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川渝地区夏季干旱气候特征及成因分析

干旱地区农业研究 2013年第4期31卷 237-244,256页

作者：易俊莲方建刚刘晓东中国科学院地球环境研究所陕西西安710075 中国科学院研究生院北京100049 陕西省气候中心陕西西安710015

利用1979—2011年英国东英吉利大学气候研究中心(CRU)整理的地面月降水资料和日本气象厅JMA)加工的全球高空等压面月平均气象场再分析资料,采用标准化降水指数(SPI),确定了川渝地区典型干旱年,讨论了川渝地区夏季典型干旱的气候特征及... 详细信息

利用1979—2011年英国东英吉利大学气候研究中心(CRU)整理的地面月降水资料和日本气象厅JMA)加工的全球高空等压面月平均气象场再分析资料,采用标准化降水指数(SPI),确定了川渝地区典型干旱年,讨论了川渝地区夏季典型干旱的气候特征及其大气环流特征。结果表明:川渝地区夏季典型干旱年具有气温高、降水少的气候特征;东亚中纬度盛行纬向气流,西风锋区偏北,冷空气多偏北东移,川渝地区及其我国北方大部分地区受大陆带状高压控制。500hPa带状高压与100hPa南亚高压中心位置基本一致,且500hPa高压中心与温度场的暖中心相对应,是持续性川渝夏季干旱具有近似正压结构的典型环流特征;同时川渝地区夏季干旱年对流层低层从云贵高原到四川盆地的西南气流明显偏弱,风场距平合成表明,云贵高原到川渝地区为东北距平风,距平风场上华南地区为明显的气旋式环流;川渝地区夏季典型干旱年整层西南气流水汽输送与常年比较明显偏小。

关键词：川渝地区夏季干旱标准化降水指数大气环流水汽输送

Effect of order–disorder transition on thermodynamic and electronic properties of σ and χ phases in W–Re alloy: the first-principles calculation

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Tungsten 2025年第1期7卷 195-213页

作者： Zhi-Peng Zhu Dian Jia William yi Wang jun-Lei yin Xing-Yu Gao Shu-Feng Yang Hai-Feng Song Jin-Shan Li State Key Laboratory of Solidification Processing Northwestern Polytechnical University Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The Tungsten-Rhenium(W-Re) alloys,celebrated for their high melting point,strength at elevated temperatures,electrical resistivity,and radiation resistance,have been widely utilized in high-temperature components,aerospace,electronics,and nuclear *** constituents of the topologically close-packed(TCP) phases,the sigma phase(σ) and chi phase(χ) formed within W-Re alloys wield considerable influence on the mechanical properties and the stability of the *** calculations were utilized in the present work to explore the structural,thermodynamic,and electronic properties of both ordered and disordered configurations within the σ and χ phases,culminating in a systematic elucidation of the higher phase stability exhibited by the ordered *** is found that the bulk modulus of these two phases is directly proportional to the concentration of Re in the alloy,while the equilibrium volume is inversely *** thermodynamic parameters of the σ and χ phases are calculated via the mean-field potential *** similar trends observed in the isobaric heat capacity,enthalpy increment,and entropy change curves for these two phases suggest they possess comparable thermodynamic *** is noteworthy that the contribution of ionic vibrations predominantly affects the isobaric heat capacity,while the contribution of thermal electronic excitations increases linearly with *** the structure and thermodynamic properties of TCP phases in W-Re alloys at low temperatures has profound significance for optimizing material performance,microstructures features,establishing theoretical foundations,and predicting material behavior.

关键词： First-principles calculations Phase stability TCP phases Thermodynamic properties W–Re alloy

Infiltration by monocytes of the central nervous system and its role in multiple sclerosis: reflections on therapeutic strategies

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Neural Regeneration Research 2025年第3期20卷 779-793页

作者： Guangyong Zhang Qing Yao Chubing Long Pengcheng yi Jiali Song Luojia Wu Wei Wan Xiuqin Rao Yue Lin Gen Wei jun ying Fuzhou Hua Department of Anesthesiology the Second Affiliated Hospital of Nanchang UniversityNanchangJiangxi ProvinceChina Key Laboratory of Anesthesiology of Jiangxi Province NanchangJiangxi ProvinceChina

Mononuclear macrophage infiltration in the central nervous system is a prominent feature of neuroinflammation. Recent studies on the pathogenesis and progression of multiple sclerosis have highlighted the multiple roles of mononuclear macrophages in the neuroinflammatory process. Monocytes play a significant role in neuroinflammation, and managing neuroinflammation by manipulating peripheral monocytes stands out as an effective strategy for the treatment of multiple sclerosis, leading to improved patient outcomes. This review outlines the steps involved in the entry of myeloid monocytes into the central nervous system that are targets for effective intervention: the activation of bone marrow hematopoiesis, migration of monocytes in the blood, and penetration of the blood–brain barrier by monocytes. Finally, we summarize the different monocyte subpopulations and their effects on the central nervous system based on phenotypic differences. As activated microglia resemble monocyte-derived macrophages, it is important to accurately identify the role of monocyte-derived macrophages in disease. Depending on the roles played by monocyte-derived macrophages at different stages of the disease, several of these processes can be interrupted to limit neuroinflammation and improve patient prognosis. Here, we discuss possible strategies to target monocytes in neurological diseases, focusing on three key aspects of monocyte infiltration into the central nervous system, to provide new ideas for the treatment of neurodegenerative diseases.

关键词： blood–brain barrier macrophages monocytes multiple sclerosis neuroinflammation review therapy

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竞争环境下双目标零售平台销售模式选择

管理工程学报 2025年第1期39卷 227-242页

作者：张冲朱祎宋君南京邮电大学管理学院江苏南京210003

电子商务行业发展迅速,具有“超越利润”战略导向以实现更广泛目标的组织正变得越来越普遍,兼顾消费者利益成为企业凸显竞争优势的方式。为此,本文构建由一个制造商和两个零售平台组成的两级供应链。其中,制造商和其中一个零售平台追求... 详细信息

电子商务行业发展迅速,具有“超越利润”战略导向以实现更广泛目标的组织正变得越来越普遍,兼顾消费者利益成为企业凸显竞争优势的方式。为此,本文构建由一个制造商和两个零售平台组成的两级供应链。其中,制造商和其中一个零售平台追求自身利润最大化,另外一个零售平台追求自身利润和消费者剩余的线性组合最大化,即考虑双目标最优。本文具体考虑两个零售平台分别选择转售模式或代理模式共四种情形,进而研究双目标零售平台销售模式选择问题,及其对供应链成员最优决策和供应链整体绩效的影响。结果表明:(1)在一定条件下,双目标零售平台能获得比竞争对手更高的利润;(2)当双目标零售平台选择转售模式时,无论其竞争对手选择哪种销售模式,其双目标策略都能使供应链总体利润得到优化;(3)当双目标零售平台的竞争对手选择代理模式时,其自身根据不同情况选择转售模式或者代理模式可以使两个零售平台的销售模式选择形成均衡。

关键词：双目标企业社会责任零售平台销售模式双渠道

探究单源双能CT螺距对标准水模能谱成像数据的影响

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CT理论与应用研究（中英文） 2017年第3期26卷 279-284页

作者：郭维亚刘义军刘爱连大连医科大学附属第一医院放射科辽宁大连116011

目的:探讨单源双能CT不同螺距的能谱成像(GSI)扫描对标准水模的CT值和水碘浓度值的影响。方法:采用GE Discovery 750 HD单源双能CT的GSI扫描模式对GE公司标准水模进行扫描,选择辐射剂量相近(180~192.5 mAs范围)的6个扫描协议,分别对标... 详细信息

目的:探讨单源双能CT不同螺距的能谱成像(GSI)扫描对标准水模的CT值和水碘浓度值的影响。方法:采用GE Discovery 750 HD单源双能CT的GSI扫描模式对GE公司标准水模进行扫描,选择辐射剂量相近(180~192.5 mAs范围)的6个扫描协议,分别对标准水模进行两种螺距(1.375︰1和0.984︰1)扫描,扫描野为M,扫描层厚5 mm,连续扫描6层,共获得12组数据。根据扫描螺距不同分为两组:大螺距组(螺距1.375︰1)、小螺距组(螺距0.984︰1)。获得的图像利用GSI分析软件,以1.25 mm进行无间隔标准算法重建70 keV单能量图像及水(碘)基物质图像,于标准水模中心及3、6、9和12点放置面积为3 000 mm^2圆形感兴趣区(ROI),对两种图像进行测量,记录各ROI的CT值及其SD值、水(碘)值及其SD值,采用SPSS软件配对样本t检验进行统计学分析。结果:大、小螺距组水的CT值分别为(1.39±1.90)HU和(1.97±1.74)HU,SD值分别为(7.21±0.55)HU和(6.47±0.56)HU;大、小螺距组水(碘)基物质图像的水(碘)值分别为1 001.95±1.47和1 002.19±1.34,其SD值分别为4.88±0.36和4.49±0.37。两组间差异均具有统计学意义(P<0.05)。结论:扫描参数螺距对GSI数据获得有影响,使用较小螺距扫描条件可提高诊断可靠性。

关键词：单源双能CT 扫描参数螺距 CT值水(碘)浓度值

Synthesis of chiral phosphine derivatives through a copper（I）-catalyzed desymmetric SNAr reaction

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Science China Chemistry 2025年

作者： Shuai Zhang Pei-Zhi Liu Yan-Bo Li Qi Zhang jun-Zhao Xiao yi-Fan Wang Tian-Yu Wei Jia-Wei Jiang Ye Wang Qian Peng liang yin Key Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences State Key Laboratory of Elemento-Organic Chemistry and Tianjin Key Laboratory of Biosensing and Molecular Recognition College of Chemistry Frontiers Science Center for New Organic Matter Nankai University Haihe Laboratory of Sustainable Chemical Transformations

Axially chiral phosphines are a class of extremely important ligands in asymmetric catalysis. Herein, an unprecedented copper（I）-catalyzed asymmetric SNAr reaction with HP（S）R2is uncovered, which delivers a series of axially chiral phosphine derivatives in high yields with excellent enantioselectivity. Furthermore, the diastereoselective reaction with the kinetic resolution of racemic HP（S）ArR proceeds smoothly, providing the products with moderate diastereoselectivity and excellent enantioselectivity. Control experiments indicate that HP（S）Ph2is much more active than HPPh2and HP（O）Ph2as the pronucleophile in the present reaction. It is found that the SNAr reaction （the first SNAr） proceeds in a desymmetric manner, providing the desired chiral products while a continued SNAr reaction （the second SNAr） slightly occurs in a kinetic resolution manner in the present catalytic system, which enhances the ee of the desired chiral products. DFTcalculations support a concerted reaction pathway rather than a step-wise mechanism. Finally, axially chiral olefin-phosphines produced by the present method work as suitable ligands in Pdcatalyzed asymmetric allylic substitution with C-, N-, and O-nucleophiles and Rh-catalyzed asymmetric addition of arylboronic acid to benzil.

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Pd-modified SmFeO_(3)with hollow tubular structure under light shows extremely high acetone gas sensitivity

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Rare Metals 2023年第2期42卷 545-557页

作者： Heng Zhang Jing Xiao jun Chen lian Zhang yi Zhang Xiang-Lin Pei College of Physics and Electronic Engineering Taishan UniversityTaian271000China School of Materials and Architectural Engineering Guizhou Normal UniversityGuiyang550025China

Currently,SmFeO_(3)-based sensors are an effective platform for detecting acetone ***,they require high operating temperatures,which increases energy consumption and safety hazards,and their response is low when the gas concentration is at 10^(-9)(PPB),which cannot meet the requirements of using exhaled breath to pre-diagnose ***,Pd-SmFeO_(3)hollow nanotubes with an extremely high specific surface area and porosity were synthesized by *** Pd doping,the specific surface area improved by more than two times,and the acetone response improved by more than three *** addition,the response further improved by more than 1.5 times,and the optimum operating temperature reduced by 100℃under light ***,the relative humidity adaptability,long-term stability,and selectivity of the material were significantly improved after Pd doping or light ***,the acetone concentration in a person’s exhaled breath was detected by a Pd-SmFeO_(3)-based gas sensor,and the error was less than 10%compared to that obtained by gas chromatography-mass spectrometry method.

关键词： Pd-SmFeO_(3) Gas sensor Acetone gas Light illumination Diabetes

A 20 μW 95 dB dynamic range 4th-order Delta-Sigma modulator with novel power efficient operational transconductance amplifier and resonator

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第6期12卷 486-498页

作者： Jian XU Xiao-bo WU Meng-lian ZHAO jun-yi SHEN Institute of VLSI Design Zhejiang University Hangzhou 310027 China

A low power high performance Delta-Sigma modulator for portable measurement applications is presented. To reduce power consumption while maintaining high performance, a fully feedforward architecture with a comprehensive system-level design is implemented. As a key building block, a novel power efficient current mirror operational transconductance amplifier (OTA) with a fast-settling less-error switched-capacitor common-mode feedback (SC CMFB) circuit is introduced, and the effects of both gain nonlinearity and 1/f noise of OTA are discussed. A new method to determine the voltage gain of an OTA is also proposed. The bottom terminal parasitic effect of poly-insulator-poly (PIP) capacitors is considered. About an extra 20% of capacitance is added to the total capacitance load. A power and area efficient resonator is adopted to realize a coefficient of 1/90 for 50% power and 75% area reduction compared with conventional designs. The chip is implemented in a low cost 0.35 μm complementary metal oxide semiconductor (CMOS) process. The total power consumption is 20 μW with a 1.5 V supply, and the measured dynamic range (DR) is 95 dB over a 1 kHz bandwidth. Experimental results show that a high figure-of-merit (FOM) is achieved for the designed modulator in comparison with those from the literature.

关键词： Low power High performance Power efficient OTA and resonator Delta-Sigma modulator

A Heuristic Sampling Method for Maintaining the Probability Distribution

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Journal of Computer Science & Technology 2021年第4期36卷 896-909页

作者： Jiao-Yun Yang jun-Da Wang yi-Fang Zhang Wen-Juan Cheng lian Li Key Laboratory of Knowledge Engineering with Big Data of Ministry of Education Hefei University of Technology Hefei 230601China National Smart EldeTca/re International Science and Technology Coopemtion Base Hefei University of Technology Hefei 230601China School of Computer Science and Information Engirwering Hefei University of TechnologyHefei 230601China School of Mathematics Hefei University of TechnologyHefei 230601China

Sampling is a fundamental method for generating data *** many data analysis methods are developed based on probability distributions,maintaining distributions when sampling can help to ensure good data analysis ***,sampling a minimum subset while maintaining probability distributions is still a *** this paper,we decompose a joint probability distribution into a product of conditional probabilities based on Bayesian networks and use the chi-square test to formulate a sampling problem that requires that the sampled subset pass the distribution test to ensure the ***,a heuristic sampling algorithm is proposed to generate the required subset by designing two scoring functions:one based on the chi-square test and the other based on likelihood *** on four types of datasets with a size of 60000 show that when the significant difference level,a,is set to 0.05,the algorithm can exclude 99.9%,99.0%,93.1%and 96.7%of the samples based on their Bayesian networks-ASIA,ALARM,HEPAR2,and ANDES,*** subsets of the same size are sampled,the subset generated by our algorithm passes all the distribution tests and the average distribution difference is approximately 0.03;by contrast,the subsets generated by random sampling pass only 83.8%of the tests,and the average distribution difference is approximately 0.24.

关键词： Bayesian network chi-square test sampling probability distribution