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Quinine-derived thiourea promoted enantioselective Michael addition reactions of 3-substituted phthalides to maleimides

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Science China Chemistry 2019年第5期62卷 649-652页

作者： jie Wang xin li Jin-Pei Cheng State Key Laboratory of Elemento-Organic Chemistry Collaborative Innovation Center of Chemical Science and EngineeringCollege of ChemistryNankai University

A highly diastereoselective and enantioselective Michael addition/desymmetrization reaction of maleimides with prochiral 3-substituted phthalides catalyzed by quinine-derived bifunctional thiourea was realized. A broad range of the 3,3′-disubstituted phthalides bearing vicinal quaternary-tertiary stereogenic centers were synthesized in moderate to good yields(up to 96%) with high diastereoselectivities(up to >19:1 dr) and enantioselectivities(up to 96:4 er).

关键词： michael addition 3,3′-disubstituted phthalides vicinal quaternary-tertiary stereogenic centers

Growth hormone stimulates remnant small bowel epithelial cell proliferation

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World Journal of Gastroenterology 2000年第6期6卷 909-913页

作者： xin Zhou Ning li jie Shou li Medical School Nanjing UniversityNanjing 210093Jiangsu ProvinceChina Research Institute of General Surgery Jinling HospitalNanjing 210002Jiangsu ProvinceChina

INTRODUCTIONCurrently the major treatment choices for shortbowel syndrome are parenteral nutrition and smallbowel *** therapies involvegreat fiscal challenge and recurring *** years have witnessed the promisingexperim... 详细信息

关键词： short bowel syndrome insulin-like growth factor I intestine small/surgery proliferation growth hormone intestinal mucosa rats

Dynamical behavior of a delayed prey-predator-scavenger system with fear effect and linear harvesting

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International Journal of Biomathematics 2021年第4期14卷 159-188页

作者： xin-You Meng jie li School of Science Lanzhou University of Technology LanzhouGansu 730050P.R.China College of Technology and Engineering Lanzhou University of Technology Lanzhou Gansu 730050P.R.China

In this paper,we propose a delayed prey-predator-scavenger system with fear effect and linear ***,we discuss the existence and stability of all possible ***,we investigate the existence of Hopf bifurcation of the delayed system by regarding the gestation period of the scavenger as a bifurcation ***,we obtain the direction of Hopf bifurcation and the stability of bifurcating periodic solutions by using the normal form theory and the central manifold *** addition,we give the optimal harvesting strategy of the delayed system based on Pontryagin's maximum principle with ***,some numerical simulations are carried out to verify our theoretical results.

关键词： Prey-predator-scavenger fear effect time delay Hopf bifurcation optimal harvesting policy

Numerical Study on the Unsteady Characteristics of the Propeller Cavitation in Uniform and Nonuniform Wake Flows

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China Ocean Engineering 2020年第5期34卷 688-696页

作者： GONG Zhao-xin CHEN Ying li jie CHEN xin LU Chuan-jing Key Laboratory of Hydrodynamics(Ministry of Education) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Propeller cavitation is a problematic issue because of its negative effects, such as performances losses, noise,vibration and erosion. Numerical methodology is an effective and efficient technical tool for the study of propeller cavitation, however, it is hard to capture tip-vortex cavitation in the previous work by using common turbulence models based on turbulent-viscosity hypothesis. In this work, the Reynolds-Averaged Naiver-Stokes(RANS)approach, adopting the Reynolds stress turbulence model(RSM), is taken to study the unsteady characteristics of the cavitation on the four-bladed INSEAN E779 A model propeller. The numerical simulation was carried out using the commercial CFD software ANSYS Fluent 14.0. One kind of uniform wake flow and two kinds of nonuniform wake flows are considered here. The results in the uniform flow show a good agreement with previous experimental results on both the sheet cavitation and the tip vortex cavitation and prove the ability of the RSM on capturing the tip vortex cavitation. Two kinds of nonuniform wake flows are designed based on the previous experimental researches and the unsteady characteristics of the propeller cavitation are analyzed by comparing the results in the uniform and two nonuniform wake flows together.

关键词： propeller cavitation wake flow Reynolds stress model

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bFGF在大鼠牙齿发育过程中表达的研究

牙体牙髓牙周病学杂志 2012年第6期22卷 327-329页

作者：黄鑫袁杰李蕾张磊张晓丹孙祥云哈尔滨医科大学口腔医学院黑龙江哈尔滨150001

目的:观察碱性成纤维细胞生长因子(basicfibroblastgrowthfactor,bFGF)在大鼠牙齿发育过程中的表达和分布变化,探讨bFGF在大鼠牙齿发育过程中的作用。方法:选用5、10、15、20、25d的大鼠,制备大鼠牙齿发育组织标本,采用免疫组织化学方... 详细信息

目的:观察碱性成纤维细胞生长因子(basicfibroblastgrowthfactor,bFGF)在大鼠牙齿发育过程中的表达和分布变化,探讨bFGF在大鼠牙齿发育过程中的作用。方法:选用5、10、15、20、25d的大鼠,制备大鼠牙齿发育组织标本,采用免疫组织化学方法观察bFGF在大鼠牙齿不同阶段的表达情况。结果:在大鼠牙齿发育早期bFGF主要在成釉细胞表达,而在中间层和牙乳头表达较少。随着牙齿的发育,在成釉细胞、成牙本质细胞、前期牙本质和牙乳头表达逐渐加强。结论:bFGF可能与大鼠前期牙本质的沉积,牙釉质和牙本质的发育形成有关。

关键词： bFGF 牙齿发育免疫组化大鼠

新辅助静脉化疗治疗中晚期宫颈癌患者的临床效果及机制分析

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现代生物医学进展 2017年第11期17卷 2113-2115,2105页

作者：祁青玲丁鑫李洁万颜婕郭桂兰王烈宏青海红十字医院妇科青海西宁810000 青海大学医学院附属医院妇科青海西宁810000

目的:探讨新辅助静脉化疗对中晚期宫颈癌患者的临床疗效及其可能作用机制。方法:收集于我院就诊或住院治疗的60例宫颈癌患者,根据治疗方案不同分为实验组和对照组,每组各30例。对照组患者采用放疗方案,实验组患者在对照组基础上应用新... 详细信息

目的:探讨新辅助静脉化疗对中晚期宫颈癌患者的临床疗效及其可能作用机制。方法:收集于我院就诊或住院治疗的60例宫颈癌患者,根据治疗方案不同分为实验组和对照组,每组各30例。对照组患者采用放疗方案,实验组患者在对照组基础上应用新辅助静脉化疗方案,21 d为一疗程,共2个疗程。治疗期间密切注意患者的生命体征,并对出现的并发症进行及时治疗。治疗结束后,对患者的血清肿瘤坏死因子-α(TNF-α)、血管内皮生长因子(VEGF)、患者副作用发生率以及临床疗效进行检测并比较。结果:与治疗前相比,两组患者治疗后的血清TNF-α、VEGF水平均显著下降(P<0.05);与对照组相比,实验组患者治疗后的血清TNF-α、VEGF水平及副作用发生率较低(P<0.05),临床治疗总有效率较高(P<0.05)。结论:新辅助静脉化疗能够显著提高中晚期宫颈癌患者的临床疗效并减少化疗相关的不良反应,这可能与其降低中晚期宫颈癌患者血清TNF-α、VEGF水平有关。

关键词：新辅助静脉化疗宫颈癌肿瘤坏死因子-α 血管内皮生长因子

A Novel Combinatorics-Based Reconfigurable Bit Permutation Network and Its Circuit Implementation

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Chinese Journal of Electronics 2015年第3期24卷 513-517页

作者： SHAN Weiwei CHEN xin LU Yinchao li jie National ASIC System Engineering Research Center Southeast University College of Electronic & Information Engineering Nanjing University of Aeronautics & Astronautics

Bit permutation is an important operation in many applications. A novel reconfigurable N × N bit permutation network with a compact structure is presented. It is based on combinatorics theory by cascading two recursive N/2 × N/2 sub-networks, while each subnetwork is cascaded by two N/4 × N/4 sub-networks, and so on cascaded until reaching the elementary 4 × 4 seed networks. Its routing algorithm is also established to determine each multiplexor’s status. Then the circuits of different sized permutation networks in a reconfigurable cipher co-processor were designed and implemented in 0.18μm CMOS process. The proposed circuit can achieve an arbitrary n × n permutation and support all types of bit permutations in many cryptographic algorithms. Plus, it consumes less multiplexors than commonly used BENES and OMFliP networks.

关键词： Bit permutation Reconfigurable Cryptographic circuit Digital integrated circuits

Assessing field vulnerability to phosphorus loss in Beijing agricultural area using Revised Field Phosphorus Ranking Scheme

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Journal of Environmental Sciences 2007年第8期19卷 977-985页

作者： li Qi CHEN li-ding QI xin ZHANG xin-yu MA Yan FU Bo-jie State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China. Graduate University of Chinese Academy of Sciences Beijing 100049 China

Guanting Reservoir, one of the drinking water supply sources of Beijing, suffers from water eutrophication. It is mainly supplied by Guishui River. Thus, to investigate the reasons of phosphorus （P） loss and improve the P management strategies in Guishui River watershed are important for the safety of drinking water in this region. In this study, a Revised Field P Ranking Scheme （PRS） was developed to reflect the field vulnerability of P loss at the field scale based on the Field PRS. In this new scheme, six factors are included, and each one was assigned a relative weight and a determination method. The affecting factors were classified into transport factors and source factors, and, the standards of environmental quality on surface water and soil erosion classification and degradation of the China were used in this scheme. By the new scheme, thirty-four fields in the Guishui River were categorized as ＂low＂, ＂medium＂ or ＂high＂ potential for P loss into the runoff. The results showed that the P loss risks of orchard and vegetable fields were higher than that of corn and soybean fields. The source factors were the main factors to affect P loss from the study area. In the study area, controlling P input and improving P usage efficiency are critical to decrease P loss. Based on the results, it was suggested that more attention should be paid on the fields of vegetable and orchard since they have extremely high usage rate of P and high soil test of P. Compared with P surplus by field measurements, the Revised Field PRS was more suitable for reflecting the characteristics of fields, and had higher potential capacity to identify critical source areas of P loss than PRS.

关键词： phosphorus loss risk assessment field scale revised phosphorus ranking scheme management strategy

The equilibrium stability for a smooth and discontinuous oscillator with dry friction

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Acta Mechanica Sinica 2016年第2期32卷 309-319页

作者： Zhi-xin li Qing-jie Cao Alain Léger School of Astronautics Centre for Nonlinear Dynamics Research Harbin Institute of Technology Harbin 150001 China Laboratoire de Mecanique et d' Acoustique CNRS 31 Chemin Joseph Aiguier 13402 Marseille Cedex 20 France

In this paper,we investigate the equilibrium stability of a Filippov-type system having multiple stick regions based upon a smooth and discontinuous（SD） oscillator with dry *** sets of equilibrium states of the system are analyzed together with Coulomb friction conditions in both（ f_n,f_s） and（x,˙x） *** the stability analysis,Lyapunov functions are constructed to derive the instability for the equilibrium set of the hyperbolic type and La Salle＇s invariance principle is employed to obtain the stability of the nonhyperbolic *** demonstrates the existence of a thick stable manifold and the interior stability of the hyperbolic equilibrium set due to the attractive sliding mode of the Filippov property,and also shows that the unstable manifolds of the hyperbolic-type are that of the endpoints with their saddle *** calculations show a good agreement with the theoretical analysis and an excellent efficien y of the approach for equilibrium states in this particular Filippov ***,the equilibrium bifurcations are presented to demonstrate the transition between the smooth and the discontinuous regimes.

关键词： SD oscillator Equilibrium set Dry friction Coulomb’s cone