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Gas flow characteristics of argon inductively coupled plasma and advections of plasma species under incompressible and compressible flows

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Chinese Physics B 2018年第12期27卷 348-360页

作者： Shu-xia zhao zhao Feng Physics Department Dalian University of Technology

In this work, incompressible and compressible flows of background gas are characterized in argon inductively coupled plasma by using a fluid model, and the respective influence of the two flows on the plasma properties is specified. In the incompressible flow, only the velocity variable is calculated, while in the compressible flow, both the velocity and density variables are calculated. The compressible flow is more realistic; nevertheless, a comparison of the two types of flow is convenient for people to investigate the respective role of velocity and density variables. The peripheral symmetric profile of metastable density near the chamber sidewall is broken in the incompressible flow. At the compressible flow, the electron density increases and the electron temperature decreases. Meanwhile, the metastable density peak shifts to the dielectric window from the discharge center, besides for the peripheral density profile distortion, similar to the incompressible *** velocity profile at incompressible flow is not altered when changing the inlet velocity, whereas clear peak shift of velocity profile from the inlet to the outlet at compressible flow is observed as increasing the gas flow rate. The shift of velocity peak is more obvious at low pressures for it is easy to compress the rarefied gas. The velocity profile variations at compressible flow show people the concrete residing processes of background molecule and plasma species in the chamber at different flow rates. Of more significance is it implied that in the usual linear method that people use to calculate the residence time, one important parameter in the gas flow dynamics, needs to be rectified. The spatial profile of pressure simulated exhibits obvious spatial gradient. This is helpful for experimentalists to understand their gas pressure measurements that are always taken at the chamber outlet. At the end, the work specification and limitations are listed.

关键词： gas flow inductively coupled plasma compressible flow fluid model

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Biome reconstruction on the Tibetan Plateau since the Last Glacial Maximum using a machine learning method

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Science China Earth Sciences 2022年第3期65卷 518-535页

作者： Feng qin Yan zhao xianyong CAO Key Laboratory ofLand Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Alpine Paleoecology and Human Adaptation(ALPHA)Group State Key Laboratory of Tibetan Plateau Earth System Science(LATPES)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Historical biome changes on the Tibetan Plateau provide important information that improves our understanding of the alpine vegetation responses to climate ***,a comprehensively quantitative reconstruction of the historical Tibetan Plateau biomes is not possible due to the lack of quantitative methods that enable appropriate classification of alpine biomes based on proxy data such as fossil pollen *** this study,a pollen-based biome classification model was developed by applying a random forest algorithm(a supervised machine learning method)based on modern pollen assemblages on and around the Tibetan Plateau,and its robustness was assessed by comparing its results with the predictions of the biomisation *** results indicated that modern biome distributions reconstructed using the random forest model based on modern pollen data generally concurred with the observed zonal *** random forest model had a significantly higher accuracy than the biomisation method,indicating the former is a more suitable tool for reconstructing alpine biome changes on the Tibetan *** random forest model was then applied to reconstruct the Tibetan Plateau biome changes from 22 ka BP to the present based on 51 fossil pollen *** reconstructed biome distribution changes on the Tibetan Plateau generally corresponded to global climate changes and Asian monsoon *** the Last Glacial Maximum,the Tibetan Plateau was mainly desert with subtropical forests distributed in the *** the last deglaciation,the alpine steppe began expanding and gradually became zonal vegetation in the central and eastern *** meadow occupied the eastern and southeastern areas of the Tibetan Plateau since the early Holocene,and the forest-meadow-steppe-desert pattern running southeast to northwest on the Tibetan Plateau was established *** the mid-Holocene,subtropical forests extended north,which reflected the“optimum”***

关键词： Biome reconstruction Random forest algorithm Biomisation method Pollen data Last Glacial Maximum Tibetan Plateau

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Variational-Iterative Solution of Ground State for Central Potential

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Communications in Theoretical Physics 2002年第7期38卷 15-18页

作者： zhao Wei-qin China Center of Advanced Science and Technology CCAST World Lab. P.O. Box 8730 Beijing 100080 China Institute of High Energy Physics the Chinese Academy of Sciences P.O. Box 9184-1 Beijing 100039 China

The newly developed iterative method based on Green function defined by quadratures along a single trajectory is combined with the variational method to solve the ground state quantum wave function for central *** an example, the method is applied to discuss the ground state solution of Yukawa potential, using Hulthen solution as the trial function.

关键词： iterative solution, variantional method, ground state

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Electrochemical studies of chloroperoxidase on poly-L-lysine film modified GC electrode

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Chinese Chemical Letters 2010年第1期21卷 93-96页

作者： zhao, Wen Wu, xia qin Lu, Zhong qing Hou, Wen Jing Li, He Xing Shanghai Normal Univ Life & Environm Sci Coll Shanghai 200234 Peoples R China

Poly-L-lysine(PLL) was first electrodeposited onto the surface of a glassy carbon(GC) *** PLL modified electrode was used to immobilize chloroperoxidase(CPO) via 1-[(3-dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride(EDC).The electrochemical behaviors of immobilized CPO on PLL/GC electrode were investigated by cyclic voltammetry(CV).The CV results obtained showed that CPO was successfully immobilized on the PLL/GC electrode and a fast direct electron transfer between CPO and PLL-GC electrod...

关键词： Chloroperoxidase Poly-L-lysine Electrodeposition Electrocatalysis Direct electrochemistry Modified electrode

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Groundstate with Zero Eigenvalue for Generalized Sombrero-Shaped Potential in N-Dimensional Space

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Communications in Theoretical Physics 2008年第7期50卷 139-141页

作者： zhao Wei-qin China Center of Advanced Science and Technology （CCAST）（World Lab.） P.O. Box 8730 Beijing 100080 China Institute of High Energy Physics the Chinese Academy of Sciences P.O. Box 918 （4-1） Beijing 100049 China

Based on an iterative method for solving the groundstate of Schrodinger equation, it is found that a kind of generalized Sombrero-shaped potentials in N-dimensional space has groundstates with zero eigenvalue. The res... 详细信息

关键词： iterative solution zero eigenvalue generalized Sombrero-shaped potential

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Cloning,expression,and characterization of a porcine pancreatic α-amylase in Pichia pastoris

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Animal Nutrition 2018年第2期4卷 234-240页

作者： Lv-hui Sun Tao qin Yan Liu Hua zhao Xinjie xia Xingen Lei Department of Animal Nutrition and Feed Science Huazhong Agricultural University International Center of Future Agriculture for Human Health Sichuan Agricultural University Wuhan Chopper Biology Co. LTD Department of Animal Science Cornell University

Pancreatic α-amylase(α-1, 4-glucan-4-glucanohydrolase, EC.3.***.1.1) plays a primary role in the intestinal digestion of feed starch and is often deficient in weanling *** objective of this study was to clone,express, and characterize porcine pancreatic α-amylase(PPA).The full-length c DNA encoding the PPA was isolated from pig pancreas by RT-PCR and cloned into the pPICZαA *** the resultant pPICZαА-PPA plasmid was transferred into Pichia pastoris, Ni Sepharose affinity column was used to purify the over-expressed extracellular recombinant PPA protein(re PPA) that contains a His-tag to the C terminus and was characterized against the natural enzyme(α-amylase from porcine pancreas).The re PPA exhibited a molecular mass of approximately 58 kDa and showed optimal temperature(50℃),optimal pH(7.5), K_m(47.8 mg/mL), and V_(max)(2,783 U/mg) similar to those of the natural *** recombinant enzyme was stable at 40℃ but lost 60% to 90%(P < 0.05) after exposure to heating at≥50℃ for 30 *** enzyme activity was little affected by Cu^(2+)or Fe^(3+), but might be inhibited(40% to 50%) by Zn^(2+)at concentrations in pig ***, Ca^(2+)exhibited a dose-dependent stimulation of the enzyme *** conclusion, the present study successfully cloned the porcine pancreatic aamylase gene and over-expressed the gene in *** as an extracellular, functional *** biochemical characterization of the over-produced enzyme depicts its potential and future improvement as an animal feed additive.

关键词： Porcine α-amylase Pancreatic Gene expression Pichia pastoris

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Quantifying the effects of stripe rust disease on wheat canopy spectrum based on eliminating non-physiological stresses

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The Crop Journal 2022年第5期10卷 1284-1291页

作者： xia Jing Kaiqi Du Weina Duan qin Zou Tingting zhao Bingyu Li Qixing Ye Lieshen Yan College of Geomatics Xi’an University of Science and TechnologyXi’an 710054ShaanxiChina Key Laboratory of Digital Earth Science Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100094China

The wheat canopy reflectance spectrum is affected by many internal and external factors such as diseases and growth stage. Separating the effects of disease stress on the crop from the observed mixed signals is crucial for increasing the precision of remote sensing monitoring of wheat stripe rust. The canopy spectrum of winter wheat infected by stripe rust was processed with the difference-in-differences(DID) algorithm used in econometrics. The monitoring accuracies of wheat stripe rust before and after processing with the DID algorithm were compared in the presence of various external factors, disease severity, and several simulated satellite sensors. The correlation between the normalized difference vegetation index processed by the DID algorithm(NDVI-DID) and the disease severity level(SL) increased in comparison with the NDVI before processing. The increase in precision in the natural disease area in the field in the presence of large differences in growth stage, growth, planting, and management of the crop was greater than that in the controlled experiment. For low disease levels(SL 40%).According to the measured hyperspectral data, the spectral reflectance of three satellite sensor levels was simulated. The wide-band NDVI was calculated. Compared with the wide-band NDVI and vegetation indexes(VI) before DID processing, there were increases in the correlation between SL and the various types of VIS-DID, as well as in the correlation between SL and NDVI-DID. It is feasible to apply the DID algorithm to multispectral satellite data and diverse types of VISfor monitoring wheat stripe rust. Our results improve the quantification of independent effects of stripe rust infection on canopy reflectance spectrum,increase the precision of remote sensing

关键词： Difference-in-differences Wheat stripe rust Severity leve Non-physiological stress Independent effects

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Theoretical Analysis of Rayleigh Backscattering Noise in Fiber Raman Amplifiers

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Communications in Theoretical Physics 2005年第5X期44卷 908-910页

作者： SHENG zhao-xia Department of Mathematics and Physical Science Tianjin University of Technology and Education Tianjin 300222 China

In this paper, a new theoretical model for Rayleigh backscattering (RB) analysis of fiber Raman amplifiers is proposed. The model includes all the interactions among the pumps, signals, and all orders of RB. The results show that the higher order RB has a negligible influence on the performance of the amplifier. The co-propagating and counterpropagating RB power of the signal grow quadratically with the net-gain of the amplifier. The signal to double Rayleigh backscattering noise ratio (OSNRDRB ) of backward-pumped FRAs is better than that of the forward-pumped ones at high net-gain level (＞ 13 dB), while at low net-gain level the OSNRDrb of the forward-pumped FRAs is slightly better than that of the backward-pumped ones.

关键词： fiber Raman amplifier Rayleigh scattering

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Intrinsic mechanism and multiphysics analysis of electromagnetic wave absorbing materials: New horizons and breakthrough

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Journal of Materials Science & Technology 2022年第35期130卷 136-156页

作者： Long xia Yuming Feng Biao zhao School of Materials Science and Engineering Harbin Institute of Technology at WeihaiWeihai 264209China School of Microelectronics Fudan UniversityShanghai 200433China

Electromagnetic absorbers(EMA) have driven the development of Electromagnetic(EM) technology and advanced EM devices. Utilizing the EM energy conversion of EM absorbers to design various devices is attractive and promising, especially in personal protection and healthcare. In this review article, the simulation and numerical analysis of EM materials are reviewed, from numerical analysis of dielectric parameters, simulation of wave absorbing performance, electromagnetic performance improvement, and structural construction optimization. For the EM response mechanism, radiation-dependent relaxation and charge transport energy transitions are dissected. For the EM calculation section, two leading roles are highlighted, including the purposeful design of EM and the provision of theoretical guidance for optimizing electromagnetic absorption performance. In addition, this work points out the current problems and potential opportunities in the numerical simulation of absorbing materials, points out the new development direction, and proposes prospects.

关键词： Microwave absorption Multiphysics simulation Dielectric parameters EMA Properties optimization

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Square-Free Pure Triangular Decomposition of Zero-Dimensional Polynomial Systems

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Journal of Systems Science & Complexity 2023年第6期36卷 2661-2680页

作者： LI Haokun xia Bican zhao Tianqi School of Mathematical Sciences Peking UniversityBeijing100871China

Triangular decomposition with different properties has been used for various types of problem *** this paper,the concepts of pure chains and square-free pure triangular decomposition(SFPTD)of zero-dimensional polynomial systems are *** of its good properties,SFPTD may be a key way to many problems related to zero-dimensional polynomial *** by the work of Wang(2016)and of Dong and Mou(2019),the authors propose an algorithm for computing SFPTD based on Gr¨obner bases *** novelty of the algorithm is that the authors make use of saturated ideals and separant to ensure that the zero sets of any two pure chains are disjoint and every pure chain is square-free,*** one hand,the authors prove the arithmetic complexity of the new algorithm can be single exponential in the square of the number of variables,which seems to be among the rare complexity analysis results for triangular-decomposition *** the other hand,the authors show experimentally that,on a large number of examples in the literature,the new algorithm is far more efficient than a popular triangular-decomposition method based on pseudodivision,and the methods based on SFPTD for real solution isolation and for computing radicals of zero-dimensional ideals are very efficient.

关键词： Gr¨obner basis pure chain square-free pure chain triangular decomposition zero-dimensional polynomial system

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