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Nonexistence and Longtime Behaviors of Solutions to a Class of Nonlinear Degenerate Parabolic Equations Not in Divergence Form

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Acta Mathematicae Applicatae Sinica 2016年第2期32卷 327-332页

作者： Yu-dong SUN Yi-min shi min WU School of Science Guizhou Minzu University Department of Applied Mathematics Northwestern Polytechnical University

In this paper, we study the nonexistence and longtime behavior of weak solution for the degenerate parabolic equation σtun=umdiv（｜▽um｜p-2▽um）＋γ｜▽um｜p＋βun with zero boundary condition. Blow-up time is der... 详细信息

关键词： nonexistence nonlinear degenerate parabolic equations weak solution blow-up

Experimental and numerical study on protective effect of RC blast wall against air shock wave

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Defence Technology（防务技术） 2024年第1期31卷 567-579页

作者： Xin-zhe nian Quan-min Xie Xin-li Kong Ying-kang Yao Kui Huang State Key Laboratory of Precision Blasting Jianghan UniversityWuhan430056China Hubei Key Laboratory of Blasting Engineering Jianghan UniversityWuhan430056China Hubei(Wuhan)Institute of Explosion and Blasting Technology Jianghan UniversityWuhan430056China College of Defense Engineering Army Engineering University of PLANanjing210007China Institute of Defense Engineering AMSPLALuoyang471023China

Prototype experiments were carried out on the explosion-proof performance of the RC blast *** mass of TNT detonated in the experiments is 5 kg and 20 kg *** shock wave overpressure was tested in different *** above experiments were numerically simulated,and the simulated shock wave overpressure waveforms were compared with that tested and given by CONWEP *** results show that the numerically simulated waveform is slightly different from the test waveform,but similar to CONWEP *** dimensional analysis and numerical simulation under different working conditions,the equation for the attenuation rate of the diffraction overpressure behind the blast wall was *** to the corresponding standards,the degree of casualties and the damage degree of the brick concrete building at a certain distance behind the wall can be determined when parameters are *** above results can provide a reference for the design and construction of the reinforced concrete blast wall.

关键词： Blast wall Shock wave Diffraction Overpressure Protection

A Copper-Catalyzed[5+1]Cycloaddition of Terminal Alkynes with Diazo Esters through a Tandem 1,5-H-shift Cyclization

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Chinese Journal of Chemistry 2023年第3期41卷 301-306页

作者： Tonggang Hao min shi Yin Wei State Key Laboratory of Organometallic Chemistry Center for Excellence in Molecular SynthesisUniversity of Chinese Academy of SciencesShanghai Institute of Organic ChemistryChinese Academy of Sciences345 Lingling RoadShanghai200032 China

A copper-catalyzed[5+1]cycloaddition reaction of terminal alkynes with diazo esters for the rapid construction of protected naphthalen-1(2H)-one derivatives in moderate to good yields has been disclosed along with good functional group compatibility and a broad substrate *** mechanistic investigations reveal that this tandem cyclization process proceeds through a Cu(I)-catalyzed coupling of terminal alkyne with diazoacetate,a 1,5-H shift process and a thermally induced pericyclic reaction via an allene *** synthetic utility and the further transformations of the obtained cycloadduct to naphthalenone,naphthol and dihydronaphthol have been also presented in this paper.

关键词： [5+1]Cycloaddition Diazo ester 1,5-H-shift One-pot synthesis Copper catalyzed

Mechanistic Studies on Propargyl Alcohol-Tethered Alkylidenecyclopropane with Aryldiazonium Salt Initiated by Visible Light

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Chinese Journal of Chemistry 2021年第2期39卷 295-300页

作者： Jiaxin Liu Yin Wei min shi State Key Laboratory of Organometallic Chemistry Center for Excellence in Molecular SynthesisUniversity of Chinese Academy of ScienceShanghai Institute of Organic ChemistryChinese Academy of Sciences345 Lingling RoadShanghai200032 China Shenzhen Grubbs Institute Southern University of Science and TechnologyShenzhenGuangdong518000 China

This paper discloses the reaction mechanism of two consecutive but different visible light photo-induced chain processes for the rapid construction of spirobi[indene]*** first process is triggered by a photo-induced single-electron-transfer(SET)of an electron donor-accepter(EDA)*** second process is initiated by a direct SET process between aryldiazonium salt and the excited allenic *** these two processes,another SET took place respectively on the in situ formed radical intermediate to realize a redox-neutral *** mechanistic studies have been carried out by control experiments,kinetic and spectroscopic analyses,deuterium labeling experiments to support these two chain processes.

关键词： Mechanistic study Photochemistry Radical ion Spirobi[indene] Radical chain

Automatic segmentation of bladder in CT images

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第2期10卷 239-246页

作者： Feng shi Jie YANG Yue-min ZHU Institute of Image Processing and Pattern Recognition Shanghai Jiao Tong University Shanghai 200240 China CREATIS. LNSA of Lyon University of Lyon 1 Villeurbanne France

Segmentation of the bladder in computerized tomography(CT) images is an important step in radiation therapy planning of prostate cancer. We present a new segmentation scheme to automatically delineate the bladder contour in CT images with three major steps. First,we use the mean shift algorithm to obtain a clustered image containing the rough contour of the bladder,which is then extracted in the second step by applying a region-growing algorithm with the initial seed point selected from a line-by-line scanning process. The third step is to refine the bladder contour more accurately using the rolling-ball algorithm. These steps are then extended to segment the bladder volume in a slice-by-slice manner. The obtained results were compared to manual segmentation by radiation oncologists. The average values of sensitivity,specificity,positive predictive value,negative predictive value,and Hausdorff distance are 86.5%,96.3%,90.5%,96.5%,and 2.8 pixels,respectively. The results show that the bladder can be accurately segmented.

关键词： Image segmentation Computerized tomography (CT) Mean shift Bladder Rolling ball

Optimal design of vibration absorber using minimax criterion with simplified constraints

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Acta Mechanica Sinica 2012年第3期28卷 848-853页

作者： Jie Fang shi-min Wang Qi Wang School of Aeronautics Science and Engineering Beihang University100191 BeijingChina

In this paper, a minimax design of damped dynamic vibration absorber for a damped primary system is investigated to minimize the vibration magnitude peaks. Moreover, to reduce the sensitivity of the primary system response to variations of the forcing frequency for a two- degree-of-freedom system, the primary system should have two equal resonance magnitude peaks. To meet this re- quirement, a set of simplified constraint equations includ- ing distribution characteristics of the resonant frequencies of the primary system is established for the minimax objective function. The modified constraint equations have less un- known variables than those by other authors, which not only simplifies the computation but also improves the accuracy of the optimal values. The advantage of the proposed method is illustrated through numerical simulations.

关键词： minimax Optimization Dynamic vibrationabsorber (DVA) Sensitivity

Privileged chiral catalysts in asymmetric Morita-Baylis-Hillman/aza-Morita-Baylis-Hillman reaction

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Chinese Science Bulletin 2010年第17期55卷 1699-1711页

作者： WEI Yin shi min State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai 200032 China

In the past decade, the asymmetric Morita-Baylis-Hillman (MBH)/aza-Morita-Baylis-Hillman (aza-MBH) reaction has attracted great attention because it leads to the formation of densely functionalized products in a catalytic and atom-economic way. The MBH/aza-MBH adducts can be further applied in a wide variety of organic synthesis, such as peptide synthesis and heterocyclic compounds synthesis. After a lot of attempts to improve the enantioselectivity, many types of chiral organocatalysts have been identified as highly enantioselective organocatalysts in MBH/aza-MBH reaction. Especially, certain "privileged chiral catalysts" are highly enantioselective in MBH/aza-MBH reaction, which are designed and developed through introducing bi-/multi-functional groups on the so-called "privileged structures" such as cinchona alkaloids, BINAP/BINOL. This review summarizes the exciting advances about the design and development of chiral catalysts derived from "privileged structures" and their applications in asymmetric MBH/aza-MBH reaction.

关键词：手性催化剂选择性反应不对称氮杂特权对映选择性有机催化剂有机合成

Increased Risk of Chronic Kidney Diseases in Patients with Metabolic Syndrome:A 3-year Prospective Cohort Study

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Current Medical Science 2019年第2期39卷 204-210页

作者： Ying HU Li-xin shi Qiao ZHANG nian-chun PENG Department of Endocrine and Metabolic Diseases the Second Affiliated Hospital of Soochow UniversitySoochow 215004China Department of Endocrine and Metabolic Diseases Affiliated Hospital of Guizhou Medical UniversityGuizhou 550004China

The relationship of metabolic syndrome(MS)and its components with incident chronic kidney disease(CKD)and rapid decline of estimated glomerular filtration rate(eGFR)was investigated.A total of 10 140 patients participating in the epidemiological study(Risk Evaluation of Cancers in Chinese Diabetic Individuals,REACTION)of risk factors of type 2 diabetes in China were followed up for 3 years,with MS being diagnosed by adult treatment panel IH(ATP IH)combined with waist circumference in Asian population and renal function being evaluated by eGFRmin^-1(1.73 m^2)^-1 and rapid decline of eGFR≤30%.The results showed that as compared with the non-MS group,the adjusted odds ratios(ORs)of CKD and rapid decline of eGFR were 1.64(OR:1.64;95%CI:1.20-2.25,P<0.05)and 1.23(OR:1.23;95%CI:1.05-1.43,P<0.05)respectively in MS *** the increase in the number(0,1,2,3 and≥4)of MS components,the prevalence of CKD was 1.42%,1.44%,2.80%,3.42%,and 4.03%(P<0.001),*** ORs of incident CKD were 1.67(OR:1.67;95%CI:1.22-2.27,P<0.05)for high TG,1.50(OR:1.50;95%CI:1.10-2.05,P<0.05)for low HDL-C,and 1.39(OR:1.39;95%CI:1.02-1.91,P<0.05)for *** risk for developing incident CKD was higher in the group with the highest HOMA-IR than in the group with the lowest HOMA-IR(OR:1.83;95%CI:1.16-2.89,P<0.05).It is suggested that MS is an independent risk factor for incident *** occurrence and development of CKD is closely related to insulin resistance.

关键词： metabolic syndrome glomemlar filtration rate insulin resistance

Efficient benzaldehyde photosynthesis coupling photocatalytic hydrogen evolution

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Journal of Energy Chemistry 2022年第3期31卷 52-60,I0003页

作者： Juanjuan Luo min Wang Lisong Chen Jianlin shi Shanghai Key Laboratory of Green Chemistry and Chemical Processes School of Chemistry and Molecular EngineeringEast China Normal UniversityShanghai 200062China State Key Laboratory of High Performance Ceramics and Superfine Microstructures Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China

Photosynthesis of organic compounds in coupling with promoted hydrogen evolution under mild conditions of light irradiation is considered as one of the most efficient and promising approach to obtain high purity hydrogen and value-added chemicals concurrently by utilizing green solar ***,we report the synthesis of Ni S nanoparticle-modified Cd S nanorod composites(Ni S/Cd S)as an efficient bifunctional catalyst for the highly selective photocatalytic synthesis of high-value-added product benzaldehyde(BAD)from aqueous solution of benzyl alcohol(BA)under oxygen-free conditions,in accompanying with the efficient hydrogen *** synergetic catalytic effect between Ni S and Cd S is proposed to play an important role in elevating the photo-redox *** composition-optimized 30%Ni S/Cd S catalyst affords an extraordinarily high H;generation rate of 207.8μmol h^(-1)and a simultaneous BAD generation rate of 163.8μmol h^(-1)under visible light irradiation,which are respectively 139 and 950 times higher than those of Cd S without Ni S *** our knowledge,these are the highest photocatalytic production rates of both H_(2)and aldehyde ever reported on the concurrent photocatalytic of aldehyde synthesis and hydrogen evolution in green aqueous *** work provides a highly efficient photosynthesis strategy for the concurrent productions of high-value-added fine chemicals and hydrogen.

关键词： Photosynthesis Aromatic aldehyde Hydrogen evolution Bifunctional catalyst