2 and 3. A significant increase in the testis glutathione-S-transferase (GST) activity was observed in Group 1, whereas no significant change was seen in Groups 2 and 3. Histological analysis of testis revealed a normal structure in Group 2. A significant decrease in the germ cell population in Group 1 was observed as compared to Group 2 with the spermatids and mature sperm affected the most. Decrease in the lumen size was also observed. In the Se-excess group (Group 3), displacement of germ cell population was observed. Further, a decrease in the LDH-X level in testis was observed in Group 1. Conclusion: Excessive oxidative stress in the Se deficient group, as indicated by changes in the GSH-Px/GST activity, affects the spermatogenic process with a reduction in mature sperm and in turn the LDH-X level.

关键词： testis lactate dehydrogenase X selenium oxidative stress

In vivo antianxiety and antidepressant activity of Murraya paniculata leaf extracts

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Journal of Integrative Medicine 2017年第4期15卷 320-325页

作者： Pragya Sharma Sonali Batra Ashwani Kumar Anupam Sharma university Institute of Pharmaceutical Sciences Panjab University

OBJECTIVE： Different parts of Murraya paniculata have been used traditionally for treating several ailments including mental disorders. The present study was designed to evaluate the antianxiety and antidepressant potential of M. paniculata leaves using elevated plus maze model and forced swim test, respectively. METHODS： Extracts of M. panicu/ata made with petroleum ether （60-80 ℃）, chloroform, ethanol and water were evaluated for antianxiety and antidepressant activity. The anxiolytic chloroform extract was subjected to column chromatography, yielding five fractions （F1-F5）. Fraction F5 （100 mg/kg）, which showed notable anxiolytic activity, was further chromatographed to get four subfractions （F5.1-F5.4）. Simultaneously, the ethano extract was partitioned with ethyl acetate to obtain ethyl acetate soluble fraction （EASF） and ethyl acetate insoluble fraction. Phytochemical screening of bioactive extracts/fractions and detection of mahanimbine in M paniculata leaf extract by thin-layer chromatography was also carried out. RESULTS： Fraction F5.3 （25 mg/kg） and EASF （20 mg/kg） showed significant anxiolytic and antidepressant activity, respectively. Thin-layer chromatography and phytochemical screening demonstrated the absence of mahanimbine in M. paniculata leaves. Coumarins were observed to be responsible for the anxiolytic activity. CONCLUSION： The results validate the traditional use of M. paniculata leaves in the treatment of menta disorders.

关键词： Murraya paniculata anxiety depressant coumarins mahanimbine plants, medicinal