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Evaluation on cutting performance of novel PDC cutter for pipe jacking machine

Underground Space 2024年第1期14卷 34-52页

作者： Long-Chuan Deng Yi-Xiang Yuan xiao-zhao li Qian-Wei Zhuang Chi Zhang Yi-Wei Chen School of Earth Sciences and Engineering Nanjing UniversityNanjingJiangsu 210023China Shanghai Tunnel Engineering Co.Ltd. Shanghai 200232China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhouJiangsu 221116China School of Mechanics and Engineering Science Shanghai UniversityShanghai 200444China

It is inevitable to cut reinforced concrete(RC)appeared in cross passage of city metro by cutting tools when constructing in densely populated *** previous cutters employed to cut RC are insufficient and easily damaged,so a new polycrystalline diamond compact(PDC)cutter is used to solve this *** on the theoretical analysis of cutting mechanism,both circular and tapered PDC cutters with cutting edge angle of 90and negative front rack angle of 10are used to cut *** peeling and breaking patterns of cutting concrete are proposed,the nodular and grainy chips are the preferred modes in cutting steel *** LS-DYNA is employed to investigate the cutting performance in *** simulation results show that the average and peak cutting forces increase with the growth of penetration depth,cutting speed,and roundness,and subsequently the recommended penetration depth less than 1.2 mm is obtained to cut RC due to the existence of steel ***,the linear cutting platform is adopted to investigate the force ability and damage state of PDC *** is concluded that the cutting force increases abruptly and fluctuates heavily when cutting the coarse *** patterns occurred in both numerical and experimental results are generally ***,the steel bar is pulled out and the PDC cutter is damaged at the penetration depth of 0.8 mm,while a good cut occurs at the penetration depth of 0.3 *** tapered PDC cutter with a relatively low cutting force is prone to be broken compared with circular PDC *** is suggested that the circular PDC cutter at the penetration depth of 0.3 mm should be used to cut RC in practical engineering.

关键词： PDC cutter RC Pipe jacking machine linear cutting tests Damage and wear LS-DYNA

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Redox-Active Dihydrophenazine-Based Macrocycle:Synthesis,Conformation-Adaptive Behavior and Host-Guest Complexation with Tetracyanoquinodimethane

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Chinese Journal of Chemistry 2024年第16期42卷 1895-1900页

作者： Qiong-Yan Hong Bin Huang Meng-Xiang Wu lin Xu xiao-li zhao Xueliang Shi Hai-Bo Yang Shanghai Key Laboratory of Green Chemistry and Chemical Processes State Key Laboratory of Petroleum Molecular&Process EngineeringSchool of Chemistry and Molecular EngineeringEast China Normal University3663 N.Zhongshan RoadShanghai 200062China

A novel macrocycle based on conformation-adaptive and electron-rich dihydrophenazine was designed and *** the one hand,the macrocycle showed host-guest interactions with tetracyanoquinodimethane(TCNQ)driving by charge transfer interaction between ***,host-guest complexation was accompanied by fluorescence quenching and conformational change of the *** the other hand,the oxidation of the macrocycle resulted in its diradical cation analogue and induced the release of the guest molecule TCNQ,thereby accomplishing reversible binding ***,this work wellillustrates the chemical and structural versatility of dihydrophenazine in the synthesis of macrocycles and their host-guest chemistry.

关键词： Dihydrophenazine Macrocycle Conformational adaptation Redox-active Host-guest interactions Charge transfer interaction Organic radical Supramolecular chemistry

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Sequence Engineering in Tuning the Circularly Polarized Luminescence of Aggregation-Induced Emission-Active Hetero[3]rotaxanes

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CCS Chemistry 2024年第10期6卷 2489-2501页

作者： Zhiyong Peng Pei-Pei Jia Xu-Qing Wang xiao-li zhao Hai-Bo Yang Wei Wang Shanghai Key Laboratory of Green Chemistry and Chemical Processes State Key Laboratory of Petroleum Molecular&Process EngineeringSchool of Chemistry and Molecular EngineeringEast China Normal UniversityShanghai 200062 Shanghai Center of Brain-Inspired Intelligent Materials and Devices East China Normal UniversityShanghai 200241

Based on a[2]rotaxane precursor with exchangeable pentafluorophenyl ester stoppers,a new wheelassembling approach has been successfully developed for the precise sequence control of hetero[3]rotaxanes,leading to the facile and efficient synthesis of both sequence isomers of hetero[3]*** importantly,taking advantage of the chirality retention along with the wheel-assembling process,corresponding sequence isomers of chiral AIEgenfunctionalized hetero[3]rotaxanes were further precisely ***,the resultant hetero[3]rotaxanes revealed remarkable sequencedependent aggregation-induced emission(AIE)behavior and circularly polarized luminescence performance with large dissymmetry factors up to 0.012,highlighting the great power of the newly coined sequence engineering concept in developing novel AIE-active chiroptical *** proof-ofconcept study lays the foundation for investigation of the structure-property relationships of heterorotaxanes that can further direct the rational design and precise synthesis of sequence-defined heterorotaxanes with desirable properties for practical applications.

关键词： mechanically interlocked molecules rotaxanes sequence isomerism aggregationinduced emission circularly polarized luminescence

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Double [5]carbohelicene: facile synthesis, chiroptical properties,isomerization study, and lasing application

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Science China Chemistry 2024年

作者： Peipei liu Yantong li Meng-Xiang Wu Hao Kang xiao-li zhao lin Xu linlin liu xiaodong li Junfeng Fang Zhiwei Fang Ya Cheng Hai-Bo Yang Huakang Yu Xueliang Shi State Key Laboratory of Petroleum Molecular&Process Engineering Shanghai Key Laboratory of Green Chemistry and Chemical ProcessesSchool of Chemistry and Molecular EngineeringEast China Normal University School of Physics and Optoelectronics South China University of Technology Institute of Polymer Optoelectronic Materials&Devices State Key Laboratory of Luminescent Materials&DevicesSouth China University of Technology School of Physics and Electronic Science Engineering Research Center of Nanophotonics&Advanced InstrumentMinistry of EducationEast China Normal University State Key Laboratory of Precision Spectroscopy School of Physics and Electronic ScienceEast China Normal University

Double carbohelicenes have attracted considerable attention due to their aesthetic structures, distinct π-conjugation extension, inherent chirality, and intriguing optical and electronic properties. Herein, the concise de novo synthesis of a new double[5]carbohelicene 1 together with its chiroptical properties, isomerization process and lasing application is presented. 1 was synthesized by a simple protocol involving the formation of a 6,6′-bipentacene as the key intermediate. It is worth noting that1 existed as two diastereomers 1-PP/MM and 1-PM, which were successfully isolated and unambiguously confirmed by Xray crystallography. The optical resolution of the racemic 1-PP/MM was successfully achieved by chiral-phase highperformance liquid chromatography（HPLC）, and 1-PP and 1-MM were characterized by circular dichroism. Interestingly, it was found that 1-PP/MM could be completely isomerized to 1-PM upon heating, and the detailed thermodynamics and kinetics of the isomerization process were systematically investigated. 1-PM exhibited deep-red luminescence with emission maximum at 723 nm and fluorescence quantum yield as high as 32.95%. Consequently, we can showcase the lasing application of 1-PM by doping with epoxy resin to assemble a bottle microlaser spontaneously, which the lasing wavelength is796.6 nm at a threshold of 0.8 mJ cm-2. We believe that our studies, including the facile synthesis methodology, detailed isomerization studies, and lasing application, will shed some light on the design and synthesis of novel carbohelical systems with more functions.

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干湿循环脆性岩石直接拉伸断裂的宏细观力学模型

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岩土力学 2024年第7期45卷 1906-1916,2049页

作者：李晓照车行李海峰戚承志北京建筑大学土木与交通工程学院北京100044

针对三峡库区消落带等长期处于干湿循环条件下导致岩石损伤破坏的工程问题,探究在干湿循环和直接拉伸荷载共同作用下,脆性岩石的宏细观断裂力学特性这个难点问题。由于干湿循环条件下的直接拉伸试验较难实现,考虑干湿循环与直接拉伸荷... 详细信息

针对三峡库区消落带等长期处于干湿循环条件下导致岩石损伤破坏的工程问题,探究在干湿循环和直接拉伸荷载共同作用下,脆性岩石的宏细观断裂力学特性这个难点问题。由于干湿循环条件下的直接拉伸试验较难实现,考虑干湿循环与直接拉伸荷载作用的宏细观力学关系模型非常欠缺。基于断裂力学理论方法,结合干湿循环试验研究方法,提出了一种干湿循环条件下脆性岩石直接拉伸断裂的宏细观力学模型。该模型是在考虑了干湿循环次数n与含水率ω对断裂韧度K_(IC)和初始损伤因子D_(0)综合影响的基础上,结合岩石初始细观裂纹损伤与裂纹断裂韧度的直接拉伸细观裂纹扩展力学模型建立的。对比分析抗拉强度、裂纹扩展极限长度l_(lim)、弹性模量、岩石劣化损伤的理论与试验结果,验证了模型的合理性。讨论了初始裂纹倾角φ、材料常数β等参数影响下,裂纹启裂应力及峰值应力随干湿循环次数n的变化规律。对比分析了干湿循环和单独含水条件对岩石劣化度力学特性的影响。

关键词：脆性岩石干湿循环直接拉伸断裂宏细观力学模型

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Vibronic effect study of ^(1)A_(2) state of H_(2)O and D_(2)O

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Chinese Physics B 2024年第5期33卷 395-399页

作者：张倍源王礼涵朱剑辉徐卫青马子茹赵小利吴勇朱林繁 Department of Modern Physics University of Science and Technology of ChinaHefei 230026China Center for Transformative Science ShanghaiTech UniversityShanghai 201210China Department of Physics Yantai UniversityYantai 264005China Institute of Applied Physics and Computational Mathematics Beijing 100088China School of Physics and Information Technology Shaanxi Normal UniversityXi'an 710119China HEDPS Center for Applied Physics and TechnologyPeking UniversityBeijing 100084China

The generalized oscillator strengths of the dipole-forbidden excitations of the ^(1)A_(2) of H_(2)O and D_(2)O were calculated with the time dependent density functional theory,by taking into account the vibronic *** is found that the vibronic effect converts the dipole-forbidden excitation of the ^(1)A_(2) into a dipole-allowed one,which enhances the intensities of the corresponding generalized oscillator strength in the small squared momentum transfer *** present investigation shows that the vibronic effect of H_(2)O is slightly stronger than that of D_(2)O,which exhibits a clear isotopic effect.

关键词： water heavy water generalized oscillator strength vibronic effect isotope effect

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All-trans retinoic acid promotes smooth muscle cell differentiation of rabbit bone marrow-derived mesenchymal stem cells

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2010年第7期11卷 489-496页

作者： Zhong-yuan SU Ying li xiao-li zhao Ming ZHANG College of life Sciences Zhejiang University Hangzhou 310058 China Zhejiang Academy of Medical Science Hangzhou 310058 China

Bone marrow-derived mesenchymal stem cells are multipotent stem cells, an attractive resource for regenerative medicine. Accumulating evidence suggests that all-trans retinoic acid plays a key role in the devel- opment and differentiation of smooth muscle cells. In the present study, we demonstrate, for the first time, that rabbit bone marrow-derived mesenchymal stem cells differentiate into smooth muscle cells upon the treatment with all-trans retinoic acid. AII-trans retinoic acid increased the expression of myocardin, caldesmon, 22-kDa smooth muscle cell- specific protein （SM22Q）, and SM-myosin heavy chains in rabbit bone marrow-derived mesenchymal stem cells, as detected by reverse transcription polymerase chain reaction （PCR）. Immunostaining of SM22a and SM-myosin heavy chains using monoclonal antibodies also indicated smooth muscle cell differentiation of rabbit bone marrow- derived mesenchymal stem cells following the treatment with all-trans retinoic acid. In addition, more than 47% of bone marrow-derived mesenchymal stem cells demonstrated the contractile phenotype of smooth muscle cells. Western blot results showed that SM-1 and SM-2 were highly expressed in the differentiated cells. These results suggest that all-trans retinoic acid may serve as a potent agent for functional smooth muscle cell differentiation in tissue engineering.

关键词： Bone marrow-derived mesenchymal stem cells Smooth muscle cells AII-trans retinoic acid Rabbit

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Numerical analysis of factors affecting the range of heat transfer in earth surrounding three subways

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Journal of China University of Mining and Technology 2008年第1期18卷 67-71页

作者： HU Zeng-hui li xiao-zhao zhao xiao-bao xiao lin WU Wei Department of Earth Sciences Nanjing University Nanjing Jiangsu 210093 China

In order to examine the factors which affect the range of heat transfer in earth surrounding subways, FLAC3D was adopted in this study to analyze these factors, under different conditions, in a systematic manner. When we compare these numerical tests, the results show that the main factors, affecting the heat transfer range are the thermal properties of the surrounding earth, the initial ground temperature and the temperature in the tunnel. The heat transfer coefficient between air and linings has little effect on the temperature distribution around the tunnel. The current results can provide a reference for improving the thermal environment in subways and optimizing the design of subwav ventilation and air conditioning.

关键词： earth surrounding subways range of heat transfer factors affecting heat transfer numerical analysis

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Effect of vanadium on dynamic continuous cooling transformation behavior of medium-carbon forging steels

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Journal of Iron and Steel Research International 2017年第6期24卷 641-648页

作者： Wei-jun Hui Na xiao xiao-li zhao Yong-jian Zhang Yu-feng Wu School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing 100044 China Faculty of Materials Science and Engineering Kunming University of Science and Technology Kunming 650093 Yunnan China

Dynamic continuous cooling transformation （CCT） behavior of medium-carbon forging steels microalloyed with different V contents up to 0.29% was investigated by means of dilatometric measurement, microstructural observation and hardness measurement. The re- sults showed that the dynamic CCT diagrams were similar and the main difference was that the fields of the transformation products were shifted to the right side of the diagrams with the increase of V content, and this effect was more noticeable with an addition of 0. 290/00 V. The At1 and At3 temperatures showed increasing trends with increasing V content, while the critical cooling rates decreased with increasing V content. The increase of V content re- sulted in significant increase of hardness and this tendency was enhanced with increasing cooling rate until the formation of acicular ferrite （AF）. A promising approach of remark- ably improving the toughness of ferritic-pearlitic medium-carbon forging steels with suit- able V addition and the introduction of AF without notable penalty on its strength level was suggested.

关键词： Dynamic CCT diagramVanadiumMicroalloyed steelMierostruetureHardness

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Hydrogen-induced delayed fracture of Cu-containing high-strength bolt steel

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Journal of Iron and Steel Research International 2023年第2期30卷 375-383页

作者： xiao-li zhao Cheng-xiang Zhang Yong-jian Zhang Wei-jun Hui Xiu-ming zhao Materials Science and Engineering Research Center School of MechanicalElectronic and Control EngineeringBeijing Jiaotong UniversityBeijing100044China School of Materials Science and Engineering Nanjing Institute of TechnologyNanjing211167JiangsuChina

The hydrogen-induced delayed fracture(HIDF)behavior of a 1300-MPa-grade high-strength bolt steel 42CrMoV containing 0.42 wt.%Cu was investigated by constant load tensile test in a pH 3.5 Walpole *** is shown that the addition of Cu is beneficial to enhance the HIDF resistance by~13%.The observation of the fracture surface revealed that the area fraction of brittle crack initiation zone decreased remarkably for the Cu-added *** the corrosion pit depth and the corrosion rate of the Cu-added steel in the Walpole solution are notably decreased,which is primarily because of the formation of a Cu-rich protective compact rust layer and slightly higher corrosion *** a result,the absorbed hydrogen content in that solution was also decreased by~21%.It is concluded that the improvement in the HIDF resistance of the tested steel is primarily due to the increase in corrosion resistance and resultant decrease in the absorbed diffusible hydrogen content in the acidic condition.

关键词： Hydrogen-induced delayed fracture Hydrogen embrittlement High-strength bolt steel Copper Corrosion

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