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The New Methods for Characterization of Molecular Weight of Supramolecular Polymers

Chinese Journal of Polymer Science 2024年第10期42卷 1403-1413页

作者： Hui Liu Rui Hu zi-Qing Hu Xiao-fan Ji Key Laboratory of Materials Chemistry for Energy Conversion and Storage Ministry of Education Hubei Key Laboratory of Materials Chemistry and Service FailureHubei Engineering Research Center for Biomaterials and Medical Protective Materials School of Chemistry and Chemical Engineering Huazhong University of Science and Technology

Supramolecular polymers, as a type of dynamic polymers, are subordinate to the interdisciplinary field of polymer chemistry and supramolecular chemistry, whose development has greatly promoted the prosperity of new materials. Notably, molecular weight is one of the most important parameters of supramolecular polymers, which affects the physical/chemical properties and processing applications of *** new methods for characterizing the molecular weight of supramolecular polymers is crucial for advancing the development of supramolecular polymers. In this review, we elaborate and summarize three strategies for characterizing the molecular weight of supramolecular polymers that recently reported by our research group according to the characteristics of supramolecular polymers, including (1) the molecular weight distinction corresponding to variable fluorescence colors,(2) matching different molecular weights with different fluorescence lifetime,(3) transforming supramolecular polymers into mechanically interlocked polymers or covalent polymers. Besides, we also discuss the limitations of current methods for characterizing supramolecular polymers. We hope that this review can promote the development of supramolecular polymers and significantly inspire to exploit new methods to characterizing molecular weight of supramolecular polymers.

关键词： Dynamic polymers Mechanically interlocked polymers Molecular weight Self-assembly Supramolecular polymers

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Microstructure and Mechanical Properties of Ductile Cast Iron in Lost Foam Casting with Vibration

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Journal of Iron and Steel Research International 2014年第11期21卷 1049-1054页

作者： Bo-tao XIAO zi-tian fan Wen-ming JIANG Xin-wang LIU Wei LONG Qiang HU State Key Laboratory of Material Processing and Die & Mould Technology Huazhong University of Science and Technology School of Materials Science and Engineering Jiangxi Science and Technology Normal University School of Mechanical & Electrical Engineering Wuhan Institute of Technology Jiangxi Key Laboratory for Advanced Copper and Tungsten Materials Jiangxi Academy of Sciences

The microstructures and mechanical properties of the ductile cast iron （DI） specimens obtained by lost foam casting （LFC） with and without vibration were investigated. The results indicate that the number of the graphite nodule increases from 175 mm 2 of the specimens produced by LFC without vibration to 334 mm^-2 of the specimens produced by LFC with vibration, and the thickness of the ferrite shell increases. Meanwhile, the amount of the carbides decreases in the specimens produced by LFC with vibration and the granule structure then forms. These are mainly attributed to the ＂crystal shower＂ caused by the vibration. In addition, the tensile strength and elongation of DI specimens produced by LFC with vibration are improved due to the dispersion-strengthening of refined carbide and Dearlite colonv, uniform distribution of the graphite nodule, and increase of the amount of dimples and tearing edges.

关键词： ductile cast iron (DI) microstructure mechanical property mechanical vibration lost foam casting (LFC)

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Effect of vibration frequency on primary phase and properties of grey cast iron fabricated by lost foam casting

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China Foundry 2020年第1期17卷 1-7页

作者： Bo-tao Xiao zi-tian fan Wen-ming Jiang Jun-huai Xiang Xue-fang Yan Jiangxi Key Laboratory of Surface Engineering Jiangxi Science and Technology Normal UniversityNanchang 330013China State Key Laboratory of Material Processing and Die&Mould Technology Huazhong University of Science&TechnologyWuhan 430074China

The properties of gray cast iron(GCI)are affected by density of matrix,size of flake graphite and primary *** this paper,the Y-type specimen of GCI was prepared by lost foam casting(LFC)with and without vibration,and the influence of vibration frequency on the density of matrix,size of primary phase,and properties of the GCI was *** results show that the length of the flake graphite and the size of the primary austenite in GCI firstly decrease and then increase with the increase of the vibration *** a vibration frequency of 35 Hz,the length of the flake graphite is the shortest,the primary austenite is the finest and the density of the matrix is the *** addition,the tensile strength,elongation and hardness of the GCI firstly increase and then decrease with the increase of the vibration frequency,due to the refinement of the primary phase and the increase of the matrix *** order to analyze the refinement mechanism of the primary phase of the GCI fabricated by the LFC with vibration,the solidification temperature fields of the GCI fabricated by the LFC with the vibration frequency of 0 and 35 Hz were *** results show that the vibration reduces the eutectic point of the GCI and increases the supercooling degree during the eutectic *** a result,the length of the flake graphite and the size of the primary austenite in GCI fabricated by LFC with the vibration frequency of 35 Hz decrease.

关键词： vibration frequency lost foam casting grey cast iron flake graphite properties

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UHPLC-MS/MS正电离喷雾模式测定腌渍蔬菜中的三氯蔗糖

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中国口岸科学技术 2024年第3期6卷 84-90页

作者：陈子凡董莹郑少锋陈碧聪张南峰河源市食品检验所河源517000 黄埔海关技术中心东莞523000 广东省口岸安全智能化检测重点实验室广州510510

本文建立一种测定腌渍蔬菜中三氯蔗糖的超高效液相色谱串联质谱仪-正电离喷雾模式(ESI+)的方法。腌渍蔬菜样品用乙腈作为提取液,加入QuECHERS试剂振摇,离心后取上层澄清液,过0.22μm滤膜后上机检测。液相色谱采用C18色谱柱,以超纯水和... 详细信息

本文建立一种测定腌渍蔬菜中三氯蔗糖的超高效液相色谱串联质谱仪-正电离喷雾模式(ESI+)的方法。腌渍蔬菜样品用乙腈作为提取液,加入QuECHERS试剂振摇,离心后取上层澄清液,过0.22μm滤膜后上机检测。液相色谱采用C18色谱柱,以超纯水和甲醇为流动相梯度洗脱分离目标物。质谱选择419 m/z作为前体离子,239 m/z作为定量离子,221 m/z、203 m/z作为定性离子,采用外标法进行定量。结果表明三氯蔗糖的标准曲线在0.5~100 ng/mL之间呈线性关系,相关系数R^(2)>0.998,加标回收率为84.3%~99.1%,精确度为5.3%,检出限为0.1μg/kg,定量限为0.2μg/kg。结果表明,该方法具有快速高效、检测下限低、灵敏度高、重复性好的特点,可作为腌渍蔬菜中三氯蔗糖含量测定方法。

关键词：三氯蔗糖超高效液相色谱三重四极杆质谱电离喷雾正模式腌渍蔬菜

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Optical Flash of GRB 990123: Constraints on the Physical Parameters of the Reverse Shock

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Chinese Journal of Astronomy and Astrophysics 2002年第5期2卷 449-453页

作者： Yi-Zhong fan, zi-Gao Dai, Yong-Feng Huang and Tan Lu Department of Astronomy, Nanjing University, Nanjing 210093 Department of Astronomy Nanjing University Nanjing 210093

The optical flash accompanying GRB 990123 is believed to be powered by the reverse shock of a thin shell. With the best-fit physical parameters for GRB 990123 and the assumption that the parameters in the optical flash are the same as in the afterglow, we show that: 1) the shell is thick rather than thin, and we have provided the light curve for the thick shell case which coincides with the observation; 2) the theoretical peak flux of the optical flash accounts for only 3×10-4 of the observed. In order to remove this discrepancy, the physical parameters, the electron energy and magnetic ratios, εe and εB, should be 0.61 and 0.39, which are very different from their values for the late afterglow.

关键词： gamma rays: bursts - gamma rays: theory

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Recycling water glass from wet reclamation sewage of waste sodium silicate-bonded sand

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China Foundry 2019年第3期16卷 198-203页

作者： Li-chi Wang Wen-ming Jiang Xiao-long Gong Fu-chu Liu zi-tian fan State Key Lab of Materials Processing and Die & Mould Technology Huazhong University of Science and Technology

Wet reclamation of waste sodium silicate-bonded sand produces much alkaline sewage and causes pollution. Recycling water glass from wet reclamation sewage of the waste sodium silicate-bonded sand can solve pollution issues and generate economic benefits. In this work, the wet reclamation sewage was filtered, and the filtrate was causticized with a quicklime powder to produce a lye. The effects of causticization temperature, causticization time, and the amount of quicklime powder on the causticization rate were studied. The lye was used to dissolve the silica in the filtration residue to prepare a sodium silicate solution. The effects of the mass of filtration residue, dissolution temperature, and dissolution time on sodium silicate modulus were studied. Finally, the recycled water glass was obtained by concentrating the sodium silicate solution, and the bonding strength of the recycled water glass was tested. The results showed that the causticization rate could be improved by increasing the amount of quicklime powder, causticization temperature, and causticization time, and the highest causticization rate was above 92%. Amorphous silica in the filtration residue dissolved in the lye. Increasing the amount of the filtration residue, dissolution temperature, and dissolution time could improve the sodium silicate modulus. The bonding strength of the recycled water glass was close to that of commercial water glass. The recycled water glass could be used as a substitute for the commercial water glass.

关键词： waste sodium silicate-bonded sand wet reclamation sewage treatment causticization recycling water glass

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Microstructure and mechanical properties of Ti6Al4V alloy prepared by selective laser melting combined with precision forging

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Transactions of Nonferrous Metals Society of China 2017年第5期27卷 1036-1042页

作者： Qi ZHANG Zheng-long LIANG Miao CAO zi-fan LIU An-feng ZHANG Bing-heng LU School of Mechanical Engineering Xi’an Jiaotong University Xi’an 710049 China

To improve the mechanical properties of Ti6Al4V alloy prepared by selective laser melting(SLM)process,the precision forging was conducted at950°C and different strains and strain *** microstructure evolution of as-built samples and forged samples in both horizontal and vertical sections was visualized and analyzed by optical microscope and X-ray *** microstructure was improved by the precision forging and subsequent water *** porosity in each section was *** can be seen that high strain rate and large deformation result in low porosity,consequently contributing to a better fatigue *** micro-hardness was lowered after precision forging and water quenching,while the difference of microhardness between the horizontal and vertical sections became smaller,which illustrated that this process can improve the anisotropy of structural components fabricated by SLM.

关键词： selective laser melting Ti6Al4V alloy precision forging microstructure anisotropy

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Magnetic vortex gyration mediated by point-contact position

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Chinese Physics B 2019年第10期28卷 531-534页

作者： Hua-Nan Li zi-Wei fan Jia-Xin Li Yue Hu Hui-Lian Liu College of Physics Jilin Normal University National Demonstration Center for Experimental Physics EducationJilin Normal University

Micromagnetic simulation is employed to study the gyration motion of magnetic vortices in distinct permalloy nanodisks driven by a spin-polarized current. The critical current density for magnetic vortex gyration, eigenfrequency, trajectory, velocity and the time for a magnetic vortex to obtain the steady gyration are analyzed. Simulation results reveal that the magnetic vortices in larger and thinner nanodisks can achieve a lower-frequency gyration at a lower current density in a shorter time. However, the magnetic vortices in thicker nanodisks need a higher current density and longer time to attain steady gyration but with a higher eigenfrequency. We also find that the point-contact position exerts different influences on these parameters in different nanodisks, which contributes to the control of the magnetic vortex gyration. The conclusions of this paper can serve as a theoretical basis for designing nano-oscillators and microwave frequency modulators.

关键词： magnetic vortex spin-polarized current point-contact micromagnetic simulation

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Microstructure and mechanical properties of a low activation cast WTaHfTiZr refractory high-entropy alloy

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China Foundry 2022年第6期19卷 489-494页

作者： Xian-neng Ma Yi-fei Hu Kai Wang Hai-long Zhang zi-tian fan Jin-ping Suo Xin-wang Liu State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China Dekai Intelligent Casting Co. Ltd.Zhuozhou 072750HebeiChina China Iron and Steel Research Institute Group Beijing 100081China AECC South Industry Company Limited Zhuzhou 412002HunanChina

In the face of the requirement that nuclear fusion reactor materials exhibit more excellent thermal,mechanical and physical properties,a novel refractory highentropy alloy,WTaHfTiZr was *** constituent elements were selected in consideration of low activation,high melting point and high *** alloys were prepared by arc *** as-cast alloy shows a dendrite microstructure with two disordered BCC phases,which caused by the preferential nucleation of W and Ta with much higher melting points during *** exhibits a high compressive yield strength of 1,900 MPa and fracture strain of 8.1% at room temperature,and its yield strengths are up to 612 MPa at 700 ℃ and 203 MPa at 1,000 ℃,*** high strengths are attributed mainly to solid solution strengthening and second phase *** alloy shows great promise as one of the next-generation nuclear fusion reactor materials.

关键词： refractory high-entropy alloy phase structure microstructure mechanical properties

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Bing Xin:The Teller of Tales

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Women of China 1999年第7期 8-11页

作者： MING zi fan fan

AT 9 p.m. on February 28, 1999,contemporary Chinese masterand famous writer Bing Xinpassed away quietly. As she wrote in herwill, "I quietly came into the world and Iwill leave it the same way." The entireliterary circle as well as other membersof society attended her funeral to mournher passing. Thousands of fire-red rosesencircled her. Several generations of herreaders came from all parts of thecountry to pay tribute to the

关键词： In Bing Xin:The Teller of Tales

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