2—甲苯缩水甘油醚协同提升环氧复合物韧性及刚性研究

电气及电子设备集成度的不断提高,对环氧复合物的热学与力学综合性能提出了更高需求。环氧复合物的耐热性能、刚性与韧性三者之间存在“跷跷板”现象,难以协同提升。该文提出将六氢邻苯二甲酸酐/四氢邻苯二甲酸酐/邻苯二甲酸酐3种固化剂复配提升环氧复合物热学性能,并采用2—甲苯缩水甘油醚协同提升环氧复合物韧性及刚性的方法。研究表明:固化剂复配的方法将环氧复合物的玻璃化转变温度Tg及热分解温度T5%分别提升了17.93%、7.72%;2—甲苯缩水甘油醚改性使得环氧复合物冲击强度和弯曲强度分别提升了123.03%、61.71%。采用分子动力学模拟,从分子角度揭示了2—甲苯缩水甘油醚提升环氧固化物性能的机理,其刚性苯环基团增强了环氧体系分子结构稳定性,柔性—C—O—C—链段改善了交联体系柔韧性。该研究提出一种不降低环氧复合物热学性能,并协同提升其韧性与刚性的可行方法,可为具备高综合热学与力学性能环氧复合物配方的设计提供新思路。

2型糖尿病发生与多溴联苯醚暴露的关系及其预测模型构建和评价

目的分析2型糖尿病(T2DM)发生与多溴联苯醚(PBDEs)暴露的关系,通过机器学习方法构建T2DM发生的预测模型并进行评价。方法在NHANES数据库筛选出1425例研究对象,其中非T2DM患者1132例、T2DM患者293例。比较非T2DM患者与T2DM患者的临床资料,取有统计学差异的临床资料进一步进行boruta特征筛选,以明确T2DM发生与PBDEs的关系及其影响因素。将筛选出的T2DM发生影响因素输入R软件,并使用R软件creatDataPartition函数将数据按照80%训练集及20%验证集随机划分。使用逻辑回归、极致梯度提升(XGBoost)、轻量梯度提升、自适应增强、K近邻、朴素贝叶斯及支持向量机等7种算法构建机器学习模型,将训练集输入模型进行训练,将验证集输入模型使用十折交叉验证对进行模型进行内部验证。结合ROC曲线以及曲线下面积(AUC)对模型进行评价,选择新疆医科大学一附院内分泌科就诊的成人T2DM患者71例及健康体检者100例对效能最好的预测模型进行外部验证。使用SHAP工具分析高效能预测模型的可解释性,判断模型在决策过程中各个特征的重要性。结果T2DM患者BMI、腰围、受教育程度、有糖尿病家族史比例、血清高密度脂蛋白及血清BDE-28、BDE-47、BDE-99、BDE-183、BDE-209浓度均高于非T2DM患者(P均<0.05),Boruta特征筛选出腰围、BMI、糖尿病家族史及血清BDE-47、BDE-99、BDE-28、BDE-209、BDE-183作为T2DM发生的影响因素纳入机器学习算法建立T2DM发生的预测模型。在训练集及验证集的内部验证中,XGBoost模型AUC值均最高,且准确度、Kappa值、灵敏度及特异度均位于前列,故选择XGBoost模型作为高效能预测模型。外部验证结果显示,XGBoost模型的准确度为0.702、灵敏度为0.549、特异度为0.787、AUC(95%CI)为0.674(0.575~0.773)。SHAP工具对XGBoost模型的预测情况进行解释性分析结果显示,腰围、血清BDE-47为最重要的预测特征,同时血清BDE-99、BDE-209及BMI、糖尿病家族史在模型中具有较高的重要性,而血清BDE-28、BDE-183在模型中重要性相对较低。结论血清BDE-47、BDE-99、BDE-28、BDE-209、BDE-183为T2DM发生的独立影响因素,基于血清PBDEs及腰围、BMI、糖尿病家族史建立的XGBoost模型对T2DM发生的预测效能较高,在T2DM发生的预测方面具有一定价值。

2,4-Dinitrophenyl Ether of Polyvinyl Alcohol and Polymer Bound Anionic SIGMA Complexes

A new electrophilic polymer, 2,4-dinitrophenyl ether of polyvinyl alcohol (PVA-DNP), having a degree of substitution of 0.5 was prepared from polyvinyl alcohol (PVA) and 1-fluro-2,4-dinitrobenzene (DNFB). The PVA-DNP polymer was characterized by NMR, IR, and UV-visible spectroscopy. The reaction of PVA-DNP with sodium methoxide was followed by NMR and UV-visible spectroscopy. Evidence of polymer bound spirocyclic SIGMA complex, C-1 and C-3 polymer bound DNP-methoxy SIGMA complexes and the formation and C-1 methoxy complex of 2,4-dinitroanisole was observed.

二甲醚辅助CO_(2)驱提高页岩油采收率可行性实验——以四川盆地长宁地区奥陶系五峰组为例

为实现CO_(2)驱替过程中CO_(2)性能最大化,进一步提高CO_(2)驱替页岩油的采收率。提出了采用二甲醚(DME)辅助CO_(2)驱油方法,基于核磁共振(NMR)技术,通过开展助溶剂辅助CO_(2)驱替岩心实验,对比了丙烷、正己烷和DME辅助CO_(2)的驱油效果,明确了DME作用下CO_(2)对不同孔径孔隙原油的动用特征。结果表明:相比纯CO_(2),摩尔分数为20%的DME−CO_(2)混合溶剂能够将CO_(2)-原油的界面张力降低45百分点,混相压力降低33百分点,原油黏度降低80百分点,可动用孔隙孔径下限由7.7 nm降至3.2 nm,页岩油采收率提高35.9百分点;并可显著提高CO_(2)动用小孔隙(0.9 nm<r<101.0 nm)和大孔隙(101.0 nm≤r<7088.0 nm)的能力,动用程度分别提高了3.3倍和1.9倍;CO_(2)混合溶剂中DME最佳摩尔分数为20%,最大不超过30%。研究成果为探索页岩油藏新的开发方式和新策略提供了参考和借鉴。

冠醚基超交联聚合物催化CO_(2)与环氧化物的环加成反应

CO_(2)与环氧化物通过环加成反应制备环状碳酸酯是CO_(2)资源化利用的有效途径之一,但工业上使用的传统催化剂往往存在着苛刻的反应条件和催化剂难以循环使用等缺点。开发能够使环加成反应在温和条件下发生的多相催化剂仍面临巨大挑战。通过Friedel-Crafts烷基化反应获得的超交联聚合物(Hypercrosslinked Polymer, HCPs)是一种具有永久孔隙率的三维网络,在CO_(2)催化转化方面具有极大的应用潜力。本文设计与合成了一种冠醚基超交联聚合物(CE-HCP-1)并将其成功地用于CO_(2)环加成反应中,分别使用两种工业催化剂(碘化钾KI或四丁基溴化铵TBAB)作为助催化剂时,均实现了在相对较温和无溶剂的条件下高效地合成系列环状碳酸酯。在KI/CE-HCP-1双组分催化系统中,在100℃和1.0 MPa的CO_(2)压力下,反应16 h,环氧氯丙烷的转化率可达90%以上,并且展现出良好的循环稳定性和底物适用性。因此,构建高效的双组分协同催化体系能为温和条件下CO_(2)的资源化利用提供良好的路径。

脲基功能聚合材料的合成及CO_(2)催化转化研究

功能有机聚合材料逐渐成为CO_(2)资源化利用领域非常有前景的催化材料之一.利用缩合反应合成了系列脲基功能聚合材料,并采用FT-IR及SEM等方法对系列聚合材料进行了表征,进一步研究了其在无溶剂且温和条件下催化CO_(2)环加成反应的效果,结果发现系列脲基-冠醚基功能化聚合材料UCPs均表现出优异的催化活性,UCPs优异的催化活性与脲基与冠醚活性位点协同效应有关.该研究对功能聚合材料的构筑具有一定的参考价值.

Preparation of Ni(HCO_3)_2 and its catalytic performance in synthesis of benzoin ethyl ether

Ni（HCO3）2 with unique phase and high crystallinity was synthesized with urea hydrolysis. The as-prepared samples were well characterized in detail. N2 adsorption and desorption result manifests a high surface area of 99.03 m2/g with a pore size of 7.8 nm. Scanning electron microscopy （SEM） and particle size distribution reveal that the diameters of the formed pellets are uniform. Thermogravimetry （TG） analysis result shows that 500 ℃ could be the appropriate temperature for converting Ni（HCO3）2 precursors into NiO via a thermal decomposition process. CO2 and NH3 temperature-programmed desorption results show that Ni（HCO3）2 has explicit acid-base sites. Transmission electron microscopy （TEM） results vividly indicate that the pellets are aggregated by hexagonal platelets and possess porous structures. Ni（HCO3）2 can efficiently catalyze the one-step synthesis of benzoin ethyl ether from benzaldehyde and ethanol, with the conversion ofbenzaldehyde up to 57.5% and nearly 100% selectivity of benzoin ethyl ether.

胃肠动力药西沙比利对表达于HEK293细胞的人ether-a-go-go相关基因2通道的影响

目的：研究胃肠动力药西沙比利对于在 HEK293细胞异源性表达的人 ether-a-go-go 相关基因2（human ether-a-go-go related gene 2,hERG2）通道性质的影响。方法用 Lipofectamine 2000将 hERG2（AF311913）瞬时转染至 HEK293细胞,使其表达hERG2通道,利用全细胞膜片钳技术记录 hERG2电流。加入西沙比利（终浓度分别为0.001,0.01,0.1,1.0,10.0μmol/ L）,分别记录加药前和加药后2~8 min 的 hERG2电流,分析西沙比利浓度和作用时间对此通道电流的影响。结果西沙比利各浓度实验组中,hERG2时间依赖性电流和尾电流幅度均下降。在去极化电压为＋20 mV 时,随西沙比利浓度升高,电流抑制率逐渐增加。西沙比利的抑制作用随时间延长逐渐增强,西沙比利浓度为1μmol/ L 时,电流在8 min 内完全消失。结论西沙比利对HEK293细胞表达的 hERG2通道的时间依赖性电流和尾电流均有抑制作用,该抑制作用具有浓度依赖性和时间依赖性,即浓度越高,时间越长,抑制效果越明显,直至电流降低至稳态或消失。

Effects of ZrO_2 on the Performance of CuO-ZnO-Al_2O_3/HZSM-5 Catalyst for Dimethyl Ether Synthesis from CO_2 Hydrogenation

A series of composite catalysts were prepared by the wet mixing method, and the mass ratio of CuO-ZnO-Al2O3-ZrO2 component to HZSM-5 zeolite （molar ratio of SiO2 to Al2O3 being 25） was 2：1. The CuO-ZnO-Al2O3-ZrO2 （CuO/ZnO/Al2O3=3/6/1 by weight） component was prepared by a modified ＇two-step＇ co-precipitation method. The effects of ZrO2 on the performance of CuO-ZnO-Al2O3/HZSMo5 catalyst for dimethyl ether synthesis from CO2 hydrogenation were investigated. It was found that ZrO2 improved the properties of CuO-ZnO-Al2O3/HZSM-5 as a structural promoter.

Dimensional Gradient Structure of CoSe2@CNTs-MXene Anode Assisted by Ether for High-Capacity,Stable Sodium Storage

Recently,abundant resources,low-cost sodium-ion batteries are deemed to the new-generation battery in the field of largescale energy storage.Nevertheless,poor active reaction dynamics,dissolution of intermediates and electrolyte matching problems are significant challenges that need to be solved.Herein,dimensional gradient structure of sheet-tube-dots is constructed with CoSe2@CNTs-MXene.Gradient structure is conducive to fast migration of electrons and ions with the association of ether electrolyte.For half-cell,CoSe2@CNTs-MXene exhibits high initial coulomb efficiency(81.7%)and excellent cycling performance(400 mAh g^-1 cycling for 200 times in 2 Ag^−1).Phase transformation pathway from crystalline CoSe2-Na2Se with Co and then amorphous CoSe2 in the discharge/charge process is also explored by in situ X-ray diffraction.Density functional theory study discloses the CoSe2@CNTs-MXene in ether electrolyte system which contributes to stable sodium storage performance owing to the strong adsorption force from hierarchical structure and weak interaction between electrolyte and electrode interface.For full cell,CoSe2@CNTs-MXene//Na3V2(PO4)3/C full battery can also afford a competitively reversible capacity of 280 mAh g^−1 over 50 cycles.Concisely,profiting from dimensional gradient structure and matched electrolyte of CoSe2@CNTs-MXene hold great application potential for stable sodium storage.

Synthesis of nanocrystalline γ-Al_2O_3 by sol-gel and precipitation methods for methanol dehydration to dimethyl ether

The capability of sol-gel and conventional precipitation techniques for the synthesis of nanocrystalline γ-alumina was investigated. These catalysts were used for vapor-phase dehydration of methanol to dimethyl ether in a fixed-bed reactor under the same operating conditions （T = 300 ？C, P = 1 bar, LHSV = 2.8, 11.7, 26.1 h？1） and characterized by means of N2 adsorption-desorption, NH3-TPD, XRD, TGA and SEM techniques. According to the experimental results, the catalysts prepared using sol-gel method in non-aqueous medium showed better performance compared with those prepared by other methods.

1,3-Bis(2-chloroethyl)-1-nitrosourea enhances the inhibitory effect of Resveratrol on 5-fluorouracil sensitive/resistant colon cancer cells

AIM:To study the mechanism of 5-fluorouracil(5-FU)resistance in colon cancer cells and to develop strategies for overcoming such resistance by combination treatment.METHODS:We established and characterized a 5-FU resistance(5-FU-R)cell line derived from continuous exposure(25μmol/L)to 5-FU for 20 wk in 5-FU sensitive HCT-116 cells.The proliferation and expression of different representative apoptosis and anti-apoptosis markers in 5-FU sensitive and 5-FU resistance cells were measured by the MTT assay and by Western blotting,respectively,after treatment with Resveratrol(Res)and/or 1,3-Bis(2-chloroethyl)-1-nitrosourea(BCNU).Apoptosis and cell cycle arrest was measured by 4',6'-diamidino-2-phenylindole hydrochloride staining and fluorescence-activated cell sorting analysis,respectively.The extent of DNA damage was measured by the Comet assay.We measured the visible changes in the DNA damage/repair cascade by Western blotting.RESULTS:The widely used chemotherapeutic agents BCNU and Res decreased the growth of 5-FU sensitive HCT-116 cells in a dose dependent manner.Combined application of BCNU and Res caused more apoptosis in5-FU sensitive cells in comparison to individual treatment.In addition,the combined application of BCNU and Res caused a significant decrease of major DNA base excision repair components in 5-FU sensitive cells.We established a 5-FU resistance cell line(5-FU-R)from 5-FU-sensitive HCT-116(mismatch repair deficient)cells that was not resistant to other chemotherapeutic agents(e.g.,BCNU,Res)except 5-FU.The 5-FU resistance of 5-FU-R cells was assessed by exposure to increasing concentrations of 5-FU followed by the MTT assay.There was no significant cell death noted in5-FU-R cells in comparison to 5-FU sensitive cells after5-FU treatment.This resistant cell line overexpressed anti-apoptotic[e.g.,AKT,nuclear factorκB,FLICE-like inhibitory protein),DNA repair(e.g.,DNA polymerase beta(POL-β),DNA polymerase eta(POLH),protein Flap endonuclease 1(FEN1),DNA damage-binding protein 2(DDB2)]and 5-FU-resistance proteins(thymidylate synthase)but under expressed pro-apoptotic proteins(e.g.,DAB2,CK1)in comparison to the parental cells.Increased genotoxicity and apoptosis were observed in resistant cells after combined application of BCNU and Res in comparison to untreated or parental cells.BCNU increased the sensitivity to Res of 5-FU resistant cells compared with parental cells.Fifty percent cell death were noted in parental cells when 18μmol/L of Res was associated with fixed concentration(20μmol/L)of BCNU,but a much lower concentration of Res(8μmol/L)was needed to achieve the same effect in 5-FU resistant cells.Interestingly,increased levels of adenomatous polyposis coli and decreased levels POL-β,POLH,FEN1 and DDB2 were noted after the same combined treatment in resistant cells.CONCLUSION:BCNU combined with Res exerts a synergistic effect that may prove useful for the treatment of colon cancer and to overcome drug resistance.

Catalytic Oxidation of Dimethyl Ether to Dimethoxymethane over Cs Modified H_3PW_(12)O_(40)/SiO_2 Catalysts

The attractive utilization route for one-step catalytic oxidation of dimethyl ether to dimethoxymethane was successfully carried out over the H3PW12O40（40%）/SiO2 catalyst, modified by Cs, K, Ni, and V. The Cs modification of H3PW12O40（40%）/SiO2 gave the most promising result of 20% dimethyl ether conversion and 34.8% dimethoxymethane selectivity. Dimethoxymethane could be synthe- sized via methoxy groups decomposed from dimethyl ether through the synergistic effect between the acid sites and the redox sites of Cs modified H3PW12O40（40%）/SiO2.

Synthesis and antibacterial activity of brominated 2′(4′)-nitro-3-hydroxy diphenyl ethers

Eight new brominated 2＇（4＇）-nitro-3-hydroxy diphenyl ethers have been designed and synthesized. The structures of new compounds were confirmed by ^1H NMR, IR and HRMS. The bioactivity tests showed that these compounds possessed antibacterial activities against the tested bacteria. These new compounds cannot be transformed into dioxins when they were manufactured and used.

Partial oxidation of dimethyl ether to H_2/syngas over supported Pt catalyst

Dimethyl ether （DME） is a non-toxic fuel with high H/C ratio and high volumetric energy density, and could be served as an ideal source of H2/syngas production for application in solid oxide fuel cells （SOFC）. This study presents results of DME partial oxidation over a 1.5 wt% Pt/Ce0.4Zr0.6O2 catalyst under the condition of gas hourly space velocity （GHSV） of 15000-60000 ml/（g·h）, molar ratio of O2/DME of 0.5 and 500-700 ℃, and this temperature range was also the operation temperature range for intermediate temperature SOFC. The results indicated that the catalyst showed good activity for the selective partial oxidation of DME to H2/syngas. Under the working conditions investigated, DME was completely converted. Increase in reaction temperature enhanced the amount of syngas, but lowered the H2/CO ratio and yield of methane; while increase in reaction GHSV resulted in only slight variation in the distribution of products. The good catalytic activity of Pt supported on Ce0.4Zr0.6O2 for the partial oxidation of DME may be directly associated with the good oxygen storage capacity of the support, which is worth of further investigation to develop materials for application in SOFC.

2D-Cell Experiment on Methyl Tert-Butyl Ether Transport in Saturated Zone of Groundwater

As an additive of gasoline,methyl ten-butyl ether(MTBE)has a higher solubility in water,which is about 20 times as high as that of benzene.This characteristic results in MTBE dissolving out of the gasoline into the soil and groundwater.Due to relative unique physicochemical behavior of MTBE it would be an ideal candidate for use in environmental forensic investigations.In order to study the transport and distribution of MTBE in saturated zone of ground water,a two-dimensional experimental cell was setup to simulate the real environment of the groundwater flow.The effects of soil and groundwater flow velocity on the MTBE transport were investigated.The results show that the mobile distance of MTBE in vertical direction was smaller than that in horizontal direction paralleling with the groundwater flow.Because the main dynamics of groundwater flow direction was convection and dispersion,the movement of MTBE is also diffusion in the vertical direction.In addition,the transport of MTBE was more quick in high permeability porous media,and the increase of groundwater flow velocity can accelerate the MTBE plume development,but the irregularity and randomness of the plume are enhanced synchronously.These research results can give some helps for the investigation of MTBE movement in the groundwater,also can make some references for other petroleum contamination behavior.

Decontamination of 2-Chloroethyl Ethyl Sulfide by Pulsed Corona Plasma

Decontamination of 2-chloroethyl ethyl sulfide （2-CEES, CH_3CH_2SCH_2CH_2C1） by pulsed corona plasma was investigated. The results show that 212.6 mg/m^3 of 2-CEES, with the gas flow rate of 2 m^3/h, can be decontaminated to 0.09 mg/m^3. According to the variation of the inlet and outlet concentration of 2-CEES vapor with retention time, it is found that the reaction of 2-CEES in a pulsed corona plasma system follows the first order reaction, with the reaction rate constant of 0.463 s^-1. The decontamination mechanism is discussed based on an analysis of the dissociation energy of chemical bonds and decontamination products. The C-S bond adjacent to the C1 atom will be destroyed firstly to form CH3CH2S. and .CH2CH2C1 radicals. CH3CH2S. can be decomposed to .C_2H_5 and .S..S can be oxidized to SO_2, while .C_2H_5 can be finally oxidized to CO_2 and H_2O. The C-Cl bond in the .CH_2CH_2C1 radical can be destroyed to form .CH_2CH_2. and .C1, which can be mineralized to CO_2, H_2O and HCl. The H atom in the .CH_2CH_2C1 radical can also be substituted by -C1 to form CHCl_2-CHCl_2.

Enhanced catalytic performance for direct synthesis of dimethyl ether from syngas over a La_2O_3 modified Cu-ZrO_2/γ-Al_2O_3 hybrid catalyst

A series of hybrid catalysts were made by physically mixing Cu-ZrO2 and γ-A12O3, for former it was modified with different loadings of La2O3 prepared by co-precipitation method. The catalysts were characterized by BET, XRD, N2O-adsorption, EXAFS, H2-TPR, NH3-TPD techniques and evaluated in the synthesis of dimethyl ether from syngas. The results show that La2O3 promoted catalysts displayed a significantly better catalytic performance compared with Cu-ZrO2#y-A12O3 catalyst in CO conversion and DME selectivity, and the optimum catalytic activity was obtained when the content of La2O3 was 12 wt%. The characterizations reveal that high copper dispersion, facile reducibility of copper particles and appropriate amount of acidic sites are responsible for the superior catalytic performance.

Solubilities of CO2 in some glycol ethers under high pressure by experimental determination and correlation

The binary vapor–liquid equilibrium data of CO_2 in diethylene glycol(monomethyl,monoethyl,monobutyl,dimethyl,diethyl,dibutyl)ether were determined from 288.15 to 318.15 K at pressure up to 6 MPa based on the constant-volume method.It was found by contrast that the ether group in solvents can promote the CO_2 absorption,but the hydroxyl group will inhibit the CO_2 absorption.Furthermore,the solubilities of CO_2 showed an upward trend with the increasing molecular lengths of absorbents.The experimental data were also correlated with a modified Patel–Teja equation of state(PT EOS)combined with the traditional van der Waals one-fluid mixing rules and the results showed a satisfactory agreement between the model and the experimental data.

Enhanced stability of Fe-modified CuO-ZnO-ZrO_(2)-Al_(2)O_(3)/HZSM-5 bifunctional catalysts for dimethyl ether synthesis from CO_(2)hydrogenation

A series of iron(Fe)modified CuO-ZnO-ZrO_(2)-Al_(2)O_(3)(CZZA)catalysts,with various Fe loadings,were prepared using a co-precipitation method.A bifunctional catalyst,consisting of Fe-modified CZZA and HZSM-5,was studied for dimethyl ether(DME)synthesis via CO_(2)hydrogenation.The effects of Fe loading,reaction temperature,reaction pressure,space velocity,and concentrations of precursor for the synthesis of the Fe-modified CZZA catalyst on the catalytic activity of DME synthesis were investigated.Long-term stability tests showed that Fe modification of the CZZA catalyst improved the catalyst stability for DME synthesis via CO_(2)hydrogenation.The activity loss,in terms of DME yield,was significantly reduced from 4.2%to 1.4%in a 100 h run of reaction,when the Fe loading amount was 0.5(molar ratio of Fe to Cu).An analysis of hydrogen temperature programmed reduction revealed that the introduction of Fe improved the reducibility of the catalysts,due to assisted adsorption of H2 on iron oxide.The good stability of Femodified CZZA catalysts in the DME formation was most likely attributed to oxygen spillover that was introduced by the addition of iron oxide.This could have inhibited the oxidation of the Cu surface and enhanced the thermal stability of copper during long-term reactions.