检索结果-南通市图书馆

Chinese Journal of Structural Chemistry 2019年第1期38卷 89-94,3页

作者： pu Xiu-Ying XU wen-Jun YI Yun-Peng LI Hao-wen LIANG Jian-Ping HAO Bao-Cheng School of Life Science and Engineering Lanzhou University of Technology Key Laboratory of New Animal Drug Project of Gansu Province Key Laboratory of Veterinary Pharmaceutical Development Ministry of AgricultureInstitute of Husbandry and Pharmaceutical Sciences of CAAS

The title compound 6?-chloro-4?-methylene-3 H-spiro [isoben zofura-1,3?-isochroman], C_(17)H_(13)ClO_2, was prepared and characterized by IR, NMR, HRMS and single-crystal X-ray diffraction. This compound has a bisbenzannulated [5,5]-spiroketals skeleton. It crystallizes in orthorhombic, space group P212121 with a = 13.383(3), b = 7.6120(17), c = 13.793(3) ?, Z = 4, Dc= 1.275 g/cm^3, μ = 0.28 mm^(–1), F(000) = 592, wR = 0.1443 and R = 0.0557. The preliminary biological test showed that the title compound has good anti-bacterial activities in vitro.

关键词： 3H-spiro[isobenzofura-1,3'-isochroman] single-crystal structure anti-bacterial

Synthesis and Microstructure Analysis of Autoclaved Aerated Concrete with Carbide Slag Addition

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2014年第5期29卷 1005-1010页

作者：范俊杰 CAO Deguang 景镇子 ZHANG Yi pu Li jing Yani School of Materials Science and Engineering Tongji University School of Materials Science and Engineering Guangxi University School of Internet of Things Engineering Jiangnan University

Synthesis of autoclaved aerated concrete （AAC） has been carried out with carbide slag addition, and the carbide slag could be used as a main material to produce the AAC with the compressive strength about 2 MPa and the density below 0.6 ***-3. In this study, quartz sand acted as frame structure phase in the matrix, and quartz addition also influenced the Si/Ca of starting material. Tobermorite and CSH gel were formed readily at 62%, which seemed to enhance the compressive strength of samples. Curing time seemed to affect the morphology of phase produced, and specimen with the plate-like tobermorite formed at 10 h appeared to have a better compressive strength development than the fiber-like one at 18 h. The higher curing temperature seemed to favor the tobermorite and CSH gel formation, which also exerted a significant effect on the strength development of the samples. On the micro-scale, the formed CSH gel was filled in the interface of the matrix, and the tobermorite appeared to grow in internal-surface of the pores and interstices. The tobermorite or/and CSH formation seemed to densify the matrix, and therefore enhanced the strength of the samples.

关键词： carbide slag autoclaved aerated concrete tobermorite CSH gel construction features

Formal modelling of list based dynamic memory allocators

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2018年第12期61卷 81-96页

作者： Bin FANG Mihaela SIGHIREANU Geguang pu wen SU Jean-Raymond ABRIAL Mengfei YANG Lei QIAO Shanghai Key Laboratory of Trustworthy Computing East China Normal University IRIF University Paris Diderot and CNRS School of Computer Engineering and Science Shanghai University

Existing implementations of dynamic memory allocators(DMA) employ a large spectrum of policies and techniques. The formal specifications of these techniques are quite complicated in isolation and very complex when combined. Therefore, the formal reasoning on a specific DMA implementation is difficult for automatic tools and mostly single-use. This paper proposes a solution to this problem by providing formal models for a full class of DMA, the class using various kinds of lists to manage the memory blocks controlled by the DMA. To obtain reusable formal models and tractable formal reasoning, we organise these models in a hierarchy ranked by refinement relations. We prove the soundness of models and the refinement relations using the modeling framework Event-B and the theorem prover Rodin. We demonstrate that our hierarchy is a basis for an algorithm theory for list based DMA: it abstracts various existing implementations of DMA and leads to new DMA implementations. The applications of this formalisation include model-based code generation, testing, and static analysis.

关键词： dynamic memory allocators formal methods refinement Event-B Rodin model-based design

Synthesis,Characterization and Catalysis of New Pillared Anionic Clays by[GaW_(11)O_(39)M(H_(2)O)]^(7-)(M=Mn^(2+),Co^(2+)or Ni^(2+))

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 1998年第3期14卷 32-36页

作者： Zhu, Zhi-ping Peng, Wan-pu Zhou, De-feng Liu, jing-fu NE Normal Univ Dept Chem Changchun 130024 Peoples R China

Pillared anionic clays or layered double hydroxides were prepared by means of hydrothermal ion exchange reaction of [Zn 2Al(OH) 6]NO 3· x H 2O (ZnAl NO 3) with [GaW 11 O 39 M(H 2O)] 7- (abbreviated as GaW 11 M, M=Mn 2+ , Co +2 or Ni 2+ ). The layered compounds were characterized by means of XRD, IR, elemental analysis and DTA. The X ray diffraction and IR spectra show that the new anionic clays synthesized are layered compounds with the gallery heights of 0.99-1.00 nm and the Keggin structure tungstogallic heteropolyanions almost completely replace the interlayer NO - 3, entering the layer and retain their Keggin structure. The DTA gives a thermostability order of ZnAl GaW 11 Ni >ZnAl GaW 11 Co>ZnAl GaW 11 Mn>ZnAl NO 3. The ctalytic tests showed that the new pillared compounds have higher catalytic activities in the cyclooxidation reaction of maleic acid.

关键词： Heteropolyanion Intercalation Pillared clay Epoxidation

Effects of two silicone resin coatings on performance of FeSiAl magnetic powder cores

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第5期31卷 1279-1288页

作者： Jia-qi Liu Zheng-qu Zhu pu Wang Yi-fan Li jing Pang Jia-quan Zhang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China Qingdao Yunlu Advanced Materials Technology Co. Ltd.Qingdao266232ShandongChina

Two silicon resins with excellent thermal stability,JH1123 and JH7102,are used as the insulated agents and binders for the gas-atomized FeSiAl powder,and corresponding magnetic powder cores(MPCs)are *** insulation capability and application prospects of the two silicon resins are evaluated by comparing the magnetic properties of the coated powder and *** scanning electron microscopy,energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy results show that uniform insulation layers are both formed on the powder ***1123 has stronger binding ability,and the JH1123-coated powder exhibits severe agglomeration,with d50(average particle size)approximately twice that of the JH7102-coated *** as-prepared MPCs exhibit outstanding soft magnetic ***,the permeability of FeSiAl@JH1123 is up to 74.0,which is 35.5%higher than that of FeSiAl@JH7102 because JH1123 can further improve the density of the *** for FeSiAl@JH7102,it has better direct current bias and lower core loss of 716.9 mW cm^(−3) at 20 mT and 1000 kHz due to its lower coercivity and greater anti-magnetic saturation ability.A comprehensive comparison shows that FeSiAl@JH1123 is suitable for medium and high frequency applications,while FeSiAl@JH7102 is more suitable for high frequency *** indicates that the use of JH1123 and JH7102 silicon resins for binding and insulated coating not only simplifies the preparation process of MPCs,but also enables the controlled production of MPCs for different applications.

关键词： FeSiAl Insulated coating Magnetic powder core Permeability Core loss

Empirical Research in Software Engineering -- A Literature Survey

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2018年第5期33卷 876-899页

作者： Li Zhang Jia-Hao Tian jing Jiang Yi-Jun Liu Meng-Yuan pu Tao Yue State Key Laboratory of Software Development Environment Beihang University Beijing 100191 China College of Software Beihang University Beijing 100191 China Simula Research Laboratory Martin Lingesvei 25 1364 Fornebu Norway

Empirical research is playing a significant role in software engineering （SE）, and it has been applied to evaluate software artifacts and technologies. There have been a great number of empirical research articles published recently. There is also a large research community in empirical software engineering （ESE）. In this paper, we identify both the overall landscape and detailed implementations of ESE, and investigate frequently applied empirical methods, targeted research purposes, used data sources, and applied data processing approaches and tools in ESE. The aim is to identify new trends and obtain interesting observations of empirical software engineering across different sub-fields of software engineering. We conduct a mapping study on 538 selected articles from January 2013 to November 2017, with four research questions. We observe that the trend of applying empirical methods in software engineering is continuously increasing and the most commonly applied methods are experiment, case study and survey. Moreover, open source projects are the most frequently used data sources. We also observe that most of researchers have paid attention to the validity and the possibility to replicate their studies. These observations are carefully analyzed and presented as carefully designed diagrams. We also reveal shortcomings and demanded knowledge/strategies in ESE and propose recommendations for researchers.

关键词： empirical software engineering empirical method systematic mapping study

Association of candidate gene polymorphisms with diabetic retinopathy in Chinese patients with type 2 diabetes

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2020年第2期13卷 301-308页

作者： wen-Ying Fan Hong Gu Xiu-Fen Yang Chong-Yang She Xi-pu Liu Ning-pu Liu Beijing Tongren Eye Center Beijing Tongren HospitalCapital Medical UniversityBeijing Ophthalmology and Visual Sciences Key LaboratoryBeijing 100730China Department of Ophthalmology Lihuili HospitalNingbo 315010Zhejiang ProvinceChina Department of Ophthalmology Friendship HospitalCapital Medical UniversityBeijing 100050China Department of Ophthalmology Beijing Chao-Yang HospitalCapital Medical UniversityBeijing 100020China Sekwa Eye Hospital Sekwa Institute of MedicineBeijing 100035China

●AIM:To investigate the association between a set of six candidate genes and the risk of diabetic retinopathy(DR)in an urban community cohort of Chinese patients with type 2 diabetes mellitus(T2 DM).●METHODS:A population-based cross-sectional *** diabetic subjects were recruited from an urban community in Beijing and categorized into groups of proliferative diabetic retinopathy(PDR),non-proliferative diabetic retinopathy(NPDR),or diabetic without any retinopathy(DWR)based on the fundus photography and duration of *** candidate genes,including advanced glycation end product specific receptor(AGER),aldose reductase(AKR1 B1),inducible nitric oxide synthase(i NOS),pigment epithelium derived factor(PEDF),tumor necrosis factor-alpha(TNF-α),and paraoxonase 1(PON1),were chosen based on Meta-analysis of genetic association studies for DR and biochemical pathways implicated in DR *** allele and genotype distribution of 21 functional singlenucleotide polymorphisms(SNPs)in those 6 candidate genes were investigated using MassARRAY genotyping system.●RESULTS:Among 1461 diabetic patients recruited from community,569 were selected in following genotyping analysis,including 97 patients with PDR,217 with NPDR,and 255 with *** the promoter variant rs1051993 in AGER gene,the distribution of allele and genotype in PDR group differed from that in DWR group(allele:P=0.011;genotype:P=0.01).Compared with DWR,patients with PDR had lower frequencies of heterozygous genotype GT(9.8%for DWR,1%for PDR,OR:0.10,95%CI:0.01-0.72)and minor allele T(4.9%for DWR,0.5%for PDR,OR:0.10,95%CI:0.01-0.75).In multivariate model,the distribution of genotype for rs1051993 in PDR group was significantly different from that in DWR group(GT vs GG:OR:0.07,95%CI:0.01-0.61,P<0.001).No association with DR was observed in other genotyped SNPs.●CONCLUSION:The data suggest a significant association of the promoter variant rs1051993 in AGER gene with PDR in Chinese cohort with T2DM.

关键词： polymorphisms diabetic retinopathy AGER AKR1B1 iNOS PEDF TNF-α PON1

Constitutive Modeling for Flow Behaviors of Superaustenitic Stainless Steel S32654 during Hot Deformation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2016年第2期23卷 178-184页

作者： En-xiang pu Han FENG Min LIU wen-jie ZHENG Han DONG Zhi-gang SONG Central Iron and Steel Research Institute Beijing 100081China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

Hot deformation behavior of superaustenitic stainless steel S32654 was investigated with hot compression tests at temperatures of 950-1250 C and strain rates of 0. 001-10 s-1. Above 1150 ℃, with strain rate lower than 0.1 s -1 , the flow curves exhibit nearly steady state behavior, while at higher strain rate, continuous flow softening occurs. To provide a precise prediction of flow behavior for the alloy, the constitutive modeling considering effect of strain was derived on the basis of the obtained experimental data and constitutive relationship which incorporated Ar- rhenius term and hyperbolic sine type equation. The material constants α, n, Q and lnA are found to be functions of the strain and can be fitted employing eighth-order polynomial. The developed constitutive model can be employed to describe the deformation behavior of superaustenitic stainless steel S32654.

关键词： S32654 superaustenitic stainless steel hot deformation constitutive modeling

Preparation of CNT/AlS i10Mg composite powders by high-energy ball milling and their physical properties

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2016年第3期23卷 330-338页

作者： Lin-zhi Wang Ying Liu wen-hou Wei Xu-guang An Tao Zhang Ya-yun pu College of Materials Science and Engineering Sichuan University Chongqing Key Laboratory of Multi-scale Manufacturing Technology Chongqing Institute of Green and Intelligent Technology Chinese Academy of Sciences College of Materials Science and Engineering Chongqing University

This study investigated the effects of carbon nanotube （CNT） concentration on the micro-morphologies and laser absorption proper- ties of CNT/AlSi10Mg composite powders produced by high-energy ball milling. A scanning electron microscope, X-ray diffractometer, laser particle size analyzer, high-temperature synchronous thermal analyzer, and UV/VIS/NIR spectrophotometer were used for the analysis of micro- graphs, phases, granulometric parameters, thermal properties, and laser absorption properties of the composite powders, respectively. The results showed that the powders gradually changed from flake- to granule-like morphology and the average particle size sharply decreased with in- creases in milling rotational speed and milling time. Moreover, a uniform dispersion of CNTs in AlSi10Mg powders was achieved only for a CNT content of 1.5wt%. Laser absorption values of the composite powders were also observed to gradually increase with the increase of CNT concentration, and different spectra displayed characteristic absorption peaks at a wavelength of approximately 826 nm.

关键词： metal matrix composites aluminum alloys carbon nanotubes powder metallurgy particle size distribution ball milling physi-cal properties

Characterization of Stratospheric Aerosol Distributions during the Volcanically Quiescent Period of 1998–2004

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2014年第4期7卷 291-296页

作者： YANG jing-Mei ZONG Xue-Mei WANG pu-Cai Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO) Institute of Atmospheric Physics Chinese Academy of Sciences

The Stratospheric Aerosol and Gas Experiment （SAGE） II aerosol extinction profiles at 1020 nm were used to study the distribution characteristics of stratospheric aerosols during the volcanically quiescent period of 1998-2004. The stratospheric aerosol distributions exhibited hemispheric asymmetry between the Northern Hemisphere （NH） and the Southern Hemisphere （SH）. In the lower stratosphere below 20 km, the zonal averaged aerosol optical depths in the NH were higher than those of the corresponding SH; whereas at higher altitudes above 20 km, the optical depths in the SH-- except the equatorial region--were higher than those of the NH. At 0-10°N and 10-20°N, the stratospheric aerosol optical depth （SAOD） exhibited larger values in boreal winter and lower values in the spring and summer; at 0-10°S and 10-20°S, the SAOD presented small seasonal variations. At 30-40°N, the SAOD presented larger values in the boreal fall and winter and lower values in the spring and summer; while at 30-40°S, the SAOD exhibited larger values in the austral winter and early spring and lower values in the summer and fall. These characteristics can mainly be attributed to the seasonal cycle of the dynamic transport, and the effects of the buildup and breakdown of the polar vortex. At 50-60°S, the SAOD exhibited extremely high values during austral winter associated with the Antarctic polar vortex boundary; at 50-60°N, the SAOD also exhibited larger values during the boreal winter, but it was much less obvious than that of its southern counterpart.

关键词： aerosol stratosphere distribution optical depth