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Synthesis of novel 15-membered macrolide derivatives

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Chinese Chemical Letters 2008年第4期19卷 409-411页

作者： Rui Qing xian shu Tao Ma Bo Jiao School of Pharmacy Shandong UniversityJinan 250012China

In order to develop new antibiotics effective against resistant bacteria,a series of novel 15-membered macrolide derivatives were designed and synthesized by the modification of hydroxyl groups at C-11,C-12 and C-4＂ ... 详细信息

关键词： Macrolide Azithromycin derivatives Synthesis 4"-Carbamate derivatives

Isolation and characterization of the trehalose-6-phosphate synthase gene from Locusta migratoria manilensis

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Insect Science 2009年第4期16卷 287-295页

作者： shu-Yan Cui Yu-xian Xia 2008-09-16 School of Bioengineering Chongqing University Chongqing Engineering Research Center for Fungal Insecticide The Key Laboratory of Gene Function and Expression Regulation Chongqing China

Trehalose plays an important role in protecting organisms from various stresses. Trehalose-6-phosphate synthase （TPS） is the key enzyme in trehalose synthesis, but in insects only a few TPS genes have been identified and their function has not been well characterized. To better understand the function of TPS in insects, a complete TPS complementary DNA （eDNA） clone was obtained from the fat body of the locust Locusta migratoria manilensis （GenBank accession number： EU131894）. The full-length cDNA is 2 806 bp, including an open reading frame of 2 442 bp, which encodes an 813 amino acids protein with a calculated molecular weight of 91 976 Daltons and an isoelectric point of 6.14. The deduced amino acid sequence is highly similar to other published insect TPS and its C-terminal also has a region homologous to trehalose phosphate phsophatase （TPP）. Semi-quantitative analysis indicated that the TPS transcript was expressed not only in fat body, but also in gut, hemolymph and leg muscle. These data may facilitate studies of TPS function in insects and improve our understanding of trehalose metabolism.

关键词： cloning Locusta migratoria-manilensis trehalose-6-phosphate synthase,RT-PCR

Application of Exp-function Method to Generalized Burgers-Fisher Equation

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Acta Mathematicae Applicatae Sinica 2010年第4期26卷 669-676页

作者： Zhen-hui xu Da-quan xian Applied Technology College Southwest University of Science and TechnologyMianyang 621010china School of Science Southwest University of Science and TechnologyMianyang 621010china

In this paper,the Exp-function method is used to construct exact solitary wave solutions for the generalized Burgers-Fisher equation with nonlinear terms of any *** the aid of Maple computation,we obtain many new and more general exact solitary wave solutions expressed by various exponential and hyperbolic *** results can successfully recover previously known solitary wave solutions that have been found by the tanh-function method and other more sophisticated methods.

关键词： Generalized Burgers-Fisher equation Exp-function method solitary solution

Sound absorption coefficient optimization of gradient sintered metal fiber felts

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Science China(Technological Sciences) 2016年第5期59卷 699-708页

作者： MENG Han REN shu Wei XIN Feng xian LU Tian Jian MOE Key Laboratory for Multifunctional Materials and Structures Xi'an Jiaotong University State Key Laboratory for Strength and Vibration of Mechanical Structures Xi'an Jiaotong University

An optimization method for sound absorption of gradient(multi-layered) sintered metal fiber felts is presented. The theoretical model based on dynamic flow resistivity is selected to calculate the sound absorption coefficient of the sintered metal fiber felts since it only requires three key morphological parameters: fiber diameter, porosity and layer thickness. The model predictions agree well with experimental measurements. Objective functions and constraint conditions are then set up to optimize separately the distribution of porosity, fiber diameter, and simultaneous porosity and fiber diameter in the metal fiber. The optimization problem for either a sole frequency or a pre-specified frequency range is solved using a genetic algorithm method. Acoustic performance comparison between optimized and non-optimized metal fibers is presented to confirm the effectiveness of the optimization method. Gradient sintered metal fiber felts hold great potential for noise control applications particularly when stringent restriction is placed on the total volume and/or weight of sound absorbing material allowed to use.

关键词： sound absorption optimization sintered metal fiber felts

Importance of storage time in mesophilic anaerobic digestion of food waste

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Journal of Environmental Sciences 2016年第7期28卷 76-83页

作者： Fan Lü xian xu Liming Shao Pinjing He State Key Laboratory of Pollution Control and Resource Reuses Tongji University Institute of Waste Treatment and Reclamation Tongji University Centre for the Technology Research and Training on Household Waste in Small Towns & Rural Area Ministry of Housing and Urban–Rural Development of PR China

Storage was used as a pretreatment to enhance the methanization performance of mesophilic anaerobic digestion of food waste. Food wastes were separately stored for 0, 1,2, 3, 4, 5, 7, and 12 days, and then fed into a methanogenic reactor for a biochemical methane potential（BMP） test lasting up to 60 days. Relative to the methane production of food waste stored for 0–1 day（285–308 m L/g-added volatile solids（VSadded））, that after2–4 days and after 5–12 days of storage increased to 418–530 and 618–696 m L/g-VSadded,respectively. The efficiency of hydrolysis and acidification of pre-stored food waste in the methanization reactors increased with storage time. The characteristics of stored waste suggest that methane production was not correlated with the total hydrolysis efficiency of organics in pre-stored food waste but was positively correlated with the storage time and acidification level of the waste. From the results, we recommend 5–7 days of storage of food waste in anaerobic digestion treatment plants.

关键词： Food waste Bio-pretreatment Storage Fermentation Biochemical methane potential Hydrolysates

Buckling of Cassini Oval Pressure Hulls Subjected to External Pressure

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China Ocean Engineering 2019年第4期33卷 503-508页

作者： TANG Wen-xian WANG Wei-min ZHANG Jian WANG shu-yan Jiangsu Provincial Key Laboratory of Advanced Manufacturing for Marine Mechanical Equipment Jiangsu University of Science and Technology Zhenjiang 212003 China School of Mechanical Engineering Jiangsu University of Science and Technology Zhenjiang 212003 China

The paper focuses on Cassini oval pressure hulls under uniform external pressure. The Cassini oval pressure hull is proposed based on the shape index of Cassini oval. The buckling of a series of Cassini oval pressure hulls with the shape index of 0.09–0.30 and one spherical pressure hull with the diameter of 2 m is devoted. Such hulls are numerically studied in the case of constant volume, material properties, and wall thickness. The results show that Cassini oval pressure hulls with the shape index of 0.10–0.11 can resist about 4% more external pressure than the spherical one. This deviates from the classical mechanics conclusion that spherical shell is the optimal shape for underwater pressure resistant structures.

关键词： pressure hull Cassini oval shell shape index buckling behaviour external pressure

Preparation and Properties of Zirconium Hydrideon the surface of MCM-41 Mesoporous Molecular Sieves

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Chemical Research in Chinese Universities 2001年第4期17卷 426-431页

作者： WANG xu-xu FU xian-zhi LEFEBVRE Frederic BASSET Jean-Marie Research Institute of Photocatalysis Fuzhou UniversityFuzhou 350002P.R.China Laboratoire de Chimie Organometallique de Surface UMR CNRS-CPE 998643Bd dull Novembre 11 Novembre 191869616 Villeurbanne CedexFrance

Zirconium monohydride bonded to the framework oxygen of MCM-41 surface was prepared by the reaction of tetraneopentyl zirconium with MCM-41 surface hydroxyl groups, followed by the hydrogenolysis of the resulted product. The surface hydride was characterized by using infrared spectroscopy, solid-state NMR, elemental analysis, gas-phase chromatography and chemical probing reaction. It was shown that this surface species is stable below 150 ’C and can catalytically crack alkanes into methane and ethane at 100 .

关键词： MCM-41 Zirconium hydride Grafting reaction Catalytic cracking

Markov Jump Processes in Estimating Sharing of Identity by Descent

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Acta Mathematicae Applicatae Sinica 2021年第1期37卷 183-191页

作者： xian CHEN Wei GUO xu-min NI School of Mathematical Sciences Xiamen UniversityXiamen 361005China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China Department of Mathematics Beijing Jiaotong UniversityBeijing 100044China

Identity by descent(IBD)sharing is a very important genomic feature in population genetics which can be used to reconstruct recent demographic *** this paper we provide a framework to estimate IBD sharing for a demographic model called two-population model with *** adopt the structured coalescent theory and use a continuous-time Markov jump process{X(t),t≥0}to describe the genealogical process in such *** we apply Kolmogorov backward equation to calculate the distribution of coalescence time and develop a formula for estimating the IBD *** simulation studies show that our method to estimate IBD sharing for this demographic model is robust and accurate.

关键词： IBD sharing structured coalescent theory Markov jump process Kolmogorov backward equation

Conceptual understandings of the ecological engineering issues in China and abroad

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Journal of Environmental Sciences 2000年第2期12卷 78-83页

作者： xu, Fu-Liu Tao, shu Departemnt of Urban and Environemmal Sciences Peking University Beijing 100871 China

The research on ecological engineering has been lasting for more than four decades. As a new, cheaper, environmentally acceptable and alternative techniques, ecological engineering has been applied to many aspects, including ecoagricultural engineering, ecosystem restoration, environmental conservation, and pollution control. This paper presents a conceptual understanding on the issues of ecological engineering, including its origin, concepts, goals, principles and applications.

关键词： ecological engineering ecologist engineer CLC number: X171 4 Document code: A