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Facile route to achieve MoSe-NiSe on nickel foam as efficient dual functional electrocatalysts for overall water splitting

《能源前沿（英文）》 2022年 第16卷 第3期   页码 483-491 doi: 10.1007/s11708-022-0813-0

摘要： Since the catalytic activity of present nickel-based synthetic selenide is still to be improved, MoSe2-Ni3Se2 was synthesized on nickel foam (NF) (MoSe2-Ni3Se2/NF) by introducing a molybdenum source. After the molybdenum source was introduced, the surface of the catalyst changed from a single-phase structure to a multi-phase structure. The catalyst surface with enriched active sites and the synergistic effect of MoSe2 and Ni3Se2 together enhance the hydrogen evolution reactions (HER), the oxygen evolution reactions (OER), and electrocatalytic total water splitting activity of the catalyst. The overpotential of the MoSe2-Ni3Se2/NF electrocatalyst is only 259 mV and 395 mV at a current density of 100 mA/cm2 for HER and OER, respectively. MoSe2-Ni3Se2/NF with a two-electrode system attains a current density of 10 mA/cm2 at 1.60 V. In addition, the overpotential of HER and OER of MoSe2-Ni3Se2/NF within 80000 s and the decomposition voltage of electrocatalytic total water decomposition hardly changed, showing an extremely strong stability. The improvement of MoSe2-Ni3Se2/NF catalytic activity is attributed to the establishment of the multi-phase structure and the optimized inoculation of the multi-component and multi-interface.

关键词： three-dimensional molybdenum nanomaterials     hydrogen evolution reaction     oxygen evolution reaction     overall water splitting    

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Experimental and numerical evaluation of multi-directional compressive and flexure behavior of three-dimensional

《结构与土木工程前沿（英文）》 2023年 第17卷 第11期   页码 1643-1661 doi: 10.1007/s11709-023-0004-z

摘要： Three-dimensional concrete printing (3DCP) can proliferate the industrialization of the construction sector, which is notoriously conservative and indolent toward changes. However, the mechanical behavior of 3DCP should be characterized and modeled considering the interfaces when its performance is thoroughly compared to that of the existing concrete construction methods. This study presents an experimental and numerical investigation of uniaxial compression and three-point bending (TPB) tests on extruded 3DCP beams in different loading directions. The orientation of translational and depositional interfaces with respect to the direction of loading influenced the strength. Both the elastic and post-damage behavior of the 3DCP specimens were compared with those of the conventionally cast specimen under quasi-static loading conditions. Despite the higher compressive strength of the casted specimen, the flexural strength of the 3DCP specimens was higher. This study employed the finite element and cohesive zone models of the appropriate calibrated traction-separation law to model fracture in the notched TPB specimens. Furthermore, the real-time acoustic emission test revealed the nature of failure phenomenon of three-dimensional-printed specimens under flexion, and accordingly, the cohesive law was chosen. The predicted load−displacement responses are in good agreement with the experimental results. Finally, the effects of cohesive thickness and notch shape on the performance under bending were explored through parametric studies.

关键词： three-dimensional printing     anisotropy     flexure     compression     cohesive zone model     finite element model    

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Inner strain determination of three-dimensional braided preforms with co-braided optical fiber sensors

LI Xianghua, LIU Xiaohui, YUAN Shenfang

《机械工程前沿（英文）》 2008年 第3卷 第4期   页码 416-420 doi: 10.1007/s11465-008-0062-x

摘要： The experimental characterization of three-dimensional (3-D) braided composites is extremely important for their design and analysis. Because of their desirable attributes and outstanding performance, optical fiber sensors (OFSs) can be embedded to monitor mechanical properties of textile composites. This paper discusses two techniques to incorporate different OFSs into 3-D braided composite preforms. The operating principle of various sensor systems is first conducted. Experiments using Michelson interferometers, FBG sensors, and micro-bend sensors are performed to verify the concept of the proposed method. Strain curves of various OFSs tests are finally compared, and they all exhibit good linearity.

关键词： different     experimental characterization     three-dimensional     composite     micro-bend    

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Numerical simulation of three-dimensional turbulent flow in multistage axial compressor blade row

JIANG Jian, LIU Bo, WANG Yangang, NAN Xiangyi

《能源前沿（英文）》 2008年 第2卷 第3期   页码 320-325 doi: 10.1007/s11708-008-0041-2

摘要： Numerical simulation of three-dimensional turbulent flow in a multistage axial compressor blade row is conducted. A high resolution, third-order ENN scheme is adopted to catch the shockwave and simulate the turbulent flow correctly,

关键词： simulation     compressor     multistage     third-order     three-dimensional turbulent    

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Mechanical behavior and permeability properties of sustainable and high-performance anisotropic three-dimensional

《结构与土木工程前沿（英文）》 2023年 第17卷 第11期   页码 1662-1674 doi: 10.1007/s11709-023-0962-1

摘要： Three-dimensional printable concrete requires further development owing to the challenges encountered, including its brittle behavior, high cement requirement for the buildability of layers, and anisotropic behavior in different directions. The aim of this study is to overcome these challenges. First, three-dimensional printable concrete mixtures were prepared using silica fume, ground blast furnace slag, and metakaolin, instead of cement, to reduce the amount of cement. Subsequently, the rheological and mechanical behaviors of these concretes were investigated. Second, three-dimensional printable concrete mixtures were prepared using 6-mm-long steel and synthetic fibers to eliminate brittleness and determine the effect of those fibers on the anisotropic behavior of the concrete. As a result of this study, it is understood that printable concretes with extremely low permeability and high buildability can be achieved using mineral additives. In addition, results showed that three-dimensional concrete samples containing short steel fibers achieve fracture energies up to 36 times greater than that of plain concrete. Meanwhile, its characteristic length values, as indicators of ductility, are 22 times higher than those of plain concrete. The weakest strength was recorded at the interfaces between layers. The bending and splitting tensile strengths of three-dimensional printed plain concrete samples were 15% and 19% lower than those of casted samples, respectively. However, the addition of fibers improved the mechanical strength of the interfaces significantly.

关键词： three-dimensional concrete printing     rheology     high performance     mineral additives     anisotropy     fiber    

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Influence of curing conditions on the shrinkage behavior of three-dimensional printed concrete formwork

《结构与土木工程前沿（英文）》 2024年 第18卷 第8期   页码 1225-1236 doi: 10.1007/s11709-024-1097-8

摘要： The use of three-dimensional (3D) printed concrete as formwork is becoming more widely applied within the industry. However, the technology is still not optimized and there are many reports of preliminary cracking during the curing of cast concrete. This is believed to result from differential shrinkage between the printed and cast concrete. These cracks (in the printed concrete or at the interface between the infill and printed concrete) form a preferential path for aggressive substances and can reduce the durability of the combined concrete element. To ensure the desired service life of the structure, it is important that the differential shrinkage between cast and printed concrete is understood. This study investigated the effect of curing conditions on the differential shrinkage behavior of 3D and cast concrete. The influence of prewetting of the dry-cured 3D printed formwork was also determined. In the experimental program, a vibrated and self-compacting concrete were used as cast material. Linear 3D printed formwork was produced and combined with cast concrete to simulate a concrete structure. Printed formwork was cured for 1, 7, or 28 d exposed to the air (relative humidity: 60% or 95%) or submerged in water. The length change of the combined elements was observed over 56 d after concrete casting and throughout the thickness of the materials. Results show that increasing the curing period in dry conditions of the printed concrete leads to an expansion of the formwork on the first day after casting. The expansion leads to a non-uniform strain evolution throughout the curing period of the combined element. Printed concrete formwork stored in wet conditions does not expand after the casting process but tends to show a decreasing linear deformation within the whole elements.

关键词： 3D concrete printing     formwork     shrinkage     curing    

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Application of three-dimensional digitalized reconstruction of latissimus dorsi myocutaneous flap

PEI Guoxian, ZHANG Yuanzhi, LI Jianwei, JIN Dan, CHEN Jionghao, LI Yanbing, ZHONG Shizhen

《医学前沿（英文）》 2008年 第2卷 第1期   页码 45-50 doi: 10.1007/s11684-008-0009-y

摘要： Developments of digital technology and three-dimensional (3D) reconstruction allowed a precise description of anatomic structures. With the introduction of Visible Human Project and Virtual Chinese Human (VCH) techniques, more detailed anatomic images could be obtained. Digitized visible models of these structures can be applied as a useful tool in clinical training. The aim of this study was to reconstruct the normal structures of thoracodorsal artery in 3D images and to establish the digitized visible models of latissimus dorsi myocutaneous (LDM) flap. The cross-sectional images from the four VCH datasets were reviewed to study LDM and thoracodorsal artery structures on a section-by-section basis. Next, two adult fresh cadaver specimens were perfused with lead oxide-gelatine mixture and subject to radiographic CT scanning on their torsos. The cross-sectional images from the CT images were reviewed to study thoracodorsal artery structures. Three-dimensional computerized reconstructions of LDM flap structures were conducted from these datasets by using Amira 3.1 (TGS) software respectively. The 3D reconstructed visible models established from these datasets perfectly displayed the anatomic characteristics of LDM flap.

关键词： Digitized     digitized     software     three-dimensional     latissimus    

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Development of rocking constraint device with vertical damping capacity for three-dimensional base-isolated

《结构与土木工程前沿（英文）》 2023年 第17卷 第3期   页码 350-367 doi: 10.1007/s11709-022-0923-0

摘要： A new rocking constraint device (RCD) is developed for three-dimensional (3D) base-isolated frame structures by connecting a custom-designed cylinder pair to provide vertical damping with replaceable damping components installed outside the cylinders when the superstructure undergoes translational motion, and rocking constraint capacity when the superstructure is susceptible to rocking. Theoretical formulas for calculating the damping and rocking constraint stiffness of the RCD are proposed. Two series of sinusoidal loading tests are conducted at different loading frequencies and amplitudes to verify the damping and rocking constraint performance of the RCD. The test results show that the cylinder without orifices on its piston can provide the desired damping with a replaceable damping component, and that the RCD can effectively suppress rocking. Although the vertical stiffness of an individual cylinder is affected by the location of the replaceable damping component and loading frequency, the average vertical stiffness of the two cylinders, which determines the rocking constraint stiffness of the RCD, is independent of the two factors. Comparisons of the test and theoretical results indicate that the errors of the proposed formulas for calculating the damping and rocking constraint stiffness of the RCD do not exceed 12.9% and 11.0%, respectively.

关键词： three-dimensional isolation     rocking behavior     rocking constraint device     replaceable damping component     sinusoidal test    

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Three-dimensional numerical simulation of the basic pulse tube refrigerator

DING Wenjing, GONG Liang, HE Yaling, TAO Wenquan

《能源前沿（英文）》 2008年 第2卷 第1期   页码 48-53 doi: 10.1007/s11708-008-0008-3

摘要： A three-dimensional physical and numerical model of the basic pulse tube refrigerator (PTR) was developed. The compressible and oscillating fluid flow and heat transfer phenomenon in the pulse tube were numerically investigated using a self-developed code. Some cross-section average parameter variations such as velocity, temperature and pressure wave during one cycle were revealed. The variations of velocity and temperature distributions in the pulse tube were also analyzed in detail for further understanding of the working process and refrigeration mechanism of PTRs.

关键词： refrigeration mechanism     three-dimensional     compressible     numerical     understanding    

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Stability of three-dimensional printable foam concrete as function of surfactant characteristics

《结构与土木工程前沿（英文）》 2023年 第17卷 第6期   页码 935-947 doi: 10.1007/s11709-023-0964-z

摘要： Extrudability is one of the most critical factors when designing three-dimensional printable foam concrete. The extrusion process likely affects the foam stability which necessitates the investigation into surfactant properties particularly for concrete mixes with high foam contents. Although many studies have been conducted on traditional foam concrete in this context, studies on three-dimensional printed foam concrete are scarce. To address this research gap, the effects of surfactant characteristics on the stability, extrudability, and buildability of three-dimensional printed foam concrete mixes with two design densities (1000 and 1300 kg/m3) using two different surfactants and stabilizers (synthetic-based sodium lauryl sulfate stabilized with carboxymethyl cellulose sodium salt, and natural-based hingot surfactant stabilized with xanthan gum) were investigated in this study. Fresh density tests were conducted before and after the extrusion to determine stability of the foam concrete. The results were then correlated with surfactant qualities, such as viscosity and surface tension, to understand the importance of key parameters in three-dimensional printing of foam concrete. Based on the experimental results, surfactant solu1tion with viscosity exceeding 5 mPa·s and surface tension lower than 31 mN/m was recommended to yield stable three-dimensional printable foam concrete mixes. Nevertheless, the volume of foam in the mix significantly affected the printability characteristics. Unlike traditional foam concrete, the variation in the stabilizer concentration and density of concrete were found to have insignificant effect on the fresh-state-characteristics (slump, slump flow, and static yield stress) and air void microstructure of the stable mixes.

关键词： foam concrete     3D printable concrete     stability     rheology     air void microstructure    

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Improving the structural efficiency of textured three-dimensional concrete printing wall by architectural

《结构与土木工程前沿（英文）》 2024年 第18卷 第5期   页码 699-715 doi: 10.1007/s11709-024-1001-6

摘要： Three-dimensional concrete printing (3DCP) technology begins to be adopted into construction application worldwide. Recent studies have focused on producing a higher concrete quality and offering a user-friendly construction process. Still, the 3DCP construction cost is unlikely to be lower than that of conventional construction, which is especially important for projects where the cost is sensitive. To broaden the 3DCP construction applications, reduction of the quantity of 3DCP material usage is needed. This work aims to perform structural analysis of several patterns of geometric textured 3DCP shell wall structures. 21 different cantilevered textured patterns of 3DCP shell wall structures were architecturally designed and then subjected to structural analysis by a finite element method (FEM). The results indicated that by designing appropriate patterns, the structural performance to weight ratio could be improved up to 300%. The study therefore offers an innovative design process for constructing 3DCP housing and suggests pre-construction analysis methods for 3DCP shell wall structures.

关键词： 3D printing     concrete     architectural design     shell wall     finite element method    

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Normal Chinese Adults (EMINCA) II focusing on left ventricular and left atrial size and function by three-dimensional

《医学前沿（英文）》 2024年 第18卷 第4期   页码 649-663 doi: 10.1007/s11684-023-1045-3

摘要： Current guidelines encourage large studies in a diverse population to establish normal reference ranges for three-dimensional (3D) echocardiography for different ethnic groups. This study was designed to establish the normal values of 3D-left ventricular (LV) and left atrial (LA) volume and function in a nationwide, population-based cohort of healthy Han Chinese adults. A total of 1117 healthy volunteers aged 18–89 years were enrolled from 28 collaborating laboratories in China. Two sets of 3D echocardiographic instruments were used, and full-volume echocardiographic images were recorded and transmitted to a core laboratory for image analysis with a vendor-independent off-line workstation. Finally, 866 volunteers (mean age of 48.4 years, 402 men) were qualified for final analysis. Most parameters exhibited substantial differences between different sex and age groups, even after indexation by body surface area. The normal ranges of 3D-LV and 3D-LA volume and function differed from those recommended by the American Society of Echocardiography and the European Association of Cardiovascular Imaging guidelines, presented by the World Alliance Societies of Echocardiography (WASE) study, and from the 2D values in the EMINCA study. The normal reference values of 3D echocardiography-derived LV and LA volume and function were established for the first time in healthy Han Chinese adults. Normal ranges of 3D-LV and 3D-LA echocardiographic measurements stratified with sex, age, and race should be recommended for clinical applications.

关键词： three-dimensional echocardiography     left ventricle     left atrium     normal reference values     Chinese adults    

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A three-dimensional two-level gradient smoothing meshfree method for rainfall induced landslide simulations

Dongdong WANG, Jiarui WANG, Junchao WU, Junjun DENG, Ming SUN

《结构与土木工程前沿（英文）》 2019年 第13卷 第2期   页码 337-352 doi: 10.1007/s11709-018-0467-5

摘要： A three-dimensional two-level gradient smoothing meshfree method is presented for rainfall induced landslide simulations. The two-level gradient smoothing for meshfree shape function is elaborated in the three-dimensional Lagrangian setting with detailed implementation procedure. It is shown that due to the successive gradient smoothing operation without the requirement of derivative computation in the present formulation, the two-level smoothed gradient of meshfree shape function is capable of achieving a given influence domain more efficiently than the standard gradient of meshfree shape function. Subsequently, the two-level smoothed gradient of meshfree shape function is employed to discretize the weak form of coupled rainfall seepage and soil motion equations in a nodal integration format, as provides an efficient three-dimensional regularized meshfree formulation for large deformation rainfall induced landslide simulations. The exponential damage and pressure dependent plasticity relationships are utilized to describe the failure evolution in landslides. The plastic response of soil is characterized by the true effective stress measure, which is updated according to the rotationally neutralized objective integration algorithm. The effectiveness of the present three-dimensional two-level gradient smoothing meshfree method is demonstrated through numerical examples.

关键词： meshfree method     landslide     rainfall     three-dimensional two-level gradient smoothing     nodal integration    

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Three-dimensional stability analysis of the dam foundation at Baise

XU Qianjun, LI Xu, CHEN Zuyu

《结构与土木工程前沿（英文）》 2007年 第1卷 第2期   页码 217-221 doi: 10.1007/s11709-007-0026-y

摘要： It is usually difficult to determine the actual safety factors of rock masses in an ordinary two-dimensional stability analysis if the safety factors of the different cross sections in the rock mass vary significantly. In addition to the actual slope, arch dam abutment, and the actual foundation of a high building, another example is that the different cross sections of the foundation in the monolith of a gravity dam vary significantly, just like the condition at the overflow dam in the Baise project. A three-dimensional stability analysis method based on the upper-bound theorem was employed to solve this problem. The parameters used in the analysis were obtained from geomechanics tests, as well as continuity simulations of the randomly distributed joints. Two failure patterns against sliding are analyzed. One pattern is the foundation slide along deep-seated planes which were determined by calculations. The other pattern is the foundation slide along the planes across the bottom of the high steps in the foundation pit. The results indicate that a special overflow dam monolith can be considered to be safe in case of considering the three dimensional effect. However, a key wall with a depth of 5m must be constructed at the upper side of this monolith in order to ensure the safety of the foundation.

关键词： ordinary two-dimensional     randomly     monolith     three-dimensional stability     different    

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Thermal analysis of lubricated three-dimensional contact bodies considering interface roughness

《机械工程前沿（英文）》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0672-8

摘要： Surface roughness and thermal action are of remarkable importance in the lubrication performance of mechanical components, especially in extreme conditions. However, available studies mainly focus on the full-film lubrication conditions without considering temperature rise and real 3D surface roughness due to the complexity of surface topography and temperature characteristics. Moreover, studies on the interfacial thermal behaviors of 3D rough surface lubricated contact in an extended range of working conditions remain limited. In this paper, a deterministic mixed thermal elastohydrodynamic lubrication model considering real 3D surface roughness and thermal effects is proposed. In this model, pressure and temperature are coupled with each other, the computation of elastic deformation is accelerated through the discrete convolution and fast Fourier transform method, the temperature field is calculated with the column sweeping technique, and the semi-system method is introduced to improve convergence and numerical stability under severe conditions. The model is validated by comparing its results with available published numerical and experimental results. The thermal behaviors of the contact interface are studied in a wide range of working conditions. The influences of surface roughness and thermal effect on lubrication performance are revealed. The results show that the proposed model can be used as a powerful analysis tool for lubrication performance and temperature prediction in various heavy-load, high-speed lubricated components over a wide range of lubrication conditions.

关键词： thermal elastohydrodynamic lubrication     surface roughness effect     thermal effect     temperature characteristics     severe conditions    

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标题 作者 时间 类型 操作

Facile route to achieve MoSe-NiSe on nickel foam as efficient dual functional electrocatalysts for overall water splitting

期刊论文

Experimental and numerical evaluation of multi-directional compressive and flexure behavior of three-dimensional

期刊论文

Inner strain determination of three-dimensional braided preforms with co-braided optical fiber sensors

LI Xianghua, LIU Xiaohui, YUAN Shenfang

期刊论文

Numerical simulation of three-dimensional turbulent flow in multistage axial compressor blade row

JIANG Jian, LIU Bo, WANG Yangang, NAN Xiangyi

期刊论文

Mechanical behavior and permeability properties of sustainable and high-performance anisotropic three-dimensional

期刊论文

Influence of curing conditions on the shrinkage behavior of three-dimensional printed concrete formwork

期刊论文

Application of three-dimensional digitalized reconstruction of latissimus dorsi myocutaneous flap

PEI Guoxian, ZHANG Yuanzhi, LI Jianwei, JIN Dan, CHEN Jionghao, LI Yanbing, ZHONG Shizhen

期刊论文

Development of rocking constraint device with vertical damping capacity for three-dimensional base-isolated

期刊论文

Three-dimensional numerical simulation of the basic pulse tube refrigerator

DING Wenjing, GONG Liang, HE Yaling, TAO Wenquan

期刊论文

Stability of three-dimensional printable foam concrete as function of surfactant characteristics

期刊论文

Improving the structural efficiency of textured three-dimensional concrete printing wall by architectural

期刊论文

Normal Chinese Adults (EMINCA) II focusing on left ventricular and left atrial size and function by three-dimensional

期刊论文

A three-dimensional two-level gradient smoothing meshfree method for rainfall induced landslide simulations

Dongdong WANG, Jiarui WANG, Junchao WU, Junjun DENG, Ming SUN

期刊论文

Three-dimensional stability analysis of the dam foundation at Baise

XU Qianjun, LI Xu, CHEN Zuyu

期刊论文

Thermal analysis of lubricated three-dimensional contact bodies considering interface roughness

期刊论文