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Chinese Physics Letters 2010年第1期27卷 206-209页

作者：负江妮张志勇闫军锋张富春 Institute of Photonics and Photon-Technology Northwest University Xi'an 710127 College of Physics and Electronic Information Yan'an University Yan'an 716000

The adsorption and reaction of CO on SrTiO3 （100） surface with and without surface oxygen vacancy are investigated by the first-principles calculation based on the density functional theory. The calculated results reveal that the oxygen vacancy site prefers to the activation of the C-O bond. The adsorption energies increase to 1.0855 and 0.3245eV for defect-CO and defect-OC orientations, respectively. Particularly the C-O bond is elongated by about 0.1285 ？ in the defect-OC orientation compared with that in the Ti-OC one without surface oxygen vacancies. There is predominantly a chemisorption mechanism between the CO molecule and the surface in the defect-CO orientation.

关键词： Cobalt Adsorption Oxygen Orientation Oriente Defects Computers

589-nm yellow laser generation by intra-cavity sum-frequency mixing in a T-shaped Nd:YAG laser cavity

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Chinese Optics Letters 2009年第9期7卷 815-818页

作者：陈秀艳李修张豪磊陈浩伟白晋涛任兆玉 Institute Shaanxi Engineering Technology Research Center for Solid State Lasers and Application Northwest University Shaanxi Department of Physics Northwest University

To obtain high power 589-nm yellow laser, a T-shaped thermal-insensitive cavity is designed. The optimal power ratio of 1064- and 1319-nm beams is considered and the fundamental spot size distribution from the output mirror to the two laser rods are calculated and simulated, respectively. As a result, a 589-nm yellow laser with the average output power of 5.7 W is obtained in the experiment when the total pumping power is 695 W. The optical-to-optical conversion efficiency from the fundamental waves to the sum frequency generation is about 15.2% and the pulse width is 150 ns at the repetition rate of 18 kHz. The instability of the yellow laser is also measured, which is less than 2% within 3 h. The beam quality factors are Mx^2 = 4.96 and My^2 = 5.08.

关键词： Conversion efficiency Mirrors Optical frequency conversion Pulsed laser applications Pumping (laser)

Electronic structure and optical properties of Nb-doped Sr_2TiO_4 by density function theory calculation

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Chinese Physics B 2009年第7期18卷 2945-2952页

作者：贠江妮张志勇 School of Information Science and Technology Northwest University

This paper investigates the effect of Nb doping on the electronic structure and optical properties of Sr2TiO4 by the first-principles calculation of plane wave ultra-soft pseudo-potential based on density functional theory （DFT）.The calculated results reveal that due to the electron doping,the Fermi level shifts into conduction bands（CBs） for Sr2NbxTi1-xO4 with x=0.125 and the system shows n-type degenerate semiconductor features. Sr2TiO4 exhibits optical anisotropy in its main crystal axes,and the c-axis shows the most suitable crystal growth direction for obtaining a wide transparent *** optical transmittance is higher than 90% in the visible range for Sr2Nb0.125Ti0.875O4.

关键词： density functional theory Sr2TiO4 Nb-doping electronic structure

Revision to Kowalskia from the Houhecun Fauna and a New Discovery of Tscherskia(Cricetidae, Rodentia) from the Youhe Fauna of Weinan, Shaanxi Province, China

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Acta Geologica Sinica(English Edition) 2021年第4期95卷 1073-1079页

作者： XIE Kun ZHANG Yunxiang LI Yongxiang State Key Laboratory of Continental Dynamics Department of GeologyNorthwest University 229 North Taibai RoadXi'an 710069China

The fossil hamster(an isolated m1) from the early Early Pleistocene Houhecun fauna found in Dali, Weinan, Shaanxi, China, originally identified as Kowalskia dalinica, is reexamined. Its unique characters, including a high crown, very small degree of division of the anteroconid and relatively large size, is taken as evidence of its attribution to the genus Sinocricetus, instead of Kowalskia(junior synonym of Neocricetodon) suggested by the original author. Therefore, the specific name of the species established based on this m1 should be changed to S. dalinicus(Wang, 1988). S. dalinicus probably has a relatively close affinity with S. major Li, 2010, but there are still some obvious differences of characters between them. The discovery of S. dalinicus in the Houhecun fauna confirms that the genus indeed survived into the Pleistocene. A broken hamster mandible, which was found in Weinan, Shaanxi, China and belongs to the late Pliocene Youhe fauna, is also described here and identified as Tscherskia sp.. This specimen represents the earliest Tscherskia in Asia so far, but fails to refute the hypothesis that the genus originated in Europe during the early Pliocene.

关键词： Houhecun fauna Youhe fauna Sinocricetus Tscherskia Kowalskia Neocricetodon

Classification and Reduction of Generalized Thin Film Equations

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Communications in Theoretical Physics 2009年第9期52卷 403-410页

作者： ZHU Chun-Rong QU Chang-Zheng Center for Nonlinear Studies Northwest University Xi＇an 710069 China College of Mathematics and Computer Science Anhui Normal University Wuhu 241000 China Department of Mathematics Northwest University Xi＇an 710069 China

Classification and reduction of the generalized fourth-order nonlinear differential equations arising from theliquid films are *** is shown that these equations have solutions on subspaces of the polynomial,exponential ortrigonometric form defined by linear nth-order ordinary differential equations with constant coefficients for n=4,...,*** examples of exact solutions are presented.

关键词： thin film equation classification invariant subspaces exact solutions

First-principles study of La and Sb-doping effects on electronic structure and optical properties of SrTiO_3

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Chinese Physics B 2010年第1期19卷 433-440页

作者：贠江妮张志勇闫军锋邓周虎 School of Information Science and Technology Northwest University Institute of Photonics and Photon-Technology of northwest university

The effects of La and Sb doping on the electronic structure and optical properties of SrTiO3 are investigated by first-principles calculation of the plane wave ultra-soft pseudo-potential based on density functional theory. The calculated results reveal that corner-shared TiO6 octahedra dominate the main electronic properties of SrTiO3, and its structural stability can be improved by La doping. The La^3＋ ion fnlly acts as an electron donor in Sr0.875La0.125TiO3 and the Fermi level shifts into the conduction bands （CBs） after La doping. As for SrSb0.125Ti0.87503, there is a distortion near the bottom of the CBs for SrSb0.125Ti0.87503 after Sb doping and an incipient localization of some of the doped electrons trapped in the Ti site, making it impossible to describe the evolution of the density of states （DOS） within the rigid band model. At the same time, the DOSs of the two electron-doped systems shift towards low energies and the optical band gaps are broadened by about 0.4 and 0.6 eV for Sr0.875La0.125TiO3 and SrSb0.125Ti0.87503, respectively. Moreover, the transmittance of SrSb0.125Ti0.87503 is as high as 95% in most of the visible region, which is higher than that of Sr0.875La0.125TiO3（85%）. The wide band gap, the small transition probability and the weak absorption due to the low partial density of states （PDOS） of impurity in the Fermi level result in the significant optical transparency of SrSb0.125Ti0.875O3.

关键词： density functional theory SrTiO3 doping electronic structure

Synthesis, Structure Characteristic and Thermal Behavior of Two New Metal-organic Azo-triazole Compounds： [Zn（phen）3]·ZTO·6H2O and [Cu（phen）3]-ZTO·6H2O

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Chemical Research in Chinese Universities 2018年第6期34卷 1009-1013页

作者： DING Zimei CAO Wenli ZHENG Hui HUANG Jie XU Kangzhen SONG Jirong Department of Chemical Engineering Northwest University Xi'an 710069 P. R. China Conservation Technology Department the Palace Museum Beijing 100009 P. R. China

[Zn（phen）3]·ZTO-6H2O（1） and [Cu（phen）3]·ZTO·6H2O（2） were synthesized by the reaction of ZnCNO3）2·6H2O/Cu（NO3）2·3H2O with 4,4-azo-1H-1,2,4-triazol-5-one（ZTO） and 1,10-phenanthroline（phen）. The two compounds were characterized by elemental analysis and IR spectrum analysis, respectively. Compound 1 was also characterized by single crystal X-ray diffraction analysis. For compound l, the coordination geometry around the Zn^2＋ is a distorted octahedron, with the bite angles of 76.7（3）°-77.6（4）° for all three phen ligands. Moreover, the thermal behaviors and thermal decomposition kinetics were studied and analyzed. Besides, thermal stability and safety parameters（TsADT, Tb） are 164.7 and 166.4℃ for compound 1, and 149.6 and 150.8℃ for compound 2, respectively.

关键词： Azo-triazole [Zn(phen)3] ZTO-6H2O,[Cu(phen)3]. ZTO·6H2O Crystal structure Thermal behavior

Synthesis,Crystal Structure and Thermal Properties of Zn（NH3）3（AFT）2

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Chinese Journal of Structural Chemistry 2019年第7期38卷 1173-1181页

作者： MA Xiao DING Zi-Mei SHANG Fan HANG Xiao-Jing WANG Xiao-Hong XU Kang-Zhen HUANG Jie School of Chemical Engineering northwest university/Shaanxi Key L aboratory of Physico-in organic Chemistry Xi 'an 710069 China Xi 'an Modern Chemistry Research Institute Xi 'an 710065 China

A new coordination compound of Zn(NH3)3(AFT)2(1,ZnC6H13N17O2,AFT =4-amino-3-(5-tetrazolate)-furazan)was synthesized and characterized by elemental analysis and FT-IR *** crystal structure was determined by X-ray single-crystal *** crystal belongs to the orthorhombic system,space group Pnma with a = 18.680(3),b = 6.9438(11),c =12.268(2)A,μ= 1.592 mm-1,V= 1591.3(4)A3,M,= 420.72,Dc=1.756 g·cm^-3,Z= 4,F(000)= 860,the final R = 0.0480 and wR = 0.1262 for the observed reflections with I>2σ(Ⅰ).The zinc(Ⅱ)ion is five-coordinated by N atoms from two AFT"ligands and three NH3 *** thermal decomposition mechanism of compound 1 was tested by differential scanning calorimetry(DSC)and thermogravimetry-derivative thermogravimetry(TG-DTG)*** DSC curve exhibits two endothermic and one exothermic *** addition,the non-isothermal kinetics parameters were calculated by using the Kissinger s method and Ozawa-Doyle's ***,the entropy of activation(ΔS≠),enthalpy of activation(ΔH≠),free energy of activation(ΔG≠)and impact sensitivity(IS)was also obtained.

关键词： 4-amino-3-(5-tetrazolate)-furazan synthesis crystal structure thermal behavior

U–Pb ages and Hf isotopes for detrital zircons from quartzite in the Paleoproterozoic Songshan Group on the southwestern margin of the North China Craton

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Chinese Science Bulletin 2008年第18期53卷 2828-2839页

作者： DIWU ChunRong SUN Yong YUAN HongLin WANG HongLiang ZHONG XingPing LIU XiaoMing State Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi'an 710069 China

In situ U-Pb dating and Lu-Hf isotopic analysis were carried out for detrital zircons from quartzite in the Paleoproterozoic Songshan Group on the southern margin of the North China Craton (NCC). The re- sults provide further constraints on the crustal formation and evolution history of NCC. Four 207Pb/206Pb age populations were obtained from 99 analyses, with clusters at ~3.40 Ga, 2.77―2.80 Ga, ~2.50 Ga and 2.34 Ga, respectively. The 3.40 Ga old zircons have similar Hf isotopic compositions to those from Ar- chean rocks in the Jidong and Anshan areas of NCC. However, crustal remnants older than 3.6 Ga have been identified in the southern margin of NCC, the South China Craton, the northwestern part of the Qinling Orogen and its adjacent area. Thus, it is not easy to trace the source rock from which the 3.40 Ga detrital zircons were derived. It can be inferred that the crustal remnants older than 3.40 Ga might have been widely distributed in the North China Craton. The 2.77―2.80 Ga zircons make up a relatively small proportion and have the highest εHf (t) values (up to 6.1±1.6), consistent with the Hf isotopic composition of the depleted mantle at 2.83 Ga. Their single-stage Hf model age of 2.83 Ga is close to their crystallized age, suggesting that their source rocks were extracted from the contemporaneous depleted mantle. The ~2.50 Ga zircon grains constitute about 85% of the total grain population and their Hf isotopic compositions indicate major growth of juvenile crust at ~2.50 Ga but minor reworking of ancient crust. The youngest zircon dated in this study gave an U-Pb age of 2337±23 Ma, which can be considered the maximum depositional age of the formation of the Songshan Group.

关键词：锆石中国北方铪同位素地质探测

Efficient Estimation of Longitudinal Data Additive Varying Coefficient Regression Models

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Acta Mathematicae Applicatae Sinica 2017年第2期33卷 529-550页

作者： Shu LIU School of Statistics and Information Shanghai University of International Business and Economics Shanghai 201620 China School of Statistics and Management Shanghai University of Finance and Economics Shanghai 200433 China

We consider a longitudinal data additive varying coefficient regression model, in which the coef- ficients of some factors （covariates） are additive functions of other factors, so that the interactions between different factors can be taken into account effectively. By considering within-subject correlation among repeated measurements over time and additive structure, we propose a feasible weighted two-stage local quasi-likelihood estimation. In the first stage, we construct initial estimators of the additive component functions by B-spline se- ries approximation. With the initial estimators, we transform the additive varying coefficients regression model into a varying coefficients regression model and further apply the local weighted quasi-likelihood method to estimate the varying coefficient functions in the second stage. The resulting second stage estimators are com- putationally expedient and intuitively appealing. They also have the advantages of higher asymptotic efficiency than those neglecting the correlation structure, and an oracle property in the sense that the asymptotic property of each additive component is the same as if the other components were known with certainty. Simulation studies are conducted to demonstrate finite sample behaviors of the proposed estimators, and a real data example is given to illustrate the usefulness of the proposed methodology.

关键词： additive vary-coefficient model longitudinal data modified Cholesky decomposition withinsubject correlation