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Localized Electrochemical Impedance Spectroscopy Study on the Corrosion Behavior of Fe-Cr Alloy in the Solution with Cl^- and SO_4^(2-)

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Journal of Wuhan University of Technology(Materials Science) 2012年第1期27卷 27-32页

作者：肖葵 ZHANG Xin D0NG Chaofang WEI Dan WANG Chen LI Xiaogang Advanced Material and Technology Institute University of Science&Technology BeijingBeijing 100083China Society Service Center China Association for Science and TechnologyBeijing 100081China Faculty of Metallurgical and Energy Engineering Kunmming University of Science and TechnologyKunming 650093China

The corrosion behaviors of Fe-Cr alloy under three different pH values solutions with C1- and SO42- were investigated by localized electrochemical impedance spectroscopy （LEIS） measurements and the corrosion products were analyzed by laser Raman spectrometry. The results show that the high corrosion resistance of Fe-Cr Alloy is attributed to a passive film which is formed more easily when the alloy contains a large quantity of Cr element. However, its corrosion resistance varies in the solutions with different pH values, especially in the initial corrosion. The average impedance values in neutral and alkaline solution are much higher than that in acidic solution because the passive film is more likely to dissolve in the acidic condition. Moreover, the destructive effect of C1- and SO42 ions on the passive film is also demonstrated in corrosion process through the change of the impedance value with the steeping time.

关键词： Fe-Cr Alloy localized electrochemical impedance spectroscopy (LEIS) corrosionproducts Raman spectroscopy

Effect of stand density and humus removal on regeneration of Pinus densiflora seedlings in a mixed conifer and broad-leaved forest

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Forestry Studies in China 2012年第2期14卷 85-91页

作者： WUChu-ping MakotoAND0 ZHANGJun SHENAi．hua YUANWei-gao ZHUJin—ru JIANGB0 ZhejiangForestryAcademy Hangzhou310023PR．China FieldScienceEducationandResearchCenter KyotoUniversityKitashirakawa—oiwakeKyoto6068502Japan

We studied the impact of stand density and forest floor humus removal on regeneration ofPinus densiflora in a mixed co- nifer and broad-leaved forest on the Daimonji-Yama Mountain, Kyoto, Japan. Three levels of stand density were set, i.e., a clear-cut site, a heavily thinned site and a lightly thinned site. In each density treatment, comparisons were carried out between humus removal （A0-free） and humus intact （A0-intact） subplots. We counted the emergence of sown pine seeds and measured survival and growth of pine seedlings over the next four years. In addition, light conditions and the recovery of understory were monitored. Results show that thinning intensity and humus removal promoted the establishment and growth of seedlings. One exception, however, was that seedling growth was minimal in the heavily thinned A0-intact subplots. This was due to a strong response of understory vegetation growth on the treatment combination, which hindered the pine seedling growth. Furthermore, we found that the canopy openness measured at 1.3-m height remained at least 35% for the heavily thinned site in 2008. The results suggest that the removal of the A0 layer after heavy thinning is the most effective and labor-saving operation for P. densifiora regeneration.

关键词： Pinus densiflora regeneration understory vegetation thinning forest operation

A Robin Problem for Quasi-linear System

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Chinese Quarterly Journal of Mathematics 2004年第2期19卷 160-163页

作者： 0UYANGCheng DepartmentofMathematics HuzhouTeacher＇sCollegeHuzhou313000China

In this paper, a Robin problem for quasi-linear system is considered. Under the appropriate assumptions, the existence of solution for the problem is proved and the asymptotic behavior of the solution is studied using... 详细信息

关键词：常微分方程非线性假设微分学

北祁连山高压变质带的变形和变质特征及其对俯冲带折返的意义

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岩石学报 2009年第9期25卷 2235-2246页

作者：曹毅宋述光 CA0 Peking Univ MOE Key Lab Orogen Belts & Crustal Evolut Dept Geol Beijing 100871 Peoples R China

北祁连造山带是早古生代大洋板块"冷"俯冲的典型地区,形成了一系列高压低温变质的岩石组合。基性榴辉岩是俯冲洋壳变质的产物,根据其结构构造特征可以划分为(1)粒状榴辉岩,峰期变质矿物组合为Grt+Omp+Phn+Rut±Lws,硬柱石呈包裹体和假... 详细信息

北祁连造山带是早古生代大洋板块"冷"俯冲的典型地区,形成了一系列高压低温变质的岩石组合。基性榴辉岩是俯冲洋壳变质的产物,根据其结构构造特征可以划分为(1)粒状榴辉岩,峰期变质矿物组合为Grt+Omp+Phn+Rut±Lws,硬柱石呈包裹体和假象分布于石榴石内,变质温压条件T=465～508℃,p=2.30～2.60GPa。(2)片状榴辉岩,岩石具片状构造,其共生矿物组合Omp+Czo/Ep+Phn+Gln构成透入性面理S_1和线理L_1,以及宏观和显微同斜褶皱F_1。其峰期变质温压条件为T=466～510℃,P=1.9～2.2GPa。(3)蓝片岩相退化变质榴辉岩,蓝片岩相变质矿物Gln+Ep+Phn±Ab强烈交代榴辉岩相矿物,并发生强烈D_2期变形作用,岩石形成明显的透入性面理S_2和线理L_2,以及同斜剪切褶皱F_2。蓝闪石和多硅白云母线理的统计揭示D_2期变形以斜向走滑剪切为主,与D_1期变形的榴辉岩的运动学特征大体相似。D_2同变质的温压条件为T=422～487℃,P=1.15～1.37GPa。高压变质带晚期的绿片岩相叠加和D_3期变形,形成透入性面理S_3和线理L_3,其运动特征为近于垂直构造线的逆冲剪切。结合榴辉岩变形特征,变质温压条件和同位素年代学资料,我们认为退变质的强弱与变形程度有密切关系。峰期变质后的榴辉岩经过早期绿帘石榴辉岩相到蓝片岩相斜向走滑剪切,和晚期绿片岩相逆冲,在泥盆纪早期快速折返的出露地表。

关键词：北祁连山高压变质带变形变质特征俯冲带折返 implications 榴辉岩相峰期变质温压条件 mineral assemblage 蓝片岩相 North Qilian Mountains isotopic geochronology 走滑剪切线理绿片岩相矿物组合变质矿物 movement Early Paleozoic

The Wavelet Property of the Geomagnetic Anomaly Signal

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Communications in Nonlinear Science and Numerical Simulation 1997年第4期2卷 244-248页

作者： Jiangfa L IN &Gang WANG&Saizhen ZHANG&Yaosong CHEN (Dept. of Mech.,Peking Univ.,Bei Jing 1 0 0 871 ,P.R.China) Department of Mechanics and Engineering Science Peking University Beijing 100871 China

In this study,wavelet analysis is utilized to analyze the geomagnetic signals for oil- gas exploration,in order to show the relation between the wavelet property of the geomagnetic signals and the underground treasure. At first,the global geomagnetic anomaly signal in the oil exploration is ***,with the wavelet theory the geomagnetic signals of an oil- gas field is *** preliminary wavelet analysis shows thatthe underground oil- gas location can be determined with the help of its regional high frequency signal distributions.

关键词： wavelet analysis geomagnetic anomaly high frequency

PERIODIC SOLUTIONS OF A CLASS OF SUPERQUADRATIC SECOND ORDER HAMILTONIAN SYSTEMS

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Applied Mathematics(A Journal of Chinese Universities) 2000年第3期15卷 259-266页

作者： Yin Qun Liu DeqingDept.of Appl.Math.,Nanjing Univ.of Science and Technology,Nanjing 2 1 0 0 94 Dept. of Appl. Math. Nanjing Univ. of Science and Technology Nanjing

In this paper, a sufficient condition for the periodic solution with prescribed period for a class of superquadratic second order Hamiltonian systems x¨+Ax+ Δ F(x)=0 is obtained by using the critical point theory, w... 详细信息

关键词： Hamiltonian system periodic solution critical point.

Design of a Low Respiratory Resistance Mask for COVID-19

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Journal of Shanghai Jiaotong university(Science) 2022年第4期27卷 543-551页

作者：杨朴凡黄淇鑫卫思霁姚远张执南 School of Mechanical and Engineering Shanghai Jiao Tong UniversityShanghai200240China iDesignLab Student Innovation CenterShanghai Jiao Tong UniversityShanghai200240China

Observational evidence suggests that mask-wearing mitigates transmission of COVID-19;at the same time high respiratory resistance leads to an unwillingness to wear *** paper proposed a respiratory drive structure to reduce the air resistance of a *** structure provides different shapes during expiration and inspiration while focusing on filtering dust,bacteria,or ***,the assembled system on the mask can be disassembled and *** porous media simulation is used to verify the model *** results of a new mask show that the ventilation resistance is reduced by 20%,and the bacterial filtration efficiency meets the requirements of YY 0469–2011.

关键词： mask conceptual structure respiratory resistance bacterial filtration efficiency

Analysis and assessment of land desertification in Xinjiang based on RS and GIS

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Journal of Geographical Sciences 2004年第2期14卷 159-166页

作者： LIHu WANGXiaofeng GA0Yaqi DepartmentofUrbanandResourcesScience NanjingUniversityNanjing210093China DepartmentofGeography XinjiangNormalUniversityUrumqi830054China XinjiangForestryInvestigationandDesignInstitute Urumqi830002China

The land desertification in Xinjiang was monitored and analyzed based on RS and GIS techniques. Satellite data interpretation was adopted to obtain the general situation of Xinjiang’s land desertification in assistance with the sampling method and on-the-spot investigations. Related monitoring and investigations showed that Xinjiang was facing with severe wide range land desertification, and its desertified area made up 77.08% of the total monitoring area. As for land types, the desertified farmland accounted for 1.92% of the total monitoring area, desertified woodland 4%, desertified grassland 45%, and unused land 49%. Accordingly, as for desertification degrees, non-desertified land occupied 22.92%, weak desertified land 5.69%, medium-degree desertified land 16.58%, severe desertified land 33.19% and super severe desertified land 21.61%. Finally, as for inducing factors, wind-eroded desertification made up 58.23%, water-eroded desertification 8.69%, salinization desertification 6.52% and frozen-melt eroded desertification 3.64%. Xinjiang’s land desertification tended to get worse and the harnessing mission remained hard.

关键词：土地监测 GIS 人造卫星沙漠化新疆土地调查

NONLINEAR STABLE ADAPTIVE CONTROL BASED UPON ELMAN NETWORKS

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Applied Mathematics(A Journal of Chinese Universities) 2000年第3期15卷 332-340页

作者： Li Xiang Chen Zengqiang Yuan ZhuzhiDept.of Computer and System Science,Nankai University,Tianjin30 0 0 71 Dept. of Computer and System Science Nankai University Tianjin

Elman networks' dynamical modeling capability is discussed in this paper *** to Elman networks' unique structure,a weight training algorithm is designed and a nonlinear adaptive controller is *** the PE presumption,neural networks controller's closed loop properties are studied and the whole Elman networks' passivity is demonstrated.

关键词： Elman networks simple recurrent neural networks nonlinear control adaptive control passivity closed loop property.