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Phase transition regulation and caloric effect

《能源前沿(英文)》 2023年 第17卷 第4期   页码 463-477 doi: 10.1007/s11708-023-0860-1

摘要: Solid state refrigeration based on caloric effect is regarded as a potential candidate for replacing vapor-compression refrigeration. Numerous methods have been proposed to optimize the refrigeration properties of caloric materials, of which single field tuning as a relatively simple way has been systemically studied. However, single field tuning with few tunable parameters usually obtains an excellent performance in one specific aspect at the cost of worsening the performance in other aspects, like attaining a large caloric effect with narrowing the transition temperature range and introducing hysteresis. Because of the shortcomings of the caloric effect driven by a single field, multifield tuning on multicaloric materials that have a coupling between different ferro-orders came into view. This review mainly focuses on recent studies that apply this method to improve the cooling performance of materials, consisting of enlarging caloric effects, reducing hysteresis losses, adjusting transition temperatures, and widening transition temperature spans, which indicate that further progress can be made in the application of this method. Furthermore, research on the sign of lattice and spin contributions to the magnetocaloric effect found new phonon evolution mechanisms, calling for more attention on multicaloric effects. Other progress including improving cyclability of FeRh alloys by introducing second phases and realizing a large reversible barocaloric effect by hybridizing carbon chains and inorganic groups is described in brief.

关键词: phase transition regulation     caloric effect     solid state refrigeration    

Calorie restriction and its impact on gut microbial composition and global metabolism

Xiaojiao Zheng, Shouli Wang, Wei Jia

《医学前沿(英文)》 2018年 第12卷 第6期   页码 634-644 doi: 10.1007/s11684-018-0670-8

摘要:

Calorie restriction (CR) is a dietary regimen that reduces calorie intake without incurring malnutrition or a reduction in essential nutrients. It has long been recognized as a natural strategy for promoting health, extending longevity, and prevents the development of metabolic and age-related diseases. In the present review, we focus on the general effect of CR on gut microbiota composition and global metabolism. We also propose mechanisms for its beneficial effect. Results showed that probiotic and butyrate-producing microbes increased their relative abundance, whereas proinflammatory strains exhibited suppressed relative abundance following CR. Analyses of the gut microbial and host metabolisms revealed that most host microbial co-metabolites were changed due to CR. Examples of dramatic CR-induced changes in host metabolism included a decrease in the rate of lipid biosynthesis and an increase in the rates of fatty acid catabolism, β-oxidation, glycogenolysis, and gluconeogenesis. The observed phenotypes and the further verification of the direct link between gut microbiota and metabolome may benefit patients that are at risk for developing metabolic disease. Thus, improved gut microbiota composition and metabolome are potential biomarkers for determining the effectiveness of dietary interventions for age-related and metabolic diseases.

关键词: caloric restriction     gut microbiota     metabolome    

Caloric evaporation of the brine in Zangnan Salt Lake

Shiqiang WANG, Yafei GUO, Nan ZHANG, Lingzhong BU, Tianlong DENG, Mianping ZHENG

《化学科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 343-348 doi: 10.1007/s11705-010-1029-0

摘要: Zangnan Salt Lake on the south of the Tibet is a type of carbonate lake with high concentrations of lithium, boron, and potassium and obviously it differs from seawater in its chemical composition. An experimental simulation of the caloric evaporation of the lake’s brine was conducted by first freezing the brine and then performing isothermal evaporation at 288.15 K. The freezing path and the physicochemical properties of the brine were determined. The crystallization sequence was natron, hydrohalite, halite, sylvite, zabuyelite, trona, aphthitalite, thermonatrite, and borax. Rubidium and cesium salts did not crystallized out but concentrated in the mother solution. The physicochemical properties (density, refractive index, conductivity, and pH) of the liquid phase changed as the evaporation progressed. In the beginning of the evaporation processes, the concentration of potassium ions in the liquid phase gradually increased but later it decreased. A peak value of 55.21 g/L was obtained when the evaporation was 88% complete. When the mineral aphthitalite began to crystallize; the concentrations of B O , Li , Rb , and Cs gradually increased as the evaporation progressed. When the evaporation was 98% complete, their concentrations in the mother liquor were 40.77 g/L, 4.838 g/L, 400.17 mg/L and 31.95 mg/L, respectively. This essential fundamental study can provide an important reference for the comprehensive utilization of brines in Zangnan Salt Lake.

关键词: Zangnan Salt Lake     evaporation     crystallization path     freezing    

Analysis of effect of different construction methods of piles on the end effect on skin friction of piles

ZHOU Hongbo, CHEN Zhuchang

《结构与土木工程前沿(英文)》 2007年 第1卷 第4期   页码 458-463 doi: 10.1007/s11709-007-0062-7

摘要: Based on the comparative analysis of end effect on skin friction of displacement-pile (driven pile), the end effect on skin friction of bored pile is studied. The end effect on skin friction between driven pile and bored pile is different and the end effect on skin friction of bored pile is reduce of skin friction in the soil layer adjacent to the pile end. The degradation degree of skin friction is deduced with the increase of the distance from pile end. The concept of additional mud cake formed by the effect of cushion at the bottom of borehole during pouring concrete is introduced to explain the mechanism of end effect on skin friction of the bored pile. The test results of post-grouting piles indicate that the post-grouting technique is an effective way to improve the end effect on skin friction of bored pile.

关键词: distance     different     concept     additional     bottom    

A review on different theoretical models of electrocaloric effect for refrigeration

《能源前沿(英文)》 2023年 第17卷 第4期   页码 478-503 doi: 10.1007/s11708-023-0884-6

摘要: The performance parameters for characterizing the electrocaloric effect are isothermal entropy change and the adiabatic temperature change, respectively. This paper reviews the electrocaloric effect of ferroelectric materials based on different theoretical models. First, it provides four different calculation scales (the first-principle-based effective Hamiltonian, the Landau-Devonshire thermodynamic theory, phase-field simulation, and finite element analysis) to explain the basic theory of calculating the electrocaloric effect. Then, it comprehensively reviews the recent progress of these methods in regulating the electrocaloric effect and the generation mechanism of the electrocaloric effect. Finally, it summarizes and anticipates the exploration of more novel electrocaloric materials based on the framework constructed by the different computational methods.

关键词: electrocaloric effect     effective Hamiltonian     phase-field modeling     different theoretical models    

A new miniaturized engine based on thermomagnetic effect of magnetic fluids

Lujun ZHOU, Yimin XUAN, Qiang LI, Wenlei LIAN

《能源前沿(英文)》 2009年 第3卷 第2期   页码 160-166 doi: 10.1007/s11708-009-0018-9

摘要: A new engine system, essentially consisting of a permanent NdFeB magnet, a kerosene-based magnetic fluid and a rotor, is proposed based on the thermomagnetic effect of a temperature-sensitive magnetic fluid. The rotor was driven by the thermal convection of the magnetic fluid in the presence of a homogeneous external magnetic field. A digital camera was used to record the rotation speed of the rotor to investigate the performance of the engine system under varying conditions such as heat load, heat sink temperature, and magnetic field distribution. The peak angle velocity obtained for the rotor was about 2.1 rad/min. The results illustrate that the rotation speed of the rotor increases as the input heat load increases, or as the heat sink temperature decreases. The performance of the motor is considerably influenced by the magnetic field imposed. Therefore, the performance of such an engine can be controlled conveniently by changing the external magnetic field and/or the temperature distribution in the fluid.

关键词: magnetic fluid     thermomagnetic effect     engine    

The cooperation effect of Ni and Pt in the hydrogenation of acetic acid

《化学科学与工程前沿(英文)》 2022年 第16卷 第3期   页码 397-407 doi: 10.1007/s11705-021-2076-4

摘要: The catalytic hydrogenation of carboxylic acid to alcohols is one of the important strategies for the conversion of biomass. Herein, a series of Ni-doped PtSn catalysts were prepared, characterized and studied in the hydrogenation of acetic acid. The Ni dopant has a strong interaction with Pt, which promotes the hydrogen adsorption, providing an activated hydrogen-rich environment for the hydrogenation. Meanwhile, the presence of Ni also improves the Pt dispersion, giving more accessible active sites for hydrogen activation. The cooperation of Pt and Ni significantly promotes the catalytic activity of the hydrogenation of acetic acid to ethanol. As a result, the catalyst with 0.1% Ni exhibits the best reaction activity, and its space time yield is twice as that of the PtSn/SiO2 catalyst. It provides a meaningful instruction on the catalyst design for the carboxylic acid hydrogenation.

关键词: acetic acid     ethanol     hydrogenation     Pt     Ni     cooperation effect    

Direct energy rebound effect for road transportation in China

《工程管理前沿(英文)》   页码 597-611 doi: 10.1007/s42524-023-0276-y

摘要: The enhancement of energy efficiency stands as the principal avenue for attaining energy conservation and emissions reduction objectives within the realm of road transportation. Nevertheless, it is imperative to acknowledge that these objectives may, in part or in entirety, be offset by the phenomenon known as the energy rebound effect (ERE). To quantify the long-term EREs and short-term EREs specific to China’s road transportation, this study employed panel cointegration and panel error correction models, accounting for asymmetric price effects. The findings reveal the following: The long-term EREs observed in road passenger transportation and road freight transportation range from 13% to 25% and 14% to 48%, respectively; in contrast, the short-term EREs in road passenger transportation and road freight transportation span from 36% to 41% and 3.9% to 32%, respectively. It is noteworthy that the EREs associated with road passenger transportation and road freight transportation represent a partial rebound effect, falling short of reaching the magnitude of a counterproductive backfire effect. This leads to the inference that the upsurge in energy consumption within the road transportation sector cannot be solely attributed to advancements in energy efficiency. Instead, various factors, including income levels, the scale of commodity trade, and industrial structure, exert more substantial facilitating influences. Furthermore, the escalation of fuel prices fails to dampen the demand for energy services, whether in the domain of road passenger transportation or road freight transportation. In light of these conclusions, recommendations are proffered for the formulation of energy efficiency policies pertinent to road transportation.

关键词: road transportation     direct energy rebound effect     asymmetric price effects     panel data model    

Photoaging mechanism of microplastics: a perspective on the effect of dissolved organic matter in natural

《环境科学与工程前沿(英文)》 2023年 第17卷 第11期 doi: 10.1007/s11783-023-1743-8

摘要:

● Microplastics (MPs) undergo photoaging in natural water under light irradiation.

关键词: Microplastics     Photoaging     Dissolved organic matter     ROS generation    

Modeling analysis on solar steam generator employed in multi-effect distillation (MED) system

Zhaorui ZHAO, Bao YANG, Ziwen XING

《能源前沿(英文)》 2019年 第13卷 第1期   页码 193-203 doi: 10.1007/s11708-019-0608-0

摘要: Recently the porous bilayer wood solar collectors have drawn increasing attention because of their potential application in solar desalination. In this paper, a thermodynamic model has been developed to analyze the performance of the wood solar collector. A modeling analysis has also been conducted to assess the performance and operating conditions of the multiple effect desalination (MED) system integrated with the porous wood solar collector. Specifically, the effects of operating parameters, such as the motive steam temperature, seawater flow rate, input solar energy and number of effects on the energy consumption for each ton of distilled water produced have been investigated in the MED desalination system combined with the bilayer wood solar steam generator. It is found that, under a given operating condition, there exists an optimum steam generation temperature of around 145°C in the wood solar collector, so that the specific power consumption in the MED system reaches a minimum value of 24.88 kWh/t. The average temperature difference is significantly affected by the solar heating capacity. With the solar capacity increasing from 50 kW to 230 kW, the average temperature difference increases from 1.88°C to 6.27°C. This parametric simulation study will help the design of efficient bilayer wood solar steam generator as well as the MED desalination system.

关键词: solar energy     steam generating     multi-effect desalination    

十二系列叔胺捕收剂对高岭石的浮选研究

曹学锋,刘长淼,胡岳华

《中国工程科学》 2011年 第13卷 第1期   页码 93-97

摘要:

研究4种十二取代叔胺(DRN,DEN,DPN和DBN)对高岭石的浮选行为。发现4种叔胺对高岭石的浮选捕收能力都较好,其中DEN最好,浮选回收率最高可达92 %以上。4种叔胺主要依靠静电引力吸附在高岭石表面,在酸性pH范围内,浮选高岭石的回收率较高,随着pH的增大,叔胺的阳离子组分减少,使得浮选回收率下降。Zeta电位研究表明,高岭石在整个pH范围内,表面主要带负电,4种叔胺与高岭石作用后,能显著增加高岭石的Zeta电位。红外光谱研究表面,4种叔胺主要与高岭石表面发生了电性作用的物理吸附。叔胺中N原子上的取代基的给电子效应和空间位阻效应是造成 4 种叔胺浮选能力差异的主要原因。

关键词: 叔胺     高岭石     浮选     静电作用     电子效应     空间效应    

Confining pressure effect on dynamic response of high rockfill dam

Xuexing CAO, Yunlong HE, Kun XIONG,

《结构与土木工程前沿(英文)》 2010年 第4卷 第1期   页码 116-126 doi: 10.1007/s11709-010-0014-5

摘要: Studies show that the dynamic properties of rockfill are strongly dependent on the confining pressure. Therefore, confining pressure effect has become a very important factor in the seismic analysis of high rockfill dam. The relationships of dynamic shear modulus versus dynamic shear strain and damping ratio versus dynamic shear strain had been improved to a certain degree on the basic of widely used Hardin-Drnevich constitutive model in this paper. Then a new model that could consider confining pressure effect has been established. Regression analysis was carried out of the dynamic triaxial experimental data of the damming materials in the Changheba hydropower station of Sichun Province, China. The results show that, the new model can fit the test data well under various confining pressures. A corresponding computational procedure was compiled and applied in the dynamic response analysis of the Changheba Dam. Comparing the calculation results between the new constitutive model and the ordinary Hardin-Drnevich model, it can be seen that the result is conservative to some extent without considering confining pressure effect.

关键词: confining pressure effect     high rockfill dam     dynamic response     Hardin-Drnevich constitutive model    

A review of salting-out effect and sugaring-out effect: driving forces for novel liquid-liquid extraction

Chuhan Fu, Zhuoxi Li, Zengran Sun, Shaoqu Xie

《化学科学与工程前沿(英文)》 2021年 第15卷 第4期   页码 854-871 doi: 10.1007/s11705-020-1980-3

摘要: Biofuels and bio-based chemicals are getting more and more attention because of their sustainable and renewable properties and wide industrial applications. However, the low concentrations of the targeted products in their fermentation broths, the complicated components of the broths and the high energy-intensive separation and purification process hinder the competitiveness of biofuels and biochemicals with the petro-based ones. Hence, the production and the separation of biofuels and bio-based chemicals in energy-saving, low-cost and greenness ways become hot topics nowadays. This review introduces the separation technologies (salting-out extraction, salting-out, sugaring-out extraction, and sugaring-out) that extract biobutanol, 1,3-propanediol, 2,3-butanediol, acetoin, organic acids and other bio-based chemicals from fermentation broths/aqueous solutions. Salting-out/sugaring-out extraction and salting-out/sugaring-out technologies display the high separating efficiency and the high targeted product yields. In addition, they are easy to operate and require low cost for separating products. Hence, they are the effective and potential technologies for separating targeted products in the wide industrial applications. The successful research into the salting-out/sugaring-out and salting-out/sugaring-out extraction not only affords biofuels and biochemical but also opens a door for the development of novel separation methods.

关键词: salting-out     sugaring-out     extraction     biofuels     biochemicals     application    

Spillover effect of environmental investment: evidence from panel data at provincial level in China

Qunhui LIN, Guanyi CHEN, Wencui DU, Haipeng NIU

《环境科学与工程前沿(英文)》 2012年 第6卷 第3期   页码 412-420 doi: 10.1007/s11783-012-0392-0

摘要: This paper considers pollution density as a function of environmental investment. The higher environmental investment, the lower pollution density. The lower the pollution density is the higher production technology becomes. This is called the spillover effect. We collected China’s panel data at the provincial level from 2005 to 2009, and tested the spillover effect of environmental investment. This paper finds that the environmental investment influenced production technology positively. There is a significant positive relation between government expenditure and spillover effect.

关键词: environmental investment     spillover effect     endogenous growth    

标题 作者 时间 类型 操作

Phase transition regulation and caloric effect

期刊论文

Calorie restriction and its impact on gut microbial composition and global metabolism

Xiaojiao Zheng, Shouli Wang, Wei Jia

期刊论文

Caloric evaporation of the brine in Zangnan Salt Lake

Shiqiang WANG, Yafei GUO, Nan ZHANG, Lingzhong BU, Tianlong DENG, Mianping ZHENG

期刊论文

李浩然:基于同伴效应与网络效应的“气代煤〞改造决策研究(2020年7月11日)

2022年05月19日

会议视频

Analysis of effect of different construction methods of piles on the end effect on skin friction of piles

ZHOU Hongbo, CHEN Zhuchang

期刊论文

A review on different theoretical models of electrocaloric effect for refrigeration

期刊论文

A new miniaturized engine based on thermomagnetic effect of magnetic fluids

Lujun ZHOU, Yimin XUAN, Qiang LI, Wenlei LIAN

期刊论文

The cooperation effect of Ni and Pt in the hydrogenation of acetic acid

期刊论文

Direct energy rebound effect for road transportation in China

期刊论文

Photoaging mechanism of microplastics: a perspective on the effect of dissolved organic matter in natural

期刊论文

Modeling analysis on solar steam generator employed in multi-effect distillation (MED) system

Zhaorui ZHAO, Bao YANG, Ziwen XING

期刊论文

十二系列叔胺捕收剂对高岭石的浮选研究

曹学锋,刘长淼,胡岳华

期刊论文

Confining pressure effect on dynamic response of high rockfill dam

Xuexing CAO, Yunlong HE, Kun XIONG,

期刊论文

A review of salting-out effect and sugaring-out effect: driving forces for novel liquid-liquid extraction

Chuhan Fu, Zhuoxi Li, Zengran Sun, Shaoqu Xie

期刊论文

Spillover effect of environmental investment: evidence from panel data at provincial level in China

Qunhui LIN, Guanyi CHEN, Wencui DU, Haipeng NIU

期刊论文