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Improving Seasonal Climate Forecasts over Various Regions of Africa Using the Multimodel Superensemble Approach 预览
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作者 Joseph Nzau Mutemi 《大气和气候科学(英文)》 2019年第4期600-625,共26页
Improvements that can be attained in seasonal climate predictions in various parts of Africa using the multimodel supersensemble scheme are presented in this study. The synthetic superensemble (SSE) used follows the a... Improvements that can be attained in seasonal climate predictions in various parts of Africa using the multimodel supersensemble scheme are presented in this study. The synthetic superensemble (SSE) used follows the approach originally developed at Florida State University (FSU). The technique takes more advantage of the skill in the climate forecast data sets from atmosphere-ocean general circulation models running at many centres worldwide including the WMO global producing centers (GPCs). The module used in this work drew data sets from the Four versions of FSU coupled model system, seven models from the DEMETER project which is the forerun to the current European Ensembles Forecast System, the NCAR Model, and the Predictive Ocean Atmosphere Model for Australia (POAMA), all making a set of 13 individual models. An archive consisting of monthly simulations of precipitation was available over all the 5 regions of Africa, namely Eastern, Central, Northern, Southern, and Western Africa. The results showed that the SSE forecast for precipitation carries a higher skill compared to each of the member models and the ensemble mean. Relative to the ensemble mean (EM), the SSE provides an improvement of 18% in simulation of season cycle of precipitation climatology. In Eastern Africa, during December-February season, a north-south gradient of precipitation prevails between Tropical East Africa and the sector of the region towards Southern Africa. This regional scale climate pattern is a direct influence of the Intertropical Convergence Zone (ITZC) across the African continent during this time of the year. The SSE emerges with superior skill scores such as lowest root mean square error above the EM and the member models, for example in the prediction of spatial location and precipitation magnitudes that characterize the see-saw precipitation pattern in Eastern Africa. In all parts of Africa, and especially Eastern Africa where seasonal precipitation variability is a frequent cause huge human suffering due to droughts and 展开更多
关键词 AFRICA RAINFALL VARIABILITY Prediction Multimodel Superensemble Synthetic SKILL
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Leaves Based Lubricant Additive Towards Improving Tribological Properties 预览
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作者 Xin Feng Yichao Hu +1 位作者 Zhengfeng Cao Yanqiu Xia 《可再生材料杂志(英文)》 2019年第5期441-449,共9页
Three kinds of crop leaf-surface waxes were extracted from wheat,corn and broomcorn leaves,respectively.The crop leaf-surface waxes as lubricant additives were added to synthetic ester and the friction and wear proper... Three kinds of crop leaf-surface waxes were extracted from wheat,corn and broomcorn leaves,respectively.The crop leaf-surface waxes as lubricant additives were added to synthetic ester and the friction and wear properties of prepared lubricants for steel-aluminum and steel-copper friction pair were investigated in detail.The scanning electron microscopy(SEM)and secondary ion mass spectrometry(SIMS)were employed to explore the friction mechanisms.The results show that crop leaf-surface waxes could successfully reduce the friction and wear of steel-aluminum and steel-copper sliding friction pairs as compared with pure synthetic ester.For example,when the concentration of wheat leaf-surface wax as additive was 2%,the COFs was decreased by 58%;the four additives can be ranked by the anti-wear capability as follows:Corn>Wheat>Glycerol>Broomcorn to steel-aluminum sliding friction pairs.The SIMS spectra of positive and negative ions on the worn surfaces have reduced the exposure of Al and increased short chain ions counts.The good friction reduction and antiwear abilities are attributed to the adsorption or reaction films formed by leafsurface wax on worn surface. 展开更多
关键词 Crop leaf-surface wax green additive synthetic ester tribological property
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Synthetic chromosome evolves the yeast genome
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作者 Fei Teng Wei Li Qi Zhou 《中国科学:生命科学英文版》 SCIE CAS CSCD 2019年第5期708-709,共2页
Genomic structural variations play a critical role in biological function and phenotypic diversity. Although smallscale variations, such as insertion, deletion, and point mutations, have been extensively investigated,... Genomic structural variations play a critical role in biological function and phenotypic diversity. Although smallscale variations, such as insertion, deletion, and point mutations, have been extensively investigated, studies on largescale structural variations such as segmental duplication,inversion, and chromosome-scale variations remain limited.In the recent decade。 展开更多
关键词 LI SYNTHETIC CHROMOSOME evolves the YEAST GENOME FIGURE
ASE萃取-GC-MS/MS法同时测定污泥中12种合成麝香
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作者 陈志冉 崔鹏 《现代化工》 CAS CSCD 北大核心 2019年第10期220-225,229共7页
利用加速溶剂萃取法(ASE)萃取污泥中合成麝香(SMs),石墨化炭黑和佛罗里硅藻土在线净化,经HP-5MS毛细管柱分离,建立了气相色谱-串联质谱法(GC-MS/MS)同时测定污泥中12种SMs残留量的分析方法。结果表明,12种SMs在0. 01~1. 0μg/m L质量浓... 利用加速溶剂萃取法(ASE)萃取污泥中合成麝香(SMs),石墨化炭黑和佛罗里硅藻土在线净化,经HP-5MS毛细管柱分离,建立了气相色谱-串联质谱法(GC-MS/MS)同时测定污泥中12种SMs残留量的分析方法。结果表明,12种SMs在0. 01~1. 0μg/m L质量浓度范围内呈良好线性关系,相关系数(r2)为0. 999 6~0. 999 9;该方法检出限为1. 5~3. 0μg/kg,定量限为5. 0~10. 0μg/kg,回收率为91. 5%~98. 8%,相对标准偏差为0. 9%~2. 8%。老化效应、基质效应对ASE萃取污泥中12种SMs的影响较小。该方法具有检出限低、回收率高、精密度好等特点。 展开更多
关键词 污泥 加速溶剂萃取 气相色谱-串联质谱法 合成 麝香
AIEgens-lightened Functional Polymers:Synthesis,Properties and Applications
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作者 Shi-Yuan Zhou Hai-Bo Wan +3 位作者 Feng Zhou Pei-Yang Gu Qing-Feng Xu Jian-Mei Lu 《高分子科学:英文版》 SCIE CAS CSCD 2019年第4期302-326,I0005共26页
Recently,polymers with aggregation-induced emission(AIE)effects have attracted significant attention due to their broad applications in luminescence sensors,stimuli responsive materials,electroluminescence devices,etc... Recently,polymers with aggregation-induced emission(AIE)effects have attracted significant attention due to their broad applications in luminescence sensors,stimuli responsive materials,electroluminescence devices,etc.In this review,we summarize recent advances concerning AIE polymers.Four types of AIE polymers including end-functionalized polymers,side-chain polymers,main-chain polymers,and other polymers according to the location of AIEgens,are described.Their synthetic preparation,optical property,AIE effects,and applications are also illustrated in this review. 展开更多
关键词 Aggregation-induced EMISSION FUNCTIONAL POLYMERS SYNTHETIC method Application
Super-resolution of geosynchronous synthetic aperture radar images using dialectical GANs
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作者 Yuanhao LI Dongyang AO +2 位作者 Corneliu Octavian DUMITRU Cheng HU Mihai DATCU 《中国科学:信息科学(英文版)》 SCIE EI CSCD 2019年第10期208-210,共3页
Dear editor,The concept of geosynchronous synthetic aperture radar (GEO SAR) system was conceived in an effort to realize a quick observation of emergency disasters (e.g., landslides and earthquakes)[1].The novel GEO ... Dear editor,The concept of geosynchronous synthetic aperture radar (GEO SAR) system was conceived in an effort to realize a quick observation of emergency disasters (e.g., landslides and earthquakes)[1].The novel GEO SAR system has the significant advantages of short-revisit time and large coverage and facilitates the nearly continuous observation of target regions, unlike the currently operatinglow earth orbit (LEO) SARs [2]. 展开更多
关键词 PALSAR image SUPER-RESOLUTION of geosynchronous synthetic APERTURE RADAR images USING DIALECTICAL GANs
How synthetic microfibers end up in food & drinking water 预览
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《中国纺织:英文版》 2019年第5期44-45,共2页
No one sets out to refresh themselves by drinking plastic. But microscopic pollution are in virtually every body of water on Earth. While the debris comes from a number of sources, including food and drink packaging a... No one sets out to refresh themselves by drinking plastic. But microscopic pollution are in virtually every body of water on Earth. While the debris comes from a number of sources, including food and drink packaging and cosmetics, research is pointing to synthetic textile microfibers as a major culprit. Studies show hundreds of thousands of microplastic particles can enter the wa-ter supply just by laundering that polo shirt, midi dress or yoga pants. 展开更多
关键词 SYNTHETIC MICROFIBERS FOOD DRINKING water
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Analysis of ship wake features and extraction of ship motion parameters from SAR images in the Yellow Sea
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作者 Kaiguo FAN Huaguo ZHANG +3 位作者 Jianjun LIANG Peng CHEN Bojian XU Ming ZHANG 《地球科学前沿:英文版》 CSCD 2019年第3期588-595,共8页
The identifying features of ship wakes in synthetic aperture radar (SAR) remote sensing images are of great importance for detecting ships and for extracting ship motion parameters. A statistical analysis was conducte... The identifying features of ship wakes in synthetic aperture radar (SAR) remote sensing images are of great importance for detecting ships and for extracting ship motion parameters. A statistical analysis was conducted on the identifying features of ship wakes in SAR images in the Yellow Sea. In this study, 1091 ship wake sub-images were selected from 327 SAR images in the Yellow Sea near Qingdao. Analysis of the identifying features of ship wakes in SAR images revealed that both turbulent wakes and Kelvin wakes account for the majority of ship wakes, with turbulent wakes occurring approximately four times as frequently as Kelvin wakes. Narrow-V wakes and internal wave wakes were comparatively rare, which is due to the peculiarities of the radar system parameters and marine environments required to observe these wakes. Additionally, we extracted ship motion parameters from four types of ship wakes in the SAR images. Specifically, internal wave wakes in SAR images in the Yellow Sea were also used to extract ship motion parameters. Validation of the extracted parameters indicated that the extraction of these parameters from ship wakes is a viable and accurate approach for the acquisition of ship motion parameters. These results provide a solid foundation for the commercialization of SAR-based technologies for detecting ships and extracting ship motion parameters. 展开更多
关键词 SYNTHETIC APERTURE RADAR remote sensing SHIP WAKE SHIP motion parameter
A SAR imaging method based on generalized minimax-concave penalty
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作者 Zhonghao WEI Bingchen ZHANG Yirong WU 《中国科学:信息科学(英文版)》 SCIE EI CSCD 2019年第2期214-216,共3页
Dear editor,Sparse signal processing offers a framework for synthetic aperture radar(SAR)imaging [1,2].As an efficient tool in sparse signal processing,L1 minimization is often used in the reconstruction of SAR images... Dear editor,Sparse signal processing offers a framework for synthetic aperture radar(SAR)imaging [1,2].As an efficient tool in sparse signal processing,L1 minimization is often used in the reconstruction of SAR images.When implemented in SAR imaging [3-5],L1 minimization offers significant improvement in the properties by suppressing the sidelobes and clutter. 展开更多
关键词 SPARSE signal framework for SYNTHETIC SIGNIFICANT improvement
ASAR波模式数据反演参数误差与海浪条纹清晰度的相关性分析 预览
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作者 曹川川 孙建 张文清 《海洋与湖沼》 CAS CSCD 北大核心 2019年第4期777-787,共11页
欧洲环境卫星-高级合成孔径雷达(Environmental Satellite-Advanced Synthetic ApertureRadar,Envisat-ASAR)波模式数据提供了全球风、浪要素信息,在海浪模式预报与同化方面有重要作用。该数据合成孔径雷达(Synthetic Aperture Radar,S... 欧洲环境卫星-高级合成孔径雷达(Environmental Satellite-Advanced Synthetic ApertureRadar,Envisat-ASAR)波模式数据提供了全球风、浪要素信息,在海浪模式预报与同化方面有重要作用。该数据合成孔径雷达(Synthetic Aperture Radar,SAR)图像普遍存在海浪条纹清晰度不同的现象,但是否影响数据精度尚无定论。本文通过比较2010年NODC(the National Oceanographic Date Center)浮标观测数据和波模式数据,发现经过官方修正后的海浪参数反而具有更大误差。进而通过对比不同条纹清晰度的SAR图像反演参数误差,揭示了ASAR产品海浪参数与浮标测量值之间的误差与海浪条纹清晰度的关系。结果表明:海浪条纹清晰的SAR图像的主波波长和主波周期的反演误差更小,而条纹不清晰SAR图像的有效波高和风速的反演误差更小。通过分析海浪参数对海浪条纹清晰度的敏感性,证实了有效波高和方位向截断波长对SAR图像条纹清晰度的响应最好,波陡次之,与卫星飞行方位角和入射角无关。因此,在反演和修正SAR波模式数据时,考虑图像的条纹清晰度,将会有效提高反演数据的精度。该研究可为高分三号等卫星的波模式数据波浪要素反演精度的提升提供有价值的参考。 展开更多
关键词 Envisat-ASAR(Environmental Satellite-Advanced Synthetic APERTURE Radar)波模式数据 NODC(the National Oceanographic DATE Center)浮标 图像条纹清晰度 误差分析
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Regulation by competition:a hidden layer of gene regulatory network
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作者 Lei Wei Ye Yuan +6 位作者 Tao Hu Shuailin Li Tianrun Cheng Jinzhi Lei Zhen Xie Michael Q.Zhang Xiaowo Wang 《中国电气与电子工程前沿:英文版》 CSCD 2019年第2期110-121,共12页
Background:Molecular competition brings about trade-offs of shared limited resources among the cellular components,and thus introduces a hidden layer of regulatory mechanism by connecting components even without direc... Background:Molecular competition brings about trade-offs of shared limited resources among the cellular components,and thus introduces a hidden layer of regulatory mechanism by connecting components even without direct physical interactions.Several molecular competition scenarios have been observed recently,but there is still a lack of systematic quantitative understanding to reveal the essence of molecular competition.Methods:Here,by abstracting the analogous competition mechanism behind diverse molecular systems,we built a unified coarse-grained competition motif model to systematically integrate experimental evidences in these processes and analyzed general properties shared behind them from steady-state behavior to dynamic responses.Results:We could predict in what molecular environments competition would reveal threshold behavior or display a negative linear dependence.We quantified how competition can shape regulator-target dose-response curve,modulate dynamic response speed,control target expression noise,and introduce correlated fluctuations between targets.Conclusions:This work uncovered the complexity and generality of molecular competition effect as a hidden layer of gene regulatory network,and therefore provided a unified insight and a theoretical framework to understand and employ competition in both natural and synthetic systems. 展开更多
关键词 systems BIOLOGY COMPUTATIONAL modeling molecular COMPETITION REGULATION SYNTHETIC BIOLOGY network MOTIF
Metal-free C3-alkoxycarbonylation of quinoxalin-2(1H)-ones with carbazates as ecofriendly ester sources
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作者 Long-Yong Xie Sha Peng +6 位作者 Tai-Gang Fan Yan-Fang Liu Meng Sun Li-Lin Jiang Xing-Xing Wang Zhong Cao Wei-Min He 《中国科学:化学英文版》 SCIE EI CAS CSCD 2019年第4期460-464,共5页
Quinoxaline-3-carboxylates and analogues are prevalent key structural motifs in bioactive natural products and synthetic drugs.However,the practical protocol for preparation of these motifs from simple raw materials u... Quinoxaline-3-carboxylates and analogues are prevalent key structural motifs in bioactive natural products and synthetic drugs.However,the practical protocol for preparation of these motifs from simple raw materials under mild conditions remains rare.In this article,we report a facile protocol for the efficient preparation of various quinoxaline-3-carbonyl compounds(30 examples,63%–92%)through oxidation coupling of quinoxalin-2(1H)-ones with readily available carbazates(or acyl hydrazines)in the presence of K2S2O8 as an oxidant in metal-and base-free conditions.When tert-butyl carbazate was used as the coupling reagent,the decarboxylation product 3-(tert-butyl)-1-methylquinoxalin-2(1H)-one was obtained.The application of this process into a gram-scale synthesis can be easily accomplished.Mechanistic investigations reveal that the functionalization of quinoxalin-2(1H)-ones via a free-radical pathway. 展开更多
关键词 quinoxalin-2(1H)-ones ALKOXYCARBONYLATION carbazates synthetic methods METAL-FREE
环丙唑醇合成新方法 预览
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作者 李洪 《四川化工》 CAS 2019年第5期20-22,共3页
环丙唑醇是一种优秀的三氮唑类杀菌剂。本文以环丙基甲基酮和对氯氰苄为起始原料经缩合、还原、氧化、环氧化和开环加成五步合成环丙唑醇。该工艺具有收率高、成本低、易于操作、产品质量稳定等优点。
关键词 环丙唑醇 环丙基甲基酮 氢化钠 1 2 4-三氮唑 合成
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The influence of hand hole on the ultimate strength and crack pattern of shield tunnel segment joints by scaled model test
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作者 Shaochun WANG Xi JIANG Yun BAI 《结构与土木工程前沿:英文版》 EI CSCD 2019年第5期1200-1213,共14页
With the shield tunnel going deeper and deeper, the circumferential axial force becomes the governing factor rather than the bending moment. The hand hole acts as a weak point and initial damage in the segment joint e... With the shield tunnel going deeper and deeper, the circumferential axial force becomes the governing factor rather than the bending moment. The hand hole acts as a weak point and initial damage in the segment joint especially when the circumferential axial force is extremely high. Despite the wide application of steel fiber or synthetic fiber in t|ie tunneling, limited researches focus on the structural responses of segment joint with macro structural synthetic fiber (MSSF). In this paper, a 1:2 reduced-scale experiment was conducted to study the structural perfonnance of the segment joint with different types of hand holes under ultra-high axial force. Special attention is paid to failure mode and structural performance (bearing capacity, deformation, cracking, and toughness). Moreover, segment joints with MSSF are also tested to evaluate the effects of MSSF on the failure mode and structural performance of the segment joints. The experiment results show that the hand hole becomes the weakest point of the segment joint under ultra-high axial force. A\/-type crack pattern is always observed before the final failure of the segment joints. Different types and sizes of the hand hole have different degree of influences on the structural behavior of segment joints. The segment joint with MSSF shows higher ultimate bearing capacity and toughness compared to segment joint with common concrete. Besides, the MSSF improves the initial cracking load and anti-spallling resistance of the segment joint. 展开更多
关键词 SHIELD TUNNELING structural synthetic fiber concrete HAND HOLE SEGMENT joint ULTIMATE bearing capacity crack pattern
Micromagnetic simulations on demagnetization processes in anisotropic Nd2Fe14B magnets
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作者 Lei Li Shengzhi Dong +5 位作者 Rui Han Kuikui Song Dong Li Minggang Zhu Wei Li Wei Sun 《中国稀土学报:英文版》 SCIE EI CAS CSCD 2019年第6期628-632,共5页
Individual grains with diverse dimensional parameters were introduced to investigate the magnetization reversals in anisotropic Nd2 Fe14B magnets. The micromagnetic simulations were carried out via Object Oriented Mic... Individual grains with diverse dimensional parameters were introduced to investigate the magnetization reversals in anisotropic Nd2 Fe14B magnets. The micromagnetic simulations were carried out via Object Oriented MicroMagnetic Framework(OOMMF). With the same bottom area and height, analysis results show that the coercive fields for different bottom shapes are of similar values. Designed as a cubic grain,the coercive field presents descending tendency as grain volume ascends. Under constant grain volume,with aspect ratio increasing, the coercive field decreases in the beginning and increases soon. Based on the demagnetization field vector, the effects of bottom shape, grain volume and aspect ratio on the coercive field can be explained. The nucleation point is chosen to discuss. Its synthetic field and reversal field are calculated by parallelogram law and inverse external field equation, respectively. The synthetic field equal to the reversal field is defined as critical field, which always shows the same tendency as the coercive field for all cases of this study. It can be concluded that critical field is qualified to be a reference index to measure the magnitude of coercive field. 展开更多
关键词 MICROMAGNETIC simulation DEMAGNETIZATION FIELD Coercive FIELD SYNTHETIC FIELD CRITICAL FIELD Rare earths
Mutant p53 in cancer therapy-the barrier or the path
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作者 Xiang Zhou Qian Hao Hua Lu 《分子细胞生物学报:英文版》 SCIE CAS CSCD 2019年第4期293-305,共13页
Since wild-type p53 is central for maintaining genomic stability and preventing oncogenesis, its coding gene TP53 is highly mutated in ~50% of human cancers, and its activity is almost abrogated in the rest of cancers... Since wild-type p53 is central for maintaining genomic stability and preventing oncogenesis, its coding gene TP53 is highly mutated in ~50% of human cancers, and its activity is almost abrogated in the rest of cancers. Approximately 80% of p53 mutations are single point mutations with several hotspot mutations. Besides loss of function and dominant-negative effect on the wild-type p53 activity, the hotspot p53 mutants also acquire new oncogenic functions, so-called ‘gain-of-functions’(GOF). Because the GOF of mutant p53 is highly associated with late-stage malignance and drug resistance, these p53 mutants have become hot targets for developing novel cancer therapies. In this essay, we review some recent progresses in better understanding of the role of mutant p53 GOF in chemoresistance and the underlying mechanisms, and discuss the pros and cons of targeting mutant p53 for the development of anti-cancer therapies. 展开更多
关键词 MUTANT p53 GAIN-OF-FUNCTION cancer therapy CHEMORESISTANCE synthetic LETHALITY
Electrochemical Oxidative Csp^3—H/S—H Cross-Coupling with Hydrogen Evolution for Synthesis of Tetrasubstituted Olefins
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作者 Fangling Lu Zengzhuan Yang +4 位作者 Tao Wang Tianhao Wang Yuying Zhang Yong Yuan Aiwen Lei 《中国化学:英文版》 SCIE CAS CSCD 2019年第6期547-551,I0002共6页
Tetrasubstituted olefins are significant scaffolds as they are prevalent in many biologically active compounds and versatile building blocks for organic synthesis. Herein, we report an electrochemical oxidative Csp^3... Tetrasubstituted olefins are significant scaffolds as they are prevalent in many biologically active compounds and versatile building blocks for organic synthesis. Herein, we report an electrochemical oxidative Csp^3—H/S—H cross-coupling reaction, in which various tetrasubstituted olefins were prepared under base-free, transition metal-free, and oxidants-free reaction conditions. 展开更多
关键词 ELECTROCHEMISTRY C-H activation CROSS-COUPLING RADICAL REACTIONS synthetic methods
A Novel Thermomorphic System for Electrocatalytic Diels-Alder Reactions
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作者 Yasushi Imada Naoki Shida +1 位作者 Yohei Okada Kazuhiro Chiba 《中国化学:英文版》 SCIE CAS CSCD 2019年第6期557-560,共4页
The discovery that lithium bis(trifluoromethane)sulfonamide (LiTFSI)/1-nitropropane (PrNO2) solution functions as a less polar alternative to lithium perchlorate (LiClO4)/nitromethane (MeNO2) solution has led to the d... The discovery that lithium bis(trifluoromethane)sulfonamide (LiTFSI)/1-nitropropane (PrNO2) solution functions as a less polar alternative to lithium perchlorate (LiClO4)/nitromethane (MeNO2) solution has led to the development of a novel thermomorphic system for electrocatalytic Diels-Alder reactions. Methyl cyclohexane (Me-c-Hex) can form a monophasic condition with LiTFSI/PrNO2 solution at room temperature, enabling the use of hydrophobic dienophiles. After the electrochemical reaction, a biphasic condition can be formed at –50℃, where the cycloadducts are selectively recovered from the upper Me-c-Hex phase and the remaining lower LiTFSI/PrNO2 solution can be reused. 展开更多
关键词 thermomorphic SYSTEM electro CATALYTIC DIELS-ALDER reaction ELECTROCHEMISTRY synthetic methods CYCLOADDITION
Transition Periods Between Sea Ice Concentration and Sea Surface Air Temperature in the Arctic Revealed by an Abnormal Running Correlation 预览
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作者 JI Xupeng ZHAO Jinping 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2019年第3期633-642,共10页
This study used the synthetic running correlation coefficient calculation method to calculate the running correlation coefficients between the daily sea ice concentration(SIC) and sea surface air temperature(SSAT) in ... This study used the synthetic running correlation coefficient calculation method to calculate the running correlation coefficients between the daily sea ice concentration(SIC) and sea surface air temperature(SSAT) in the Beaufort-Chukchi-East Siberian-Laptev Sea(BCEL Sea), Kara Sea and southern Chukchi Sea, with an aim to understand and measure the seasonally occurring changes in the Arctic climate system. The similarities and differences among these three regions were also discussed. There are periods in spring and autumn when the changes in SIC and SSAT are not synchronized, which is a result of the seasonally occurring variation in the climate system. These periods are referred to as transition periods. Spring transition periods can be found in all three regions, and the start and end dates of these periods have advancing trends. The multiyear average duration of the spring transition periods in the BCEL Sea, Kara Sea and southern Chukchi Sea is 74 days, 57 days and 34 days, respectively. In autumn, transition periods exist in only the southern Chukchi Sea, with a multiyear average duration of only 16 days. Moreover, in the Kara Sea, positive correlation events can be found in some years, which are caused by weather time scale processes. 展开更多
关键词 ARCTIC SEA ice CONCENTRATION SEA surface air temperature synthetic running CORRELATION coefficient transition period
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Joint Monitoring of Ground and Sky for Cereal Crops Based on Scatterometer Measurement and ASAR Images 预览
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作者 Lei He Feng-Jin Xiao 《电子科技学刊:英文版》 CAS CSCD 2019年第3期278-288,共11页
The joint monitoring of the ground and sky for cereal crops based on microwave data has become a popular method for researches on earth surface objects. Focused on the sensitivity of backscatter from the scatterometer... The joint monitoring of the ground and sky for cereal crops based on microwave data has become a popular method for researches on earth surface objects. Focused on the sensitivity of backscatter from the scatterometer measurement and advanced synthetic aperture radar (ASAR) images to cereal parameters of rice, nine acquisitions, including rice parameters related eco-physiological variables and scattering coefficients, have been carried over the paddy field corresponding to rice growth stages. This paper analyzes the relationship between the corresponding backscatter to the cereal parameters based on the measurement at the interesting bands, polarizations, and incidence angels. Further, a modified water cloud model is built based on the ground measurement and advanced integrated equation model (AIEM), and then cereal parameters from ASAR images are retrieved and verified. The research results show that the sensitivity of backscatter to cereals from the sensor of the radar scatterometer could be helpful to build the retrieve model for synthetic aperture radar (SAR) images, which can achieve the scientific goals of the joint monitoring of ground and sky for cereal crops. 展开更多
关键词 Backscatter CEREAL JOINT MONITORING SCATTEROMETER synthetic APERTURE radar(SAR)
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