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Recent advances in transition-metal catalyzed nitrene transfer reactions with carbamates

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Chinese Chemical Letters 2024年第3期35卷 76-86页

作者： Yanshu Luo Xinyu zhang Yuanzhi xia College of Chemistry and Materials Engineering Wenzhou UniversityWenzhou 325035China

Nitrene transfer reactions are powerful tools in synthetic organic *** recent years,transitionmetal catalyzed nitrene transfer reactions with carbamates as the nitrene precursors have been widely *** species undergoes facile C-H amination,aziridination,and bifunctionalization of alkenes under the catalysis of different transition metals including Rh,Fe,Ru and others,enabling the efficient construction of various nitrogen-containing *** this review,the recent developments in nitrene transfer reactions with carbamates via N-O bond cleavage were introduced based on different types of reaction,and the key mechanistic information and synthetic applications of the methodologies were discussed.

关键词： Transition-metal catalysis Nitrene transfer Carbamate C—H amination Aziridination Bifunctionalization

N-Heterocyclic carbene-catalyzed enantioselective(dynamic) kinetic resolutions and desymmetrizations

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Science China Chemistry 2024年第2期67卷 482-511页

作者： Yi zhang Hui cai Xiuhai Gan Zhichao Jin National Key Laboratory of Green Pesticide Key Laboratory of Green Pesticide and Agricultural BioengineeringMinistry of EducationGuizhou UniversityHuaxi DistrictGuiyang550025China

N-heterocyclic carbene-catalyzed enantioselective kinetic resolutions,dynamic kinetic resolutions,and desymmetrization reactions are systematically *** content is organized according to the activation modes involved i... 详细信息

关键词： N-heterocyclic carbene kinetic resolution dynamic kinetic resolution desymmetrization organocatalysis

A reduced-order model for fast predicting ionized flows of hypersonic vehicles along flight trajectory

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Chinese Journal of Aeronautics 2024年第1期37卷 89-105页

作者： Jingchao zhang Chunsheng NIE Jinsheng cai Shucheng PAN School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Science and Technology on Space Physics Laboratory China Academy of Launch Vehicle TechnologyBeijing 100076China Institute of Extreme Mechanics Northwestern Polytechnical UniversityXi’an 710072China

An improved Reduced-Order Model(ROM)is proposed based on a flow-solution preprocessing operation and a fast sampling strategy to efficiently and accurately predict ionized hypersonic *** ROM is generated in low-dimensional space by performing the Proper Orthogonal Decomposition(POD)on snapshots and is coupled with the Radial Basis Function(RBF)to achieve fast prediction ***,due to the disparate scales in the ionized flow field,the conventional ROM usually generates spurious negative ***,this issue is addressed by performing flow-solution preprocessing in logarithmic space to improve the conventional ***,extra orthogonal polynomials are introduced in the RBF interpolation to achieve additional improvement of the prediction *** addition,to construct high-efficiency snapshots,a trajectory-constrained adaptive sampling strategy based on convex hull optimization is *** evaluate the performance of the proposed fast prediction method,two hypersonic vehicles with classic configurations,i.e.a wave-rider and a reentry capsule,are used to validate the proposed *** two cases show that the proposed fast prediction method has high accuracy near the vehicle surface and the free-stream region where the flow field is *** with the conventional ROM prediction,the prediction results are significantly improved by the proposed method around the discontinuities,*** shock wave and the ionized *** a result,the proposed fast prediction method reduces the error of the conventional ROM by at least 45%,with a speedup of approximately 2.0×105compared to the Computational Fluid Dynamic(CFD)*** test cases demonstrate that the method developed here is efficient and accurate for predicting ionized hypersonic flows.

关键词： Reduced-order model Radial basis function Constrained sampling Transfer function Fast flow prediction Ionized hypersonic flows

Heterointerface Engineering-Induced Oxygen Defects for the Manganese Dissolution Inhibition in Aqueous Zinc Ion Batteries

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Energy & Environmental Materials 2024年第3期7卷 112-122页

作者： Wentao Qu Yong cai Baohui Chen Ming zhang Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics&Devices School of Physics and ElectronicsHunan UniversityChangsha 410082China Engineering Research Center of Advanced Semiconductor Technology and Application of Ministry of Education&Key Laboratory for Micro-/Nano-Optoelectronic Devices of Ministry of Education College of Semiconductors(College of Integrated Circuits)Hunan UniversityChangsha 410082China Changsha Semiconductor Technology and Application Innovation Research Institute College of Semiconductors(College of Integrated Circuits)Hunan UniversityChangsha 410082China State Key Laboratory of Disaster Prevention&Reduction for Power Grid Transmission and Distribution Equipment(Hunan Electric Power Corporation Disaster Prevention and Reduction Center) Changsha 410007China

Manganese-based material is a prospective cathode material for aqueous zinc ion batteries(ZIBs)by virtue of its high theoretical capacity,high operating voltage,and low ***,the manganese dissolution during the electrochemical reaction causes its electrochemical cycling stability to be *** this work,heterointerface engineering-induced oxygen defects are introduced into heterostructure MnO_(2)(δa-MnO_(2))by in situ electrochemical activation to inhibit manganese dissolution for aqueous zinc ion ***,the heterointerface between the disordered amorphous and the crystalline MnO_(2)ofδa-MnO_(2)is decisive for the formation of oxygen *** the experimental results indicate that the manganese dissolution ofδa-MnO_(2)is considerably inhibited during the charge/discharge *** analysis indicates that the oxygen defect regulates the electronic and band structure and the Mn-O bonding state of the electrode material,thereby promoting electron transport kinetics as well as inhibiting Mn ***,the capacity ofδa-MnO_(2)does not degrade after 100 cycles at a current density of 0.5 Ag^(-1)and also 91%capacity retention after 500cycles at 1 Ag^(-1).This study provides a promising insight into the development of high-performance manganese-based cathode materials through a facile and low-cost strategy.

关键词： electrochemical activation heterointerface manganese dissolution inhibition oxygen defects zinc ion batteries

Performance Enhancement of Single-Phase Immersion Liquid-Cooled Data Center Servers

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Journal of Thermal Science 2024年第5期33卷 1757-1772页

作者： GE Junlei xia Feifan zhang Chengbin HUANG Yongping School of Energy and Environment Southeast UniversityNanjing 210096China Wuhan Digital Engineering Research Institute Wuhan 430205China

As the promising cooling method for the next generation of data centers,the internal heat transport mechanism and enhancement mechanism of single-phase immersion liquid-cooled(SPILC)systems are not yet well *** address this,a steady-state three-dimensional numerical model is constructed herein to analyze flow and thermal transport capacities in servers using SPILC and traditional air-cooling ***,this paper emphasizes the influence of component positioning,and underscores the benefits of optimizing coolant flow distribution using *** results indicate that the SPILC system outperforms the traditional air-cooling approach at the same inlet Reynolds number(Re).When Re=10000,the SPILC method reduces the maximum temperature by up to 70.13%,increases the average convective heat transfer coefficient by287.5%,and provides better overall thermal uniformity in data center ***,placing devices downstream of high-power components creates"thermal barriers"and degrades thermal transport for upstream devices due to increased flow *** spacing between high-power devices can lead to the formation of bypass channels,further deteriorating heat ***,the addition of baffles in the inlet section of SPILC systems effectively enhances heat dissipation *** maximize the heat dissipation capacity,minimizing bypass channels and optimizing the flow distribution of coolants are crucial.

关键词： single-phase immersion liquid-cooled performance enhancement data center

Efficient energy transfer from self-trapped excitons to Mn^(2+) dopants in CsCdCl_(3):Mn^(2+) perovskite nanocrystals

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1456-1461页

作者： Anran zhang Xinquan Zhou Ranran Gu Zhiguo xia State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied TechniquesSchool of Materials Science and EngineeringSouth China University of TechnologyGuangzhou 510641China School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510641China

Mn^(2+)doping has been adopted as an efficient approach to regulating the luminescence properties of halide perovskite nano-crystals(NCs).However,it is still difficult to understand the interplay of Mn^(2+)luminescence and the matrix self-trapped exciton(STE)emission *** this study,Mn^(2+)-doped CsCdCl_(3) NCs are prepared by hot injection,in which CsCdCl_(3) is selected because of its unique crystal structure suitable for STE *** blue emission at 441 nm of undoped CsCdCl_(3) NCs originates from the defect states in the ***^(2+)doping promotes lattice distortion of CsCdCl_(3) and generates bright orange-red light emission at 656 *** en-ergy transfer from the STEs of CsCdCl_(3) to the excited levels of the Mn^(2+)ion is confirmed to be a significant factor in achieving efficient luminescence in CsCdCl_(3):Mn^(2+)*** work highlights the crucial role of energy transfer from STEs to Mn^(2+)dopants in Mn^(2+)-doped halide NCs and lays the groundwork for modifying the luminescence of other metal halide perovskite NCs.

关键词： perovskite nanocrystals self-trapped excitons luminescence energy transfer

Examining the association between delay discounting,delay aversion and physical activity in Chinese adults with type-2 diabetes mellitus

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World Journal of Diabetes 2024年第4期15卷 675-685页

作者： Yong-Dong An Guo-xia Ma Xing-Kui cai Ying Yang Fang Wang Zhan-Lin zhang Department of Endocrinology People's Hospital of Linxia Hui Autonomous PrefectureLinxia Hui Autonomous Prefecture 731100Gansu ProvinceChina Department of Gynecology People's Hospital of Linxia Hui Autonomous PrefectureLinxia Hui Autonomous Prefecture 731100Gansu ProvinceChina The First Clinical Medical College Lanzhou UniversityLanzhou 730013Gansu ProvinceChina Department of Internal Medicine People's Hospital of HezhengLinxia Hui Autonomous Prefecture 731200Gansu ProvinceChina Department of Geratology People's Hospital of Linxia Hui Autonomous PrefectureLinxia Hui Autonomous Prefecture 731100Gansu ProvinceChina Department of Medical People's Hospital of Linxia Hui Autonomous PrefectureLinxia Hui Autonomous Prefecture 731100Gansu ProvinceChina

BACKGROUND The role of physical activity in diabetes is critical,influencing this disease's development,man-agement,and overall *** China,22.3%of adults do not meet the minimum level of physical activity recommended by the World Health ***,it is imperative to identify the factors that contributing to lack of physical activity must be *** To investigate the relationship among delay discounting,delay aversion,glycated hemoglobin(HbA1c),and various levels of physical activity in Chinese adults diagnosed with type 2 diabetes mellitus(T2DM).METHODS In 2023,400 adults with T2DM were recruited from the People's Hospital of Linxia Hui Autonomous Prefecture of Gansu Province.A face-to-face questionnaire was used to gather demographic data and details on physical activity,delay discounting,and delay *** addition,HbA1c levels were measured in all 400 *** primary independent variables considered were delay discounting and delay *** outcome variables included HbA1c levels and different intensity levels of physical activity,including walking,moderate physical activity,and vigorous physical *** linear regression models were utilized to assess the relationship between delay discounting,delay aversion,and HbA1c levels,along with the intensity of different physical activity measured in met-hours per *** After controlling for the sample characteristics,delay discounting was negatively associated with moderate physical activity(β=-2.386,95%CI:-4.370 to-0.401).Meanwhile,delay aversion was negatively associated with the level of moderate physical activity(β=-3.527,95%CI:-5.578 to-1.476)in the multiple linear regression model,with statistically significant *** Elevated delay discounting and increased delay aversion correlated with reduced levels of moderate physical *** suggests that delay discounting and aversion may influence engagement in moderate physical activity.

关键词： Type 2 diabetes mellitus Delay discounting Delay aversion Physical activity

Study on cumulative effects of biological craniocerebral trauma under repeated blast

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Theoretical & Applied Mechanics Letters 2024年第3期14卷 174-183页

作者： Xingyuan Huang Bingchen xia Lijun Chang Zhikang Liao Hui Zhao Zhihua cai Hunan Provincial Key Laboratory of Health Maintenance for Mechanical Equipment Hunan University of Science and TechnologyXiangtan 411201China School of Mechanical and Electrical Engineering Foshan UniversityFoshan 528231China Institute for Traffic Medicine PLA Army Characteristic Medical CenterChongqing 400042China

Repeated blast impacts on personnel in explosive environments can exacerbate craniocerebral *** existing studies focus on the injury effects of a single blast,lacking in-depth analysis on the injury effects and cumulative effects of repeated ***,rats were used as the experimental samples to suffer from explosion blasts with different peak air overpressures(167 kPa~482 kPa)and varying number of repeated *** cumulative effect of craniocerebral trauma was most pronounced for moderate repeated blast,showing approximately 95%increase of trauma severity with penta blast,and an approximately 85%increase of trauma severity with penta minor *** cumulative effect of craniocerebral trauma from severe,repeated blast has a smaller rate of change compared to the other two *** severity of trauma from penta blast increased by approximately 69%compared to a single *** physiological,pathological and biochemical analysis show that the degree of neurological trauma caused by repeated blasts is higher than that of single blasts,and the pathological trauma to brain tissue is more extensive and *** trauma degree remains unchanged after double blast,increases by one grade after triple or quadruple blast,and increases by two grades after penta blast.

关键词： Repeated blast Craniocerebral trauma Trauma severity grade Cumulative effects

Laparoscopic radical cystectomy with orthotopic ileal neobladder in the female： report of 14 cases

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Chinese Medical Journal 2008年第10期121卷 923-926页

作者： LIN Tian-xin zhang cai-xia XU Ke-wei HUANG Hai JIANG Chun HAN Jin-li YAO You-sheng GUO Zheng-hui XIE Wen-lian YIN Xin-bao HUANG Jian Department of Urology Second Affiliated Hospital Sun Yat-sen University Guangzhou Guangdong 510120 China

Background Bladder carcinoma is the most common malignant urological tumor in China. We present our preliminary experience and results of laparoscopic radical cystectomy （LRC） with orthotopic ileal neobladder in female patients with bladder carcinoma. Methods From February 2003 to February 2008, 14 female patients with bladder carcinoma underwent LRC with orthotopic ileal neobladder. Nine of these patients underwent hysterectomy and ovariectomy, and the other 5 had preservation of the uterus and ovarian appendage. Standard bilateral pelvic lymphadenectomy was followed by radical cystectomy that was completed laparoscopically with hysterectomy and ovariectomy when needed. The tumor was removed by a 4-5 cm lower midline abdominal incision, followed by the construction of ileal neobladder and the extracorporeal anastomosis of ureter-neobladder. The neobladder was anastomosed to the urethral stump under a laparoscope. Results The mean operative time and blood loss in the 14 patients were 350.2 minutes and 349.8 ml, respectively. Postoperative complications included uretero-pouch anastomotic stricture in 1 patient and pouch-vaginal fistula in 1 patient. Follow-up time of all patients ranged from 3 to 60 months, and 12 patients were followed up for more than 6 months and achieved micturition in half a year. One patient had occasional day-time urinary incontinence and 2 had night-time incontinence. Two patients who had undergone hystectomy and ovariectomy had voiding difficulties after one year, which was treated by intermittent self-catheterization. The mean volume of the neobladder and the residual urine were 333.6 ml and 31.2 ml, respectively. Surgical margins were tumor free for all patients. One patient had bone metastasis and died 11 months after the operation. Conclusions LRC with orthotopic ileal neobladder in female patients is a technically feasible, safe and mini-invasive procedure with a low morbidity and acceptable neobladder function. Long-term follow-u

关键词： bladder cancer laparoscopy ileal neobladder