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Isoselective Ring-opening Polymerization of Racemic Lactide Catalyzed by N-heterocyclic Olefin/(Thio)urea Organocatalysts

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Chinese Journal of Polymer Science 2021年第6期39卷 709-715,I0006页

作者： Zhen-Yu Wang Guang-Qiang Xu Li Zhou Cheng-Dong lv Ru-Lin Yang Bing-Zhe Dong Qing-Gang Wang Key Laboratory of Biobased Materials Qingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdao 266101China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

The isoselective ring-opening polymerization of racemic lactide was achieved by combining N-heterocyclic olefin(NHO)with mono(thio)ureas or bis(thio)ureas as catalytic *** polymerization process shows high stereoselectivity,controllability and reactivity,delivering multi-block isotactic polylactides with high chain-end fidelity and narrow molecular weight *** enhancement of catalytic performance was observed in the following order:bisthiourea(DTU)

关键词： mechanism. heterocyclic polymerization

无菌体液分离病原菌菌种构成分布情况及耐药性变迁

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齐齐哈尔医学院学报 2024年第12期45卷 1156-1166页

作者：吕宏培王远刘丽萍王优良曹明月大庆龙南医院检验科黑龙江大庆163000 大庆龙南医院输血科黑龙江大庆163000

目的了解2017—2023年本院无菌体液标本检出病原菌的分布及其耐药性变迁,为本地区医疗机构经验使用抗菌药物提供及时依据。方法选取2017—2023年本院无菌体液标本,排除同一患者重复株,使用WHONET 5.6软件对药物敏感性数据进行统计分析... 详细信息

目的了解2017—2023年本院无菌体液标本检出病原菌的分布及其耐药性变迁,为本地区医疗机构经验使用抗菌药物提供及时依据。方法选取2017—2023年本院无菌体液标本,排除同一患者重复株,使用WHONET 5.6软件对药物敏感性数据进行统计分析。结果共检出菌株6711株,其中革兰阴性杆菌3927株,革兰阳性球菌2530株,真菌145株,厌氧菌59株。分离病原菌前五位依次为大肠埃希菌、凝固酶阴性葡萄球菌、肺炎克雷伯菌、金黄色葡萄球菌、铜绿假单胞菌。肠杆菌目细菌中,大肠埃希菌和阴沟肠杆菌对常用抗菌药物的耐药性较稳定,肺炎克雷伯菌对抗菌药物的耐药性明显升高。大肠埃希菌和肺炎克雷伯菌对碳青霉烯类耐药率平均为1.2%和12.8%。铜绿假单胞菌对常用抗菌药物的耐药率较低且有降低趋势,鲍曼不动杆菌对常用抗菌药物的耐药率较高且稳定。甲氧西林耐药金黄色葡萄球菌(MRSA)和甲氧西林耐药凝固酶阴性葡萄球菌(MRCNS)的检出率分别为31.2%和71.4%,两者对常用抗菌药物的耐药性较稳定,MRSA的检出率有一定程度的降低。屎肠球菌和粪肠球菌对万古霉素和利奈唑胺均保持高度活性,对常用抗菌药物的耐药性较稳定。结论2017—2023年本院无菌体液病原菌以革兰阴性杆菌为主。及时监测病原菌种类、分布和耐药情况以指导临床合理用药,可有效减缓细菌耐药性的产生。

关键词：无菌体液病原菌耐药性耐药率变迁

Reconstruction of Core-Shell Dispersed Particles in Impact Polypropylene Copolymer during Extrusion

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Chinese Journal of Polymer Science 2015年第4期33卷 633-645页

作者： Feng Chen Bi-wei Qiu Ya-nan Ye Yu-hua lv 上官勇刚 Yi-hu Song 郑强 MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang University

We reported an approach to reconstruct the complex phase morphology of impact polypropylene copolymer （IPC） with core-shell dispersed particles and to optimize its toughness in approximate shear condition. The molten-state annealing results indicate that the phase structure with core-shell dispersed particles is unstable and could be completely destroyed by static annealing, resulting in the degradation of impact strength. By using a co-rotating twin screw extruder, we found that the dispersed particle with core-shell structure could be rebuilt in appropriate condition with the recovery of excellent impact strength due to both the huge interfacial tension during solidification and the great difference in viscosity of components. Results reveal that almost all the extruded IPCs show the impact strength 60%-90% higher than that of annealed IPCs at room temperature. And the twice-extruded IPC shows the highest impact strength, 446% higher than that of IPC annealed for 30 min. As for low temperature tests, the impact strength of extruded IPCs also increases by 33%-58%. According to adjusting the processing conditions including extrusion speed, extrusion frequency and temperature, an optimization of toughness was well established.

关键词： Impact polypropylene copolymer Shear Phase morphology Core-shell dispersed particle Impact strength.

Electron doping induced semiconductor to metal transitions in ZrSe2 layers via copper atomic intercalation

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Nano Research 2018年第9期11卷 4914-4922页

作者： Zahir Muhammad Kejun Mu Haifeng lv Chuanqiang Wu Zia ur Rehman Muhammad Habib Zhe Sun Xiaojun Wu Li Song National Synchrotron Radiation Laboratory CAS Center for Excellence in Nanoscience CAS Key Laboratory of Strongly-coupled Quantum Matter Physics University of Science and Technology of China Hefei 230029 China CAS Key Laboratory of Materials for Energy Conservation Synergetic Innovation Centre of Quantum Information & Quantum Physics CAS Center for Excellence in Nanoscience and Department of Material Science and Engineering University of Science and Technology of China Hefei 230026 China

Atomic intercalation in two-dimensional （2D） layered materials can be used to engineer the electronic structure at the atomic scale and generate tuneable physical and chemical properties which are quite distinct in comparison with the pristine material. Among them, electron-doped engineering induced by intercalation is an efficient route to modulate electronic states in 2D layers. Herein, we demonstrate a semiconducting to metallic phase transition in zirconium diselenide （ZrSe2） single crystals via controllable incorporation of copper （Cu） atoms. Our angle resolved photoemission spectroscopy （ARPES） measurements and first-principles density functional theory （DFT） calculations dearly revealed the emergence of conduction band dispersion at the M/L point of the Brillouin zone due to Cu-induced electron doping in ZrSe2 interlayers. Moreover, electrical measurements in ZrSe2 revealed semiconducting behavior, while the Cu-intercalated ZrSe2 exhibited a linear current-voltage curve with metallic character. The atomic intercalation approach may have high potential for realizing transparent electron-doping systems for many specific 2D-based nanoelectronic applications.

关键词： layered materials phase transition angle resolved photoemission spectroscopy electron doping

Highly sensitive humidity sensors based on hexagonal boron nitride nanosheets for contactless sensing

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Nano Research 2023年第7期16卷 10279-10286页

作者： Hang Liu Jinxu Qin Xigui Yang Chaofan lv Wentao Huang Fukui Li Chuang Zhang Yanran Wu Lin Dong Chongxin Shan Henan Key Laboratory of Diamond Optoelectronic Materials and Devices Key Laboratory of Materials PhysicsMinistry of EducationSchool of Physics&MicroelectronicsZhengzhou UniversityZhengzhou 450052China Institute of Quantum materials and Physics Henan Academy of SciencesZhengzhou 450046China

Humidity sensors with high sensitivity,rapid response,and facile fabrication process for contactless sensing applications have received considerable attention in recent ***,humidity sensors based on hexagonal boron nitride(h-BN)nanosheets that are synthesized by a facile ultrasonic process have been fabricated,which display an ultrahigh sensitivity of 28,384%at 85%relative humidity(RH),rapid response/recovery time(3.0/5.5 s),and long-term stability in a wide humidity detection range(11%-85%RH),superior to most of the reported humidity *** high sensitivity can be ascribed to the massive hydrophilic functional groups absorbed on the h-BN nanosheet *** from the high humidity sensing performances,contactless Morse code messaging and human writing and speech recognition have been *** work demonstrates the great potential of the high-performance h-BN nanosheet-based humidity sensors for future contactless sensing devices.

关键词： boron nitride humidity sensors contactless detection speech recognition

A novel data channel fault detection mechanism in optical burst switching networks

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High Technology Letters 2007年第3期13卷 307-311页

作者：常交法 Wang Ruyan Long Keping Yang Xiaolong lv Kewei Duan Zhenying Special Research Centre for Optical Intemet and Wireless Infonnation Networks Chongqing University of Posts and Telecom Chongqing 400065 P.R. China Patent Examination Cooperation Center of State Intellectual Property Office of PRC Beijing 100083 P.R. China School of Communication and Infonnation Engineering University of Electronic Science and Technology of China Chengdu 610054 P.R. China

Fault detection in optical burst switching （OBS） networks will be a challenging task in the future. A novel mechanism based on probe burst （PB） and a new key concept is proposed to detect faults of OBS networks by sampling the health of data channels, which solve the difficulty of optical monitoring schemes while keeps the transparency of data network to Internet protocol （IP） packets. It takes full advantage of the characteristics of OBS, including architecture and signalling scheme, and introduces the excellent performances of single-hop-test used in electrical communication networks into OBS environment while avoids the shortcoming that any optical burst must undergo an optical-electric-optical （OEO） conversion. Well designed PB can provide exact criterion for judging whether protection/restoration should be excuted according to hard or soft fault identification.

关键词： optical burst switching (OBS) fault detection fault management all-optical network probe burst(PB)

Enhanced unipolar electrical fatigue resistance and related mechanism in grain-oriented Pb(Mg_(1/3)Nb_(2/3))O_(3)-Pb(Zr,Ti)O_(3)piezoceramics

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Journal of Materials Science & Technology 2023年第14期145卷 40-47页

作者： Linjing Liu Bin Yang Rui lv Qiangwei Kou Shuai Yang Hang Xie Yuan Sun Yunfei Chang Shan-Tao Zhang Fei Li Functional Materials and Acousto-Optic Instruments Institute School of Instrumentation Science and EngineeringHarbin Institute of TechnologyHarbin 150080China Electronic Materials Research Laboratory(Key Lab of Education Ministry) State Key Laboratory for Mechanical Behavior of Materials and School of Electronic Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China National Laboratory of Solid State Microstructures and College of Engineering and Applied Science Nanjing UniversityNanjing 210093China

Piezoceramics with high and fatigue-resisted piezoelectric properties are strongly desired for actuator *** this work,textured Pb(Mg_(1/3)Nb_(2/3))O_(3)-Pb(Zr,Ti)O_(3)ceramics with Lotgering factor F_(001)∼98%were fabricated by templated grain growth ***[001]c-grain orientation(f∼90%and r∼0.22)of the textured ceramics effectively produced about 230%enhanced piezoelectric coefficient d_(33)^(∗)(i.e.,S_(max)/E_(max))and substantially improved unipolar electrical fatigue *** polarization P max and d_(33)^(∗)of the textured ceramics were nearly maintained up to 106 unipolar cycles,while 19%and 14%degradations were respectively observed from randomly oriented ***,normal-ized d_(33)^(∗)of the textured ceramics shows better unipolar fatigue resistance than those of piezoceramics reported *** lower bipolar strain asymmetryγs(∼4%)was observed from the textured samples fatigued after 106 unipolar cycles as compared toγs∼23%for randomly oriented *** charged defect accumulation model described the serious fatigue deteriorations in randomly ori-ented ceramics,the current work revealed that substantially enhanced unipolar fatigue resistance of the textured ceramics is mainly associated with the inherent fatigue anisotropy,weakened local bias fields owing to both enhanced domain mobility and lower defect density near grain boundaries/interfaces,and increased intrinsic contribution due to more tetragonal *** superior characteristics suggest the great potential of textured ceramics for high-performance and robust actuator applications.

关键词： Ceramics Grain orientation Piezoelectric strain Unipolar fatigue Defect accumulation

An Improved WM Fuzzy Modeling Method for Blast Furnace Gas System

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An Improved WM Fuzzy Modeling Method for Blast Furnace Gas S...

UHPC套拱加固技术在柏垭子隧道中的应用研究

第36届中国控制会议

作者： Yanwei Zhai Zheng lv Ying Liu Jun Zhao Wei Wang School of Control Science and Engineering Dalian University of Technology

ISBN: (纸本)9781538629185

The blast furnace gas is an important secondary energy for the iron and steel *** an effective model to describe the state of BFG system is of great significant to maintain the system balance and *** the strong coupling characteristics of the blast furnace gas system and the high level noises in the industrial data,a simplex unscented kalman filter-based Wang-Mendel modeling method is proposed in this paper to improve the accuracy and generalization ability of the fuzzy *** the proposed method,the maximum posterior estimation of the center value in each fuzzy rule space is calculated in the probability density distribution perspectives by incorporating the kalman filtering method into rule extraction process,which eliminates the influence of noises effectively and improves the accuracy of the fuzzy *** experimental results by using the Lorenz time series with noises and the industrial data demonstrated that the proposed method could extract the fuzzy rules from the data accurately and had good performance for blast furnace gas system modeling.

关键词： Wang-Mendel fuzzy model simplex unscented kalman filter rules extraction blast furnace gas system

来源： cnki会议评论

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山西建筑 2024年第17期50卷 148-151页

作者：刘琴宝朱小明吕维东王庆蒲建军甘肃省陇南公路事业发展中心甘肃兰州746005 甘肃省交通规划勘察设计院股份有限公司甘肃兰州730030

通过调研国内公路隧道套拱加固技术,分析了UHPC套拱的应用场景,提出了适用于两车道公路运营隧道的UHPC套拱预制单元划分,并依托实际工程分析了套拱装配施工中的质量控制等关键问题。研究表明:UHPC套拱的应用场景为衬砌结构厚度不足伴随... 详细信息

通过调研国内公路隧道套拱加固技术,分析了UHPC套拱的应用场景,提出了适用于两车道公路运营隧道的UHPC套拱预制单元划分,并依托实际工程分析了套拱装配施工中的质量控制等关键问题。研究表明:UHPC套拱的应用场景为衬砌结构厚度不足伴随衬砌裂缝等严重病害缺陷,既有建筑限界富余不足以使用传统混凝土套拱加固的公路隧道;两车道公路隧道UHPC套拱宜划分为拱顶、左右拱肩、左右拱腰、左右墙脚共7个单元进行预制,叠合式套拱应增加与既有衬砌的连接;套拱单元精准安装就位技术是套拱装配施工的关键技术,直接决定了套拱加固的成败,研发一款适用于装配式套拱加固施工的公路隧道专业设备是保证施工质量的关键。10 cm厚度UHPC套拱在柏垭子隧道中加固效果良好,可为同类型病害运营公路隧道的维修加固提供借鉴。

关键词：衬砌加固技术 UHPC套拱套拱装配施工技术加固效果