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Numerical simulation and experimental research on heat transfer and flow resistance characteristics ofasymmetric plate heat exchangers

Shaozhi ZHANG, Xiao NIU, Yang LI, Guangming CHEN, Xiangguo XU

《能源前沿（英文）》 2020年第14卷第2期页码 267-282 doi: 10.1007/s11708-020-0662-7

摘要： The asymmetric plate heat exchanger (APHE) has the possibility of achieving balanced pressure drops on both hot and cold sides for situations with unbalanced flow, which may in turn enhance the heat transfer. In this paper, the single-phase water flow and heat transfer of an APHE consisted of two types of plates are numerically (400≤ ≤12000) and experimentally (400≤ ≤3400) investigated. The numerical model is verified by the experimental results. Simulations are conducted to study the effects of , an asymmetric index proposed to describe the geometry of APHEs. The correlations of the Nusselt number and friction factor in the APHEs are determined by taking and working fluids into account. It is found that an optimal exists where the pressure drops are balanced and the heat transfer area reaches the minimum. The comparison between heat transfer and flow characteristics of the APHEs and the conventional plate heat exchanger (CPHE) is made under various flow rate ratios of the hot side and the cold side and different allowable pressure drops. The situations under which APHE may perform better are identified based on a comprehensive index .

关键词： plate heat exchanger asymmetric simulation correlation heat transfer enhancement

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Asymmetric transfer hydrogenation of prochiral ketone catalyzed over Fe-CS/SBA-15 catalyst

XUE Ping, WU Tao

《化学科学与工程前沿（英文）》 2007年第1卷第3期页码 251-255 doi: 10.1007/s11705-007-0045-1

摘要： A heterogeneous chiral catalyst Fe(III)-CS (chitosan) complex/mesoporous molecular sieve SBA-15 (Santa Barbara Amorphous) was prepared. The asymmetric transfer hydrogenations of prochiral acetophenone and 4-methyl-2-pentanone to corresponding chiral alcohols were carried out on Fe-CS/SBA-15 at atmosphere pressure using 2-propanol as hydrogen donor. Effects of Fe content in catalyst, reaction temperature, reaction time and promoter KOH concentration on the conversion of substrates and enantioselectivity were investigated. Fe-CS/SBA-15 with 2.2% mass fraction Fe exhibits considerable enantioselectivity and catalytic activity for the asymmetric transfer hydrogenations of aromatic ketone and aliphatic ketone. Under optimal reaction conditions: KOH concentration 0.03 mol/L, reaction temperature 70ºC and reaction time 4 h, enantiomer excess (ee) of ()-1-phenylethanol and conversion of acetophenone can reach 87.4% and 27.7%, respectively. Under the above KOH concentration and reaction temperature and reaction time of 8 h, the ee of ()-4-methyl-2-pentanol and conversion 4-methyl-2-pentanone amounted to 50.2% and 25.5%, respectively.

关键词： asymmetric transfer enantioselectivity Fe-CS/SBA-15 aliphatic aromatic

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在非对称大规模MIMO系统中基于集成—迁移学习的信道参数预测 Research Article

何遵文1,李悦1,张焱1,张万成1,张恺恩1,郭柳1,王海明2

《信息与电子工程前沿（英文）》 2023年第24卷第2期页码 275-288 doi: 10.1631/FITEE.2200169

摘要：近年来，多智能体深度强化学习（multi-agent deep 为降低第六代移动网络中的数据处理负担和硬件成本，非对称大规模多入多出（multiple-input multiple-output，MIMO）系统被提出。然而，在非对称大规模MIMO系统中，上行和下行无线信道之间的互易性是无效的。因此，需要基站和用户设备都发送导频来预测双向信道，这会消耗更多传输和计算资源。本文提出一种基于集成迁移学习的非对称大规模MIMO系统的信道参数预测方法，可以预测多个下行信道参数，包括路径损耗、多径数、时延扩展和角度扩展。选择上行信道参数和环境特征来预测下行参数。此外，提出一种基于SHAP（SHapley Additive exPlanations）值和最小描述长度标准的两步特征选择算法，以降低由弱相关或不相关特征引起的计算复杂度和对模型准确性的负面影响。引入实例迁移方法，以支持预测模型应对在新的传播条件下难以在短时间内收集足够训练数据的问题。仿真结果表明，该方法比反向传播神经网络和3GPP TR 38.901信道模型更准确。当波束宽度或通信扇区发生变化时，所提出的基于实例迁移的方法在预测下行参数方面优于没有迁移学习的方法。

关键词：非对称大规模MIMO系统；信道模型；集成学习；实例迁移；参数预测

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用于个人降温和保暖的具有定制热传导和热辐射特性的双功能非对称织物 Article

Yucan Peng, Hiang Kwee Lee, David S. Wu, Yi Cui

《工程（英文）》 2022年第10卷第3期页码 167-173 doi: 10.1016/j.eng.2021.04.016

摘要：

为了让人体感到热舒适，同时节约能源，个人热管理正逐渐成为一种颇有前景的策略。通过更好地控制人体散热，个人热管理可以实现有效的个人降温和保暖。本文提出了一种简单的表面改性方法，在商用织物的基础上定制热传导和热辐射特性，以便更好地管理从人体到环境的整个传热路径。本文对一种同时具有降温和保暖效果的双功能非对称织物（BAF）进行论证。凭借粗糙度不对称和表面改性等优点，BAF在降温模式下通过增强热传导和热辐射表现出显著的降温效果；在保暖模式下，两条路径的散热都减少，从而实现个人保暖。结果表明，在BAF的降温和保暖模式下测得的皮肤温差可达4.6 ℃，表明一件BAF衣服可以扩大人体的热舒适区。希望本研究可为用于个人热管理的织物的设计提供新的视角，并为现有的用于个人降温和保暖的织物的简单改性提供新的解决方案。

关键词：织物个人热管理双功能非对称织物热传导热辐射

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A pseudocapacitive molecule-induced strategy to construct flexible high-performance asymmetric supercapacitors

《化学科学与工程前沿（英文）》 2023年第17卷第9期页码 1208-1220 doi: 10.1007/s11705-023-2304-1

摘要： The combination of high-voltage windows and bending stability remains a challenge for supercapacitors. Here, we present an “advantage-complementary strategy” using sodium lignosulfonate as a pseudocapacitive molecule to regulate the spatial stacking pattern of graphene oxide and the interfacial architectures of graphene oxide and polyaniline. Flexible and sustainable sodium lignosulfonate-based electrodes are successfully developed, showing perfect bending stability and high electronic conductivity and specific capacitance (521 F·g⁻¹ at 0.5 A·g^–1). Due to the resulting rational interfacial structure and stable ion-electron transport, the asymmetric supercapacitors provide a wide voltage window reaching 1.7 V, outstanding bending stability and high energy-power density of 83.87 Wh·kg^–1 at 3.4 kW·kg^–1. These properties are superior to other reported cases of asymmetric energy enrichment. The synergistic strategy of sodium lignosulfonate on graphene oxide and polyaniline is undoubtedly beneficial to advance the process for the construction of green flexible supercapacitors with remarkably wide voltage windows and excellent bending stability.

关键词： molecular synergy pseudocapacitive lignosulfonate flexible electronic devices asymmetric supercapacitor wide voltage windows

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Synthesis of iron(II) complexes with asymmetric N

Wolfgang Bauer, Tanja Ossiander, Birgit Weber

《化学科学与工程前沿（英文）》 2018年第12卷第3期页码 400-408 doi: 10.1007/s11705-018-1753-4

摘要：

The synthesis of new Schiff base-like ligands with asymmetric substituents pattern and their iron complexes with pyridine as axial ligand is described. Two of the ligands and one of the iron(II) complexes were characterized by single crystal X-ray structure analysis. One of the the iron(II) complexes shows spin crossover behavior while the others remain in the high spin state. The influence of the reduced symmetry of the ligand on the properties of the complexes is discussed.

关键词： iron Schiff base-like ligands magnetism spin crossover X-ray structures

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Preparation of D-lysine by chemical reaction and microbial asymmetric transformation

LIU Yi, JIAO Qingcai, YIN Xiaoxing

《化学科学与工程前沿（英文）》 2008年第2卷第1期页码 40-43 doi: 10.1007/s11705-008-0023-2

摘要： The DL-lysine crystals from the racemization of L-lysine was treated as substrate with AS1.1009 intact cells as biocatalysts to produce crystalline D-lysine with a yield of 56.6% from the reaction mixture after simple purification. In the presence of 0.10 molar equivalent of salicylaldehyde, L-lysine racemization can be completed within 4 h in 1.0 mol/L of NaOH at 100°C. The activation energy of the processes was 62187.86 J/mol. The characteristics of AS1.1009 decarboxylase were studied. Under the conditions of pH 8.0, temperature 37°C, cell concentration 10 g/L, tween-80 0.5 g/L, substrate concentration 30 g/L, and the specific activity of up to 3840 U, L-lysine can be completely degraded by the decarboxylase for 12 h under the optimal conditions.

关键词： substrate temperature specific activity presence decarboxylase

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Evaluation of a novel Asymmetric Genetic Algorithm to optimize the structural design of 3D regular and

Mohammad Sadegh ES-HAGHI, Aydin SHISHEGARAN, Timon RABCZUK

《结构与土木工程前沿（英文）》 2020年第14卷第5期页码 1110-1130 doi: 10.1007/s11709-020-0643-2

摘要： We propose a new algorithm, named Asymmetric Genetic Algorithm (AGA), for solving optimization problems of steel frames. The AGA consists of a developed penalty function, which helps to find the best generation of the population. The objective function is to minimize the weight of the whole steel structure under the constraint of ultimate loads defined for structural steel buildings by the American Institute of Steel Construction (AISC). Design variables are the cross-sectional areas of elements (beams and columns) that are selected from the sets of side-flange shape steel sections provided by the AISC. The finite element method (FEM) is utilized for analyzing the behavior of steel frames. A 15-storey three-bay steel planar frame is optimized by AGA in this study, which was previously optimized by algorithms such as Particle Swarm Optimization (PSO), Particle Swarm Optimizer with Passive Congregation (PSOPC), Particle Swarm Ant Colony Optimization (HPSACO), Imperialist Competitive Algorithm (ICA), and Charged System Search (CSS). The results of AGA such as total weight of the structure and number of analyses are compared with the results of these algorithms. AGA performs better in comparison to these algorithms with respect to total weight and number of analyses. In addition, five numerical examples are optimized by AGA, Genetic Algorithm (GA), and optimization modules of SAP2000, and the results of them are compared. The results show that AGA can decrease the time of analyses, the number of analyses, and the total weight of the structure. AGA decreases the total weight of regular and irregular steel frame about 11.1% and 26.4% in comparing with the optimized results of SAP2000, respectively.

关键词： optimization steel frame Asymmetric Genetic Algorithm constraints of ultimate load constraints of serviceability limits penalty function

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Preparation and characterization of asymmetric ultrafiltration membrane for effective recovery of proteases

Nora’aini ALI, Fadhilati HASSAN, Sofiah HAMZAH

《化学科学与工程前沿（英文）》 2012年第6卷第2期页码 184-191 doi: 10.1007/s11705-012-1288-z

摘要： The wash water generated from the surimi processing industry contains a large amount of proteases which are widely used in the food and biotechnology industries. Asymmetric polysulfone and polyethersulfone ultrafiltration (PSf-UF and PES-UF) membranes with three different polymer concentrations were screened for their abilities to recover proteases from surimi wash water. In-house fabricated membranes were prepared via a simple dry/wet phase inversion technique and were characterized in terms of permeability coefficient, membrane morphology and molecular weight cut-off (MWCO). The ability of the UF membranes to remove commercial proteases was tested at various pressures (up to 10 bars). The membrane with the best performance, 15 wt-% PSf-UF, was further tested with actual surimi wash water. The effect of the pH of the feed solution (4 to 8) in the pre-treatment stage was also evaluated to recover the highest amount of proteases. The highest retention of protease was 96% with a flux of 25.6 L/(m ·h) which was achieved with the 15 wt-% PSf-UF membrane.

关键词： membrane ultrafiltration proteases surimi wash water

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Isolation of microbe for asymmetric reduction of prochiral aromatic ketone and its reaction characters

YANG Zhonghua, WANG Yu, WANG Guanghui, ZENG Rong, YAO Shanjing

《化学科学与工程前沿（英文）》 2007年第1卷第4期页码 416-420 doi: 10.1007/s11705-007-0076-7

摘要： The favorable microbes for the asymmetric reduction of prochiral aromatic ketones was isolated from soil using acetophenone as the sole carbon source, when the asymmetric reduction of acetophenone (ACP) to chiral ?-phenethyl alcohol (PEA) was chosen as the model reaction. Two microbe strains with excellent catalytic activity were obtained. They were and identified by bacteria identification. The product of the asymmetric reduction of ACP catalyzed by was mainly R-PEA and that by was mainly S-PEA. The yield and enantiomeric excesses (e.e.) could respectively reach 75% and 90% for , and 80% and 70% for , much higher than those catalyzed by baker s yeast.

关键词： excellent catalytic prochiral aromatic enantiomeric -phenethyl catalytic activity

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大屯矿区深部软岩巷道非对称变形机理及控制对策研究

傅清国,邹朝阳

《中国工程科学》 2011年第13卷第11期页码 102-106

摘要：

通过对孔庄矿工程地质情况调查与分析，结合室内岩石力学实验，运用三维数值模拟方法，研究巷道非对称变形时周围岩体的位移场分布规律，分析巷道推进到上部工作面下方时的应力分布规律。理论研究结果表明，孔庄矿－785 m水平轨道大巷非对称变形主要受其上部采空区煤柱的集中压力控制，黏土矿物遇水膨胀、岩层结构及高地应力作用进一步恶化了巷道围岩结构。该研究可为孔庄矿深部巷道非对称变形控制对策提供初步的理论依据。

关键词：深部软岩巷道非对称变形控制对策

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超小间距非对称浅埋隧道施工监控量测及分析

王云龙,谭忠盛,陈鹰

《中国工程科学》 2012年第14卷第11期页码 24-28

摘要：

以青岛胶州湾海底隧道团岛段小间距隧道为例，通过现场监测结果分析了小间距非对称浅埋隧道的围岩压力特征及支护受力，结果表明该隧道后行洞围岩压力及支护受力都较大，这种结果有别于大部分小间距对称隧道的理论预测及实测结果。为有效缓解这些问题，对支护参数进行及时调整，增强后行洞的径向支护能力并对中间岩柱采取加固措施。继后施工中的监测结果显示，后行洞的稳定性得到了有效的控制，为类似小间距隧道的设计和施工提供了借鉴和参考。

关键词：隧道超小间距非对称浅埋监测

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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

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胶州湾海底隧道不对称双连拱断面施工优化分析

王凯,张成平,王梦恕

《中国工程科学》 2012年第14卷第1期页码 90-97

摘要：

以青岛胶州湾海底隧道中的不对称双连拱隧道为工程背景，选取主隧道与匝道交叉口段的典型断面建立数值计算模型，针对不同的施工开挖顺序和掘进进尺制订了4种施工方案，并采用有限差分软件FLAC3D进行动态施工的三维数值模拟，计算分析并比较各方案的地表沉降、拱顶沉降和支护结构位移以及围岩应力和支护结构应力的分布情况，明确不对称双连拱隧道施工中结构变形及应力的最不利位置。分析结果表明，先施工中导洞再施工匝道断面右导洞并采用小进尺的施工方案更有利于控制围岩的稳定性，并据此提出了合理的施工方案建议。

关键词：海底隧道不对称双连拱隧道施工方案优化施工顺序开挖进尺

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Augmentation of natural convective heat transfer by acoustic cavitation

Jun CAI, Xiulan HUAI, Shiqiang LIANG, Xunfeng LI,

《能源前沿（英文）》 2010年第4卷第3期页码 313-318 doi: 10.1007/s11708-009-0064-3

摘要： An experimental study was conducted to investigate the effects of acoustic cavitation on natural convective heat transfer from a horizontal circular tube. The experimental results indicated that heat transfer could be enhanced by acoustic cavitation and had the best effect when the head of the ultrasonic transducer was over the midpoint of the circular tube, and the distance between the head and the tube equaled 15 mm. The augmentation at low heat flux was better than that in the case of high heat flux. Based on experimental results, the correlation formula of Nusselt number for water was obtained.

关键词： heat transfer enhancement augmentation acoustic cavitation acoustic streaming convective heat transfer