检索结果-南通市图书馆

The effect of K2siF6 on the MgH2 hydrogen storage properties

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 Magnesium and Alloys 2020年第3期8卷 832-840页

作者： M.Ismail M.s.Yahya N.A.sazelee N.A.Ali F.A.Halim Yap N.s.Mustafa Energy storage Research Group Faculty of Ocean Engineering Technology and InformaticsUniversity Malaysia Terengganu21030 Kuala TerengganuMalaysia Faculty of Innovative Design and Technology Universiti Sultan Zainal AbidinGong Badak Campus21300 Kuala NerusTerengganuMalaysia

The catalytic effect of K2siF6 on MgH2 was first timely *** MgH2+5 wt.%K2siF6 was prepared via the ball milling *** catalyst had lessened the initial decomposition temperature by 134℃ and 48℃ as compared to both pristine and milled MgH2 samples,*** 2 minutes,4.5 wt.%of hydrogen was absorbed(250℃)by the doped composite,which was 0.8 wt.%higher than the milled ***,for the desorption kinetics(320℃,1 atm),the amount of desorbed hydrogen was increased by 2.4 wt.%and 2.3 wt.%for the first 10 and 20 ***,contracting volume and johnson-Mehl-Avrami models were used to analyse the kinetics *** decomposition activation energy calculated based on Kissinger equation was 114 kj/*** for the active species,Mg2si,MgF2 and KH were formed during the heating *** active species are speculated to be responsible for the improvement of the hydrogenation properties of the composite.

关键词： Catalytic effect Magnesium hydride Hydrogen storage sorption properties Contracting volume model

synthesis,Urease Inhibition and Molecular Modelling studies of Novel Derivatives of the Naturally Occurring b-Amyrenone

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Natural Products and Bioprospecting 2019年第1期9卷 49-59页

作者： jean j.K.Bankeu Hira sattar Yannick s.F.Fongang syeda W.Muhammadi Conrad V.simoben Fidele Ntie-Kang Guy R.T.Feuya Marthe A.T.Tchuenmogne Mehreen Lateef Bruno N.Lenta Muhammad s.Ali Augustin s.Ngouela Department of Chemistry Faculty of ScienceThe University of BamendaP.O.Box 39BambiliCameroon International Center for Chemical and Biological sciences University of KarachiKarachi 75270Pakistan Department of Chemistry Higher Teacher Training CollegeUniversity of MarouaP.O.Box 55MarouaCameroon Department of Pharmaceutical Chemistry Martin-Luther University of Halle-WittenbergWolfgang-Langenbeck-Str.406120 Halle(Saale)Germany Department of Chemistry Faculty of ScienceUniversity of BueaP.O.Box 63BueaCameroon Department of Chemistry Faculty of ScienceScientific and Technical University of MasukuBox 943FrancevilleGabon Department of Chemistry Faculty of ScienceUniversity of Yaounde´IP.O.Box 812Yaounde´Cameroon Multi-Disciplinary Research Laboratory(MDRL) Bahria University Medical and Dental CollegeBahria UniversityKarachiPakistan Department of Chemistry Higher Teacher Training CollegeUniversity of Yaounde´IP.O.Box 47Yaounde´Cameroon

Urease enzyme(UE)has been reported to be a potent virulence factor for Helicobacter pylori(HP)bacteria indicated to be responsible for various gastrointestinal ***,the spread of HP,currently regarded by the World Health Organization as a class 1 carcinogen,could be better controlled by targeting *** is in this line that we have synthesized three new derivatives(2–4)of the naturally occurring olean-12-en-3-one(1),which was previously isolated from the figs of Ficus vallis-choudae Delile(Moraceae).Among the synthesized compounds,3 and 4 contain an indole *** structures were unambiguously assigned by spectroscopic and spectrometric techniques(1D-NMR,2D-NMR and Ms).The starting material and the synthesized compounds were screened for UE inhibition activity,and showed significant activities with IC50 values ranging from 14.5 to 24.6 lM,with compound(1)being the most potent as compared to the positive control thiourea(IC50=21.6 lM).Amongst the synthetic derivatives,compound 4 was the most potent(IC50-=17.9 lM),while the others showed activities close to that of the *** addition,molecular docking study of target compounds 2–4 was performed in an attempt to explore their binding mode for the design of more potent UE inhibitors.

关键词： Helicobacter pylori Urease inhibition Docking Olean-12-en-3-one derivatives

Real meromorphic functions and linear differential polynomials

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

science China Mathematics 2010年第3期53卷 739-748页

作者： LANGLEY j. K. school of Mathematical sciences University of Nottingham

We determine all real meromorphic functions f in the plane such that f has finitely many zeros, the poles of f have bounded multiplicities, and f and F have finitely many non-real zeros, where F is a linear differential polynomial given by F = f (k) +Σk-1j=0ajf(j) , in which k≥2 and the coefficients aj are real numbers with a0≠0.

关键词： non-real zeros meromorphic function linear differential polynomial

Dust in the jupiter system outside the rings

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Astrodynamics 2019年第1期3卷 17-29页

作者： Xiaodong Liu jürgen schmidt Astronomy Research Unit University of OuluOulu90014Finland

jupiter is one of the major targets for planetary exploration,and dust in the jovian system is of great interest to researchers in the field of planetary *** this paper,we review the five dust populations outside the ring system:grains in the region of the Galilean moons,potential dust from plumes on Europa,jovian stream particles,particles in the outer region of the jovian system ejected from the irregular satellites,and dust in the region of the Trojan *** physical environment for the dust dynamics is described,including the gravity,the magnetic field and the plasma *** each population,the dust sources are described,and the relevant perturbation forces are *** and results from modeling are reviewed,and the distributions of the individual dust populations are *** understanding of the jovian dust environment allows to assess the dust hazard to spacecraft,and to characterize the material exchange between the jovian moons,their surface properties and distribution of non-icy constituents.

关键词： cicumplanetary dust interplanetary dust stream particles planetary rings Europa plume jupiter Galilean moons Trojan asteroids meteoroids space debris

LuNet-LightGBM:An Effective Hybrid Approach for Lesion segmentation and DR Grading

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer systems science & Engineering 2023年第7期46卷 597-617页

作者： sesikala Bapatla j.Harikiran school of Computer science and Engineering VIT-AP UniversityAmaravatiAndhra Pradesh522237India school of Computer science and Engineering VIT-AP UniversityAmaravathi522237India

Diabetes problems can lead to an eye disease called Diabetic Retinopathy(DR),which permanently damages the blood vessels in the *** not treated early,DR becomes a significant reason for *** identify the DR and determine the stages,medical tests are very labor-intensive,expensive,and *** address the issue,a hybrid deep and machine learning techniquebased autonomous diagnostic system is provided in this *** proposal is based on lesion segmentation of the fundus images based on the LuNet *** a Refined Attention Pyramid Network(RAPNet)is used for extracting global and local *** increase the performance of the classifier,the unique features are selected from the extracted feature set using Aquila Optimizer(AO)***,the LightGBM model is applied to classify the input image based on the *** investigations have been done to analyze the performance of the proposed framework on three publically available datasets(MEssIDOR,APTOs,and IDRiD)using several performance metrics such as accuracy,precision,recall,and *** proposed classifier achieves 99.29%,99.35%,and 99.31%accuracy for these three datasets *** outcomes of the experiments demonstrate that the suggested technique is effective for disease identification and reliable DR grading.

关键词： Deep learning diabetic retinopathy DR grading lightGBM LuNet lesion segmentation

Gut-associated lymphoid tissue or so-called “dome” carcinoma of the colon: Review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World journal of Gastrointestinal Oncology 2019年第1期11卷 59-70页

作者： Aoife j McCarthy Runjan Chetty Department of Anatomical Pathology Laboratory Medicine Program University Health Network Department of Laboratory Medicine and Pathobiology Faculty of Medicine University of Toronto

AIM To present a comprehensive review of the etiology, clinical features, macroscopic and pathological findings, and clinical significance of Gut-associated lymphoid tissue or "dome" carcinoma of the *** The English language medical literature on gut-or gastrointestinal-associated lymphoid tissue(GALT) or "dome" carcinoma of the colon was searched and *** GALT/dome-type carcinomas of the colon are thought to arise from the M-cells of the lymphoglandular complex of the intestine. They are typically asymptomatic and have a characteristic endoscopic plaque-or "dome"-like appearance. Although the histology of GALT/dome-type carcinomas displays some variability, they are characterized by submucosal localization, a prominent lymphoid infiltrate with germinal center formation, tumor-infiltrating lymphocytes, absence of desmoplasia, and dilated glands lined by columnar epithelial cells with bland nuclear features and cytoplasmic eosinophilia. None of the patients reported in the literature with follow-up have developed metastatic disease or local *** Increased awareness amongst histopathologists of this variant of colorectal adenocarcinoma is likely to lead to the recognition of more cases.

关键词： Dome-type carcinoma Gastrointestinal-associated lymphoid tissue carcinoma Gut-associated lymphoid tissue Lymphoglandular complex Colorectal cancer

Animal behavior can inform conservation policy, we just need to get on with the jobor can it？

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2014年第4期60卷 479-485页

作者： Ximena j. NELsON, Editor school of Biological sciences University of Canterbury Private Bag 4800 Christchurch New Zealand

1 Conservation Behavior as an Emerging Discipline on the Brink of success, or Unrealistic Ideal？ It seems intuitively sensible that an understanding of the behavioral characteristics of animals, such as their home ranges, diets, mating systems, and dispersal me- chanisms, may be useful to inform conservation efforts in determining, for example, suitable reintroduction areas, or the design of dispersal corridors.

关键词：行为特征动物减排新兴学科活动范围交配系统疏散通道再引入

Oil quenched malleable iron,the strength of an old material in a “green cast” development and a new future

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Foundry 2010年第4期7卷 447-455页

作者： Cornelis j.van Ettinger Gieterij Doesburg B.Ubbinkweg 26981 EC DoesburgThe Netherlands

Malleable iron lost the interest and the development stopped in the turbulent seventies of tremendous developments of new technologies. The personal computer, emission spectrometer, thermal analysis, cold-box core system and automatic vertical moulding were introduced into the foundry industry. Experience shows that these new technologies do not always match up with malleable iron. solidifciation and mould filling simulation programs are not always capable to handle a low carbon equivalent iron like malleable iron. Recent developments show however by using these new technologies and combined with practical experience, it is possible to increase the casting yield of malleable iron to the same level as ductile iron. The mechanical properties, especially the yield strength of malleable iron according to the standard are equivalent to those of ductile iron, however the yield strength of oil quenched malleable iron is signifciantly higher than that of ductile iron. An extensive investigation is made between ductile iron, air quenched and oil quenched malleable irons based on the properties of more than 350 test bars produced under the same conditions. The results are compared with the existing international standards and discussed. Other properties like fatigue strength and response to surface treatments as induction hardening are also discussed. The costs of malleable iron are reviewed and compared with other ferro alloys. These recent developments in increasing the casting yield, the understanding of the strength, makes malleable iron competitive with ductile iron and cheaper than the first grade of ausferritic ductile iron, or steel qualities. It is possible to design lighter and save weight which is essential in the automotive industry. An example of "green cast" development for typical applications, used in automotive transmissions and engines are shown.

关键词： malleable iron ductile iron oil quenched mechanical properties automotive industry

A Generalized Discrete Morse-Floer Theory

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Communications in Mathematics and statistics 2019年第3期7卷 225-252页

作者： jürgen jost sylvia Yaptieu Max Planck Institute for Mathematics in the sciences Inselstrasse 2204103 LeipzigGermany santa Fe Institute for the sciences of Complexity Santa FeNM 87501USA

Forman has developed a version of discrete Morse theory that can be understood in terms of arrow patterns on a(simplicial,polyhedral or cellular)complex without closed orbits,where each cell may either have no arrows,receive a single arrow from one of its facets,or conversely,send a single arrow into a cell of which it is a *** following arrows,one can then construct a natural Floer-type boundary ***,we develop such a construction for arrow patterns where each cell may support several outgoing or incoming arrows(but not both),again in the absence of closed *** main technical achievement is the construction of a boundary operator that squares to 0 and therefore recovers the homology of the underlying complex.

关键词： CW complex Boundary operator Floer theory Poincarépolynomial Betti number Discrete Morsetheory Discrete Morse-Floertheory Conleytheory