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Experimental study on bubble behavior and CFD simulation of large-scale slurry bubble column reactor

Haoyi SUN, Tao LI, Weiyong YING, Dingye FANG

《化学科学与工程前沿(英文)》 2010年 第4卷 第4期   页码 515-522 doi: 10.1007/s11705-010-0516-7

摘要: Slurry bubble column reactors (SBCR) is a three-phase fluidized reactor with outstanding advantages compared with other reactors and is difficult to scale-up due to lack of information on hydrodynamics and mass transfer over a wide range of operating conditions of commercial interest. In this paper, an experiment was conducted to investigate the bubble behavior in SBCR with a height of 5600 mm and an interior diameter of 480 mm. Bubble rise velocity, bubble diameter, and gas holdup in different radial and axial positions are measured in SBCR using four-channel conductivity probe. Tap water, air, and glass beads (mean diameter 75–150 μm) are used as liquid, gas, and solid phases, respectively. It shows that hydrodynamic parameters have good regularity in SBCR. Moreover, a commercial computational fluid dynamics (CFD) package, Fluent, was used to simulate the process in SBCR. The simulations were carried out using axi-symmetric 2-D grids. Data obtained from experiment and CFD simulation are compared, and results show that the tendency of simulation is almost uniform with the experiment, which can help to obtain further understanding about multiphase flow process and establish a model about the synthesis of alcohol ether fuel in SBCR.

关键词: SBCR     four-channel conductivity probe     hydrodynamics     CFD    

Activated carbon induced oxygen vacancies-engineered nickel ferrite with enhanced conductivity for supercapacitor

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 2088-2100 doi: 10.1007/s11705-023-2352-6

摘要: Activated carbon induced oxygen vacancies-engineered nickel ferrite with enhanced conductivity for supercapacitor application

关键词: nickel ferrite conductivity     carbon oxygen vacancies    

Chemical probe systems for assessing liquid–liquid mixing efficiencies of reactors

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1323-1335 doi: 10.1007/s11705-022-2275-7

摘要: Liquid–liquid mixing, including homogeneous and heterogeneous mixing, widely exists in the chemical industry. How to quantitatively characterize the mixing performance is important for reactor assessment and development. As a convenient and direct method for mixing characterization, the chemical probe method uses some special test reactions to characterize the mixing results. Here, the working principle and selection requirements of this method are introduced, and some common chemical probe systems for homogeneous and heterogeneous mixing processes are reviewed. The characteristics and applications of these systems are illustrated. Finally, the development of the new system is proposed.

关键词: mixing     chemical probe     liquid–liquid     heterogeneous    

Permeability and thermal conductivity of host compressed natural graphite for consolidated activated

Bo TIAN, Liwei WANG, Zhequan JIN, Ruzhu WANG

《能源前沿(英文)》 2011年 第5卷 第2期   页码 159-165 doi: 10.1007/s11708-011-0145-y

摘要: Permeability and thermal conductivity test units were set up to study the heat and mass transfer performance of the host material, i.e. expanded natural graphite (ENG), for consolidated activated carbon (AC) adsorbent. The permeability was tested with nitrogen as the gas source, and the thermal conductivity was studied using steady-state heat source method. The results showed that the values of permeability and thermal conductivity were 10 to 10 m and 1.7 to 3.2 W/(m·K), respectively, while the density compressed expanded natural graphite (CENG) varied from 100 to 500 kg/m . The permeability decreased with the increasing density of CENG, whereas the thermal conductivity increased with the increasing density of CENG. Then the thermal conductivity and permeability of granular AC were researched. It was discovered that the thermal conductivity of samples with different grain size almost kept constant at 0.36 W/(m·K) while the density was approximately 600 kg/m . This means that the thermal conductivity was not related to the grain size of AC. The thermal conductivity of CENG was improved by 5 to 10 times compared with that of granular AC. Such a result showed that CENG was a promising host material for AC to improve the heat transfer performance, while the mass transfer performance should be considered in different conditions for utilization of adsorbent.

关键词: permeability     thermal conductivity     expanded nature graphite     activated carbon    

A highly selective fluorescent probe for real-time imaging of UDP-glucuronosyltransferase 1A8 in living

《化学科学与工程前沿(英文)》 2022年 第16卷 第1期   页码 103-111 doi: 10.1007/s11705-021-2064-8

摘要: Uridine diphosphate (UDP)-glucuronosyltransferases (UGTs) are enzymes involved in the biotransformation of important endogenous compounds such as steroids, bile acids, and hormones as well as exogenous substances including drugs, environmental toxicants, and carcinogens. Here, a novel fluorescent probe BDMP was developed based on boron-dipyrromethene (BODIPY) with high sensitivity for the detection of UGT1A8. The glucuronidation of BDMP not only exhibited a red-emission wavelength (λex/λem = 500/580 nm), but also displayed an excellent UGT1A8-dependent fluorescence signal with a good linear relationship with UGT1A8 concentration. Based on this perfect biocompatibility and cell permeability, BDMP was successfully used to image endogenous UGT1A8 in human cancer cell lines (LoVo and HCT15) in real time. In addition, BDMP could also be used to visualize UGT1A8 in tumor tissues. These results suggested that BDMP is a promising molecular tool for the investigation of UGT1A8-mediated physiological function in humans.

关键词: UDP-glucuronosyltransferase 1A8     fluorescent probe     subtype selectivity     fluorescence imaging    

A dual-function chemical probe for detecting erasers of lysine lipoylation

Yusheng Xie, Jie Zhang, Liu Yang, Qingxin Chen, Quan Hao, Liang Zhang, Hongyan Sun

《化学科学与工程前沿(英文)》 2022年 第16卷 第1期   页码 121-127 doi: 10.1007/s11705-021-2051-0

摘要: Lysine lipoylation plays vital roles in cell metabolism and redox processes. For example, removal of lipoylation will decrease pyruvate dehydrogenase activity and affect the citric acid cycle. Despite the important functions of lysine lipoylation, the mechanisms for the addition and removal of this modification remain largely unexplored. Very few useful chemical tools are available to study the interactions of lysine lipoylation with its regulatory delipoylation proteins. For example, immunoaffinity purification-mass spectrometry is one of such tools, which highly relies on antibody efficiency and purification techniques. Single-step activity based fluorogenic probes developed by our groups and others is also an efficient method to study the deacylation activity. Affinity-based labeling probe using photo-cross-linker is a powerful platform to study the transient and dynamic interactions of peptide ligands with the interacting proteins. Herein, we have designed and synthesized a dual-function probe KTLlip for studying enzymatic delipoylation (eraser) activity and interaction of lysine lipoylation with the eraser at the same time. We show that KTLlip can be used as a useful tool to detect delipoylation as demonstrated by its ability to fluorescently label the eraser activity of recombinant Sirt2. We envision that the probe will help delineate the roles of delipoylation enzyme in biology.

关键词: dual-function     fluorescent probe     labeling     photo-cross-linker     lipoylation modification     eraser     sirtuin    

A novel flavonol-based colorimetric and turn-on fluorescent probe for rapid determination of hydrazine

《化学科学与工程前沿(英文)》 2023年 第17卷 第1期   页码 24-33 doi: 10.1007/s11705-022-2171-1

摘要: Hydrazine is extremely toxic and causes severe harm to human body. Herein, a novel fluorescent probe 4-oxo-2-styryl-4H-chromen-3-yl thiophene-2-carboxylate (FHT) was synthesized for detecting hydrazine by using natural cinnamaldehyde as starting material. This probe exhibited significantly enhanced fluorescence response towards hydrazine over various common metal ions, anions, and amine compounds. The detection limit of probe FHT for hydrazine was as low as 0.14 μmol·L–1, significantly lower than that of the threshold value of 0.312 μmol·L–1, imposed by the Environmental Protection Agency. Moreover, the proposed probe was able to detect hydrazine within wide pH (5–10) and linear detection ranges (0–110 μmol·L–1). This probe was employed for determining trace hydrazine in different environmental water samples. The probe FHT-loaded filter paper strips were able to conveniently detect hydrazine of low concentration through distinct naked-eye and fluorescent color changes. Importantly, the probe FHT with low cytotoxicity was successfully applied to visualize hydrazine in living Hela cells and zebrafish.

关键词: cinnamaldehyde     3-hydroxychromone derivative     hydrazine     fluorescent probe    

Equivalent thermal conductivity of heat pipes

LU Zesheng, MA Binghui

《机械工程前沿(英文)》 2008年 第3卷 第4期   页码 462-466 doi: 10.1007/s11465-008-0087-1

摘要: In precision machining, the machining error from thermal distortion carries a high proportion of the total errors. If a precision machining tool can transfer heat fast, the thermal distortion will be reduced and the machining precision will be improved. A heat pipe working based on phase transitions of the inner working liquid transfers heat with high efficiency and is widely applied in spaceflight and chemical industries. In mechanics, applications of heat pipes are correspondingly less. When a heat pipe is applied to a hydrostatic motorized spindle, the thermal distortion cannot be solved during the heat transfer process because thermal conductivity or equivalent thermal conductivity should be provided first for special application in mechanics. An equivalent thermal conductivity model based on equivalent thermal resistances is established. Performance tests for a screen wick pipe, gravity pipe, and rotation heat pipe are done to validate the efficiency of the equivalent thermal conductivity model. The proposed model provides a calculation method for the thermal distortion analysis of heat pipes applied in the motorized spindle.

关键词: proposed     distortion analysis     hydrostatic motorized     motorized spindle     Performance    

Landing control method of a lightweight four-legged landing and walking robot

《机械工程前沿(英文)》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0707-1

摘要: The prober with an immovable lander and a movable rover is commonly used to explore the Moon’s surface. The rover can complete the detection on relatively flat terrain of the lunar surface well, but its detection efficiency on deep craters and mountains is relatively low due to the difficulties of reaching such places. A lightweight four-legged landing and walking robot called “FLLWR” is designed in this study. It can take off and land repeatedly between any two sites wherever on deep craters, mountains or other challenging landforms that are difficult to reach by direct ground movement. The robot integrates the functions of a lander and a rover, including folding, deploying, repetitive landing, and walking. A landing control method via compliance control is proposed to solve the critical problem of impact energy dissipation to realize buffer landing. Repetitive landing experiments on a five-degree-of-freedom lunar gravity testing platform are performed. Under the landing conditions with a vertical velocity of 2.1 m/s and a loading weight of 140 kg, the torque safety margin is 10.3% and 16.7%, and the height safety margin is 36.4% and 50.1% for the cases with or without an additional horizontal disturbance velocity of 0.4 m/s, respectively. The study provides a novel insight into the next-generation lunar exploration equipment.

关键词: landing and walking robot     lunar exploration     buffer landing     compliance control    

hydrophobic environment triggering reactive fluorescence probe to real-time monitor mitochondrial DNA

《化学科学与工程前沿(英文)》 2022年 第16卷 第1期   页码 92-102 doi: 10.1007/s11705-021-2063-9

摘要: Mitochondrial DNA has a special structure that is prone to damage resulting in many serious diseases, such as genetic diseases and cancers. Therefore, the rapid and specific monitoring of mitochondrial DNA damage is urgently needed for biological recognition. Herein, we constructed an in situ hydrophobic environment-triggering reactive fluorescence probe named MBI-CN. The fluorophore was 2-styrene-1H-benzo[d]imidazole, and malononitrile was introduced as a core into a molecule to initiate the hydrolysis reaction in the specific environment containing damaged mitochondrial DNA. In this design, MBI-CN conjugates to mitochondrial DNA without causing additional damages. Thus, MBI-CN can be hydrolyzed to generate MBI-CHO in an in situ hydrophobic environment with mitochondrial DNA damage. Meanwhile, MBI-CHO immediately emitted a significative fluorescence signal changes at 437 and 553 nm within 25 s for the damaged mitochondria DNA. Give that the specific and rapid response of MBI-CN does not cause additional damages to mitochondrial DNA, it is a potentially effective detection tool for the real-time monitoring of mitochondrial DNA damage during cell apoptosis and initial assessment of cell apoptosis.

关键词: hydrolysis reaction     mitochondrial DNA damage     in situ hydrophobic environment trigger     fluorescence probe     apoptosis    

A multi-probe micro-fabrication apparatus based on the friction-induced fabrication method

Zhijiang WU, Chenfei SONG, Jian GUO, Bingjun YU, Linmao QIAN

《机械工程前沿(英文)》 2013年 第8卷 第4期   页码 333-339 doi: 10.1007/s11465-013-0276-4

摘要:

A novel multi-probe micro-fabrication apparatus was developed based on the friction-induced fabrication method. The main parts of the apparatus include actuating device, loading system, and control system. With a motorized linear stage, the maximum fabrication area of 50 mm × 50 mm can be achieved, and the maximum sliding speed of probes can be as high as 10 mm/s. Through locating steel micro balls into indents array, the preparation of multi-probe array can be realized by a simple and low-cost way. The cantilever was designed as a structure of deformable parallelogram with two beams, by which the fabrication force can be precisely controlled. Combining the friction-induced scanning with selective etching in KOH solution, various micro-patterns were fabricated on Si(100) surface without any masks or exposure. As a low-cost and high efficiency fabrication device, the multi-probe micro-fabrication apparatus may encourage the development of friction-induced fabrication method and shed new light on the texture engineering.

关键词: friction-induced fabrication     silicon     surface texture     friction     multi-probe    

Tailoring electrical conductivity of two dimensional nanomaterials using plasma for edge electronics:

Aswathy Vasudevan, Vasyl Shvalya, Aleksander Zidanšek, Uroš Cvelbar

《化学科学与工程前沿(英文)》 2019年 第13卷 第3期   页码 427-443 doi: 10.1007/s11705-019-1805-4

摘要: Since graphene has been discovered, two-dimensional nanomaterials have attracted attention due to their promising tunable electronic properties. The possibility of tailoring electrical conductivity at the atomic level allows creating new prospective 2D structures for energy harvesting and sensing-related applications. In this respect, one of the most successful way to manipulate the physical properties of the aforementioned materials is related to the surface modification techniques employing plasma. Moreover, plasma-gaseous chemical treatment can provide a controlled change in the bandgap, increase sensitivity and significantly improve the structural stability of material to the environment as well. This review deals with recent advances in the modification of 2D carbon nanostructures for novel ‘edge’ electronics using plasma technology and processes.

关键词: graphene     edge electronics     2D nanomaterials     plasma     electrical conductivity    

Motion planning and tracking control of a four-wheel independently driven steered mobile robot with multiple

Xiaolong ZHANG, Yu HUANG, Shuting WANG, Gen LI, Yuanlong XIE, Wei MENG

《机械工程前沿(英文)》 2021年 第16卷 第3期   页码 504-527 doi: 10.1007/s11465-020-0626-y

摘要: Safe and effective autonomous navigation in dynamic environments is challenging for four-wheel independently driven steered mobile robots (FWIDSMRs) due to the flexible allocation of multiple maneuver modes. To address this problem, this study proposes a novel multiple mode-based navigation system, which can achieve efficient motion planning and accurate tracking control. To reduce the calculation burden and obtain a comprehensive optimized global path, a kinodynamic interior–exterior cell exploration planning method, which leverages the hybrid space of available modes with an incorporated exploration guiding algorithm, is designed. By utilizing the sampled subgoals and the constructed global path, local planning is then performed to avoid unexpected obstacles and potential collisions. With the desired profile curvature and preselected mode, a fuzzy adaptive receding horizon control is proposed such that the online updating of the predictive horizon is realized to enhance the trajectory-following precision. The tracking controller design is achieved using the quadratic programming (QP) technique, and the primal–dual neural network optimization technique is used to solve the QP problem. Experimental results on a real-time FWIDSMR validate that the proposed method shows superior features over some existing methods in terms of efficiency and accuracy.

关键词: mobile robot     multiple maneuvering mode     motion planning     tracking control     receding horizon control    

Review of self-referenced measurement algorithms: Bridging lateral shearing interferometry and multi-probe

Dede ZHAI, Shanyong CHEN, Ziqiang YIN, Shengyi LI

《机械工程前沿(英文)》 2017年 第12卷 第2期   页码 143-157 doi: 10.1007/s11465-017-0432-3

摘要:

With the development of new materials and ultra-precision processing technology, the sizes of measured objects increase, and the requirements for machining accuracy and surface quality become more exacting. The traditional measurement method based on reference datum is inadequate for measuring a high-precision object when the quality of the reference datum is approximately within the same order as that of the object. Self-referenced measurement techniques provide an effective means when the direct reference-based method cannot satisfy the required measurement or calibration accuracy. This paper discusses the reconstruction algorithms for self-referenced measurement and connects lateral shearing interferometry and multi-probe error separation. In lateral shearing interferometry, the reconstruction algorithms are generally categorized into modal or zonal methods. The multi-probe error separation techniques for straightness measurement are broadly divided into two-point and three-point methods. The common features of the lateral shearing interferometry method and the multi-probe error separation method are identified. We conclude that the reconstruction principle in lateral shearing interferometry is similar to the two-point method in error separation on the condition that no yaw error exists. This similarity may provide a basis or inspiration for the development of both classes of methods.

关键词: self-referenced measurement     lateral shearing interferometry     multi-probe error separation     surface metrology    

Modeling of ion conductivity in Nafion membranes

YANG Zhen, PENG Xiaofeng, WANG Buxuan, DUAN Yuanyuan, LEE Duujong

《能源前沿(英文)》 2007年 第1卷 第1期   页码 58-66 doi: 10.1007/s11708-007-0005-y

摘要: A theoretical investigation was conducted to describe the ion transport behavior in a Nafion Membrane of proton exchange membrane fuel cells (PEMFC). By analyzing the surface energy configuration of the ionic clusters in a Nafion membrane, an equivalent field intensity, , was introduced to facilitate the analysis of surface resistance against ion conduction in the central region of clusters. An expression was derived for ionic conductivity incorporating the influence of surface resistance. A face-centered cubic (FCC) lattice model for a spatial cluster distribution was used to modify the effect of water content on ionic conductivity in the polymeric matrix, i.e., the regions between clusters. Compared with the available empirical correlations, the new expression showed much better agreement with the available experimental results, which indicates the rationality to consider the structural influence on ion conduction in water-swollen Nafion membranes.

关键词: face-centered     polymeric     theoretical investigation     conduction     equivalent    

标题 作者 时间 类型 操作

Experimental study on bubble behavior and CFD simulation of large-scale slurry bubble column reactor

Haoyi SUN, Tao LI, Weiyong YING, Dingye FANG

期刊论文

Activated carbon induced oxygen vacancies-engineered nickel ferrite with enhanced conductivity for supercapacitor

期刊论文

Chemical probe systems for assessing liquid–liquid mixing efficiencies of reactors

期刊论文

Permeability and thermal conductivity of host compressed natural graphite for consolidated activated

Bo TIAN, Liwei WANG, Zhequan JIN, Ruzhu WANG

期刊论文

A highly selective fluorescent probe for real-time imaging of UDP-glucuronosyltransferase 1A8 in living

期刊论文

A dual-function chemical probe for detecting erasers of lysine lipoylation

Yusheng Xie, Jie Zhang, Liu Yang, Qingxin Chen, Quan Hao, Liang Zhang, Hongyan Sun

期刊论文

A novel flavonol-based colorimetric and turn-on fluorescent probe for rapid determination of hydrazine

期刊论文

Equivalent thermal conductivity of heat pipes

LU Zesheng, MA Binghui

期刊论文

Landing control method of a lightweight four-legged landing and walking robot

期刊论文

hydrophobic environment triggering reactive fluorescence probe to real-time monitor mitochondrial DNA

期刊论文

A multi-probe micro-fabrication apparatus based on the friction-induced fabrication method

Zhijiang WU, Chenfei SONG, Jian GUO, Bingjun YU, Linmao QIAN

期刊论文

Tailoring electrical conductivity of two dimensional nanomaterials using plasma for edge electronics:

Aswathy Vasudevan, Vasyl Shvalya, Aleksander Zidanšek, Uroš Cvelbar

期刊论文

Motion planning and tracking control of a four-wheel independently driven steered mobile robot with multiple

Xiaolong ZHANG, Yu HUANG, Shuting WANG, Gen LI, Yuanlong XIE, Wei MENG

期刊论文

Review of self-referenced measurement algorithms: Bridging lateral shearing interferometry and multi-probe

Dede ZHAI, Shanyong CHEN, Ziqiang YIN, Shengyi LI

期刊论文

Modeling of ion conductivity in Nafion membranes

YANG Zhen, PENG Xiaofeng, WANG Buxuan, DUAN Yuanyuan, LEE Duujong

期刊论文