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Chinese Journal of Polymer Science 2024年第6期42卷 751-765页

作者： Jun-Hao Zhou li-ming tang Key Laboratory of Advanced Materials of Ministry of Education of China Department of Chemical EngineeringTsinghua UniversityBeijing100084China

In this study,a series of hindered urea bond(HUB)containing polyurethane-urea methacrylate prepolymers and a none HUB containing polyurethane methacrylate prepolymer were prepared using isobornyl methacrylate as the reactive diluent via one-pot *** prepolymers were characterized fully by various ***,their thermosets were fabricated via UV curing in presence of a photo initiator,and their mechanical property and thermal behavior were investigated and *** from the none HUB containing thermoset,the HUB containing thermosets(defined as PUT)could be recycled and reprocessed by hot press under relatively mild conditions with high recovery ratio of mechanical ***,zinc oxide(ZnO)nanoparticles were modified with 3-(trimethoxysilyl)propyl methacrylate and the modified ZnO(defined as ZnO-TPM)was dispersed and polymerized into PUT matrix to prepare their *** influence of ZnO-TPM on the mechanical performance of the composites was evaluated,which indicated that the Young’s modulus and tensile strength increased gradually to the maximum values at ZnO-TPM content of 1 wt%and then *** composites also displayed good reprocessability with improved recovery ratio compared to the pure PUT *** addition,the composite materials exhibited strong UV absorption capacity,implying their potential application in the circumstance where UV-shielding was required.

关键词： Polyurethane-urea methacrylate Hindered urea bond ZnO nanoparticles Reprocessing UV curing

INFLUENCE OF MOLECULAR STRUCTURES OF SECONDARY AMINE TERMINATED POLY(ESTER-AMINE)S ON THE CURING PERFORMANCE WITH EPOXY RESIN

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Chinese Journal of Polymer Science 2007年第6期25卷 545-553页

作者： li-ming tang Ji Feng Yu Wang Advanced Materials Laboratory Department of Chemical Engineering Tsinghua University Beijing 100084 China

Five secondary amine terminated poly（ester-amine）s （defined as PEA） with controlled molecular structures were synthesized through reacting excessive piperazine with phthalicdiglycol diacrylate （PDDA） and 1,1,1-trimethylolpropane triacrylate （TMPTA） at a constant secondary amine/acrylate group ratio of 1.5/1 and at different PDDA/TMPTA molar ratios. Both IR and ^1H-NMR spectra indicated that all acrylate groups were consumed in the reaction, based on which the structural parameters were calculated from the ^1H-NMR spectra. With decreasing PDDA/TMPTA ratio, the content of secondary amine, degree of branching, molecular weight, Tg and Td increased accordingly. These polymers were further used as both crosslinkers and flexibilizers for a linear epoxy resin E51 to form cured films under ambient condition. The gel content, relative hardness and Tg of the resulting films increased as PEA molecules changed from linear to highly branching structures. Due to the flexibility of PEA molecules, all the films possessed excellent mechanical performance.

关键词： Poly(ester-amine) Molecular structure Epoxy resin Cured film.

Highly stable supramolecular hydrogels formed from 1,3,5-benzenetricarboxylic acid and hydroxyl pyridines

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Chinese Chemical Letters 2009年第10期20卷 1259-1262页

作者： li ming tang Yu Jiang Wang Laboratory of Advanced Materials Department of Chemical Engineering Tsinghua University Beijing 100084 China

New supramolecular hydrogels with the maximal sol-gel transition temperature （Tgel） of 95 ℃ were obtained by using gelators formed from 1,3,5-benzenetricarboxylic acid （BTA） and para-hydroxyl pyridine （PHP） or meta-hydroxyl pyridine （MHP）. The single crystal structure of the complex formed from BTA and ortho-hydroxyl pyridine （OHP） indicated that the molecules assembled into superstructure via both hydrogen bonds and π--π stacking interaction.

关键词： Supramolecular hydrogel Gelator Hydrogen bond

Experimental evaluation of the effect of an internal heat exchanger on a transcritical CO_2 ejector system

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第2期12卷 146-153页

作者： Xiao-xiao XU Guang-ming CHEN li-ming tang Zhi-jiang ZHU Shuang liU Institute of Refrigeration and Cryogenics State Key Laboratory of Clean Energy Utilization Zhejiang University Hangzhou 310027 China

This study presents experimental results focused on a performance comparison of a transcritical CO2 ejector system without an internal heat exchanger(IHX) (EJE-S) to a transcritical CO2 ejector system with an IHX(EJE-IHX-S) . The comparison includes the effects of changes in operating conditions such as cooling water flow rate and inlet temperature. Experiments are conducted to assess the influence of the IHX on the heating coefficient of performance(COPr) ,heating capacity,entrainment ratio,pressure lift,and other parameters. The primary flow rate of the EJE-IHX-S is higher than that of the EJE-S. The pressure lift and actual ejector work recovery are reduced when the IHX is added to the transcritical CO2 ejector system. Using a more practical performance calculation,the compression ratio in the EJE-S is reduced by 10.0%-12.1%,while that of EJE-IHX-S is reduced only by 5.6%-6.7% compared to that of a conventional transcritical CO2 system. Experimental results are used to validate the findings that the IHX weakens the contribution of the ejector to the system performance.

关键词： CO2 ejector system Transcritical cycle Heating coefficient of performance (COPr)

Influence of gelator structures on formation and stability of supramolecular hydrogels

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Chinese Chemical Letters 2007年第12期18卷 1548-1550页

作者： Shunji Kono Yu Jiang Wang li ming tang Laboratory of Advanced Materials Department of Chemical Engineering Tsinghua University Beijing 100084 PR China Department of Organic ＆ Polymeric Materials Graduate School of Science ＆ Engineering Tokyo Institute of Technology

A supramolecular hydrogel （defined as G1） formed from 1,2,4,5-benzene tetracarboxylic acid （BTCA） and 2-amino-3- hydroxypyridine possessed higher Tgel than that of another hydrogel （defined as G2） formed from BTCA and 3-hydroxypyridine. Based on the analysis of their xerogels by 1H NMR, IR and XRD, the higher stability of G1 was attributed to the formation of stronger hydrogen binding enhanced by the ortho amino group of 2-amino-3-hydroxypyridine.

关键词： Supramolecular hydrogel Gelation Hydrogen bond

Effect of Temperature, pH and Salt on Fluorescent Quality of Water Extractable Organic Matter in Black Soil

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Journal of Integrative Agriculture 2013年第7期12卷 1251-1257页

作者： li ming-tang ZHAO Lan-po ZHANG Jin-jing College of Resource and Environmental Science Jilin Agricultural University

Water erosion is the major reason for the loss of soil organic carbon in the Northeast China, which leads to the soil quality deterioration and adjacent water pollution. In this study, the effect of extraction temperature, pH value, and salt on the water extractable organic matter （WEOM） was determined by means of the UV absorbance, fluorescence excitation-emission matrix, and derived fluorescence indexes. In general, the carbon content and aromaticity of WEOM increased with the increasing of extraction temperature, with the exception that there was no significant difference in the amount at 0 and 20℃. More fluorophores, especially microbially-derived organic matter were extracted at high temperature. The pH values of extractant, including 5, 7, and 10, showed no effect on the carbon amount of WEOM, whereas the aromaticity and microbially-derived component gradually increased with the increasing of pH values. The fluorescence intensity of humic acid-like fluorophore was stronger in neutral and alkali condition than that in acidic condition. The addition of 10 mmol L-1 CaCl2 significantly decreased the carbon amount of recovered WEOM. Moreover, it significantly decreased the aromaticity of WEOM and the quantity of fulvic acid-like and humic acid-like fluorophores, whereas increased the percentage of tyrosine-like and tryptophan-like fluorophores in the total fluorophores and the amount of microbially-derived organic matter. Generally, 10 mmol L-1 KCl showed the same influence trend, but with low influence degree.

关键词： black soil water extractable organic matter soil profile fluorescence spectroscopy

Experimental investigation of an adjustable ejector for CO_2 heat pump water heaters

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第11期10卷 1678-1682页

作者： Guang-ming CHEN li-xia liANG li-ming tang Xiao-xiao XU Zhi-jiang ZHU Qi CHEN State Key Laboratory of Clean Energy Utilization Institute of Refrigeration and Cryogenics Zhejiang University Hangzhou 310027 China

An adjustable ejector expansion device for a CO2 heat pump water heater (HPWP) is proposed to improve the system performance. It has been designed to investigate experimentally the effects of the motive nozzle throat area of the ejector, entrained flow pressure, back pressure and primary flow pressure on the entrainment ratio. Experiments based on different motive nozzle throat areas were conducted and the results of the prototype ejector using CO2 as working fluid are presented. The results show that an adjustable ejector can achieve high performance and work well in a wide range of working conditions.

关键词： Adjustable elector System nerformance CO2 heat oumo water heater (HPWH) Entrainment ratio

Coordinated organogel templated fabrication of silver/polypyrrole composite nanowires

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Chinese Chemical Letters 2011年第1期22卷 123-126页

作者： Bo Tian li li ming tang Kai Chen Yu Xia Xin Jin Laboratory of Advanced Materials Department of Chemical Engineering Tsinghua University Beijing 100084 China

A new method to fabricate metal/conducting polymer composite nanowires is presented by taking silver/polypyrrole composite nanowires as an example. A silver （D-coordinated organogel as template was prepared firstly, and redox-polymerization of pyrrole took place on the gel fiber, giving product of silver/polypyrrole nanowires. The silver/polypyrrole nanowires were characterized by multiple techniques. This strategy could be carried out in one-step procedure at room temperature, and it proves the utility of coordinated organogels in template synthesis of polymer nanostructures.

关键词： Coordinated organogel Template polymerization Polypyrrole Composite nanowires

Tumor suppressor role of mi R-133a in gastric cancer by repressing IGF1R

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World Journal of Gastroenterology 2015年第10期21卷 2949-2958页

作者： Yu Gong Jun Ren Kun liu li-ming tang Department of Gastrointestinal Surgery Nanjing Medical University Affiliated Changzhou No. 2 People’s Hospital

AIM:To investigate the function and mechanism of mi R-133a in gastric cancer(GC)and its relationship with clinicopathological characteristics of ***:A total of 105 GC patients who underwent surgical resection as primary treatment were selected for this ***-time quantitative reverse transcriptase polymerase chain(q RT-PCR)was used to examine the expression levels of mi R-133a in human GC and adjacent non-tumor tissues,as well as in GC cell lines(SGC-7901,BGC-823,MGC-803,and AGS)and a human gastric mucosal epithelial cell line(GES-1).The biological role of mi RNA(mi R)-133a was assessed in the GC cell lines using MTT,apoptosis,migration and invasion,and colony formation assays,and xenograft tumorigenesis.q RT-PCR and western blot analyses were used to evaluate the potential target gene expression of mi ***’s correlation was calculated to evaluate the correlation between mi R-133a and insulinlike growth factor 1 receptor(IGF1R)*** regulation of IGF1R by mi R-133a was verified using the luciferase reporter ***:In 80%of the 105 GC patients,the mean expression of mi R-133a was significantly downregulated in tumor tissues compared with adjacent normal tissues(1.215±0.1477 vs 3.093±0.4104,Plines inhibited proliferation(0.4787±0.0219 vs 0.7050±0.0147,P=0.0013 in SGC-7901 cells;and 0.5448±0.0085vs 0.7270±0.0084,P=0.001 in MGC-803 cells);migration(0.6333±0.0233 vs 1.037±0.0584,P=0.003 in SGC-7901 cells;0.6126±0.0311 vs 1.024±0.0456,P=0.0017 in MGC-803 cells);and invasion(0.613±0.0399 vs 1.033±0.0278,P=0.0013 in SGC-7901 cells;0.7433±0.0221 vs 1.017±0.0311,P=0.002 in MGC-803 cells).It also induced apoptosis(18.19%±0.2483%vs 5.887%±0.3837%,P<0.0001 in SGC-7901 cells;22.69%±0.7846%vs9.347%±0.301

关键词： Gastric cancer mi R-133a Tumor suppressor Insulin-

Assembling and releasing performance of supramolecular hydrogels formed from simple drug molecule as the hydrogelator

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Chinese Chemical Letters 2007年第8期18卷 1009-1012页

作者： Yu Jiang Wang liang Yan li ming tang Jian Yu Laboratory of Advanced Materials Department of Chemical Engineering Tsinghua University Beijing 100084 China

A simple drug compound, 4-oxo-4-（2-pyridinylamino） butanoic acid （defined as AP）, was able to gel water at 4 wt% concentration under various conditions. In the superstructure, AP molecules assembled into fibrous aggregates driving by hydrogen bonds and π-π stacking interaction. The gels with different backbone structures released drug molecules in different speeds.

关键词： Supramolecular hydrogel Hydrogelator Releasing