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Fabrication of micro/nano-structures by electrohydrodynamic jet technique

Dazhi WANG, Xiaojun ZHAO, Yigao LIN, Tongqun REN, Junsheng LIANG, Chong LIU, Liding WANG

《机械工程前沿(英文)》 2017年 第12卷 第4期   页码 477-489 doi: 10.1007/s11465-017-0461-y

摘要:

Electrohydrodynamic jet (E-Jet) is an approach to the fabrication of micro/nano-structures by the use of electrical forces. In this process, the liquid is subjected to electrical and mechanical forces to form a liquid jet, which is further disintegrated into droplets. The major advantage of the E-Jet technique is that the sizes of the jet formed can be at the nanoscale far smaller than the nozzle size, which can realize high printing resolution with less risk of nozzle blockage. The E-Jet technique, which mainly includes E-Jet deposition and E-Jet printing, has a wide range of applications in the fabrication of micro/nano-structures for micro/nano-electromechanical system devices. This technique is also considered a micro/nano-fabrication method with a great potential for commercial use. This study mainly reviews the E-Jet deposition/printing fundamentals, fabrication process, and applications.

关键词: electrohydrodynamic jet deposition     electrohydrodynamic jet printing     micro/nano-structures     film    

Stability of an annular viscous liquid jet in compressible gases with different properties inside andoutside of the jet

Chunji YAN, Maozhao XIE,

《能源前沿(英文)》 2010年 第4卷 第2期   页码 198-204 doi: 10.1007/s11708-009-0054-5

摘要: A spatial linear instability analysis is conducted on an annular viscous liquid jet injected into compressible gases and a three-dimensional model of the jet is developed. The model takes into account differences between the velocities, densities of the gases inside and outside of the liquid jet. Theoretical analysis reveals that there exist 9 dimensionless parameters controlling the instability of the liquid jet. Numerical computations reveal some basic characteristics in the breakup and atomization process of the liquid jet as well as influences of these relevant parameters. Major observations and findings of this study are as follows. The Mach number plays a destabilizing role and the inner Mach number has a greater effect on the jet instability than the outer Mach number. The Reynolds number always tends to promote the instabilities of the liquid jet, but its influence is very limited. The Weber number and the gas-to-liquid density ratio also have unstable effects and can improve the atomization of liquid jets. Furthermore, the effects of the Weber number and gas-to-liquid density ratio on the maximum growth rates of axisymmetric and non-axisymmetric disturbances and corresponding dominant wave numbers are manifested in a linear way, while that of the Mach number is non-linear. The effect of Reynolds on the maximum growth rates is non-linear, but the dominant wavenumber is almost not affected by the Reynolds number.

关键词: liquid jet     dominant wave number     compressibility     instability    

Combustion and emissions of RP-3 jet fuel and diesel fuel in a single-cylinder diesel engine

《能源前沿(英文)》 2023年 第17卷 第5期   页码 664-677 doi: 10.1007/s11708-021-0787-3

摘要: The combustion characteristics and emission behaviors of RP-3 jet fuel were studied and compared to commercial diesel fuel in a single-cylinder compression ignition (CI) engine. Engine operational parameters, including engine load (0.6, 0.7, and 0.8 MPa indicating the mean effective pressure (IMEP)), the exhaust gas recirculation (EGR) rate (0%, 10%, 20%, and 30%), and the fuel injection timing (−20, −15, −10, and −5 ° crank angle (CA) after top dead center (ATDC)) were adjusted to evaluate the engine performances of RP-3 jet fuel under changed operation conditions. In comparison to diesel fuel, RP-3 jet fuel shows a retarded heat release and lagged combustion phase, which is more obvious under heavy EGR rate conditions. In addition, the higher premixed combustion fraction of RP-3 jet fuel leads to a higher first-stage heat release peak than diesel fuel under all testing conditions. As a result, RP-3 jet fuel features a longer ignition delay (ID) time, a shorter combustion duration (CD), and an earlier CA50 than diesel fuel. The experimental results manifest that RP-3 jet fuel has a slightly lower indicated thermal efficiency (ITE) compared to diesel fuel, but the ITE difference becomes less noticeable under large EGR rate conditions. Compared with diesel fuel, the nitrogen oxides (NOx) emissions of RP-3 jet fuel are higher while its soot emissions are lower. The NOx emissions of RP-3 can be effectively reduced with the increased EGR rate and delayed injection timing.

关键词: RP-3 jet fuel     diesel     engine     combustion     emissions    

Effects of rotor and stator geometry on dissolution process and power consumption in jet-flow high shear

Lin Yang, Wenpeng Li, Junheng Guo, Wei Li, Baoguo Wang, Minqing Zhang, Jinli Zhang

《化学科学与工程前沿(英文)》 2021年 第15卷 第2期   页码 384-398 doi: 10.1007/s11705-020-1928-7

摘要: The jet-flow high shear mixer (JF-HSM) is a new type of intensified equipment with special configurations of the rotor and the stator. The mass transfer property and power consumption were studied in the solid-liquid system for a series of JF-HSMs involving different configuration parameters, such as rotor diameter, rotor blade inclination, rotor blade bending direction, stator diameter, and stator bottom opening diameter. The flow characteristics were examined by computational fluid dynamic simulations. Results indicate that the turbulent power consumption of the JF-HSM is affected by the change in rotor blade inclination and stator bottom opening. With the increase in the shear head size and the change in the rotor into a backward-curved blade, the solid-liquid mass transfer rate can be remarkably increased under the same input power. Dimensionless correlations for the mass transfer coefficient and power consumption were obtained to guide the scale-up design and selection of such a new type of equipment to intensify the overall mixing efficiency.

关键词: jet-flow high shear mixer     solid particle dissolution     power consumption characteristics     CFD Simulation    

A potentiometric cobalt-based phosphate sensor based on screen-printing technology

Lei ZHU,Xiaohong ZHOU,Hanchang SHI

《环境科学与工程前沿(英文)》 2014年 第8卷 第6期   页码 945-951 doi: 10.1007/s11783-013-0615-z

摘要: A potentiometric cobalt-based screen-printing sensor was fabricated by electroplating cobalt on the surface of a screen-printing electrode as the sensitive layer for the determination of dihydrogenphosphate ( ) in wastewater samples. The electrochemical performance of this sensor was fully examined to determine its detection calibration, detection limit, response time, selectivity, and interference with pH, various ions, and dissolved oxygen (DO). The cobalt-based phosphate sensor showed a phosphate-selective potential response in the range of 10 mol·L to 10 mol·L , yielding a detection limit of 3.16 × 10 mol?L and a slope of -37.51 mV?decade in an acidic solution (pH 4.0) of . DO and pH were found to interfere with sensor responses to phosphate. Ultimately, the performance of the sensor was validated for detecting wastewater samples from the Xiaojiahe Wastewater Treatment Plant against the standard spectrophotometric methods for analysis. The discrepancy between the two methods was generally ±5% (relative standard deviation). Aside from its high selectivity, sensitivity, and stability, which are comparable with conventional bulk Co-wire sensors, the proposed phosphate sensor presents many other advantages, such as low price, compactness, ease of use, and the possibility of integration with other analytical devices, such as flow injectors.

关键词: phosphate     cobalt     screen-printing technology     electroplate     wastewater    

Convective mass transfer from a horizontal rotating cylinder in a slot air jet flow

Hongting MA , Dandan MA , Na YANG ,

《能源前沿(英文)》 2009年 第3卷 第3期   页码 289-296 doi: 10.1007/s11708-009-0019-8

摘要: The effects of air jet impinging on the mass transfer characteristics from a rotating spinning cylinder surface were experimentally investigated. The effects of rotational Reynolds number

关键词: air jet impinging     rotating cylinder     critical point     mass transfer characteristics    

Simulation of steel beam under ceiling jet based on a wind–fire–structure coupling model

《结构与土木工程前沿(英文)》 2023年 第17卷 第1期   页码 78-98 doi: 10.1007/s11709-022-0936-8

摘要: For localized fires, it is necessary to consider the thermal and mechanical responses of building elements subject to uneven heating under the influence of wind. In this paper, the thermomechanical phenomena experienced by a ceiling jet and I-beam in a structural fire were simulated. Instead of applying the concept of adiabatic surface temperature (AST) to achieve fluid–structure coupling, this paper proposes a new computational fluid dynamics–finite element method numerical simulation that combines wind, fire, thermal, and structural analyses. First, to analyze the velocity and temperature distributions, the results of the numerical model and experiment were compared in windless conditions, showing good agreement. Vortices were found in the local area formed by the upper and lower flanges of the I-beam and the web, generating a local high-temperature zone and enhancing the heat transfer of convection. In an incoming-flow scenario, the flame was blown askew significantly; the wall temperature was bimodally distributed in the axial direction. The first temperature peak was mainly caused by radiative heat transfer, while the second resulted from convective heat transfer. In terms of mechanical response, the yield strength degradation in the highest-temperature region in windless conditions was found to be significant, thus explaining the stress distribution of steel beams in the fire field. The mechanical response of the overall elements considering the incoming flows was essentially elastic.

关键词: CFD–FEM coupling     steel beam     wind     ceiling jet     numerical heat transfer    

forces on rheological properties, and resulting extrudability and constructability of three-dimensional printing

《结构与土木工程前沿(英文)》   页码 1295-1309 doi: 10.1007/s11709-023-0999-1

摘要: Extrudability and constructability are two important, yet contradictory issues pertaining to the construction of three-dimensional (3D) printing concrete. Extrudability is easily achieved when 3D printing cement mortar has a high water content and low cohesion, but the printed structure is easily collapsible. However, a 3D printing cement mortar with a low water content and high cohesion has a relatively stable printed structure although the cement mortar might not be extrudable. This study proposes a particle-based method to simulate 3D printing mortar extrusion and construction as an overall planning tool for building design. First, a discrete element model with time-varying liquid bridge forces is developed to investigate the microscopic effects of these forces on global rheological properties. Next, a series of numerical simulations relevant to 3D printable mortar extrudability and constructability are carried out. The study demonstrates that the effects of time-varying liquid bridge forces on rheological properties and the resulting extrudability and constructability of 3D printing mortar are considerable. Furthermore, an optimized region that satisfies both the extrusion and construction requirements is provided for 3D printing industry as a reference.

关键词: particle-based simulation     liquid bridge force     rheological property     3D printing mortar     extrudability     constructability    

Research and application of visual location technology for solder paste printing based on machine vision

Luosi WEI, Zongxia JIAO

《机械工程前沿(英文)》 2009年 第4卷 第2期   页码 184-191 doi: 10.1007/s11465-009-0034-9

摘要: A location system is very important for solder paste printing in the process of surface mount technology (SMT). Using machine vision technology to complete the location mission is new and very efficient. This paper presents an integrated visual location system for solder paste printing based on machine vision. The working principle of solder paste printing is introduced and then the design and implementation of the visual location system are described. In the system, two key techniques are completed by secondary development based on VisionPro. One is accurate image location solved by the pattern-based location algorithms of PatMax. The other one is camera calibration that is achieved by image warping technology through the checkerboard plate. Moreover, the system can provide good performances such as high image locating accuracy with 1/40 sub-pixels, high anti-jamming, and high-speed location of objects whose appearance is rotated, scaled, and/or stretched.

关键词: machine vision     visual location     solder paste printing     VisionPro    

RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 2161-2161 doi: 10.1007/s11705-009-0143-3

摘要: RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

关键词: tee junction     Momentum exchange coefficient     RETRACTED    

An experimental study on spray auto-ignition of RP-3 jet fuel and its surrogates

Yaozong DUAN, Wang LIU, Zhen HUANG, Dong HAN

《能源前沿(英文)》 2021年 第15卷 第2期   页码 396-404 doi: 10.1007/s11708-020-0715-y

摘要: Jet fuel is widely used in air transportation, and sometimes for special vehicles in ground transportation. In the latter case, fuel spray auto-ignition behavior is an important index for engine operation reliability. Surrogate fuel is usually used for fundamental combustion study due to the complex composition of practical fuels. As for jet fuels, two-component or three-component surrogate is usually selected to emulate practical fuels. The spray auto-ignition characteristics of RP-3 jet fuel and its three surrogates, the 70% mol -decane/30% mol 1,2,4-trimethylbenzene blend (Surrogate 1), the 51% mol -decane/49% mol 1, 2, 4-trimethylbenzene blend (Surrogate 2), and the 49.8% mol -dodecane/21.6% mol -cetane/28.6% mol toluene blend (Surrogate 3) were studied in a heated constant volume combustion chamber. Surrogate 1 and Surrogate 2 possess the same components, but their blending percentages are different, as the two surrogates were designed to capture the H/C ratio (Surrogate 1) and DCN (Surrogate 2) of RP-3 jet fuel, respectively. Surrogate 3 could emulate more physiochemical properties of RP-3 jet fuel, including molecular weight, H/C ratio and DCN. Experimental results indicate that Surrogate 1 overestimates the auto-ignition propensity of RP-3 jet fuel, whereas Surrogates 2 and 3 show quite similar auto-ignition propensity with RP-3 jet fuel. Therefore, to capture the spray auto-ignition behaviors, DCN is the most important parameter to match when designing the surrogate formulation. However, as the ambient temperature changes, the surrogates matching DCN may still show some differences from the RP-3 jet fuel, e.g., the first-stage heat release influenced by low-temperature chemistry.

关键词: RP-3 jet fuel     surrogate     spray auto-ignition     constant volume combustion chamber    

Liquid metal printing opening the way for energy conservation in semiconductor manufacturing industry

《能源前沿(英文)》 2022年 第16卷 第4期   页码 542-547 doi: 10.1007/s11708-022-0834-8

Formation of coke in thermal cracking of jet fuel under supercritical conditions

ZHU Yuhong, YU Caixiang, LI Zimu, MI Zhentao, ZHANG Xiangwen

《化学科学与工程前沿(英文)》 2008年 第2卷 第1期   页码 17-21 doi: 10.1007/s11705-008-0024-1

摘要: Continuous-flow reactor experiments were carried out to study coke formation from thermal cracking of home-made jet fuel RP-3 under supercritical conditions. The mechanism and precursor of coke forming were analyzed. The starting cracking temperature of RP-3 fuel was determined to be 471.8°C by differential scanning calorimetry (DSC). Temperature-programmed oxidation and scanning electron microscopy (SEM) characterizations of the stressed tubes showed that there are three different coke species including chemisorbed carbon, amorphous carbon and filamentous coke in the solid deposits. More than 90% of coke deposits are carried away by the supercritical fluid, which has strong capabilities of extraction for coke deposits and their precursors. There were 17.1 wt-% of iron and 11.1 wt-% of chromium found on the coke surface detected by energy dispersive spectroscopy (EDS) which suggests carburetion on alloy. RP-3 fuel and its cracking liquids were analyzed by GC-MS,which showed that the content of alkyl benzene and alkyl naphthalene increased evidently in cracking liquids.

关键词: dispersive spectroscopy     different     extraction     calorimetry     filamentous    

水射流技术在石油工程中的应用及前景展望

沈忠厚,李根生,王瑞和

《中国工程科学》 2002年 第4卷 第12期   页码 60-65

摘要:

论述了水射流技术在我国石油工程中的研究和应用情况。应用实验方法建立了淹没非自由射流压力及水功率衰减计算模型,建立了以井底获得最大水功率,优选水力参数设计的新方法和新模型。应用瞬态流理论及水声学原理建立了两种谐振腔的基本关系式和结构数学模型。建立了在钻井双向应力作用下,岩石裂纹发展方向模型。介绍了研制的3种新型高效钻头,即加长喷嘴牙轮钻头、自振射流钻头和射流及机械联合破岩钻头。展望了水射流技术在超高压射流钻井、稠油及低渗油藏开采、提高采收率等方面的应用前景。

关键词: 水射流技术     石油钻井     油气开采     高压和超高压射流    

陶瓷喷墨打印增材制造技术 Review

Brian Derby

《工程(英文)》 2015年 第1卷 第1期   页码 113-123 doi: 10.15302/J-ENG-2015014

摘要:

陶瓷喷墨打印是一种基于微滴累加的成形技术,典型的微滴体积为10~100 pL。实现微滴累加成形的关键是开发稳定的陶瓷墨水,合适的墨水需要满足由雷诺数和韦伯数定义的流变特性参数空间。在微滴累加成形过程中,微滴首先与成形面碰撞变形并消耗动能,然后在毛细管力作用下铺展并达到平衡状态。已经可以确定的是打印过程中微滴相互作用并形成一维线性特征的机理,但是对二维和三维结构成形机理的认识还处于较低水平,成形二维面的稳定性低于成形一维线性结构。多数情况下,墨水通过蒸发固化,微滴碰撞基体所产生的“咖啡环”缺陷需要通过固化工艺加以控制。已经有大量文献报道了使用喷墨打印技术成形各种类型小型陶瓷零件的成功案例。作为一种未来的制造技术,陶瓷喷墨打印技术有广阔的应用前景。本综述的目的是探索陶瓷喷墨打印技术未来潜在的研究领域,加强对这种制造方法的理解。

关键词: 增材制造     3D打印     喷墨打印     陶瓷零件    

标题 作者 时间 类型 操作

Fabrication of micro/nano-structures by electrohydrodynamic jet technique

Dazhi WANG, Xiaojun ZHAO, Yigao LIN, Tongqun REN, Junsheng LIANG, Chong LIU, Liding WANG

期刊论文

Stability of an annular viscous liquid jet in compressible gases with different properties inside andoutside of the jet

Chunji YAN, Maozhao XIE,

期刊论文

Combustion and emissions of RP-3 jet fuel and diesel fuel in a single-cylinder diesel engine

期刊论文

Effects of rotor and stator geometry on dissolution process and power consumption in jet-flow high shear

Lin Yang, Wenpeng Li, Junheng Guo, Wei Li, Baoguo Wang, Minqing Zhang, Jinli Zhang

期刊论文

A potentiometric cobalt-based phosphate sensor based on screen-printing technology

Lei ZHU,Xiaohong ZHOU,Hanchang SHI

期刊论文

Convective mass transfer from a horizontal rotating cylinder in a slot air jet flow

Hongting MA , Dandan MA , Na YANG ,

期刊论文

Simulation of steel beam under ceiling jet based on a wind–fire–structure coupling model

期刊论文

forces on rheological properties, and resulting extrudability and constructability of three-dimensional printing

期刊论文

Research and application of visual location technology for solder paste printing based on machine vision

Luosi WEI, Zongxia JIAO

期刊论文

RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

期刊论文

An experimental study on spray auto-ignition of RP-3 jet fuel and its surrogates

Yaozong DUAN, Wang LIU, Zhen HUANG, Dong HAN

期刊论文

Liquid metal printing opening the way for energy conservation in semiconductor manufacturing industry

期刊论文

Formation of coke in thermal cracking of jet fuel under supercritical conditions

ZHU Yuhong, YU Caixiang, LI Zimu, MI Zhentao, ZHANG Xiangwen

期刊论文

水射流技术在石油工程中的应用及前景展望

沈忠厚,李根生,王瑞和

期刊论文

陶瓷喷墨打印增材制造技术

Brian Derby

期刊论文