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Thermal decomposition of poly(ethylene terephthalate)/mesoporous molecular sieve composites

RUN Mingtao, ZHANG Dayu, WU Sizhu, WU Gang

《化学科学与工程前沿（英文）》 2007年 第1卷 第1期   页码 50-54 doi: 10.1007/s11705-007-0010-z

摘要： The nonisothermal and isothermal degradation processes of poly (ethylene terephthalate)/mesoporous molecular sieve (PET/MMS) composites synthesized by in-situ polymerization were studied by using thermogravimetric analysis in nitrogen. The nonisothermal degradation of the composite is found to be the first-order reaction. An iso-conversional procedure developed by Ozawa is used to calculate the apparent activation energy (), which is an average value of about 260 kJ/mol with the weight conversion from 0% to 30%, and is higher than that of neat PET. Isothermal degradation results are confirmed with the nonisothermal process, in which PET/MMS showed higher thermal stability than neat PET. The polymer in mesoporous channels has more stability due to the protection of the inorganic pore-wall. These results indicate that mesoporous MMS in PET/MMS composites improve the stability of the polymer.

关键词： polymerization     isothermal degradation     conversion     nonisothermal degradation     activation    

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A conceptual methodology for simultaneous optimization of water and heat with non-isothermal mixing

Yanlong Hou, Wanni Xie, Zhenya Duan, Jingtao Wang

《化学科学与工程前沿（英文）》 2017年 第11卷 第2期   页码 154-165 doi: 10.1007/s11705-016-1593-z

摘要： A new conceptual methodology is proposed to simultaneously integrate water allocation and energy networks with non-isothermal mixing. This method employs a simultaneous model and includes two design steps. In the first step, the water allocation network (WAN), which could achieve the targets of saving water and energy, is obtained by taking account the temperature factor into the design procedure. The optimized targets of both freshwater and energy are reached at this step which ensures this approach is a simultaneous one. In the second step, based on the obtained WAN, the whole water allocation and heat exchange network (WAHEN) is combined with the non-isothermal mixing to reduce the number of heat exchangers. The thus obtained WAHEN can achieve three optimization targets (minimization of water, energy and the number of heat exchangers). Furthermore, the effectivity of our method has been demonstrated by solving two literature examples.

关键词： simultaneous integration     non-isothermal mixing     multi-target optimization     water and energy networks    

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木粉/聚丙烯复合材料的非等温结晶动力学分析

黄浪,王海刚,王清文

《中国工程科学》 2014年 第16卷 第4期   页码 21-24

摘要：

通过共混造粒热压方法制备聚丙烯（PP）基木塑复合材料（WPC），用差示扫描量热法研究其非等温结晶行为，分别用Jeziorny 法和Mo法对所得的数据进行处理分析。结果表明：Jeziorny 法和Mo法能较理想地处理PP 基WPC的非等温结晶过程，复合材料中木粉的加入缩短了结晶时间，提高了PP 的结晶温度，降低了结晶速率。

关键词： PP     WPC     非等温结晶     结晶动力学    

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Effect of Joule heating on electro-osmotic flow in a closed-end micro-channel with isothermal and convective

Liang ZHAO, Linhua LIU,

《能源前沿（英文）》 2009年 第3卷 第4期   页码 381-388 doi: 10.1007/s11708-009-0057-2

摘要： The effect of Joule heating on the steady state electro-osmotic flow in a closed-end micro-channel is studied through numerical simulation with the finite volume method. The velocity field and the temperature field are described by a rigorous mathematical model. Thermophysical properties including viscosity and thermal conductivity are considered to be temperature-dependent. The simulations show that the presence of Joule heating causes an increase in temperature and a decrease in viscosity in the whole micro-channel, which, thereafter, induce a large velocity near the wall and an increase in fluid velocity at the central region in order to maintain a zero flow rate at the cross section of the micro-channel. The effect of Joule heating on the induced pressure gradient is also studied, which is very important for the application of the closed-end micro-channel as a micro-actuator. The results reveal that the induced pressure gradient, taking into consideration Joule heating, is significantly smaller than that without considering Joule heating when the wall temperature of the micro-channel is constant. The induced pressure gradient difference between considering Joule heating and without considering Joule heating is small under the convective boundary condition.

关键词： closed-end micro-channel     electrical double layer     electro-osmotic flow     induced pressure gradient     Joule heating    

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Robust optimization of the billet for isothermal local loading transitional region of a Ti-alloy rib-web

Ke WEI, Xiaoguang FAN, Mei ZHAN, Miao MENG

《机械工程前沿（英文）》 2018年 第13卷 第3期   页码 376-384 doi: 10.1007/s11465-018-0500-3

摘要：

Billet optimization can greatly improve the forming quality of the transitional region in the isothermal local loading forming (ILLF) of large-scale Ti-alloy rib-web components. However, the final quality of the transitional region may be deteriorated by uncontrollable factors, such as the manufacturing tolerance of the preforming billet, fluctuation of the stroke length, and friction factor. Thus, a dual-response surface method (RSM)-based robust optimization of the billet was proposed to address the uncontrollable factors in transitional region of the ILLF. Given that the die underfilling and folding defect are two key factors that influence the forming quality of the transitional region, minimizing the mean and standard deviation of the die underfilling rate and avoiding folding defect were defined as the objective function and constraint condition in robust optimization. Then, the cross array design was constructed, a dual-RSM model was established for the mean and standard deviation of the die underfilling rate by considering the size parameters of the billet and uncontrollable factors. Subsequently, an optimum solution was derived to achieve the robust optimization of the billet. A case study on robust optimization was conducted. Good results were attained for improving the die filling and avoiding folding defect, suggesting that the robust optimization of the billet in the transitional region of the ILLF was efficient and reliable.

关键词： isothermal local loading forming     rib-web component     transitional region     robust optimization     dual response surface method    

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The dehydration behavior and non-isothermal dehydration kinetics of donepezil hydrochloride monohydrate

Tiantian LIU, Yuanyuan RAN, Bochao WANG, Weibing DONG, Songgu WU, Junbo GONG

《化学科学与工程前沿（英文）》 2014年 第8卷 第1期   页码 55-63 doi: 10.1007/s11705-013-1352-3

摘要： Powders of donepezil hydrochloride monohydrate (Form I) underwent isomorphic dehydration, losing 3% w/w water between 90% and 10% relative humidity (RH) without changing its powder X-ray pattern. Below 10% RH, additional dehydration occurred in conjunction with a reversible phase transition between the monohydrate state and a dehydrated state, with a 4.0% w/w loss to 0% RH. A combination of methods was used to understand the structural changes occurring during the desolvation process, including dynamic vapor sorption measurements, thermal analysis and powder X-ray diffraction. Form I showed the characteristics of the channel hydrate, whose non-isothermal dehydration behavior proceeds in two steps: (1) the loss of non-crystalline water adsorbed on the surface, and (2) the loss of one crystalline water in the channel. Dehydrated Form I is structurally similar to the monohydrate Form I. According to the heat of fusion and the crystal density criteria, the two crystal forms belonged to the univariant system, and the anhydrate (Form III) is stable. The dehydration kinetics was achieved from the TG-DTG curves by both the Achar method and the Coats-Redfern method with 15 frequently cited basic kinetic models. The dynamic dehydration processes for steps 1 and 2 were best expressed by the Zhuralev-Lesokin-Tempelman equation, suggesting a three-dimensional diffusion-controlled mechanism.

关键词： dehydration     thermal analysis     transformation     dehydration kinetics    

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Thermodynamic assessment of hydrogen production via solar thermochemical cycle based on MoO

Jiahui JIN, Lei WANG, Mingkai FU, Xin LI, Yuanwei LU

《能源前沿（英文）》 2020年 第14卷 第1期   页码 71-80 doi: 10.1007/s11708-019-0652-9

摘要： Inspired by the promising hydrogen production in the solar thermochemical (STC) cycle based on non-stoichiometric oxides and the operation temperature decreasing effect of methane reduction, a high-fuel-selectivity and CH -introduced solar thermochemical cycle based on MoO /Mo is studied. By performing HSC simulations, the energy upgradation and energy conversion potential under isothermal and non-isothermal operating conditions are compared. In the reduction step, MoO : CH = 2 and 1020 K< <1600 K are found to be most favorable for syngas selectivity and methane conversion. Compared to the STC cycle without CH , the introduction of methane yields a much higher hydrogen production, especially at the lower temperature range and atmospheric pressure. In the oxidation step, a moderately excessive water is beneficial for energy conversion whether in isothermal or non-isothermal operations, especially at H O: Mo= 4. In the whole STC cycle, the maximum non-isothermal and isothermal efficiency can reach 0.417 and 0.391 respectively. In addition, the predicted efficiency of the second cycle is also as high as 0.454 at = 1200 K and = 400 K, indicating that MoO could be a new and potential candidate for obtaining solar fuel by methane reduction.

关键词： MoO2/Mo based on solar thermochemical cycle     methanothermal reduction     isothermal and non-isothermal operation     syngas and hydrogen production     thermodynamic analysis    

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Influence of construction-induced damage on the degradation of freeze–thawed lightweight cellular concrete

《结构与土木工程前沿（英文）》 2021年 第15卷 第3期   页码 781-792 doi: 10.1007/s11709-021-0733-9

摘要： During the construction of lightweight cellular concrete (LCC), material damage frequently occurs, causing the degradation and deterioration of the mechanical performance, durability, and subgrade quality of LCC. The construction-induced damage can be more significant than those from the service environment of LCC, such as freeze–thaw (F–T) action in cold regions. However, the effect of construction-induced damage on LCC during F–T cycles is often ignored and the deterioration mechanisms are not yet clarified. In this study, we investigated the factors causing damage during construction using a sample preparation method established to simulate the damage in the laboratory setting. We conducted F–T cycle tests and microstructural characterization to study the effect of microstructural damage on the overall strength of LCC with different water contents under F–T actions. We established the relationship between the pore-area ratio and F–T cycle times, pore-area ratio, and strength, as well as the F–T cycle times and strength under different damage forms. The damage evolution is provided with the rationality of the damage equation, verified by comparing the measured and predicted damage variables. This study would serve as a guide for the construction and performance of LCC in cold regions.

关键词： lightweight cellular concrete     construction-induced damage     freeze-thaw action     microstructure     degradation mechanism    

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Efficient degradation of orange II by ZnMn

Qingzhuo Ni, Hao Cheng, Jianfeng Ma, Yong Kong, Sridhar Komarneni

《化学科学与工程前沿（英文）》 2020年 第14卷 第6期   页码 956-966 doi: 10.1007/s11705-019-1907-z

摘要： A ZnMn O catalyst has been synthesized via a sucrose-aided combustion method and characterized by various analytical techniques. It is composed of numerous nanoparticles (15–110 nm) assembled into a porous structure with a specific surface area (SSA) of 19.1 m ·g . Its catalytic activity has been investigated for the degradation of orange II dye using three different systems, i.e., the photocatalysis system with visible light, the chemocatalysis system with bisulfite, and the photo-chemical catalysis system with both visible light and bisulfite. The last system exhibits the maximum degradation efficiency of 90%, much higher than the photocatalysis system (15%) and the chemocatalysis system (67%). The recycling experiments indicate that the ZnMn O catalyst has high stability and reusability and is thus a green and eximious catalyst. Furthermore, the potential degradation mechanisms applicable to the three systems are discussed with relevant theoretical analysis and scavenging experiments for radicals. The active species such as Mn(III), O , h , e , SO and HO are proposed to be responsible for the excellent degradation results in the photo-chemical catalysis system with the ZnMn O catalyst.

关键词： ZnMn2O4     photo-chemical catalysis     bisulfite     dye degradation    

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Promotive effect of pyridine on indole degradation by activated sludge under anoxic conditions

LI Yongmei, GU Guowei, LI Wenshu

《环境科学与工程前沿（英文）》 2007年 第1卷 第4期   页码 493-497 doi: 10.1007/s11783-007-0079-0

摘要： Batch experiments were carried out to investigate the promotive effect of pyridine on indole degradation under denitrifying conditions. The seed sludge was obtained from a local coal-coking wastewater treatment facility and was acc

关键词： wastewater treatment     coal-coking wastewater     promotive     degradation    

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anchored alginate/poly(acrylic acid/acrylamide) double-network hydrogel composites for efficient catalytic degradation

《化学科学与工程前沿（英文）》 2023年 第17卷 第7期   页码 893-905 doi: 10.1007/s11705-022-2290-8

摘要： A novel alginate/poly(acrylic acid/acrylamide) double-network hydrogel composite with silver nanoparticles was successfully fabricated using the sol–gel method. The presence of carboxyl and amide groups in the network structure provided abundant active sites for complexing silver ions, facilitating the in situ reduction and confinement of silver nanoparticles. In batch experiments, the optimal silver loading was 20%, and 5 mmol·L–1 of p-nitrophenol was completely degraded in 113 s with a rate constant value of 4.057 × 10−2 s–1. In the tap water system and simulated seawater system, the degradation time of p-nitrophenol at the same concentration was 261 and 276 s, respectively, with a conversion rate above 99%. In the fixed-bed experiment, the conversion rate remained above 74% after 3 h at a flowing rate of 7 mL·min–1. After 8 cycling tests, the conversion rate remained at 98.7%. Moreover, the catalyst exhibited outstanding performance in the degradation experiment of four typical organic dyes.

关键词： double-network hydrogel     dye degradation     silver nanoparticles     alginate    

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Sustainable wood-based nanotechnologies for photocatalytic degradation of organic contaminants in aquatic

《环境科学与工程前沿（英文）》 2021年 第15卷 第4期 doi: 10.1007/s11783-020-1346-6

摘要：

•Wood and its reassemblies are ideal substrates to develop novel photocatalysts.

关键词： Wood     Nanocatalysts     Photodegradation     Organic contaminants     Composites    

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Thermal degradation kinetics and lifetime estimation for polycarbonate/polymethylphenylsilsesquioxane

Jiangbo WANG, Zhong XIN

《化学科学与工程前沿（英文）》 2009年 第3卷 第2期   页码 167-171 doi: 10.1007/s11705-009-0006-y

摘要： The thermal degradation behaviors of polycarbonate/polymethylphenylsilsesquioxane (FRPC) composites were investigated by thermogravimetric analysis (TGA) under isothermal conditions in nitrogen atmosphere. The isothermal kinetics equation was used to describe the thermal degradation process. The results showed that activation energy ( ), in the case of isothermal degradation, was a quick increasing function of conversion (α) for polycarbonate (PC) but was a strong and decreasing function of conversion for FRPC. Under the isothermal condition, the addition of polymethylphenylsilsesquioxane (PMPSQ) retardanted the thermal degradation and enhanced the thermal stability of PC during the early and middle stages of thermal degradation. It also indicated a possible existence of a difference in nucleation, nuclei growth, and gas diffusion mechanism in the thermal degradation process between PC and FRPC. Meanwhile, the addition of PMPSQ influenced the lifetime of PC, but the composite still met the demand in manufacturing and application.

关键词： polycarbonate     polymethylphenylsilsesquioxane     thermal degradation kinetics     activation energy     lifetime    

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bismuth oxyiodide with highly exposed (110) facets on curved carbon nitride for the photocatalytic degradation

《化学科学与工程前沿（英文）》 2022年 第16卷 第7期   页码 1125-1138 doi: 10.1007/s11705-021-2116-0

摘要： Crystalline materials with specific facet atomic arrangements and crystal facet structures exhibit unique functions according to their facet effects, quantum size effects and physical and chemical properties. In this study, a novel high-exposure (110) facet of bismuth oxyiodide (BiOI) was prepared (denoted as BiOI-110), and designed as nanosheets rich in oxygen vacancies by crystal facet design and regulation. Graphitic carbon nitride was designed as curved carbon nitride with dibromopyrazine, denoted as DCN, which contributed to a significant structural distortion in plane symmetry and improved the separation of charge carriers. Novel heterostructured BiOI-110/DCN nanosheets with a high-exposure (110) facet and abundant oxygen vacancies were successfully designed to enhance the photocatalytic degradation of organic pollutants. It was demonstrated that complete and tight contact between BiOI-110 and DCN was achieved by changing the size and crystal facet of BiOI. Oxytetracycline (OTC) and methyl blue dyes were used as targets for pollutant degradation, and 85.6% and 96.5% photocatalytic degradation efficiencies, respectively, were observed in the optimal proportion of 7% BiOI-110/DCN. The experimental results and electron spin resonance analysis showed that •O2– and h+ played a major role in the process of pollutant degradation. Additionally, high-resolution liquid chromatography-mass spectrography was used to identify the reaction intermediates of OTC, and the possible degradation pathway of this pollutant was proposed. Finally, the excellent reusability of BiOI-110/DCN nanomaterials was confirmed, providing a new approach for the removal of antibiotics that are difficult to biodegrade. Overall, crystal facet design has been proven to have broad prospects in improving the water environment.

关键词： high-exposure (110) facet     oxygen vacancy-rich     BiOI-110/DCN heterojunction     photocatalytic degradation     visible-light-response    

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UV-LED/P25-based photocatalysis for effective degradation of isothiazolone biocide

《环境科学与工程前沿（英文）》 2021年 第15卷 第5期 doi: 10.1007/s11783-020-1379-x

摘要：

• UV-LED with shorter wavelength was beneficial for photocatalytic degradation.

关键词： Degradation     Photocatalytic     LED     CMIT     P25    

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标题 作者 时间 类型 操作

Thermal decomposition of poly(ethylene terephthalate)/mesoporous molecular sieve composites

RUN Mingtao, ZHANG Dayu, WU Sizhu, WU Gang

期刊论文

A conceptual methodology for simultaneous optimization of water and heat with non-isothermal mixing

Yanlong Hou, Wanni Xie, Zhenya Duan, Jingtao Wang

期刊论文

木粉/聚丙烯复合材料的非等温结晶动力学分析

黄浪,王海刚,王清文

期刊论文

Effect of Joule heating on electro-osmotic flow in a closed-end micro-channel with isothermal and convective

Liang ZHAO, Linhua LIU,

期刊论文

Robust optimization of the billet for isothermal local loading transitional region of a Ti-alloy rib-web

Ke WEI, Xiaoguang FAN, Mei ZHAN, Miao MENG

期刊论文

The dehydration behavior and non-isothermal dehydration kinetics of donepezil hydrochloride monohydrate

Tiantian LIU, Yuanyuan RAN, Bochao WANG, Weibing DONG, Songgu WU, Junbo GONG

期刊论文

Thermodynamic assessment of hydrogen production via solar thermochemical cycle based on MoO

Jiahui JIN, Lei WANG, Mingkai FU, Xin LI, Yuanwei LU

期刊论文

Influence of construction-induced damage on the degradation of freeze–thawed lightweight cellular concrete

期刊论文

Efficient degradation of orange II by ZnMn

Qingzhuo Ni, Hao Cheng, Jianfeng Ma, Yong Kong, Sridhar Komarneni

期刊论文

Promotive effect of pyridine on indole degradation by activated sludge under anoxic conditions

LI Yongmei, GU Guowei, LI Wenshu

期刊论文

anchored alginate/poly(acrylic acid/acrylamide) double-network hydrogel composites for efficient catalytic degradation

期刊论文

Sustainable wood-based nanotechnologies for photocatalytic degradation of organic contaminants in aquatic

期刊论文

Thermal degradation kinetics and lifetime estimation for polycarbonate/polymethylphenylsilsesquioxane

Jiangbo WANG, Zhong XIN

期刊论文

bismuth oxyiodide with highly exposed (110) facets on curved carbon nitride for the photocatalytic degradation

期刊论文

UV-LED/P25-based photocatalysis for effective degradation of isothiazolone biocide

期刊论文