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李钒 《天津职业院校联合学报》2014,(12):94-97
研究了稀释剂乙二醇二缩水甘油醚降低环氧树脂粘度的效果;选择了两种导热填料MgO和Al2O3复配环氧胶粘剂;研究了固化物的导热性能,最终确定在环氧树脂E-51和固化剂TE-80中添加40wt%的稀释剂乙二醇二缩水甘油醚和80wt%MgO得到低粘度导热环氧胶粘剂。 相似文献
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陈宝璠 《三明高等专科学校学报》2012,(6):66-71
以聚乙二醇单甲醚（MPEG－1200）与丙烯酸（从）为单体,通过酯化,合成聚乙二醇单甲醚丙烯酸酯大分子单体（MPEGAA）。再用MPEG从与丙烯酸（从）和2－丙烯酰胺－2－甲基丙烯磺酸钠（AMPS）共聚,即制得MPE—GAA－从－AMPS三元共聚聚羧酸类高效减水剂。用红外光谱（FT—IR）表征了该高效减水剂的分子结构。并重点研究了MPEG支链长度、MPEG从／从摩尔比和MPEG从／AMPS摩尔比等因素对水泥分散效果的影响．同时用SEM观察了水泥石的微观结构．进一步探讨该减水剂对水泥水化过程作用的微观机理。结果表明。该高效减水剂对水泥具有良好的分散性及分散保持性能,掺量（固掺量）为0．3％,mw/mc=0．29时,水泥净浆初始流动度为300mm。30min可达322mm,120min经时损失率只有5％。SEM分析表明,该高效减水剂对水泥水化晶体生长时形成的晶体结构更为密实有利。 相似文献
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以丙烯酸(AA)、马来酸酐(MA)和聚乙二醇(PEG)为原料,以过硫酸钾(KPS)为引发剂,通过原位酯化法合成P(AA-co-MA)/PEG三元共聚型聚羧酸减水剂,探讨各合成因素对减水剂性能的影响。研究表明,最佳合成工艺为:n(PEG):n(AA):n(MA)=1.0:1.2:1.0,引发剂用量为1.5%(相对PEG、AA和MA总物质的量分数)、聚合温度为80℃、反应时间为6h。此条件下制得的减水剂具有最优的水泥净浆流动度。 相似文献
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采用溶胶-凝胶法制备了二氧化硅负载硅钨钼酸催化剂.以其为催化剂,对以丁酮和乙二醇为原料合成丁酮乙二醇缩酮的反应条件进行了研究,较系统地研究了酮醇物质的量比、催化剂用量、带水剂环己烷,反应时间对收率的影响.实验表明,二氧化硅负载硅钨钼酸催化剂是合成丁酮乙二醇缩酮的良好催化剂,在n（丁酮）∶n（乙二醇）=1∶1.4,催化剂用量为原料总质量的0.6%,环己烷作带水剂10 mL,反应时间75min的优化条件下,丁酮乙二醇缩酮的收率可达96.77%. 相似文献
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Tea polyphenols have been shown to have anticancer activity in many studies.In the present study,we investigated effects of theaflavin-3-3'-digallate(TF3),one of the major theaflavin monomers in black tea,in combination with ascorbic acid(AA),a reducing agent,and(-)-epigallocatechin-3-gallate(EGCG),the main polyphenol presented in green tea,in combination with AA on cellular viability and cell cycles of the human lung adenocarcinoma SPC-A-1 cells.The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT) assay showed that the 50% inhibition concentrations(IC50) of TF3,EGCG,and AA on SPC-A-1 cells were 4.78,4.90,and 30.62 μmol/L,respectively.The inhibitory rates of TF3 combined with AA(TF3+AA) and EGCG combined with AA(EGCG+AA) at a molar ratio of 1:6 on SPC-A-1 cells were 54.4% and 45.5%,respectively.Flow cytometry analysis showed that TF3+AA and EGCG+AA obviously increased the cell population in the G0/G1 phase of the SPC-A-1 cell cycle from 53.9% to 62.8% and 60.0%,respectively.TF3-treated cells exhibited 65.3% of the G0/G1 phase at the concentration of its IC50.Therefore,TF3+AA and EGCG+AA had synergistic inhibition effects on the proliferation of SPC-A-1 cells,and significantly held SPC-A-1 cells in G0/G1 phase.The results suggest that the combination of TF3 with AA or EGCG with AA enhances their anticancer activity. 相似文献
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以水-95%乙醇为溶剂,以氯化苄和对甲苯酚为原料,在相转移催化作用下,利用微波辐射合成对甲苯基苄基醚。实验表明,对甲苯酚、氯化苄、氢氧化钠的摩尔比为1：1.1：1.1,400W下微波辐射反应6min。对甲苯基苄基醚的产率为96.21%。 相似文献
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研究了共聚物P（MPEGMA／AA）中单体聚乙二醇单甲醚甲基丙烯酸酯（MPEGMA,分子量550）、丙烯酸（AA）摩尔配比对阻垢分散性能的影响,并用X衍射（XRD）和电子扫描电镜（SEM）观察了碳酸钙垢晶型变化．结果表明,当共聚物中MPEGMA摩尔含量为1％～5％,共聚物具有较好的阻垢分散性能;ρCa^2＋为625mg／L,ρhco3^-为600mg／L,阻垢剂用量20mg／L时,阻碳酸钙率达70％以上;阻垢剂用量为5mg／L,阻磷酸钙率达80％以上,分散氧化铁上层清液最小透光率为62％．阻垢剂的侧链聚醚对碳酸钙垢具有晶格扭曲和分散作用． 相似文献
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合成了既含氢键供体 ,又含氢键受体的强亲水性氢键吸附剂—聚 (N—乙烯基乙酰胺 )。通过测定它对水溶液中单宁的等温吸附线 ,利用热力学函数关系计算吸附热ΔHm值 ,证明其吸附机理为氢键吸附。通过测定它对 60 0mgL- 1 以下单宁水溶液的动态吸附性能 ,发现在流速为 3BV/h ,流出液体积为1 0 0BV时 ,单宁的去除率在 90 %以上 ,说明该吸附剂是一种较好的单宁去除剂 ,具有一定的应用价值 相似文献
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With N-vinyl-2-pyrrolidone (NVP) and itaconic acid ( IA ), poly ( N-vinyl-2-pyrrolidone/itaconic acid) [ P(NVP/IA) ] hydrogel was synthesized by free radical solution polymerization. The structure of this P(NVP/IA) was characterized by IR. Effects of concentration of itaconic acid, amount of cross-link agent,N, N‘-methylene-bis-acrylamide, reaction temperature, and time on properties of swelling ratio (SR) of the hydrogel were investigated. The results show that the best swelling property of the hydrogel is obtained at 50 ℃ and 1.5 h. pH sensitivity increases as the concentration of itaconic acid in the hydrogel system increases.Swelling ratio of the hydrogel decreases as the amount of cross-link agent increases. 相似文献
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Jian Chen Qing-wei Zhao Gen-ming Shi Lin-run Wang 《Journal of Zhejiang University. Science. B》2012,13(11):875-883
Objective: XRCC1 polymorphism is a research hotpot in individual treatment for non-small cell lung cancer (NSCLC). To obtain the association between XRCC1 polymorphism and clinical outcome of platinum-based treatment for NSCLC, a meta-analysis was conducted. Methods: Databases including PubMed, Embase, Cochrane, and Chinese National Knowledge Infrastructure (CNKI) were searched for publications that met the inclusion criteria. A fixed effect model was used to estimate pooled odds ratio (OR) and hazard ratio (HR) with 95% confidence interval (CI) for the association between XRCC1 Arg399Gln and response or survival of platinum-based treatment for advanced NSCLC. A chi-squared-based Q-test was used to test the heterogeneity hypothesis. Egger’s test was used to check publication bias. Results: Seventeen published case-control studies that focus on the association between XRCC1 Arg399Gln and response or survival of platinum-based treatment for advanced NSCLC in 2 256 subjects were included in this meta-analysis, of whom 522 were AA genotypes (23.2% frequency), 916 AG genotypes (40.6% frequency), and 818 GG genotypes (36.2% frequency). The overall response rate (ORR) was 45.2% (110/243) for AA genotype patients, 29.9% for AG genotype (73/244), and 30.7% for GG genotype (124/403). The heterogeneity test did not show any heterogeneity and the Egger’s test did not reveal an obvious publication bias among the included studies. The meta-analysis indicated that AA genotype patients presented higher response rates toward platinum drug treatment compared with G model (GG+GA) patients (GG vs. AA model: OR=0.489, 95% CI 0.266–0.900, P=0.021; AG vs. AA model: OR=0.608, 95% CI 0.392–0.941, P=0.026; GA+AA vs. GG model: OR=1.259, 95% CI 0.931–1.701, P=0.135; GG+GA vs. AA model: OR=0.455, 95% CI 0.313–0.663, P=0.0001). However, no evidence validates XRCC1 associates with the survival following platinum drug therapy. Conclusions: Our meta-analysis suggested that XRCC1 Arg399Gln is related with the sensitivity of NSCLC patients to platinum-based treatment. AA genotype patients present more desirable curative effectiveness compared with other patients. 相似文献
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Silicon carbide nanotubes (SiCNTs) with special morphology synthesized by supercritical hydrothermal method at 470 °C and
8 MPa have been reported in this paper. SiCNTs with special morphology were characterized by transmission electron microscopy
(TEM) and high-resolution TEM (HRTEM). There are two kinds of silicon carbide with special morphology: One is oval SiCNTs
with small aspect ratio, the other is bamboo cone-shape structure. SiCNTs have been analyzed by fluorescence spectrometer.
The results indicate that the SiCNTs have strong photoluminescence (PL) property. The SiCNTs with oval shape are one kind
of intermediate state of growth process of nanotube. The growth mechanism of silicon nanotubes has been proposed based on
experiment data. The investigations of growth mechanism of SiCNTs with bamboo structure show that the defect produced in the
growth process play the important role in SiCNTs with special structure. 相似文献
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The effects of the concentration of dissolved total organic carbon(TOC),the TOC/Br-ratio,bromide ion levels,the chlorine to ammonia-N ratio(Cl:N),the monochloramine dose and the chlorine dose on the formation of trihalomethanes(THMs)(including chloroform,bromodichloromethane,chlorodibromomethane,and bromoform)from chlorination were investigated using aqueous humic acid(HA)solutions.The profile of the chloramine decay was also studied under various bromide ion concentrations.Monochloramine decayed in the presence of organic material and bromide ions.The percentage of chloroform and brominated THMs varied according to the TOC/Br-ratio.Total THMs(TTHMs)formation increased from 112 to 190 μg/L with the increase concentrations of bromide ions from 0.67 to 6.72 mg/L,but the chlorine-substituted THMs were replaced by bromine-substituted THMs.A strong linear correlation was obtained between the monochloramine dose and the formation of THMs for Cl:N ratios of 3:1 and 5:1.These ratios had a distinct effect on the formation of chloroform but had little impact on the formation of bromodichloromethane or chlorodibromomethane.The presence of bromide ions increased the rate of monochloramine decay. 相似文献
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INTRODUCTION H.264 (Wiegand et al., 2003) is the latest video coding standard developed by the ISO/IEC Moving Picture Experts Group (MPEG) and the ITU-T Video Coding Experts Group (VCEG). Besides many new technologies which can bring high compression effi-ciency, H.264 also provides other tools to flexibly adapt to different transmission networks, such as flexible macroblock ordering (FMO) (Wenger and Horowitz, 2002a; 2002b) for dealing with data er-rors/losses in error prone… 相似文献
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丙烯酸/甲基丙烯酸β羟乙酯共聚物耐盐性高吸水性树脂研究 总被引：3，自引：0，他引：3
以甲基丙烯酸β羟乙酯（HEMA）和丙烯酸（AA）为原料，N，N，-亚甲基双丙烯酰胺为交联剂。采用水溶液聚合法合成了耐盐性能较好的高吸水性树脂。在AA／HEMA为95／5（摩尔比），交联剂和引发剂质量分数为0．03％和0．14％，中和度为80％时，合成树脂的吸水率为570g／g，吸收1％的氯化钠溶液能力接近100g／g，在5％盐水中的吸液能力依然超过50g／g。 相似文献
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CAO Pin-lu LIU Bao-chang YIN Kun ZHANG Zu-pei 《浙江大学学报(A卷英文版)》2006,7(8):1318-1323
INTRODUCTION Polycrystalline diamond compacts (PDC), con-sisting of a polycrystalline diamond (PCD) layer on a WC-Co substrate, and having high hardness and abrasive resistance, are used in a variety of drilling and machining applications (Farhad, 2001; Sadi and Muzaffer, 2001). However, due to differences of thermal and mechanical properties in diamond and WC-Co substrate, residual thermal stresses develop in regions near the interfaces during fabrication. The diamond coating exhib… 相似文献