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External calibrator in global signal experiment for detection of the epoch of reionization

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Research in Astronomy and Astrophysics 2021年第10期21卷 17-26页

作者： Yan Huang Xiang-Ping Wu Quan Guo Qian Zheng Bi-Ying Li Huan-Yuan shan ke-jia Lee Hai-Guang Xu National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China School of Physics and Astronomy Shanghai Jiao Tong University800 Dongchuan RoadShanghai 200240China

We present a conceptual design study of external calibrators in the 21 cm experiment towards detecting the globally averaged radiation of the epoch of reionization(EoR).Employment of external calibrator instead of internal calibrator commonly used in current EoR experiments allows removing instrumental effects such as beam pattern,receiver gain and instability of the system if the conventional three-position switch measurements are implemented in a short time ***,in the new design the antenna system is placed in an underground anechoic chamber with an open/closing ceiling to maximally reduce the environmental effect such as RFI and ground radiation/*** appears that three of the four external calibrators proposed in this paper,including two indoor artificial transmitters and one outdoor celestial radiation(the Galactic polarization),fail to meet our *** motion of the Galactic diffuse emission turns out to be the most probable source as an external calibrator,for which we have discussed the observational strategy and the algorithm of extracting the EoR signal.

关键词： cosmology:observations dark ages reionization radio lines:general methods:observational

Robust and High-Wettability Pristine Poly(ether ether ketone) Nanofiber Separator for Heat-Resistant and Safe Lithium-Ion Battery

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Chinese Journal of Polymer Science 2023年第12期41卷 1937-1946,I0009页

作者： Xin-ke Dai Feng-shan Yu jia-Wei Wen Chun-Xia Wang Xin-Long Ma Wang Yang Guo-Yong Huang Hai-Mu Ye College of New Energy and Materials China University of PetroleumBeijing 102249China State key Laboratory of Heavy Oil Processing China University of PetroleumBeijing 102249China

Separator is a pivotal component of lithium-ion batteries(LIBs)and determines the electrochemical performance and ***,with the increase in energy density and application scenarios,commercial polyolefin separators are increasingly unable to undertake heavy responsibility of battery safety ***,a new kind of nanofiber separator based on poly(ether ether ketone)(PEEK)with excellent thermal stability,self-extinguishing,and superior electrochemical properties is *** inheritance of intrinsic properties from raw PEEK materials and optimized hot-pressing operation endows the separator with high robustness and wettability,showing tensile strength of 15.8 MPa and a contact angle of 17.2°.The high thermal stability of PEEK can ensure the separator to preserve the structural integrity and microstructure at temperatures beyond 300℃,and the excellent self-extinguishing peculiarity of PEEK capacitates the high safety of ***,benefitting from high porosity and polar surface,the PEEK separator shows high electrolyte uptake of 245.5%and exhibits a wider electrochemical window and faster lithium-ion transport number than commercial polyolefin ***,cells assembled with PEEK separator display better performance than the ones with PE separator,and the PEEK LIB has been successfully used to light up a lamp at a high temperature of 150℃.

关键词： Separator Lithium-ion battery Heat-resistance PEEK

An insoluble polysaccharide from the sclerotium of Poria cocos improves hyperglycemia, hyperlipidemia and hepatic steatosis in ob/ob mice via modulation of gut microbiota

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Chinese Journal of Natural Medicines 2019年第1期17卷 3-14页

作者： SUN shan-shan WANG Kai MA ke BAO Li LIU Hong-Wei School of Life Sciences University of Science and Technology of China State key Laboratory of Mycology Institute of MicrobiologyChinese Academy of Sciences University of Chinese Academy of Sciences

Metabolic syndrome characterized by obesity, hyperglycemia and liver steatosis is becoming prevalent all over the world. Herein, a water insoluble polysaccharide(WIP) was isolated and identified from the sclerotium of Poria cocos, a widely used Traditional Chinese Medicine. WIP was confirmed to be a(1-3)-β-D-glucan with an average Mw of 4.486 × 10~6 Da by NMR and SEC-RI-MALLS analyses. Furthermore, oral treatment with WIP from P. cocos significantly improved glucose and lipid metabolism and alleviated hepatic steatosis in ob/ob mice. 16 S DNA sequencing analysis of cecum content from WIP-treated mice indicated the increase of butyrate-producing bacteria Lachnospiracea, Clostridium. It was also observed that WIP treatment elevated the level of butyrate in gut, improved the gut mucosal integrity and activated the intestinal PPAR-γ pathway. Fecal transplantation experiments definitely confirmed the causative role of gut microbiota in mediating the benefits of WIP. It is the first report that the water insoluble polysaccharide from the sclerotium of P. cocos modulates gut microbiota to improve hyperglycemia and hyperlipidemia. Thereby, WIP from P. cocos, as a prebiotic, has the potential for the prevention or cure of metabolic diseases and may elucidate new mechanism for the efficacies of this traditional herbal medicine on the regulation of lipid and glucose metabolism.

关键词： Poria cocos Water insoluble polysaccharide Metabolic syndrome Prebiotics Gut microbiota

SR-AFU: super-resolution network using adaptive frequency component upsampling and multi-resolution features

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Frontiers of Computer Science 2023年第1期17卷 123-132页

作者： ke-jia CHEN Mingyu WU Yibo ZHANG Zhiwei CHEN School of Computer Science Nanjing University of Posts and TelecommunicationsNanjing 210023China jiangsu key Laboratory of Big Data Security&Intelligent Processing Nanjing University of Posts and TelecommunicationsNanjing 210023China College of Telecommunications and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China

Image super-resolution (SR) is one of the classic computer vision tasks. This paper proposes a super-resolution network based on adaptive frequency component upsampling, named SR-AFU. The network is composed of multiple cascaded dilated convolution residual blocks (CDCRB) to extract multi-resolution features representing image semantics, and multiple multi-size convolutional upsampling blocks (MCUB) to adaptively upsample different frequency components using CDCRB features. The paper also defines a new loss function based on the discrete wavelet transform, making the reconstructed SR images closer to human perception. Experiments on the benchmark datasets show that SR-AFU has higher peak signal to noise ratio (PSNR), significantly faster training speed and more realistic visual effects compared with the existing methods.

关键词： super-resolution multi-resolution features adaptive frequency upsampling wavelet transformation

Rhinogobius immaculatus, a new species of freshwater goby (Teleostei Gobiidae) from the Qiantang River, China

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Zoological Research 2018年第6期39卷 396-405页

作者： Fan Li shan Li jia-Kuan Chen Institute of Biodiversity Science Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering Fudan UniversityShanghai 200433 China shanghai Ocean University Shanghai 200090 China shanghai Natural History Museum Branch of Shanghai Science & Technology Museum Shanghai 200041 China

A new freshwater goby, Rhinogobius immaculatus sp. nov., is described here from the Qiantang River in China. It is distinguished from all congeners by the following combination of characters： second dorsal-fin rays I, 7-9; anal-fin rays I, 6-8; pectoral-fin rays 14-15; longitudinal scales 29-31; transverse scales 7-9; predorsal scales 2-5; vertebrae 27 （rarely 28）; preopercular canal absent or with two pores; a red oblique stripe below eye in males; branchiostegal membrane mostly reddish-orange, with 3-6 irregular discrete or connected red blotches on posterior branchiostegal membrane and lower operculum in males; caudal-fin base with a median black spot; and no black blotch on anterior part of first dorsal fin in males.

关键词： Gobiidae Rhinogobius New species Qiantang River China

WATuning:A Workload-Aware Tuning System with Attention-Based Deep Reinforcement Learning

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Journal of Computer Science & Technology 2021年第4期36卷 741-761页

作者： jia-ke Ge Yan-Feng Chai Yun-Peng Chai key Laboratory of Data Engineering and Knowledge Engineering of Ministry of Education Renmin University of China Beijing 100872China School of Information Renmin University of ChinaBeijing 100872China College of Computer Science and Technology Taiyuan University of Science and TechnologyTaiyuan 030027China

Configuration tuning is essential to optimize the performance of systems(e.g.,databases,key-value stores).High performance usually indicates high throughput and low *** present,most of the tuning tasks of systems are performed artificially(e.g.,by database administrators),but it is hard for them to achieve high performance through tuning in various types of systems and in various *** recent years,there have been some studies on tuning traditional database systems,but all these methods have some *** this article,we put forward a tuning system based on attention-based deep reinforcement learning named WATuning,which can adapt to the changes of workload characteristics and optimize the system performance efficiently and ***,we design the core algorithm named ATT-Tune for WATuning to achieve the tuning task of *** algorithm uses workload characteristics to generate a weight matrix and acts on the internal metrics of systems,and then ATT-Tune uses the internal metrics with weight values assigned to select the appropriate ***,WATuning can generate multiple instance models according to the change of the workload so that it can complete targeted recommendation services for different types of ***,WATuning can also dynamically fine-tune itself according to the constantly changing workload in practical applications so that it can better fit to the actual environment to make *** experimental results show that the throughput and the latency of WATuning are improved by 52.6%and decreased by 31%,respectively,compared with the throughput and the latency of CDBTune which is an existing optimal tuning method.

关键词： attention mechanism auto-tuning system reinforcement learning(RL) workload-aware

Type Synthesis of 1T2R Parallel Mechanisms Using Structure Coupling-Reducing Method

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Chinese Journal of Mechanical Engineering 2019年第5期32卷 70-79页

作者： Haitao Liu ke Xu Huiping Shen Xianlei shan Tingli Yang key Laboratory of Mechanism Theory and Equipment Design Ministry of EducationTianjin UniversityTianjin 300350China School of Mechanical Engineering Changzhou UniversityChangzhou 213164China

Direct kinematics with analytic solutions is critical to the real-time control of parallel ***,the type synthesis of a mechanism having explicit form of forward kinematics has become a topic of *** on this purpose,this paper deals with the type synthesis of 1T2R parallel mechanisms by investigating the topological structure coupling-reducing of the 3UPS&UP parallel *** the aid of the theory of mechanism topology,the analysis of the topological characteristics of the 3UPS&UP parallel mechanism is presented,which shows that there are highly coupled motions and constraints amongst the limbs of the *** methods for structure coupling-reducing of the 3UPS&UP parallel mechanism are proposed,resulting in eight new types of 1T2R parallel mechanisms with one or zero coupling *** obtained parallel mechanism is taken as an example to demonstrate that a mechanism with zero coupling degree has an explicit form for forward *** process of type synthesis is in the order of permutation and combination;therefore,there are no *** method is also appli cable to other configurations,and novel topological structures having simple forward kinematics can be obtained from an original mechanism via this method.

关键词： Type synthesis Structure coupling-reducing Coupling degree Parallel mechanism

Effect of temperature on the passivation behavior of steel rebar

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International Journal of Minerals,Metallurgy and Materials 2014年第5期21卷 455-461页

作者： shan-meng Chen Bei Cao Yin-shun Wu ke Ma School of Materials Science and Engineering University of Science and Technology Beijing

Steel rebar normally forms an oxide or rusty skin before it is embedded into concrete and the passivation properties of this skin will be heavily influenced by temperature. To study the effect of temperature on the passivation properties of steel rebar under different surface conditions, we conducted scanning electron microscopy （SEM） observations and electrochemical measurements, such as measurements of the free corrosion potential and polarization curves of HPB235 steel rebar. These measurements identified three kinds of surfaces： polished, oxide skin, and rusty skin. Our results show that the passivation properties of all the surface types decrease with the increase of temperature. Temperature has the greatest effect on the rusty-skin rebar and least effect on the polished steel rebar, because of cracks and crevices on the mill scale on the steel rebar＇s surface. The rusty-skin rebar exhibits the highest corrosion rate because crevice corrosion can accelerate the corrosion of the steel rehar, particularly at high temperature. The results also indicate that the threshold temperatures of passivation for the oxide-skin rebar and the rusty-skin rebar are 37℃and 20℃, respectively.

关键词： steel rebar steel corrosion passivation temperature

Chlorobenzenes in waterweeds from the Xijiang River (Guangdong section) of the Pearl River

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Journal of Environmental Sciences 2007年第10期19卷 1171-1177页

作者： DU Qing-ping jia Xiao-shan HUANG Cai-na Faculty of Environmental Science and Engineering Guangdong University of Technology Guangzhou 510006 China School of Environmental Science and Engineering Sun Yat-sen University Guangzhou 510275 China

The Xijiang River is the major source of water for about 4.5 millions of urban population and 28.7 millions of rural population. The water quality is very important for the health of the rural population. The concentration and distribution of chlorobenzenes （CBs） in both water and waterweeds collected from 4 stations in the Xijiang River （Gangdong section） of the Pearl River in April and November were determined. The result showed that nearly every congener of CBs was detected. The total contents of CBs （ZCBs） in the river water ranged from 111.1 to 360.0 ng/L in April and from 151.9 to 481.7 ng/L in November, respectively. The pollution level of CBs in the water in April was higher than that in November. The contents of ZCBs in waterweeds ranged from 13.53×10^2μg/g to 38.27×10^2μg/g dry weight （dw）. There was no significant difference between April and November in waterweeds. The distribution of CBs in roots, caulis, and leaves of Vallisneria spiralis L. showed different patterns. The leaves mainly contained low-molecular-weight CBs （DCBs）, whereas the roots accumulated more PCBs and HCBs. The average lgBCFlip （bioconcentration factor） of CBs ranged from 0.64 to 3.57 in the waterweeds. The spatial distribution character of CBs in the Xijiang River was： Fengkai County 〈 Yunan County 〈 Yun＇an County 〈 Gaoyao County according to the ZCBs, and the pollution deteriorated from the upstream to the downstream of the Xijiang River. Further analysis demonstrated that the discharge of waste containing CBs may be the main source of CBs pollution in the Xijiang River .

关键词： chlorobenzenes pollution water water weeds distribution bioconcentration factor