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Metal Free Mono- and 2,3-Bis-sulfenylation of Indoles in Water with Sodium Sulfinates as a Sulfur Source

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Chinese Journal of Chemistry 2018年第9期36卷 819-825页

作者： Changqing Liu Jian Fan Manyi Wu Jiahui Chen Yiming Zhao Meihua xie Key Laboratory of Functional Molecular Solids Ministry of Education Anhui Laboratory of Molecule-Based Materials College of Chemistry and Materials Science Anhui Normal University Wuhu Anhui 241000 China Department of Chemistry 8engbu Medical College Bengbu Anhui 233030 China

An iodine-PPh3 mediated sulfenylation of indoles in water with stable and odorless sodium sulfinates as the sulfur source is described. The reaction could afford monosulfenylated indoles in moderate to excellent yields under metal free conditions. Moreover, double C--H sulfenylation of in- doles at 2- and 3-positions has also been achieved by using excess sodium sulfinates under the optimized reaction conditions.

关键词： indole sodium sulfinate sulfenylation

Relationship between equatorial pressure oscillations and tropical cyclones landing over China

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Science China Earth Sciences 2008年第1期51卷 123-133页

作者： JI ZhongPing xie JiongGuang LIANG Jian JIN RongHua WEN Jing WENG XiangYu Guangzhou Central Weather Observatory Guangzhou 510080China State Meteorological Center Beijing 100081China

With daily reanalysis data by NCEP/NCAR and data of tropical cyclones landing over China from 1949 to 2005, the variation of low-frequency oscillations of equatorial pressure and their relationship with tropical cyclones landing over China in the summer half of the years (June through October) are studied for the 57 years, using spectral analysis and correlation analysis. The results show that the summertime equatorial pressure is mainly of periodic oscillations of 5―7 days and 10―30 days and the interannual variation of the intensity of its quasi-biweekly oscillation is significantly positive correlation with the number of tropical cyclones landing over China. The quasi-biweekly oscillation is filtered from daily equatorial pressure in May―November over the 57 years with inverse wavelet transform and the probability for tropical cyclones landing on coastal China within four days before and after the oscillatory valleys of quasi-biweekly pressure at the equator is 59.7% and 73.0% for June to October and July to September respectively. The model of atmospheric circulation for quasi-biweekly oscillatory valleys of equatorial pressure in association with or without tropical cyclones landing over China in July―September is set up with the composite analysis method. When the valleys are associated with (without) landfall, zonal (meridional) circulation prevails in the mid and high latitudes of the Eastern Hemisphere, the high pressure ridge is weak (strong) near the Sea of Okhotsk, the westerly zone is northward (southward), the subtropical high is westward (eastward) in location and strong (weak) in intensity, the cross-equatorial flow is strong (weak) in southeast Asia, Southwest Monsoon is strong (weak) and stronger (weaker) while in the valleys of pressure, being favorable (unfavorable) for tropical cyclones landing over China. The atmospheric circulation model for oscillatory valleys of biweekly equatorial pressure in association with (without) tropical cyclones lan

关键词： equatorial pressure quasi-biweekly oscillatory valleys landfall tropical cyclones China atmospheric circulation models

Robust Variable-Pitch Control Design of PMSG Via Perturbation Observer

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Energy Engineering 2021年第4期118卷 911-929页

作者： Yilin Hu Yan xie Bo Li Yiqiang Jiang Fu Bao Department of International Applied Technology Yibin UniversityYibin644000China School of Information and Communication Engineering Hainan UniversityHaikou570000China School of Physics and Information Engineering Zhaotong UniversityZhaotong657000China

Wind turbine employs pitch angle control to maintain captured power at its rated value when the wind speed is higher than rated *** work adopts a perturbation observer based sliding-mode control(POSMC)strategy to realize robust variable-pitch control of permanent magnet synchronous generator(PMSG).POSMC combines system nonlinearities,parametric uncertainties,unmodelled dynamics,and time-varying external disturbances into a perturbation,which aims to estimate the perturbation via a perturbation observer without an accurate system ***,sliding mode control(SMC)is designed to completely compensate perturbation estimation in real-time for the sake of achieving a global consistent control performance and improving system robustness under complicated *** results indicate that,compared with vector control(VC),feedback linearization control(FLC),and nonlinear adaptive control(NAC),POSMC has the best control performance in ramp wind and random wind and the highest robustness in terms of parameter ***,the integral absolute error index of!m of POSMC is only 11.69%,12.10%and 15.14%of that of VC,FLC and NAC in random wind speed.

关键词： Variable-pitch control permanent magnet synchronous generator perturbation observer

Calibration of Binding Energy Positions with C1s for XPS Results

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Journal of Wuhan University of Technology(Materials Science) 2020年第4期35卷 711-718页

作者： FANG De HE Feng xie Junlin XUE Lihui State Key Laboratory of Silicate Materials for Architectures Wuhan University of TechnologyWuhan 430070China Center for Materials Research and Analysis Wuhan University of TechnologyWuhan 430070China School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China

The adventitious carbon located at 284.8 eV was used to calibrate samples without the carbon *** the carbon is as a major part of the inorganic material,the adventitious carbon should be identified and used as the *** is no adventitious carbon on the surfaces of the polymer materials,so using C1s of the carbon in the polymer itself to calibrate the charging effect is ***,compared with gold and argon,a more practical and convenient method based on C1s is proposed to get the right positions for binding energy peaks.

关键词： XPS calibration charging effect binding energy C1s

PHOSPHORUS SEGREGATION AND ANNEALING EMBRITTLEMENT OF Ni-P AMORPHOUS

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Acta Metallurgica Sinica(English Letters) 1991年第8期4卷 103-107页

作者： Qu Zhe xie Tiansheng Institute of Metal Research,Academia Sinica,Shenyang,China Acad Sinica Shenyang China

Phosphorus segregation and embrittlement of Ni-P amorphous annealed at the temperatures below crystallization have been *** phosphorus enrichs on free surface and its level increases with annealing *** is fairly coincident with the measured toughness which decreases with annealing *** ion-sputtering revealed that a phosphorus depletion zone in the subsurface layers forms due to element redistribution during *** thickness and amplitude of the phosphorus depletion zone depend on the an- nealing temperature. The formation of depletion zone and the mechanism of embrittlement of Ni-P amorphous during annealing have been discussed based on the theory of the activation energy of atomic diffusion in the amorphous being variable.

关键词： Ni-P amorphous phosphorus segregation annealing embrittlement

Sleep Apnea Monitoring System Based on Commodity WiFi Devices

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Computers, Materials & Continua 2021年第11期69卷 2793-2806页

作者： Xiaolong Yang Xin Yu Liangbo xie Hao Xue Mu Zhou Qing Jiang School of Communication and Information Engineering Chongqing University of Posts and TelecommunicationsChongqing400065China School of Computing Technologies RMIT UniversityMelbourneVictoria3001Australia

To address the limitations of traditional sleep monitoring methods that highly rely on sleeping posture without considering sleep apnea,an intelligent apnea monitoring system is designed based on commodity WiFi in this *** utilizing linear fitting and wavelet transform,the phase error of channel state information(CSI)of the receiving antenna is eliminated,and the noise of the signal amplitude is ***,the short-time Fourier transform(STFT)and sliding window method are combined to segment received wireless ***,several important statistical characteristics are extracted,and a back propagation(BP)neural network model is built to identify apnea ***,interferences caused by changes of sleeping posture are *** experimental results demonstrate that the proposed system can identify apnea state with an accuracy of over 95.6%.Furthermore,the accuracy can still reach more than 94.8%when the test environment layout is ***,the proposed system can be used as a daily apnea monitoring system at home and provide users with health information.

关键词： WiFi channel state information apnea neural network

In situ Nd isotopic measurement of natural geological materials by LA-MC-ICPMS

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Chinese Science Bulletin 2008年第7期53卷 1062-1070页

作者： YANG YueHeng SUN JinFeng xie LieWen FAN HongRui WU FuYuan State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

Using newly determined Sm isotopic abundances for correcting the isobaric interference of 144Sm on 144Nd and the established mass bias relationship between Sm and Nd, a series of in situ Nd isotopic measurements were conducted for relatively high Nd concentrations of natural geological materials, including apatite, titanite, monazite and perovskite on a Neptune multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS), coupled to a 193 nm ArF excimer laser ablation system. The results show that Ce has no significant influence on the precision and accuracy of Nd isotopic analyses for LREE-enriched geological minerals and that our approach is efficient in obtaining reliable 143Nd/144Nd and 147Sm/144Nd ratios for those materials with Sm/Nd<1 (147Sm/144Nd<0.6). When combined with trace element and U-Pb isotope data, the in situ Nd isotopic data can provide important information on geological processes.

关键词：钕同位元素测量方法地质材料

Effects of a polyamine inhibitor on the microstructure and macromechanical properties of hydrated shale

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Petroleum 2022年第4期8卷 538-545页

作者： Yunlei Hu Xiangchao Shi Qingling Li Leiyu Gao Feng Wu Gang xie State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500China

China is rich in shale gas resources,however,wellbores in shale gas reservoirs are frequently *** has a serious impact on the shale gas drilling ***,a common additive in water-based shale drilling fluids,can effectively inhibit shale ***,there is a lack of quantitative research on the effect of polyamine inhibitors on the microstructure and macromechanical properties of ***,this study investigated those issues via a systematic hydration experiment carried out on shale from the Longmaxi *** results show that microfractures are created and expand during shale hydration,that they also connect to form a complex microfracture network,and that 3%polyamine inhibitors(polyamine solution with volume fraction of 3%)can effectively inhibit their *** ultrasonic velocities and UCS of the Longmaxi shale are significantly anisotropic;the former first increases and then decreases with the laminae angle,reaching its maximum when the laminae angle is 30°.The UCS of the shale is highest and lowest,respectively,when the laminae angles are 0°or 90°and 30°.In general,these UCS appear as a"U"pattern,high on two sides with a dip in the *** can effectively inhibit both the expansion of shale and the reduction of P-wave and S-wave velocities,the UCS,and elastic *** UCS of a shale sample was reduced by 28%e40%after immersion for 96 h in water,compared to 2%e20%after immersion in a 3%polyamine inhibitor for the same amount of *** inhibiting effect of the polyamine was remarkable.

关键词： Polyamine Microfracture Macromechanical properties Hydration Anisotropy

Studies on Temporal and Spatial Variations of Phytoplankton in Lake Chaohu

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Journal of Integrative Plant Biology 2007年第4期49卷 409-418页

作者： Dao-Gui Deng Ping xie Qiong Zhou Hua Yang Long-Gen Guo Donghu Experimental Station of Lake Ecosystems State Key Laboratory for Freshwater Ecology and Biotechnology of China Institute of Hydrobiology the Chinese Academy of Sciences Wuhan 430072 China

Temporal and spatial variations of the phytoplankton assemblage in Lake Chaohu, a large shallow eutrophic lake in China, were studied from September 2002 to August 2003. A total of 191 phytoplankton species was identified, among which Chlorophytes （101） ranked the first, followed by Cyanophytes （46） and Bacillariophytes （28）. On aver- age over the entire lake, the maximum total algal biomass appeared in June （19.70 mg/L） with a minimum （5.05 mg/ L） in November. In terms of annual mean biomass, cyanobacteria contributed 45.43% to total algal biomass, followed by Chlorophytes （27.14%）, and Bacillariophytes （20.6%）. When nitrate （NOs-N） and ammonium （NH4-N） concentrations dropped in spring, fixing-nitrogen cyanobacterium （Anabaena） developed quickly and ranked the first in terms of biomass in summer. It is likely that dominance of zooplanktivorous fish and small crustacean zooplankton favored the development of the inedible filamentous or colony forming cyanobacteria. The persistent dominance of cyanobacteria throughout all seasons may indicate a new tendency of the response of phytoplankton to eutrophication in Lake Chaohu.

关键词： cyanobacterial blooms eutrophication Lake Chaohu phytoplankton zooplankivorous fish.