Search | Engineering

订阅投稿

首页工程期刊工程焦点工程成就工程前沿关于我们 English

资源类型

期刊论文 49

年份

2023 3

2022 7

2021 2

2020 5

2019 3

2018 2

2017 3

2016 2

2015 2

2013 4

2012 3

2010 6

2009 2

2008 2

2007 1

2003 1

2001 1

展开︾

关键词

Mittag-Leffler稳定性；分数阶；四元数神经网络；脉冲 1

pH值 1

丙烯 1

传递阻力 1

初值位移调控；忆阻系统；忆导；线平衡点集 1

反渗透 1

变形 1

可计算一般均衡 1

吉布斯能 1

吸附 1

响应面分析法 1

地下水 1

塔底应力 1

塔顶偏位 1

天钩控制 1

建模 1

悬索桥 1

智能控制 1

有限元法 1

展开︾

检索范围：

排序：展示方式：

Thermodynamic analysis of reaction pathways and equilibrium yields for catalytic pyrolysis of naphtha

《化学科学与工程前沿（英文）》 2022年第16卷第12期页码 1700-1712 doi: 10.1007/s11705-022-2207-6

摘要： The chain length and hydrocarbon type significantly affect the production of light olefins during the catalytic pyrolysis of naphtha. Herein, for a better catalyst design and operation parameters optimization, the reaction pathways and equilibrium yields for the catalytic pyrolysis of C_5–8 n/iso/cyclo-paraffins were analyzed thermodynamically. The results revealed that the thermodynamically favorable reaction pathways for n/iso-paraffins and cyclo-paraffins were the protolytic and hydrogen transfer cracking pathways, respectively. However, the formation of light paraffin severely limits the maximum selectivity toward light olefins. The dehydrogenation cracking pathway of n/iso-paraffins and the protolytic cracking pathway of cyclo-paraffins demonstrated significantly improved selectivity for light olefins. The results are thus useful as a direction for future catalyst improvements, facilitating superior reaction pathways to enhance light olefins. In addition, the equilibrium yield of light olefins increased with increasing the chain length, and the introduction of cyclo-paraffin inhibits the formation of light olefins. High temperatures and low pressures favor the formation of ethylene, and moderate temperatures and low pressures favor the formation of propylene. n-Hexane and cyclohexane mixtures gave maximum ethylene and propylene yield of approximately 49.90% and 55.77%, respectively. This work provides theoretical guidance for the development of superior catalysts and the selection of proper operation parameters for the catalytic pyrolysis of C_5–8 n/iso/cyclo-paraffins from a thermodynamic point of view.

关键词： naphtha catalytic pyrolysis reaction pathway equilibrium yield

HTML PDF 收藏

Measurement and correlation of the solid-liquid equilibrium of 2-(

Yanhong SUN, Zhiyong LI, Chuang XIE, Wei CHEN, Cui ZHANG

《化学科学与工程前沿（英文）》 2013年第7卷第1期页码 110-115 doi: 10.1007/s11705-013-1316-7

摘要： In this work, the enthalpy of fusion and melting points of 2-( -butyl)-5-methylphenol (2B5MP) and 2-( -butyl)-4-methylphenol (2B4MP) were measured by differential scanning calorimetry (DSC). The binary solid-liquid equilibrium (SLE) of both compounds were predicted by integrated computer aided system (ICAS) and measured by DSC. The corresponding eutectic molar composition is 0.6998 and the eutectic temperature is 281.96 K. The quasi-static heat capacities of 2B5MP and 2B4MP were evaluated by stochastic temperature modulation DSC technique (TOPEM). The SLE experimental data were correlated using the Margules, Wilson, and non-random two liquid (NRTL) equations and a good agreement between measurement and calculation could be obtained.

关键词： solid-liquid equilibrium (SLE) eutectic integrated computer aided system (ICAS) TOPEM correlation

HTML PDF 收藏

Brown marine algae turbinaria conoides as biosorbent for Malachite green removal: Equilibrium and kinetic

R. RAJESH KANNAN, M. RAJASIMMAN, N. RAJAMOHAN, B. SIVAPRAKASH,

《环境科学与工程前沿（英文）》 2010年第4卷第1期页码 116-122 doi: 10.1007/s11783-010-0006-7

摘要： In this study, the biosorption of Malachite green (MG) onto Turbinaria conoides, brown marine algae, was studied with respect to initial pH, temperature, initial dye concentration, and sorbent dosage. The optimum initial pH and temperature values for MG removal were found to be 8.0 and 30°C, respectively. Sorbent dosage was found to strongly influence the removal of MG. Equilibrium studies were carried out to test the validity of the Langmuir ( = 66.6 mg/g and = 0.526 mL mol/L) and the Freundlich ( = 1.826 and = 3.751 mg/g) isotherms. The kinetic studies indicated the validity of the pseudo first-order and second-order equation.

关键词： Malachite green (MG) Turbinaria conoides marine algae equilibrium studies biosorption

HTML PDF 收藏

Non-equilibrium model for catalytic distillation process

WANG Feng, ZHAO Ning, LI Junping, XIAO Fukui, WEI Wei, SUN Yuhan

《化学科学与工程前沿（英文）》 2008年第2卷第4期页码 379-384 doi: 10.1007/s11705-008-0071-7

摘要： A new improved tri-diagonal method was developed for the non-equilibrium stage model of the catalytic distillation by coupling consumptive reaction coefficient. The reactions in the distillation column were divided into generative reaction and consumptive reaction. The non-equilibrium stage model was introduced for the catalytic distillation process of the dimethyl carbonate (DMC) synthesis by urea methanolysis over solid based catalyst, and the improved tri-diagonal method was used to solve the model equations. Comparison of predicted results with experiment data shows that the mean relative error of the yield of DMC was 3.78% under different conditions such as different operating pressures and reaction temperatures. The improved tri-diagonal matrix method could avoid the negative values of the liquid compositions during the calculations and restrain the fluctuation of compositions by slowing down the variations of the values in the iteration. The modeling results show that the improved tri-diagonal method was appropriate for system containing a wide range of boiling point components and a different rate of reactions.

HTML PDF 收藏

into nitrogen and sulfur co-doped carbon nanotubes for effective desulfurization of liquid phases: Equilibrium

《环境科学与工程前沿（英文）》 2021年第15卷第5期 doi: 10.1007/s11783-021-1397-3

摘要：

• Synthesis of NS-CNTS is used in a high desulfurization performance.

关键词： Dibenzothiophene (DBT) Tertiary methyl mercaptan Adsorption Carbon nano tube (CNT) Desulfurization Doping

HTML PDF 收藏

Removal of Rhodamine B from aqueous solutions and wastewater by walnut shells: kinetics, equilibrium

Jasmin Shah, M. Rasul Jan, Attaul Haq, Younas Khan

《化学科学与工程前沿（英文）》 2013年第7卷第4期页码 428-436 doi: 10.1007/s11705-013-1358-x

摘要： An adsorption study of Rhodamine B (RB) dye from aqueous solutions was carried out using walnut shells pretreated by different methods. In addition to the effects of the pretreatment, the effects of various parameters like pH, adsorbent dose, contact time, initial dye concentration and temperature on the adsorption of RB was studied. The adsorption process was highly pH dependent and a maximum adsorption was achieved at pH 3.0. The best fit for the rates of dye adsorption was a pseudo-second-order kinetic model with good correlation coefficients ( >0.99). Langmuir isotherms were used to determine that the maximum loading capacity of the different walnut shells and the RB capacities ranged from 1.451–2.292 mg·g . The dye adsorption was also evaluated thermodynamically. Positive standard enthalpy (? °) values were obtained indicating that the RB adsorption process is endothermic as well as ? ° and ? ° values showed that adsorption process is spontaneous with an increased randomness at the solid-liquid interface. Desorption studies were carried out to explore the feasibility of regenerating the used walnut shells and it was found that 97.71%–99.17% of the retained RB was recovered with 0.1 mol?L NaOH solution. The walnut shells were also successfully used to remove RB from industrial effluents.

关键词： Rhodamine B walnut shell adsorption kinetics isotherms regeneration

HTML PDF 收藏

地下水碳酸平衡检查系统

刘建刚,郑克勋,傅伟宁,吴顺华

《中国工程科学》 2003年第5卷第9期页码 61-64

摘要：

文章主要研究地下水在不同温度和CO₂分压条件下碳酸三种存在形式与pH值的关系，以便更有效地对地下水水质资料进行可靠性检查。分析认为HCO₃^-出现峰值的分界pH₀值，纯水在CO₂分压1～10⁵Pa，温度0～30℃时的变化范围为7.92～8.60，碳酸盐岩地下水的变化范围为8.28～8.57。pH₀值随温度的升高而降低。石灰岩和白云岩的pH₀十分接近，碳酸盐岩地区的平衡特性将取决于方解石成分。

关键词：碳酸盐岩地下水碳酸平衡 pH值

HTML PDF 收藏

Phase equilibrium of the ternary system of NH 4 Cl—CaCl 2 —H 2 O at 50°C

Xia LI, Junsheng YUAN, Zhiyong JI, Jianxin CHEN,

《化学科学与工程前沿（英文）》 2010年第4卷第1期页码 75-77 doi: 10.1007/s11705-009-0296-0

摘要： The equilibrium data on the ternary system of NHCl—CaCl—HO at 50°C were investigated using the wet-residue method. The experimental results show that there are three pure phase crystal areas of NHCl, 2NHCl·CaCl·3HO and CaCl·2HO, two mixture phase crystal areas of NHCl and 2NHCl·CaCl·3HO, and 2NHCl·CaCl·3HO and CaCl·2HO in the system. A new hydration double salt (2NHCl·CaCl·3HO) was found in the ternary equilibrium system for the first time.

HTML PDF 收藏

Statics of levitated vehicle model with hybrid magnets

Desheng LI, Zhiyuan LU, Tianwu DONG

《机械工程前沿（英文）》 2009年第4卷第1期页码 35-39 doi: 10.1007/s11465-009-0002-4

摘要： By studying the special characteristics of permanent and electronic magnets, a levitated vehicle model with hybrid magnets is established. The mathematical model of the vehicle is built based on its dynamics equation by studying its machine structure and working principle. Based on the model, the basic characteristics and the effect between the excluding forces from permanent magnets in three different spatial directions are analyzed, statics characteristics of the interference forces in three different spatial directions are studied, and self-adjusting equilibrium characteristics and stabilization are analyzed. Based on the structure above, the vehicle can levitate steadily by control system adjustment.

关键词： magnetic levitation permanent magnet modeling equilibrium

HTML PDF 收藏

Biosorption of Cr(III) from aqueous solution by freeze-dried activated sludge: Equilibrium, kinetic and

Qian YAO, Hua ZHANG, Jun WU, Liming SHAO, Pinjing HE,

《环境科学与工程前沿（英文）》 2010年第4卷第3期页码 286-294 doi: 10.1007/s11783-010-0025-4

摘要： Batch biosorption experiments were conducted to remove Cr(III) from aqueous solutions using activated sludge from a sewage treatment plant. An investigation was conducted on the effects of the initial pH, contact time, temperature, and initial Cr(III) concentration in the biosorption process. The results revealed that the activated sludge exhibited the highest Cr(III) uptake capacity (120 mg·g) at 45°C, initial pH of 4, and initial Cr(III) concentration of 100 mg·L. The biosorption results obtained at various temperatures showed that the biosorption pattern accurately followed the Langmuir model. The calculated thermodynamic parameters, Δ (−0.8– −4.58 kJ·mol), Δ (15.6–44.4 kJ·mol), and Δ (0.06–0.15 kJ·mol·K) clearly indicated that the biosorption process was feasible, spontaneous, endothermic, and physical. The pseudo first-order and second-order kinetic models were adopted to describe the experimental data, which revealed that the Cr(III) biosorption process conformed to the second-order rate expression and the biosorption rate constants decreased with increasing Cr(III) concentration. The analysis of the values of biosorption activation energy ( = −7 kJ·mol) and the intra-particle diffusion model demonstrated that Cr(III) biosorption was film-diffusion-controlled.

关键词： activated sludge biosorption chromium film diffusion kinetics thermodynamics

HTML PDF 收藏

Stability analysis of layered slopes in unsaturated soils

Guangyu DAI; Fei ZHANG; Yuke WANG

《结构与土木工程前沿（英文）》 2022年第16卷第3期页码 378-387 doi: 10.1007/s11709-022-0808-2

摘要： This study presents stability analyses of layered soil slopes in unsaturated conditions and uses a limit equilibrium method to determine the factor of safety involving suction stress of unsaturated soil. One-dimensional steady infiltration and evaporation conditions are considered in the stability analyses. An example of a two-layered slope in clay and silt is selected to verify the used method by comparing with the results of other methods. Parametric analyses are conducted to explore the influences of the matric suction on the stability of layered soil slopes. The obtained results show that larger suction stress provided in unsaturated clay dominates the stability of the layered slopes. Therefore, the location and thickness of the clay layer have significant influences on slope stability. As the water level decreases, the factor of safety reduces and then increases gradually in most cases. Infiltration/evaporation can obviously affect the stability of unsaturated layered slopes, but their influences depend on the soil property and thickness of the lower soil layer.

关键词： slope stability suction stress unsaturated soil layered slope limit equilibrium

HTML PDF 收藏

Molecular dynamics simulation of diffusivity

LIU Juanfang, ZENG Danling, LI Qin, GAO Hong

《能源前沿（英文）》 2008年第2卷第3期页码 359-362 doi: 10.1007/s11708-008-0039-9

摘要： Equilibrium molecular dynamics simulation was performed on water to calculate its diffusivity by adopting different potential models. The results show that the potential models have great influence on the simulated results. In addit

关键词： diffusivity Equilibrium molecular influence potential

HTML PDF 收藏

矿物浮选吸附平衡模型构建与应用：精准解析矿物表面离子 / 药剂特征吸附

高雅,付心壮,韩海生,王丽,岳彤,孙伟

《中国工程科学》 2023年第25卷第6期页码 248-258 doi: 10.15302/J-SSCAE-2023.07.020

摘要：

矿物浮选吸附平衡模型是准确描述矿物浮选过程中所涉及的矿物表面离子 / 药剂吸附平衡的数学模型，首次实现了矿物表面位点与浮选药剂吸附作用亲和性的量化解析。传统浮选理论对矿物表面作用位点缺乏科学描述，难以阐明浮选药剂的吸附作用能力及平衡状态，新浮选药剂体系开发多以“试错法”“复配法”等经验性方法为主。药剂选择性吸附作为浮选作业的核心机制，若不能准确预测其在各矿物表面的吸附行为，将严重限制浮选工艺智能化控制的发展。本文详细论述了矿物浮选吸附平衡模型的构建原理，以赤铁矿 ‒ 石英和一水硬铝石 ‒ 高岭石两个浮选体系为例，通过对少量实验数据的拟合计算，解析出矿物表面活性位点密度Ns、加 / 去质子反应常数Kt1/Kt2、药剂吸附常数Kf等矿物浮选特征常数。将解析的矿物浮选特征常数代入到平衡模型中，预测出各条件下矿物表面电性、离子及浮选药剂的吸附量，通过零电点、实验及测试等方法验证了可靠性，形成了矿物浮选过程预测系统的内核算法。该算法对各条件下每种矿物药剂吸附的初步准确预测，可在一定程度上反映其可浮性趋势，有助于缩短浮选工艺开发周期，对矿物表面药剂吸附机理研究、浮选药剂分子设计、浮选工艺流程优化及智能控制等具有重要意义。

关键词：矿物加工；浮选机理；矿物浮选吸附平衡模型；可浮性预测；矿物浮选特征常数

HTML PDF 收藏

Thermally developing forced convection and the corresponding thermal stresses in a porous plate channel

YANG Xiao, LIU Xuemei

《机械工程前沿（英文）》 2007年第2卷第1期页码 57-61 doi: 10.1007/s11465-007-0009-7

摘要： Based on the Darcy fluid model, by considering the effects of viscous dissipation due to the interaction between solid skeleton and pore fluid flow and thermal conduction in the direction of the fluid flow, the thermally developing forced convection of the local thermal equilibrium and the corresponding thermal stresses in a semi-infinite saturated porous plate channel are investigated in this paper. The expressions of temperature, local Nusselt number and corresponding thermal stresses are obtained by means of the Fourier series, and the distributions of the same are also shown. Furthermore, influences of the P晱let number () and Brinkman number () on temperature, Nusselt number () and thermal stress are revealed numerically.

关键词： semi-infinite saturated direction interaction skeleton thermal equilibrium

HTML PDF 收藏

The relevance of James Lovelock’s research and philosophy to environmental science and academia

《环境科学与工程前沿（英文）》 2023年第17卷第3期 doi: 10.1007/s11783-023-1639-7

摘要： James E. Lovelock, famed for his Gaia hypothesis, which views the Earth as a living integrated and interconnected self-regulating system whose equilibrium comes about from complex energy-based interactions and feedback loops, ultimately sustaining life, passed away at the end of July, 2022 at the age of 103. Not only are the adaptive mechanisms of Gaia central to the conversation of environmental homeostasis, they lie at the heart of climate change and global warming. Lovelock is also remembered as the co-inventor of the electron capture detector that eventually allowed for the sensitive detection of chlorofluorocarbons and pesticides. Finally, Lovelock’s free-spirited nature and research independence allow academia to rethink current research’s modus operandi.

关键词： Academic independence Climate change Electron capture detector Environmental equilibrium Global warming Homeostasis