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Catalytical oxidation of styrene by molecularly imprinted polymer with phenylacetic acid as template and hemin as co-monomer

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Chinese Chemical Letters 2007年第8期18卷 981-984页

作者： jun wang Zhi Yong Chen mei Ping Zhao Yuan Zong Li The Key Laboratory of Bioorganic Chemistry and Molecular Engineering College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

This letter used the molecular imprinting technology to build up the microenvironment around co-monomer bemin to mimic the cytochrome P450 catalyzing the epoxidation of styrene. The results showed that the conversion rates of products were obviously enhanced by molecularly imprinted polymers, compared to free heroin solution, using three kinds of oxidants. The used axial ligand in polymers synthesis also improved the total conversion rates.

关键词： Molecularly imprinted polymers Enzyme mimic Cytochrome P450 Styrene Epoxidation

Drift of Spiral Waves in Complex Ginzburg-Landau Equation

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Communications in Theoretical Physics 2006年第4期45卷 647-652页

作者： YANG jun-Zhong ZHANG mei School of Science Beijing University of Posts and Telecomunications Beijing 100876 China Center for Advanced Study Tsinghua University Beljing 100084 China

The spontaneous drift of the spiral wave in a finite domain in the complex Ginzburg Landau equation is investigated numerically. By using the interactions between the spiral wave and its images, we propose a phenomeno... 详细信息

关键词： oscillatory medium spontaneous drift of spiral wave attractor

An Improved Golden Jackal Optimization Algorithm Based on Multi-strategy Mixing for Solving Engineering Optimization Problems

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Journal of Bionic Engineering 2024年第2期21卷 1092-1115页

作者： jun wang Wen-chuan wang Kwok-wing Chau Lin Qiu Xiao-xue Hu Hong-fei Zang Dong-mei Xu College of Water Resources North China University of Water Resources and Electric PowerZhengzhou450046People’s Republic of China Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHong KongPeople’s Republic of China

Nowadays,optimization techniques are required in various engineering domains to find optimal solutions for complex *** a result,there is a growing tendency among scientists to enhance existing nature-inspired algorithms using various evolutionary strategies and to develop new nature-inspired optimization methods that can properly explore the feature *** recently designed nature-inspired meta-heuristic,named the Golden Jackal Optimization(GJO),was inspired by the collaborative hunting actions of the golden jackal in nature to solve various challenging ***,like other approaches,the GJO has the limitations of poor exploitation ability,the ease of getting stuck in a local optimal region,and an improper balancing of exploration and *** overcome these limitations,this paper proposes an improved GJO algorithm based on multi-strategy mixing(LGJO).First,using a chaotic mapping strategy to initialize the population instead of using random parameters,this algorithm can generate initial solutions with good diversity in the search ***,a dynamic inertia weight based on cosine variation is proposed to make the search process more realistic and effectively balance the algorithm's global and local search ***,a position update strategy based on Gaussian mutation was introduced,fully utilizing the guidance role of the optimal individual to improve population diversity,effectively exploring unknown regions,and avoiding the algorithm falling into local *** evaluate the proposed algorithm,23 mathematical benchmark functions,CEC-2019 and CEC2021 tests are *** results are compared to high-quality,well-known optimization *** results of the proposed method are compared from different points of view,including the quality of the results,convergence behavior,and *** superiority and high-quality performance of the proposed method are demonstrated by comparing the ***,to demonstrate

关键词： Golden jackal optimization Chaotic mapping Dynamic inertia weight Dimensional Gaussian variation Muskingum

Palladium-catalyzed synthesis of 1,2,3,4-tetraalkyl-1,4-diarylbutadienes by cross-coupling of zirconacyclopentadienes with aryl iodides

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Chinese Chemical Letters 2015年第10期26卷 1303-1306页

作者： Hui wang jun-Qiu Li Li-Shan Zhou jun Liu Juan Li Hong-mei Qu Key Laboratory of Systems Bioengineering Ministry of Education Tianjin Key Laboratory of Biological and Pharmaceutical Engineering Department of Pharmaceutical Engineering School of Chemical Engineering and Technology Tianjin University CNOOC Tianjin Chemical Research and Design Institute

A novel method for the synthesis of 1,2,3,4-tetraalkyl-1,4-diarylbutadienes was developed via palladiumcatalyzed cross-coupling of zirconacyclopentadienes with aryl iodides. Equivalent of Cu Cl was introduced to promote the reaction. The desired products were obtained in good to excellent yields and several of them were reported for the first time.

关键词： Zirconacyclopentadiene Cross-coupling reaction Palladium-catalyzed CuCl 1 2 3 4-Tetraalkyl-1 4-diarylbutadienes

Improving WC-Co coating adhesive strength on rough substrate:Finite element modeling and experiment

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Journal of Materials Science & Technology 2020年第2期37卷 1-8页

作者： Adnan Tahir Guang-Rong Li mei-jun Liu Guan-jun Yang Cheng-Xin Li Yu-Yue wang Chang-Jiu Li State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi’an Jiaotong UniversityXi’an710049China

The adhesive strength in a coating-substrate system is of primary importance for the coating lifetime in ***,the underlying mechanism is not fully understood due to the complex internal structure of composite *** this study,the effect of substrate roughness on the adhesive strength of WCCo coatings was investigated by experiment and *** show that the adhesive strength is significantly affected by the *** the case of the Ra<2μm,the adhesive strength is approximately 35–46 *** the Ra is 4μm,the adhesive strength increases to nearly 60 MPa.A finite element model was developed to correlate the roughness with adhesive *** is found that the predicted values are well consistent with the experimental *** addition,with the increase of the roughness,the residual stress would be changed from concentrated state to widespread state,which decreases the critical stress to result in crack ***’s why a larger roughness can cause a higher adhesive *** study gives understanding on the mechanism of adhesive strength affected by roughness,which contributes to the parameter optimization with better performance.

关键词： Adhesive strength Roughness Lifetime Simulation XFEM Residual stress

MemSC： A Scan-Resistant and Compact Cache Replacement Framework for Memory-Based Key-Value Cache Systems

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Journal of Computer Science & Technology 2017年第1期32卷 55-67页

作者： mei Li Hong-jun Zhang Yan-jun Wu Chen Zhao National Engineering Research Center of Fundamental Software Institute of Software Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Beijing 100190 China

Memory-based key-value cache systems, such as Memcached and Redis, have become indispensable components of data center infrastructures and have been used to cache performance-critical data to avoid expensive back-end database accesses. As the memory is usually not large enough to hold all the items, cache replacement must be performed to evict some cached items to make room for the newly coming items when there is no free space. Many real-world workloads target small items and have frequent bursts of scans （a scan is a sequence of one-time access requests）. The commonly used LRU policy does not work well under such workloads since LRU needs a large amount of metadata and tends to discard hot items with scans. Small decreases in hit ratio can result in large end-to-end losses in these systems. This paper presents MemSC, which is a scan-resistant and compact cache replacement framework for Memcached. MemSC assigns a multi-granularity reference flag for each item, which requires only a few bits （two bits are enough for general use） per item to support scanresistant cache replacement policies. To evaluate MemSC, we implement three representative cache replacement policies （MemSC-HM, MemSC-LH, and MemSC-LF） on MemSC and test them using various workloads. The experimental results show that MemSC outperforms prior techniques. Compared with the optimized LRU policy in Memcached, MemSC-LH reduces the cache miss ratio and the memory usage of the resulting system by up to 23% and 14% respectively.

关键词： key-value cache system cache replacement scan resistance space efficiency

Monochromatic energy computed tomography image for active intestinal hemorrhage:A model investigation

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World Journal of Gastroenterology 2015年第1期21卷 214-220页

作者： Wen-Dong Liu Xing-wang Wu jun-mei Hu Bin wang Bin Liu Department of Radiology the First Affiliated Hospital of Anhui Medical University Department of Epidemiology and Statistics Anhui Medical University

AIM: To investigate the value of computed tomography(CT) spectral imaging in the evaluation of intestinal ***: Seven blood flow rates were simulated in *** spectral CT and mixed-energy CT scanswere performed for each rate(0.5,0.4,0.3,0.2,0.1,0.05 and 0.025 m L/min).The detection rates and the contrast-to-noise ratios(CNRs) of the contrast agent extravasation regions were compared between the two scanning methods in the arterial phase(AP) and the portal venous phase(PVP).Comparisons of the CNR values between the PVP and the AP were made for each energy level and carried out using a completely random t test.A χ2 test was used to compare the detection rates obtained from the two scanning ***: The total detection rates for energy spectral CT and mixed-energy CT in the AP were 88.57%(31/35) and 65.71%(23/35),respectively,and the difference was significant(χ2 = 5.185,P = 0.023); the total detection rates in the PVP were 100.00%(35/35) and 91.4%(32/35),respectively,and the difference was not significant(χ2 = 1.393,P = 0.238).In the AP,the CNR of the contrast agent extravasation regions was 3.58 ± 2.09 on the mixed-energy CT images,but the CNRs were 8.78 ± 7.21 and 8.83 ± 6.75 at 50 and 60 keV,respectively,on the single-energy CT images,which were significantly different(3.58 ± 2.09 vs 8.78 ± 7.21,P = 0.031; 3.58 ± 2.09 vs 8.83 ± 6.75,P = 0.029).In the PVP,the differences between the CNRs at 40,50 and 60 keV different monochromatic energy levels and the polychromatic energy images were significant(19.35 ± 10.89 vs 11.68 ± 6.38,P = 0.010; 20.82 ± 11.26 vs 11.68 ± 6.38,P = 0.001; 20.63 ± 10.07 vs 11.68 ± 6.38,P = 0.001).The CNRs at the different energy levels in the AP and the PVP were significantly different(t =-2.415,-2.380,-2.575,-2.762,-2.945,-3.157,-3.996 and-3.189).CONCLUSION: Monochromatic energy imaging spectral CT is superior to polychromatic energy images for the detection of intestinal hemorrhage,and the detection was easier in t

关键词： Spectral imaging Computed tomography Monochromatic

Oxidative stress and DNA damages induced by cadmium accumulation

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Journal of Environmental Sciences 2007年第5期19卷 596-602页

作者： LIN Ai-jun ZHANG Xu-hong CHEN mei-mei CAO Qing Department of Environmental Science and Engineering Beijing University of Chemical Technology Beijing 100029 China Department of Soil Environmental Sciences Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Beijing City University Beijing 100083 China

Experimental evidence shows that cadmium （Cd） could induce oxidative stress and then causes DNA damage in animal cells, however, whether such effect exists in plants is still unclear. In the present study, Vicia faba plants was exposed to 5 and 10 mg/L Cd for 4 d to investigate the distribution of Cd in plant, the metal effects on the cell lipids, antioxidative enzymes and DNA damages in leaves. Cd induced an increase in Cd concentrations in plants. An enhanced level of lipid peroxidation in leaves and an enhanced concentration of H2O2 in root tissues suggested that Cd caused oxidative stress in Vicia faba. Compared with control, Cd-induced enhancement in superoxide dismutase activity was significant at 5 mg/L than at 10 mg/kg in leaves, by contrast, catalase and peroxidaseactivities were significantly suppressed by Cd addition. DNA damage was detected by neutral/neutral, alkaline/neutral and alkaline/alkaline Comet assay. Increased levels of DNA damages induced by Cd occurred with reference to oxidative stress in leaves, therefore, oxidative stress induced by Cd accumulation in plants contributed to DNA damages and was possibly an important mechanism of Cd-phytotoxicity in Vicia faba plants.

关键词： Cd Vicia faba oxidative stress DNA damage

A Degenerate KAM Theorem for Partial Differential Equations with Unbounded Perturbations

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Acta Mathematica Sinica,English Series 2024年第11期40卷 2719-2734页

作者： mei Na GAO Jian jun LIU School of Mathematics Physics and Statistics Shanghai Polytechnic UniversityShanghai201209P.R.China School of Mathematics Sichuan UniversityChengdu610065P.R.China

In this paper,an infinite dimensional KAM theorem with unbounded perturbations and double normal frequencies is established under qualitative non-degenerate *** is an extension of the degenerate KAM theorem with bounded perturbations by Bambusi,Berti,Magistrelli,and *** applications,for derivative nonlinear Schrödinger equation with periodic boundary conditions,quasi-periodic solutions around constant solutions are obtained.

关键词： KAM theorem derivative nonlinear Schrödinger equation quasi-periodic solutions