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Crown ether-thiourea conjugates as ion transporters

Zhixing Zhao, Bailing Tang, Xiaosheng Yan, Xin Wu, Zhao Li, Philip A. Gale, Yun-Bao Jiang

《化学科学与工程前沿(英文)》 2022年 第16卷 第1期   页码 81-91 doi: 10.1007/s11705-021-2049-7

摘要: Na , Cl and K are the most abundant electrolytes present in biological fluids that are essential to the regulation of pH homeostasis, membrane potential and cell volume in living organisms. Herein, we report synthetic crown ether-thiourea conjugates as a cation/anion symporter, which can transport both Na and Cl across lipid bilayers with relatively high transport activity. Surprisingly, the ion transport activities were diminished when high concentrations of K ions were present outside the vesicles. This unusual behavior resulted from the strong affinity of the transporters for K ions, which led to predominant partitioning of the transporters as the K complexes in the aqueous phase preventing the transporter incorporation into the membrane. Synthetic membrane transporters with Na , Cl and K transport capabilities may have potential biological and medicinal applications.

关键词: ion transport     thiourea     crown ether     symport    

Solvent-resistant porous membranes using poly(etherether ketone): preparation and application

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1536-1559 doi: 10.1007/s11705-022-2221-8

摘要: Poly(ether−ether ketone) (PEEK) is a linear aromatic macromolecule, which can form semi-crystalline aggregative status, allowing PEEK materials to have strong environment tolerance and excellent physicochemical properties. PEEK materials have become a promising alternative to fabricate particular membranes used in extreme conditions. In the past few decades, many researches and evolutions have emerged in membrane fabrication with PEEK materials and its applications for treating organic solvents and their mixtures; however, there are little systematic and comprehensive literature to summarize fabrication approaches, compile applications, and elaborate PEEK property-structure relationship. In this review, the main approaches to fabricate PEEK-based membranes are illustrated concretely, including conventional thermal-induced and non-solvent-induced phase separation, and novel chemical-induced crystallization; the representative applications in ultrafiltration, nanofiltration and membrane contactor containing organic solvents are demonstrated systematically. Meanwhile, the mechanism to tune PEEK solubility in solvents, which can be achieved by altering monomers in synthesis processes or changing membrane preparation routes, is deeply analyzed. Moreover, the existing problems and the future prospects are also discussed. This review provides positive guidance for designing and fabricating membranes using PEEK and its derivative materials for task-specific applications in harsh conditions.

关键词: PEEK     phase inversion     solvent-resistant membrane     nanofiltration     membrane contactor    

Enhancing fatigue life of cylinder-crown integrated structure by optimizing dimension

Weiwei ZHANG,Xiaosong WANG,Zhongren WANG,Shijian YUAN

《机械工程前沿(英文)》 2015年 第10卷 第1期   页码 102-110 doi: 10.1007/s11465-015-0329-y

摘要:

Cylinder-crown integrated hydraulic press (CCIHP) is a new press structure. The hemispherical hydraulic cylinder also functions as a main portion of crown, which has lower weight and higher section modulus compared with the conventional hydraulic cylinder and press crown. As a result, the material strength capacity is better utilized. During the engineering design of cylinder-crown integrated structure, in order to increase the fatigue life, structural optimization on the basis of the adaptive macro genetic algorithms (AMGA) is first conducted to both reduce weight and decrease peak stress. It is shown that the magnitude of the maximum principal stress is decreased by 28.6%, and simultaneously the total weight is reduced by 4.4%. Subsequently, strain-controlled fatigue test is carried out, and the stress-strain hysteresis loops and cyclic hardening curve are obtained. Based on linear fit, the fatigue properties are calculated and used for the fatigue life prediction. It is shown that the predicted fatigue life is significantly increased from 157000 to 1070000 cycles after structural optimization. Finally, according to the optimization design, a 6300 kN CCIHP has been manufactured, and priority application has been also suggested.

关键词: cylinder-crown integrated hydraulic press (CCIHP)     adaptive macro genetic algorithms (AMGA)     strain-controlled fatigue test    

Sulfonated poly(ether ether ketone)/zirconium tricarboxybutylphosphonate composite proton-exchange membranes

GAO Qijun, HUANG Mianyan, WANG Yuxin, CAI Yuquan, XU Li

《化学科学与工程前沿(英文)》 2008年 第2卷 第1期   页码 95-101 doi: 10.1007/s11705-008-0012-5

摘要: Sulfonated poly(ether ether ketone) (SPEEK) is a very promising alternative membrane material for direct methanol fuel cells. However, with a fairly high degree of sulfonation (DS), SPEEK membranes can swell excessively and even dissolve at high temperature. This restricts membranes from working above a high tolerable temperature to get high proton conductivity. To deal with this contradictory situation, insolvable zirconium tricarboxybutylphosphonate (Zr(PBTC)) powder was employed to make a composite with SPEEK polymer in an attempt to improve temperature tolerance of the membranes. SPEEK/Zr(PBTC) composite membranes were obtained by casting a homogeneous mixture of Zr(PBTC) and SPEEK in N,N-dimethylacetamide on a glass plate and then evaporating the solvent at 60°C. Many characteristics were investigated, including thermal stability, liquid uptake, methanol permeability and proton conductivity. Results showed significant improvement not only in temperature tolerance, but also in methanol resistance of the SPEEK/Zr(PBTC) composite membranes. The membranes containing 30 wt-% ∼ 40 wt-% of Zr(PBTC) had their methanol permeability around 10 cm·s at room temperature to 80°C, which was one order of magnitude lower than that of Nafion115. High proton conductivity of the composite membranes, however, could also be achieved from higher temperature applied. At 100% relative humidity, above 90°C the conductivity of the composite membrane containing 40 wt-% of Zr(PBTC) exceeded that of the Nafion115 membrane and even reached a high value of 0.36 S·cm at 160°C. Improved applicable temperature and high conductivity of the composite membrane indicated its promising application in DMFC operations at high temperature.

关键词: homogeneous mixture     PBTC     zirconium tricarboxybutylphosphonate     Nafion115     DMFC    

Biomass to dimethyl ether by gasification/synthesis technology

Tiejun WANG, Yuping LI, Longlong MA, Chuangzhi WU

《能源前沿(英文)》 2011年 第5卷 第3期   页码 330-339 doi: 10.1007/s11708-010-0121-y

摘要: Technical and economic analysis was done for the biomass to dimethyl ether (DME) technology to promote the gasification/synthesis route for biofuel production and its application as a fossil fuel substitute. The technology of biomass gasification/synthesis has obvious advantages, including production flexibility, environmental friendliness, economic feasibility, and application versatility. Biomass gasification/synthesis technology integrates bio-DME synthesis, fertilizer production, electricity generation, and waste heat utilization to convert waste biomass residues to DME for use as liquid petroleum gas, transportation fuel substitute, and chemical intermediates, which has been proven to be one of the most effective and clean biomass utilization routes. The 1000 t/a-scale demonstration plant has a bio-DME production rate of 6 to 7 / , biomass gasification efficiency of≥82%, once-through CO conversion of ≥70%, DME selectivity (DME/DME+other organic products) of ≥90%, and a total system efficiency of ≥38%. The demonstration plant also has self-sufficient steam and electricity supply. The 10,000tons/a-scale bio-DME production cost with or without feedstock subsidy is estimated to be 1968 Yuan/t and 2868 Yuan/t, respectively in China. Because of the limitation in biomass feedstock collection cost, massive and disperse commercial plants with a capacity of 10000 t/a bio-DME are more suitable for rural areas.

关键词: technical and economic analysis     biomass     dimethyl ether     gasification/synthesis    

Dimethyl ether as alternative fuel for CI engine and vehicle

Zhen HUANG , Xinqi QIAO , Wugao ZHANG , Junhua WU , Junjun ZHANG ,

《能源前沿(英文)》 2009年 第3卷 第1期   页码 99-108 doi: 10.1007/s11708-009-0013-1

摘要: As a developing and the most populous country in the world, China faces major challenges in energy supply and environmental protection. It is of great importance to develop clean and alternative fuels for internal combustion engines. On the basis of researches on DME engine and vehicle at Shanghai Jiaotong University in the last twelve years, fuel injection, combustion, performance and exhaust emissions of DME engine and DME vehicle are introduced in this paper. The results indicate that DME engines can achieve high thermal efficiency and ultra low emissions, and will play a significant role in meeting the energy demand while minimizing environmental impact in China.

关键词: dimethyl ether (DME)     fuel injection     combustion process     emission control     CI engine     vehicle    

Study on direct alcohol/ether fuel synthesis process in bubble column slurry reactor

Zhen CHEN, Haitao ZHANG, Weiyong YING, Dingye FANG

《化学科学与工程前沿(英文)》 2010年 第4卷 第4期   页码 461-471 doi: 10.1007/s11705-010-0517-6

摘要: The recent studies of direct alcohol/ether synthesis process in slurry reactors were reviewed, and the research work in our laboratory was carried out in this paper. a global kinetics model for direct dimethyl ether (DME) synthesis from syngas over a novel Cu-Zn-Al-Zr slurry catalyst was established according to the total of 25 experimental data, and a steady-state one-dimensional mathematical model was further developed in bubble column slurry reactor (BCSR), which was assumed that the bubble phase was plug flow, and the liquid phase was fully mixed flow. The numerical simulations of reactor design of 100000 t/a dimethyl ether pilot plant indicate that higher pressure and lower temperature were favorable to the increase of CO conversion, selectivity of dimethyl ether, product yield and height of slurry bed. The optimal operating conditions for DME synthesis process were obtained: reaction temperature at 240°C, reactor pressure at 5 MPa and reactor diameter of 2.5 m.

关键词: syngas     alcohol/ether fuel     slurry catalyst     bubble column slurry reactor     global kinetics     mathematical model    

Enhanced debromination of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) by zero-valent zinc with ascorbic

Chaojin Jiang, Xiaoqian Jiang, Lixun Zhang, Yuntao Guan

《环境科学与工程前沿(英文)》 2020年 第14卷 第3期 doi: 10.1007/s11783-020-1224-2

摘要: Highly efficient debromination of BDE-47 was achieved in the ZVZ/AA system. BDE-47 debromination by the ZVZ/AA can be applied to a wide range of pH. AA inhibits the formation of (hydr)oxide and accelerates the corrosion of ZVZ. Reduction mechanism of BDE-47 debromination by the ZVZ/AA system was proposed. A new technique of zero-valent zinc coupled with ascorbic acid (ZVZ/AA) was developed and applied to debrominate the 2,2′,4,4′-Tetrabromodiphenyl ether (BDE-47), which achieved high conversion and rapid debromination of BDE-47 to less- or non-toxic forms. The reaction conditions were optimized by the addition of 100 mg/L ZVZ particles and 3 mmol/L AA at original solution pH= 4.00 using the solvent of methanol/H2O (v:v= 4:6), which could convert approximately 94% of 5 mg/L BDE-47 into lower-brominated diphenyl ethers within a 90 min at the ZVZ/AA system. The high debromination of BDE-47 was mainly attributed to the effect of AA that inhibits the formation of Zn(II)(hydr)oxide passivation layers and promotes the corrosion of ZVZ, which leads to increase the reactivity of ZVZ. Additionally, ion chromatography and gas chromatography mass spectrometry analyses revealed that bromine ion and lower-debromination diphenyl ethers formed during the reduction of BDE-47. Furthermore, based on the generation of the intermediates products, and its concentration changes over time, it was proposed that the dominant pathway for conversion of BDE-47 was sequential debromination and the final products were diphenyl ethers. These results suggested that the ZVZ/AA system has the potential for highly efficient debromination of BDE-47 from wastewater.

关键词: 2     2′     4     4′-tetrabromodiphenyl ether (BDE-47)     Ascorbic acid     Reductive debromination     Zero-valent zinc    

Exergy losses in premixed flames of dimethyl ether and hydrogen blends

Tongbin ZHAO, Jiabo ZHANG, Dehao JU, Zhen HUANG, Dong HAN

《能源前沿(英文)》 2019年 第13卷 第4期   页码 658-666 doi: 10.1007/s11708-019-0645-8

摘要: A second-law thermodynamic analysis was conducted for stoichiometric premixed dimethyl ether (DME)/hydrogen (H )/air flames at atmospheric pressure. The exergy losses from the irreversibility sources, i.e., chemical reaction, heat conduction and species diffusion, and those from partial combustion products were analyzed in the flames with changed fuel blends. It is observed that, regardless of the fuel blends, chemical reaction contributes most to the exergy losses, followed by incomplete combustion, and heat conduction, while mass diffusion has the least contribution to exergy loss. The results also indicate that increased H substitution decreases the exergy losses from reactions, conduction, and diffusion, primarily because of the flame thickness reduction at elevated H substitution. The decreases in exergy losses by chemical reactions and heat conduction are higher, but the exergy loss reduction by diffusion is slight. However, the exergy losses from incomplete combustion increase with H substitution, because the fractions of the unburned fuels and combustion intermediates, e.g., H and OH radical, increase. The overall exergy losses in the DME/H flames decrease by about 5% with increased H substitution from 0% to 100%.

关键词: second law analysis     flame     dimethyl ether (DME)     hydrogen     binary fuels    

Removal of decabromodiphenyl ether (BDE-209) by sepiolite-supported nanoscale zerovalent iron

Rongbing FU,Na MU,Xiaopin GUO,Zhen XU,Dongsu BI

《环境科学与工程前沿(英文)》 2015年 第9卷 第5期   页码 867-878 doi: 10.1007/s11783-015-0800-3

摘要: Nanoscale zerovalent iron (nZVI) synthesized using sepiolite as a supporter was used to investigate the removal kinetics and mechanisms of decabromodiphenyl ether (BDE-209). BDE-209 was rapidly removed by the prepared sepiolite-supported nZVI with a reaction rate that was 5 times greater than that of the conventionally prepared nZVI because of its high surface area and reactivity. The degradation of BDE-209 occurred in a stepwise debromination manner, which followed pseudo-first-order kinetics. The removal efficiency of BDE-209 increased with increasing dosage of sepiolite-supported nZVI particles and decreasing pH, and the efficiency decreased with increasing initial BDE-209 concentrations. The presence of tetrahydrofuran (THF) as a cosolvent at certain volume fractions in water influenced the degradation rate of sepiolite-supported nZVI. Debromination pathways of BDE-209 with sepiolite-supported nZVI were proposed based on the identified reaction intermediates, which ranged from nona- to mono-brominated diphenylethers (BDEs) under acidic conditions and nona- to penta-BDEs under alkaline conditions. Adsorption on sepiolite-supported nZVI particles also played a role in the removal of BDE-209. Our findings indicate that the particles have potential applications in removing environmental pollutants, such as halogenated organic contaminants.

关键词: sepiolite-supported nanoscale zerovalent iron     decabromodiphenyl ether     debromination     adsorption     mechanism    

基于拱顶沉降控制的卵砾石地层浅埋隧道施工优化

喻军,刘松玉,龚晓南

《中国工程科学》 2013年 第15卷 第10期   页码 97-102

摘要:

某卵砾石地层浅埋公路隧道施工开挖,围岩的稳定性与拱顶沉降存在密切的关系,因此采用仿真分析法以拱顶沉降为控制目标,确保围岩的稳定,分析不同的施工方案得到拱顶沉降规律,达到优化施工的目的;同时,分析了不同的开挖路径和台阶长度,提出了一种最佳的施工方案。结果表明:在浅埋隧道开挖时容易引起拱顶沉降,并且随着施工方案的不同,拱顶沉降有较大的差异。在几种施工方法中,发现CRD法(交叉中隔墙法)比较适合,原因是拱顶沉降最小,应力释放较慢,在渐近的过程中有效地实现了应力的转移,较台阶法和CD法(中隔墙法)有大的优势,并与现场监测进行了对比分析,结果较为吻合。得到的结论可为类似工程提供参考。

关键词: 卵砾石     隧道围岩     数值分析     施工优化     拱顶沉降     现场监测    

A density functional theory study on the mechanism of Dimethyl ether carbonylation over heteropolyacids

Kai Cai, Ying Li, Hongbao Shen, Zaizhe Cheng, Shouying Huang, Yue Wang, Xinbin Ma

《化学科学与工程前沿(英文)》 2021年 第15卷 第2期   页码 319-329 doi: 10.1007/s11705-020-1957-2

摘要: Dimethyl ether (DME) carbonylation is considered as a key step for a promising route to produce ethanol from syngas. Heteropolyacids (HPAs) are proved to be efficient catalysts for DME carbonylation. In this work, the reaction mechanism of DME carbonylation was studied theoretically by using density functional theory calculations on two typical HPA models (HPW, HSiW). The whole process consists of three stages: DME dissociative adsorption, insertion of CO into methoxyl group and formation of product methyl acetate. The activation barriers of all possible elementary steps, especially two possible paths for CO insertion were calculated to obtain the most favorable reaction mechanism and rate-limiting step. Furthermore, the effect of the acid strength of Brønsted acid sites on reactivity was studied by comparing the activation barriers over HPW and HSiW with different acid strength, which was determined by calculating the deprotonation energy, Mulliken population analyses and adsorption energies of pyridine.

关键词: dimethyl ether     carbonylation     mechanism     heteropolyacids     density functional theory    

Performance and emission characteristics of QHCCI dimethyl ether engine

WANG Ying, LI Wei, ZHOU Longbao, LIU Shenghua, HU Tiegang

《能源前沿(英文)》 2008年 第2卷 第4期   页码 401-405 doi: 10.1007/s11708-008-0075-5

摘要: Experimental investigation into the effects of different pilot amounts of dimethyl ether (DME) on the performance and emission of a single-cylinder direct-injection DME engine is conducted. The results show that a DME engine can operate at a wider range of speeds and loads at quasi-homogenous charge compression ignition (QHCCI) mode. The brake thermal efficiency increases while the exhaust temperature decreases. NO emission decreases by about 30%–50% although there is a slight increase in HC and CO emissions. NO, HC and CO emissions increase with an increase in the amount of DME pilot. QHCCI is a good way to increase thermal efficiency and decrease NO emission.

关键词: Experimental investigation     single-cylinder direct-injection     exhaust temperature     dimethyl     compression ignition    

Impact of dimethyl ether on engine seal materials

WU Ning, ZHANG Wugao, HUANG Zhen

《能源前沿(英文)》 2008年 第2卷 第3期   页码 279-284 doi: 10.1007/s11708-008-0042-1

摘要: The resistance of many kinds of rubber materials to dimethyl ether (DME) was studied. Both the mass and volume change of rubber materials, which were put in DME and then exposed to the air for different periods of time were measured. The results show that fluorine rubber (FKM), silicone rubber (SIR), and nitrile rubber (NBR) are unsuitable as seal materials for DME engines. Common polyvinylchloride (PVC) dissolved completely in DME, which has almost no impact on vulcanizing nylon material. The constitution of ethylene propylene terpolymer rubber (EPDM) has a major impact on its resistance to DME. A kind of EPDM with good resistance to DME was found, whose reliability was validated by 100 hours of DME engine operation.

关键词: impact     Common polyvinylchloride     different     constitution     ethylene propylene    

Adsorption properties of polycarboxylate ether-based superplasticizer on cement particles and their resultant

Jinyoung YOON; Byoung Il CHOI; Jae Hong KIM

《结构与土木工程前沿(英文)》 2022年 第16卷 第4期   页码 506-514 doi: 10.1007/s11709-022-0813-5

摘要: The cement dispersion performance of a polycarboxylate (PCE)-based superplasticizer is highly related to their adsorption behaviors as a function of time. This study evaluated effects of PCEs on rheological properties of cementitious materials. First, characteristics of PCEs were characterized via permeation chromatography (GPC) and Fourier-transform infrared spectrometry (FT-IR). The adsorption behavior of single and blended PCEs on cementitious composites was identified using total organic carbon analyzer (TOC). Based on the measurement of PCE adsorption, the changes of rheological properties of cementitious materials as well as the number of dispersed cement particles were characterized using a rheometer and laser spectroscopy, respectively. The experimental results support the systematic mechanism of PCE adsorption, cement dispersion, and the decrease in viscosity of cementitious materials.

关键词: adsorption     polycarboxylate     superplasticizer     rheology     dispersion    

标题 作者 时间 类型 操作

Crown ether-thiourea conjugates as ion transporters

Zhixing Zhao, Bailing Tang, Xiaosheng Yan, Xin Wu, Zhao Li, Philip A. Gale, Yun-Bao Jiang

期刊论文

Solvent-resistant porous membranes using poly(etherether ketone): preparation and application

期刊论文

Enhancing fatigue life of cylinder-crown integrated structure by optimizing dimension

Weiwei ZHANG,Xiaosong WANG,Zhongren WANG,Shijian YUAN

期刊论文

Sulfonated poly(ether ether ketone)/zirconium tricarboxybutylphosphonate composite proton-exchange membranes

GAO Qijun, HUANG Mianyan, WANG Yuxin, CAI Yuquan, XU Li

期刊论文

Biomass to dimethyl ether by gasification/synthesis technology

Tiejun WANG, Yuping LI, Longlong MA, Chuangzhi WU

期刊论文

Dimethyl ether as alternative fuel for CI engine and vehicle

Zhen HUANG , Xinqi QIAO , Wugao ZHANG , Junhua WU , Junjun ZHANG ,

期刊论文

Study on direct alcohol/ether fuel synthesis process in bubble column slurry reactor

Zhen CHEN, Haitao ZHANG, Weiyong YING, Dingye FANG

期刊论文

Enhanced debromination of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) by zero-valent zinc with ascorbic

Chaojin Jiang, Xiaoqian Jiang, Lixun Zhang, Yuntao Guan

期刊论文

Exergy losses in premixed flames of dimethyl ether and hydrogen blends

Tongbin ZHAO, Jiabo ZHANG, Dehao JU, Zhen HUANG, Dong HAN

期刊论文

Removal of decabromodiphenyl ether (BDE-209) by sepiolite-supported nanoscale zerovalent iron

Rongbing FU,Na MU,Xiaopin GUO,Zhen XU,Dongsu BI

期刊论文

基于拱顶沉降控制的卵砾石地层浅埋隧道施工优化

喻军,刘松玉,龚晓南

期刊论文

A density functional theory study on the mechanism of Dimethyl ether carbonylation over heteropolyacids

Kai Cai, Ying Li, Hongbao Shen, Zaizhe Cheng, Shouying Huang, Yue Wang, Xinbin Ma

期刊论文

Performance and emission characteristics of QHCCI dimethyl ether engine

WANG Ying, LI Wei, ZHOU Longbao, LIU Shenghua, HU Tiegang

期刊论文

Impact of dimethyl ether on engine seal materials

WU Ning, ZHANG Wugao, HUANG Zhen

期刊论文

Adsorption properties of polycarboxylate ether-based superplasticizer on cement particles and their resultant

Jinyoung YOON; Byoung Il CHOI; Jae Hong KIM

期刊论文