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Surface tension of liquid metal: role, mechanism and application

Xi ZHAO, Shuo XU, Jing LIU

《能源前沿（英文）》 2017年第11卷第4期页码 535-567 doi: 10.1007/s11708-017-0463-9

摘要： Surface tension plays a core role in dominating various surface and interface phenomena. For liquid metals with high melting temperature, a profound understanding of the behaviors of surface tension is crucial in industrial processes such as casting, welding, and solidification, etc. Recently, the room temperature liquid metal (RTLM) mainly composed of gallium-based alloys has caused widespread concerns due to its increasingly realized unique virtues. The surface properties of such materials are rather vital in nearly all applications involved from chip cooling, thermal energy harvesting, hydrogen generation, shape changeable soft machines, printed electronics to 3D fabrication, etc. owing to its pretty large surface tension of approximately 700 mN/m. In order to promote the research of surface tension of RTLM, this paper is dedicated to present an overview on the roles and mechanisms of surface tension of liquid metal and summarize the latest progresses on the understanding of the basic knowledge, theories, influencing factors and experimental measurement methods clarified so far. As a practical technique to regulate the surface tension of RTLM, the fundamental principles and applications of electrowetting are also interpreted. Moreover, the unique phenomena of RTLM surface tension issues such as surface tension driven self-actuation, modified wettability on various substrates and the functions of oxides are discussed to give an insight into the acting mechanism of surface tension. Furthermore, future directions worthy of pursuing are pointed out.

关键词： surface tension liquid metal soft machine printed electronics electrowetting self-actuation

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表面张力辅助去核法对小鼠卵母细胞的去核研究

孟庆刚,朱士恩,曾申明,张忠诚

《中国工程科学》 2001年第3卷第11期页码 65-69

摘要：

论述了一种新的小鼠卵母细胞去核方法一一表面张力辅助去核法（STA),并同时与其他3种去核方法（简称A法、B法、C法）进行比较。STA法是将卵母细胞核在固定管的辅助下，借助液体表面张力通过透明带上的破口被挤出。经STA法去核的卵母细胞质体用于电融合介导的小鼠耳成纤维细胞核移植实验，结果有 76.1 %细胞与细胞质体融合形成重组胚，85.4 %的重组胚形成原核，49.4%卵裂形成2-细胞。

关键词：表面张力辅助去核卵母细胞小鼠

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Rhamnolipid synthesis and production with diverse resources

Qingxin Li

《化学科学与工程前沿（英文）》 2017年第11卷第1期页码 27-36 doi: 10.1007/s11705-016-1607-x

摘要： Rhamnolipids are one of the most effective biosurfactants that are of great interest in industrial applications such as enhancing oil recovery, health care, cosmetics, pharmaceutical processes, food processing, detergents for protein folding, and bioremediation due to their unique characteristics such as low toxicity, surface active property to reduce surface/interfacial tensions, and excellent biodegradability. The genes and metabolic pathways for rhamnolipid synthesis have been well elucidated, but its cost-effective production is still challenging. , the most powerful rhamnolipid producer, is an opportunistic pathogen, which limits its large scale production and applications. Rhamnolipid production using engineered strains other than such as and has received much attention. The highest yield of rhamnolipids is achieved when oil-type carbon sources are used, but using cheaper and renewable carbon sources such as lignocellulose would be an attractive strategy to reduce the production cost of rhamnolipids for various industrial applications.

关键词： biosurfactant rhamnolipid Pseudomonas waste surface tension

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Effects of fatty acid chain length and degree of unsaturation on the surface activities of monoacyl trehaloses

Yue-E SUN, Wenshui XIA, Xueyan TANG, Zhiyong HE, Jie CHEN,

《化学科学与工程前沿（英文）》 2009年第3卷第4期页码 407-412 doi: 10.1007/s11705-009-0255-9

摘要： The surface properties of monoacyl trehaloses with different acyl chains were investigated at 30°C, 40°C, 50°C, and 60°C. Monoacyl trehaloses were enzymatically synthesized and purified with silica gel column chromatography and semi-preparative high-performance liquid chromatography (HPLC), and the purity of products was identified by mass spectrometry (MS) and nuclear magnetic resonance (NMR). The surface tension of monoacyl trehalose in pure water was measured using Doüy ring method at different temperatures. The critical micelle concentrations (CMC), surface tension at the CMC, , and residual area per molecule, , were estimated from the curves. The CMC value of unsaturated monoacyl trehalose was affected by both the degree of unsaturation and the acyl chain length, and the effect of chain length on the CMC value was much stronger than that of the unsaturation degree. However, there was no significant dependency of the value and a values on the chain length or the unsaturated degree.

关键词： high-performance liquid tension different spectrometry chromatography

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Behavior of dam concrete under biaxial compression-tension and triaxial compression-compression-tension

WANG Huailiang, SONG Yupu

《结构与土木工程前沿（英文）》 2008年第2卷第4期页码 323-328 doi: 10.1007/s11709-008-0043-5

摘要： In order to meet the requirement for nonlinear analysis and design of mass concrete structures, the deformation behavior and strength of three-graded concrete specimens 250 mm × 250 mm × 400 mm with a maximum aggregate size of 80 mm and the corresponding wet-screened concrete specimens 150 mm × 150 mm × 300 mm with a maximum aggregate size of 40 mm were studied experimentally. Specimens subjected to biaxial compression-tension (C-T) and triaxial compression-compression-tension (C-C-T) stress states. Test data indicate that both the deformation and strength of the mass concrete specimens are lower than those of the corresponding wet-screened concrete small specimens, but the initial tangent modulus of the stress-strain curve of the former is greater than that of the latter. Test results show that the wet-screened effect and size effect of the specimens under complex stress states are obvious such that these should be considered in the design of mass concrete structures. In addition, respective failure criteria for mass concrete in principal stress space and octahedron stress space are proposed.

关键词： requirement wet-screened concrete compression-tension maximum aggregate principal

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Seismic stability of earth slopes with tension crack

Yundong ZHOU, Fei ZHANG, Jingquan Wang, Yufeng GAO, Guangyu DAI

《结构与土木工程前沿（英文）》 2019年第13卷第4期页码 950-964 doi: 10.1007/s11709-019-0529-3

摘要： Cracks at the crest of slopes frequently occur during earthquakes. Such cracks result from limited tension strength of the soil. A tension cut-off in Mohr-Coulomb shear strength can represent this limited strength. Presented is an extension of variational analysis of slope stability with a tension crack considering seismicity. Both translational and rotational failure mechanisms are included in a pseudo-static analysis of slope stability. Developed is a closed-form to assess the seismic stability of slopes with zero tensile strength. The results indicate that the presence of the tension crack has significant effects on the seismic stability of slopes, i.e. leading to small value of the yield acceleration. Considering soil tension strength in seismic slope analysis may lead to overestimation on the stability, as much as 50% for vertical slopes. Imposing tension crack results in transit of the critical failure mode to a straight line from a log-spiral, except for flat slopes with small soil cohesion. Under seismic conditions, large cohesion may increase the depth of crack, moving it closer to the slope.

关键词： slope stability tension crack limit equilibrium seismic effect

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Correlation between tension softening relation and crack extension resistance in concrete

Xiufang ZHANG , Shilang XU ,

《结构与土木工程前沿（英文）》 2009年第3卷第3期页码 323-329 doi: 10.1007/s11709-009-0041-2

摘要： Changes of the material fracture energy consumption with crack propagation can be described by a crack extension resistance curve, one of the fundamental fracture criteria in crack mechanics. Recently, experimental observation of the fracture behavior in concrete was used to develop a new fracture criterion, the crack extension resistance curve, to analyze crack propagation during the entire concrete fracture process. The variation of the crack extension resistance is mainly associated with the energy consumption in the fracture process zone ahead of the stress-free crack tip. The crack extension resistance is then a function of the softening curve, which is a basic mechanical property in the fracture process zone. The relationship between the softening curve and the crack extension resistance curve is then analyzed based on results of three-point bending beams tests. The results indicate that the characteristic points of the crack extension resistance curve is closely related to the characteristic point on used tension softening curve.

关键词： concrete fracture process zone crack extension G_R resistance tension softening curve

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Calculation method of load distribution on pipe threaded connections under tension load

Shoujun CHEN, Lianxin GAO, Qi AN

《机械工程前沿（英文）》 2011年第6卷第2期页码 241-248 doi: 10.1007/s11465-011-0219-x

摘要：

This paper presents a new calculation method that can calculate the load distribution on pipe threaded connections under tension load. On the basis of elastic mechanics, the new method was developed by analyzing each thread tooth, and a new deformation and covariant equation by making a mechanics analysis on each thread tooth was obtained. Compared with the traditional method proposed by the previous references, the new deformation and covariant equation could be used to describe the relation between the previous and the next thread tooth. By applying the new method on the sample of P-110S pipe threaded connection, the obtained results show that the load on thread tooth mainly concentrates on the four or five threads engaged and the middle teeth were not utilized well to bear the loads. The model offers a new way to calculate the loads carried on the thread teeth under tension load.

关键词： load distribution calculation method pipe threaded connections tension load

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Comparing the effects of Bassini versus tension-free hernioplasty: 3 years’ follow-up

Yulong SHI, Zhongxue SU, Leping LI, Hongjun LIU, Changqing JING,

《医学前沿（英文）》 2010年第4卷第4期页码 463-468 doi: 10.1007/s11684-010-0050-5

摘要： In order to compare the effects of Bassini and tension-free mesh hernioplasty, a total of 552 patients with inguinal hernia who were subjected to surgical treatment in our hospital were randomly divided into the following two groups: the Bassini group (=269) and the tension-free mesh group (=283). The recurrence rates, pain, discomfort, and other complications were recorded, and the causes of the complications were explored. The recurrence rate in the Bassini group was 8.9% (24/269), significantly higher than that in the tension-free repair group (2.8%, 8/283). In addition, the recurrence rates in the Bassini and tension-free groups before 2004 were 12.6% and 5.6%, respectively, which were markedly higher than the rates after 2004 (5.3% and 0.7%, respectively). The rate of post-operative discomfort and pain within the first three months was higher in the Bassini group compared to the tension-free group (25.7% 18.5%, respectively). However, there was no difference after three months in the rate of post-operative discomfort and pain, incidence of infection, or scrotal edema between the two groups. The average hospital stay in the Bassini group was longer than that in the tension-free repair group (7.6€±€1.2 4.5€±€2.2 days, respectively), but the cost was lower (4518.0€±€510 6221.3€±€578 yuan, respectively). Thus, tension-free mesh hernioplasty is indicated for most inguinal hernia patients due to the low recurrence rate, rapid recovery time, and treatment success, but the traditional Bassini procedure has lower cost and other beneficial effects and is still suitable for some patients.

关键词： hernioplasty Bassini repair tension-free repair complication

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Unconventional hydrodynamics of hybrid fluid made of liquid metals and aqueous solution under applied fields

Xu-Dong ZHANG, Yue SUN, Sen CHEN, Jing LIU

《能源前沿（英文）》 2018年第12卷第2期页码 276-296 doi: 10.1007/s11708-018-0545-3

摘要： The hydrodynamic characteristics of hybrid fluid made of liquid metal/aqueous solution are elementary in the design and operation of conductive flow in a variety of newly emerging areas such as chip cooling, soft robot, and biomedical practices. In terms of physical and chemical properties, such as density, thermal conductivity and electrical conductivity, their huge differences between the two fluidic phases remain a big challenge for analyzing the hybrid flow behaviors. Besides, the liquid metal immersed in the solution can move and deform when administrated with non-contact electromagnetic force, or even induced by redox reaction, which is entirely different from the cases of conventional contact force. Owing to its remarkable capability in flow and deformation, liquid metal immersed in the solution is apt to deform on an extremely large scale, resulting in marked changes on its boundary and interface. However, the working mecha- nisms of the movement and deformation of liquid metal lack appropriate models to describe such scientific issues via a set of well-established unified equations. To promote investigations in this important area, the present paper is dedicated to summarizing this unconventional hydrodynamics from experiment, theory, and simulation. Typical experimental phenomena and basic working mechanisms are illustrated, followed by the movement and deformation theories to explain these phenomena. Several representative simulation methods are then proposed to tackle the governing functions of the electrohydrodynamics. Finally, prospects and challenges are raised, offering an insight into the new physics of the hybrid fluid under applied fields.

关键词： liquid metal hybrid fluid hydrodynamics surface tension applied fields self-actuation

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High-precision gyro-stabilized control of a gear-driven platform with a floating gear tension device

《机械工程前沿（英文）》 2021年第16卷第3期页码 487-503 doi: 10.1007/s11465-021-0635-5

摘要： This study presents an improved compound control algorithm that substantially enhances the anti-disturbance performance of a gear-drive gyro-stabilized platform with a floating gear tension device. The tension device can provide a self-adjustable preload to eliminate the gap in the meshing process. However, the weaker gear support stiffness and more complex meshing friction are also induced by the tension device, which deteriorates the control accuracy and the ability to keep the aim point of the optical sensors isolated from the platform motion. The modeling and compensation of the induced complex nonlinearities are technically challenging, especially when base motion exists. The aim of this research is to cope with the unmeasured disturbances as well as the uncertainties caused by the base lateral motion. First, the structural properties of the gear transmission and the friction-generating mechanism are analyzed, which classify the disturbances into two categories: Time-invariant and time-varying parts. Then, a proportional-integral controller is designed to eliminate the steady-state error caused by the time-invariant disturbance. A proportional multiple-integral-based state augmented Kalman filter is proposed to estimate and compensate for the time-varying disturbance that can be approximated as a polynomial function. The effectiveness of the proposed compound algorithm is demonstrated by comparative experiments on a gear-drive pointing system with a floating gear tension device, which shows a maximum 76% improvement in stabilization precision.

关键词： inertially stabilized platform floating gear tension device nonlinear friction disturbance compensation proportional multiple-integral observer

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悬索桥短吊索索力测试的探讨

齐东春,郭健,沈锐利

《中国工程科学》 2010年第12卷第7期页码 78-83

摘要：

因难以准确确定吊索的计算长度和抗弯刚度，按照公式法计算短吊索的索力误差一般较大。以新沟河大桥悬索桥吊索索力测试为研究背景，分析了吊索的边界条件、抗弯刚度、计算索长及线密度等因素对索力测试精度的影响，表明公式法的简化假设对短吊索不适用。介绍了有限元法分析吊索索力的方法，按吊索的实际尺寸建立有限元模型，首先识别出吊索的抗弯刚度，然后建立各吊索的索力—频率对应表格，查表即可得到实测频率对应的索力。该方法应用到新沟河大桥的施工监控，证明是一种行之有效的方法。

关键词：短吊索索力测试频率法抗弯刚度有限元法

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study on the confine-stiffening effect and fractal cracking of square concrete filled steel tubes in tension

《结构与土木工程前沿（英文）》 2021年第15卷第6期页码 1317-1336 doi: 10.1007/s11709-021-0763-3

摘要： Tension stress in steel-concrete composite is widely observed in engineering design. Based on an experimental program on tension performance of three square concrete-filled tubes (SCFT), the tension theory of SCFT is proposed using a mechanics-based approach. The tension stiffening effect, the confining strengthening effect and the confining stiffening effect, observed in tests of SCFTs are included in the developed tension theory model. Subsequently, simplified constitutive models of steel and concrete are proposed for the axial tension performance of SCFT. Based on the MSC.MARC software, a special fiber beam-column element is proposed to include the confining effect of SCFTs under tension and verified. The proposed analytical theory, effective formulas, and equivalent constitutive laws are extensively verified against three available tests reported in the literature on both global level (e.g., load-displacement curves) and strain level. The experimental verification proves the accuracy of the proposed theory and formulations in simulating the performance of SCFT members under tension with the capability to accurately predict the tensile strength and stiffness enhancements and realistically simulate the fractal cracking phenomenon.

关键词： square concrete filled tubes confine-stiffening confine-strengthening fractal cracking fracture

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Elongation distribution between tension leveler and temper mill for pickling line 2030 in Baosteel

LIU Xiancui, SU Lanhai, LI Zhongfu, ZHANG Qingdong, FU Zhilin, HE Chun

《机械工程前沿（英文）》 2007年第2卷第3期页码 297-300 doi: 10.1007/s11465-007-0052-4

摘要： Research into plate elongation distribution between the tension leveler and temper mill for pickling line 2030 at Baosteel is conducted. The study, which involved performance testing of mechanics, is designed at different elongation distributions and analyzed from many aspects. Finally, the optimal elongation of the tension leveler and temper mill is given.

关键词： elongation distribution Baosteel Research different elongation performance

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连轧张力公式的实验验证和分析

张进之,赵厚信,王喆,王保罗

《中国工程科学》 2008年第10卷第4期页码 73-77

摘要：

连轧张力公式是连轧理论和实践的核心问题，该问题国内外都有大量的研究，20世纪60年代笔者推导了连轧张力微分方程、多机架动态张力公式、稳态张力公式，理论上已作过深入、广泛的分析讨论。日本在20世纪70年代对连轧张力公式进行了理论上的推导和实验验证，特别是浅川基男等人的连轧实验结果更为重要。为此引用了浅川基男的实验数据和宝钢2 050 mm热连轧机上的实测数据，验证了连轧张力公式。

关键词：连轧张力公式实验验证解析解定常性