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FLUORENE-BRIDGED POLYPHENYLQUINOXALINES WITH HIGH SOLUBILITY AND GOOD THERMAL STABILITY:SYNTHESIS AND PROPERTIES

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Chinese Journal of Polymer Science 2010年第6期28卷 971-980页

作者： Cheng Li Zhuo Li Jin-gang Liu hai-xia Yang Shi-yong Yang Laboratory of Advanced Polymer Materials Institute of ChemistryChinese Academy of SciencesBeijing 100190China

A novel fluorene-bridged tetraketone monomer,9,9-bis[(4-benzilyloxy)phenyl]fluorene(FLTK) was synthesized and *** tetraketone was polymerized with various aromatic tetraamines to afford a series of polyphenylquinoxalines(PPQs).The obtained polymers were found to be soluble in common organic solvents such as N-methyl-2-pyrrolidone(NMP),chloroform and *** and tough PPQ films obtained by spin-casting their NMP solutions exhibited tensile strengths higher than 60 *** films also demonstrated good thermal stability up to 500℃in nitrogen and glass transition temperatures higher than 280℃.In addition,the PPQ films exhibited good hydrolytic stability. High surface and volume resistivity retentions were achieved for the films after immersion or boiling in water for 24 h.

关键词： Polyphenylquinoxaline Fluorene Solubility Thermal stability Hydrolytic stability

Difference in normal corneal thickness and curvature between Mongolian and Han nationalities

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International Journal of Ophthalmology(English edition) 2015年第2期8卷 399-402页

作者： hai-xia Zhao Li Zhang Wen-Ying Guan Department of Ophthalmology the Affiliated Hospital of Inner Monogolia Medical University

AIM: To investigate the differences in central corneal thickness(CCT) and curvature in myopic patients with different genders between Mongolian and Han nationalities in the Inner Mongolia ***: Patients with myopia, among whom 122cases(244 eyes) were Mongolian and 150 cases(300eyes) were Han, were selected. Pentacam was used to measure the corneal curvature, whereas CCT was determined by Pentacam, Orbscan and ultrasound ***: Comparisons of the curvature of men and women in Mongolia showed a significant difference(P <0.05) by comparing of the CCT values measured by three methods in Han and Mongolian in Inner Mongolia, we can draw a conclusion that the CCT values measured by Pentacam are less than the values by Orbscan and ultrasound pachymetry, and there are statistically significant difference in CCT measurement among the instruments except between the Orbscan and ultrasound pachymetry. The CCT values of Mongolians are more than Han people, and the analysis exhibited statistical significance. The CCT values measured by Orbscan in Mongolia of women are more than men, the difference showed statistical ***: Corneal curvature in Mongolian females was significantly higher than that in males. However, no significant difference was observed among Han males and females. The CCT values of Mongolian females were higher than those of males. The normal CCT values measured by Pentacam in Mongolian myopic patients were smaller than those obtained by Orbscan or ultrasound. The normal CCT values of Mongolian patients with myopia were higher than those reported for domestic people.

关键词： pentacam orbscan mongolian nationality Han nationality gender central corneal thickness

Analysis of oxide layer structure in nitrided grain-oriented silicon steel

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International Journal of Minerals,Metallurgy and Materials 2019年第12期26卷 1531-1538页

作者： xiao-long Wu xia Li Ping Yang Zhi-wei Jia hai-li Zhang School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Iron and Steel Research Institute Angang GroupAnshan 114000China

The production of low-temperature reheated grain-oriented silicon steel is mainly based on the acquired inhibitor *** to the additional nitriding process,a high nitrogen content exists in the oxide layer,which changes the structure of the oxide *** this study,the structure of the surface oxide layer after nitriding was analyzed by scanning electron microscopy(SEM),electron back-scattered diffraction(EBSD),glow discharge spectrometry(GDS),and X-ray diffraction(XRD).The size and orientation of ferritic grains in the oxide layer were characterized,and the distribution characteristics of the key elements along the thickness direction were *** results show that the oxide layer of the steel sample mainly comprised particles of Fe2SiO4 and spherical and lamellar SiO2,and Fe4N and fcc-Fe phases were also ***,the size and orientation of ferritic grains in the oxide layer were different from those of coarse matrix ferritic grains beneath the oxide layer;however,some ferritic grains exhibited same orientations as those in the neighboring *** nitrogen content was detected in the oxide layer than that in the matrix beneath the oxide *** form of nitrogen enrichment in the oxide layer was analyzed,and the growth mechanism of ferritic grains during the oxide layer formation is proposed.

关键词： grain-oriented silicon steel decarburization annealing oxide layer ferritic grains silica

Aerodynamics of indirect thrust measurement by the impulse method

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Acta Mechanica Sinica 2011年第2期27卷 152-163页

作者： Cheng-Kang Wu hai-Xing Wang xian Meng Xi Chen Wen-xia Pan PanInstitute of Mechanics Chinese Academy of Sciences 100190 Beijing China School of Astronautics Beijing University of Aeronautics and Astronautics 100191 Beijing China Department of Engineering Mechanics Tsinghua University 100084 Beijing China

The aerodynamic aspects of indirect thrust measurement by the impulse method have been studied both experimentally and numerically. The underlying basic aerodynamic principle is outlined, the phenomena in subsonic, supersonic and arc-heated jets are explored, and factors affecting the accuracy of the method are studied and discussed. Results show that the impulse method is reliable for indirect thrust measurement if certain basic requirements are met, and a simple guideline for its proper application is given.

关键词： Thrust measurement Impulse method Aerodynamic features Cold jet Arc-heated jet

Localization and Dynamic Change of Saponin in Vegetative Organs of Polygala tenuifolia

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Journal of Integrative Plant Biology 2009年第6期51卷 529-536页

作者： Hong-Mei Teng Min-Feng Fang xia Cai Zheng-hai Hu Key Laboratory of Resource Biology and Biotechnology in West China (Northwest University) Ministry of Education Xi'an 710069 China Department of Life Sciences Yuncheng Coflege Yuncheng 044000 China

Anatomical, histochemical and phytochemical methods were used to investigate the structure, localization and dynamic changes of total saponin and senegenin of vegetative organs in Polygala tenuifolia Willd. Histochemical localization results showed that saponin accumulated mainly in parenchyma cells of vegetative organs. The phytochemical results also showed that the saponin accumulated in the vegetative organs of P. tenuifolia, with higher content in roots and lower content in the aerial parts that included stems and leaves. The saponin content and dry weight of the vegetative organs of P. tenuifolia had dynamic variance at the developmental stages and all reached the highest level in the post-fruit period. Hence, the roots and aerial parts should be gathered in August to make full use of the plant. As the root is the main medicinal organ of P. tenuifolia, the content of total saponin and senegenin of different aged and different parts of the root were determined. The content of total saponin and senegenin exhibited a sustained decreasing trend with increasing root age; therefore, the annual roots had high quality. The content of total saponin and senegenin in different parts of the root showed obvious variation. The content in the ＂skin areas＂ was much higher than that of xylem. The results offer a theoretical basis for determining the appropriate harvesting stage and a reasonable harvest of P. tenuifolia.

关键词： dynamic change localization Polygala tenuifolia saponin senegenin structure vegetative organs.

Localization and Dynamic Change of Saikosaponin in Root of Bupleurum chinense

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Journal of Integrative Plant Biology 2008年第8期50卷 951-957页

作者： Ling-Ling Tan xia Cai Zheng-hai Hu Xi-Lu Ni Key Laboratory of Resource Biology and Biotechnology in West China (Northwest University) Ministry of Education Xi'an 710069 China Ningxia Forestry Institute Yinchuan 750004 China

Anatomical, histochemical and phytochemical methods were used to investigate the structure, the localization and content changes of total saikosaponin and saikosaponin-a of the roots of Bupleurum chinense DC. at different developmental stages. Results showed that saikosaponin was mainly distributed in pericycle and primary phloem in the young root; but in the mature root, it was mainly distributed in vascular cambium and secondary phloem. During the whole growth period from the pre-blossom, blossom, fruit, and fruit mature periods until the pre-withering period, it was in the fruit mature period that both the total saikosaponin content and the saikosaponin-a content reached the highest level. So the last 20 d of October was considered as the right collecting season for the drug of B. chinense. In addition, the quality of 1-year-old drug was better than that of 2-year-old drug due to its higher saikosaponin content. On the other hand, judging from the external characteristics of the drug, the one with an acerose taproot and more lateral roots was of better quality. The results offered theoretical bases for selecting medicinal material of high quality and determining the most appropriate harvesting stage and part of B. chinense.

关键词： Bupleurum chinense content dynamic change localization saikosaponin-a structure of root total saikosaponin

ShadowEth： Private Smart Contract on Public Blockchain

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Journal of Computer Science & Technology 2018年第3期33卷 542-556页

作者： Rui Yuan Yu-Bin xia hai-Bo Chen Bin-Yu Zang Jan Xie Institute of Parallel and Distributed Systems Shanghai Jiao Tong University Shanghai 200240 China Cryptape Inc. Hangzhou 310007 China

Blockchain is becoming popular as a distributed and reliable ledger which allows distrustful parties to transact safely without trusting third parties. Emerging blockchain systems like Ethereum support smart contracts where miners can run arbitrary user-defined programs. However, one of the biggest concerns about the blockchain and the smart contract is privacy, since all the transactions on the chain are exposed to the public. In this paper, we present ShadowEth, a system that leverages hardware enclave to ensure the confidentiality of smart contracts while keeping the integrity and availability based on existing public blockchains like Ethereum. ShadowEth establishes a confidential and secure platform protected by trusted execution environment （TEE） off the public blockchain for the execution and storage of private contracts. It only puts the process of verification on the blockchain. We provide a design of our system including a protocol of the cryptographic communication and verification and show the applicability and feasibility of ShadowEth by various case studies. We implement a prototype using the Intel SGX on the Ethereum network and analyze the security and availability of the system.

关键词： blockchain smart contract privacy trusted execution environment hardware-enclave

Facile preparation of Fe/N-based biomass porous carbon composite towards enhancing the thermal decomposition of DAP-4

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Defence Technology（防务技术） 2024年第1期31卷 288-294页

作者： Er-hai An xiao-xia Li Cun-juan Yu Ying-xin Tan Zi-jun Fan Qing-xia Li Peng Deng Xiong Cao School of Environment and Safety Engineering North University of ChinaTaiyuan030051PR China College of Safety and Emergency Management Engineering Taiyuan University of Science and TechnologyTaiyuan030024PR China

Fe/N-based biomass porous carbon composite(Fe/N-p Carbon) was prepared by a facile high-temperature carbonization method from biomass,and the effect of Fe/N-p Carbon on the thermal decomposition of energetic molecular perovskite-based material DAP-4 was *** porous carbonaceous materials was considered as the micro/nano support layers for in situ deposition of Fe/N ***/Np Carbon was prepared simply by the high-temperature carbonization *** was found that it showed the inherent catalysis properties for thermal decomposition of *** heat release of DAP-4/Fe/N-p Carbon by DSC curves tested had increased slightly,compared from DAP-4/Fe/N-p *** decomposition temperature peak of DAP-4 at the presence of Fe/N-p Carbon had reduced by 79°C from384.4°C(pure DAP-4) to 305.4°C(DAP-4/Fe/N-p Carbon-3).The apparent activation energy of DAP-4thermal decomposition also had decreased by 29.1 J/*** possible catalytic decomposition mechanism of DAP-4 with Fe/N-p Carbon was proposed.

关键词： Biomass materials Porous carbon DAP-4 Thermal decomposition Facile method

Cu-Doped KNSBN Single Crystals

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Chinese Physics Letters 1996年第10期13卷 757-760页

作者： xia hai-rui WANG Cheng-jian CHEN Huan-chu YANG Zhao-he Department of Physics Shandong UniversityJihan 250100 Institute of Crystal Materials Shandong UniversityJihan 250100

The preparation procedure, the transmissivity, and the two-wave coupling properties of coppermodified potassium sodium strontium barium niobate (KNSBN) crystals are reported. The Cu ions doped in KNSBN can form two deep energy levels. This means that they are able to act as centers for free charge carrier stimulation and recombination. The two-wave coupling gain coefficient of KNSBN: Cu is two times larger than that of KNSBN. The photorefractive sensitivity of KNSBN: Cu is estimated to be in the order of 10^(-3)cm^(2)/J.

关键词： KNSBN coupling potassium