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Preparation and shaping of solid acid SO_4^(2-)/TiO_2 and its application for esterification of propylene glycol monomethyl ether and acetic acid

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Chinese Journal of Chemical Engineering 2017年第9期25卷 1207-1216页

作者： Zhixian Huang Yixiong Lin Ling Li Changshen Ye Ting Qiu School of Chemical Engineering Fuzhou University

The solid acid SO_4^(2-)/TiO_2 was prepared by immersion method and applied for synthesis of propylene glycol methyl ether acetate(PMA) through esterification reaction of propylene glycol monomethyl ether(PM)and acetic acid(HAc). The optimal catalyst preparation condition was determined by orthogonal analysis of parameters in a five-factor and four-level test. The obtained solid acid catalysts were characterized in detail by means of X-ray powder diffraction, thermogravimetry, pyridine adsorbed IR analysis, scanning electron microscopy, and BET surface area method. Synthesis of PMA was studied in this paper through experimental investigation of reaction conditions such as temperature, molar ratio of reactants, catalyst dosage and agitation speed. Based on its possible reaction mechanism, a pseudo-homogeneous kinetic model was established and its activation energies E_a^+ and E_a^-,65.68 × 10~3J·mol^(-1) and 57.78 × 10~3J·mol^(-1), were estimated. To prepare shaped solid acid catalyst SO_4^(2-)/TiO_2, the shaping method of impregnation–shaping–impregnation was applied. The optimal molding formulation of solid acid catalyst, obtained from the orthogonal test, was found to be binder 7 wt%, reinforcing agent 20 wt%, pore forming material 2.5 wt%, and lubricant 4 wt%.The results of performance test of catalyst demonstrated that the shaped solid acid catalyst exhibited high activity and stability.

关键词： Propylene glycol methyl ether acetate Solid acid shaping Kinetic modeling

High-contrast imaging based on wavefront shaping to improve low signal-to-noise ratio photoacoustic signals using superpixel method

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Chinese Physics B 2020年第3期29卷 251-258页

作者： Xinjing Lv Xinyu Xu Qi Feng Bin Zhang Yingchun Ding Qiang Liu College of Mathematics and Physics Beijing University of Chemical TechnologyBeijing 100029China State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentsTsinghua UniversityBeijing 100084China

Photoacoustic(PA) imaging has drawn tremendous research interest for various applications in biomedicine and experienced exponential growth over the past decade. Since the scattering effect of biological tissue on ultrasound is two-to three-orders magnitude weaker than that of light, photoacoustic imaging can effectively improve the imaging ***, as the depth of imaging further increases, the incident light is seriously affected by scattering that the generated photoacoustic signal is very weak and the signal-to-noise ratio(SNR) is quite low. Low SNR signals can reduce imaging quality and even cause imaging failure. In this paper, we proposed a new wavefront shaping and imaging method of low SNR photoacoustic signal using digital micromirror device(DMD) based superpixel method. We combined the superpixel method with DMD to modulate the phase and amplitude of the incident light, and the genetic algorithm(GA) was used as the wavefront shaping algorithm. The enhancement of the photoacoustic signal reached 10.46. Then we performed scanning imaging by moving the absorber with the translation stage. A clear image with contrast of 8.57 was obtained while imaging with original photoacoustic signals could not be achieved. The proposed method opens new perspectives for imaging with weak photoacoustic signals.

关键词： photoacoustic imaging wavefront shaping superpixel method high contrast imaging

A Satellite Communication System Transmission Scheme Based on Probabilistic shaping

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China Communications 2019年第10期16卷 226-233页

作者： Wei Zhang Xia Sheng Xishuo Wang Qi Zhang Science and Technology on Information Systems Engineering Laboratory National University of Defense TechnologyFuyuan road NO. 1Changsha410000China China Academy of Space Technology (CAST) Beijing 100094China School of Electronic Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China Beijing Key Laboratory of Space-Ground Interconnection and Convergence Beijing University of Posts and TelecommunicationsBeijing 100876China State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and TelecommunicationsBeijing 100876China

In this paper, A transmission scheme based on probabilistic shaping applied to satellite communication systems is proposed. 16QAM is taken as an example to establish a 1GBaud ROF experimental system working in Ka-band. The experiment results show that the PS-16QAM signal has better performance in terms of bit error rate than the uniform 16QAM, and its performance is close to the uniform 8QAM scheme.

关键词： probabilistic shaping satellite communication Ka-band

Two-dimensional beam shaping and homogenization of high power laser diode stack with rectangular waveguide

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Frontiers of Optoelectronics 2019年第3期12卷 311-316页

作者： Yuchen SONG Yunfeng CHEN Jianguo XIN Teng SUN School of Information and Electronics Beijing Institute of TechnologyBey ing 100081China

In this paper, the research work of twodimensional beam shaping and homogenization of high power laser diode (LD) stack by a rectangular waveguide is presented. Both the theoretical simulation and experiment results have shown that the diode stack beam can be shaped into a uniform square spot with a dimension of 10 mm×10 mm and the non-uniformity less than 5% along both directions of slow axis and fast axis, the shaped beam has a uniform pumping depth over 10 mm, which is well to be used for a rectangular laser medium end pumping.

关键词： beam shaping high power laser diode (LD) stack laser end pumping

The shaping of milk-flavored white tea:More than a change in appearance

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Journal of Integrative Agriculture 2024年第11期23卷 3912-3922页

作者： Jiao Feng Weisu Tian Jinyuan Wang Shuping Ye Guanjun Pan Bugui Yu Fang Wang Hongzheng Lin Zhilong Hao College of Horticulture Fujian Agriculture and Forestry UniversityFuzhou 350002China Key Laboratory of Tea Science in Universities of Fujian Province Fuzhou 350002China Zhenghe Ruiming Tea Co. Ltd.Zhenghe 353600China Tea Sensory Evaluation Research Center Ningde Normal UniversityNingde 352000China

Tea’s popularity and flavor are influenced by factors like cultivation and processing methods and shaping techniques also have an impact on tea *** study employed targeted metabolomics and chemometrics to investigate how shaping techniques affect the flavor of milk-flavored white tea(MFWT).The results showed that the tea cake sample with the shortest pressing time(Y90)has the highest amino acid content and milky aroma *** were variations in amino acids,catechins,and soluble sugars among MFWT samples with different shaping *** total contents of amino acids and catechins in tea cake sample(Y90)were significantly lower than those in the loose tea sample(SC)and bundle-like tea sample(SG),while the total sugar content was significantly higher than that in SC(P1)in Y90 remained lower relative to SC and SG(P<0.05),but the proportion was not different from that in SC and SG,minimally affecting the overall *** short-time pressing method might be suitable for mass production of *** findings provide insights into improving the tightness of the appearance of MFWT with minimal impact on tea flavor.

关键词： shaping milk-flavored white tea Camellia sinensis tea processing tea flavor

Mechanical Properties of Coating and Part by Laser Engineered Net shaping by Nanoindentation Testing

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稀有金属材料与工程 2011年第S4期40卷 261-265页

作者： Xue Chunfang1,Tian Xinli2,Lin Keling11Department of Mechanical Engineering,Armored Force Engineering Institute,Beijing 100072,China2National Key Laboratory for Equipment Remanufacturing,Armored Force Engineering Institute,Beijing 100072,China Armored Force Engn Inst Dept Mech Engn Beijing 100072 Peoples R China Armored Force Engn Inst Natl Key Lab Equipment Remfg Beijing 100072 Peoples R China

The mechanical properties,such as hardness and modulus of elasticity of coatings and the part of thin walls of Ni-based and Co-based alloy prepared by LENS were measured by nanoindentation testing,scanning electron microscopy and energy dispersive spectroscopy were used to analyze their microstructure,the affect of parameters on structure and mechanical properties were *** results showed that the mechanical properties were basically identical with the whole coating;the hardness and modulus of elasticity of nanoindentation were evenly distributed in the defect *** average hardness and modulus of elasticity of coating of Ni-based alloy are 8.29GPa and *** average hardness and modulus of elasticity of coating of Co-based alloy are 7.08GPa and *** modulus of elasticity of part of thin walls has relationship with the grain orientation.

关键词： nanoindentation laser engineered net shaping (LENS) solidify speediness mechanical property.

Cold Hydrostatic Sintering:From shaping to 3D printing

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Journal of Materiomics 2019年第3期5卷 496-501页

作者： Anna Jiang Daoyao Ke Ludi Xu Qiang Xu Jiang Li Jiabei Wei Chunfeng Hu Salvatore Grasso Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu610031China Key Laboratory of Transparent Opto-functional Inorganic Materials Shanghai Institute of CeramicsChinese Academy of SciencesShanghai201899China

We developed a novel consolidation technique,Cold Hydrostatic Sintering(CHS),which allows near full densification of *** technique is inspired by biosilicification and geological formation of siliceous *** established cold sintering method which is based on uniaxial pressure,CHS employs an isostatic pressure to enable room temperature consolidation of bulks having a complex threedimensional *** resulting material is transparent(in line transmittance exceeding 70% in the visible range)and *** drying,the Vickers hardness was as high 1.4 GPa which half of materials consolidated at 1200℃ and it is the highest among all materials processed at room *** CHS method,because of its simplicity,might be suitable for broad range of applications including 3D printing,mould forming and preparation of multi-layered *** of the absence of the firing step,CHS could be directly integrated in the manufacturing of a wide range of hybrid(organic/inorganic)materials for functional and biological applications.

关键词： Silica Cold Hydrostatic Sintering(CHS) shaping 3D printing

Study on DC welding parameters of Al-alloy shaping based on arc-welding robot

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China Welding 2008年第4期17卷 43-46页

作者：杜乃成胡绳荪杨雪梅冯胜强 School of Materials Science and Engineering Tianjin University Tianjin Institute of Process Automation and Instrumentation International Division of China Petroleum Pipeline Bureau

The Al-alloy arc-welding shaping system based on arc-welding robot is established, and the Al-alloy shaping manufacture is realized with the DC （direct current） gas metal arc welding （GMAW）. The research indicates that the metal transfer type of DC GMA W, heat input and the initial temperature of the workpiece greatly affect the Al-alloy shaping based on arc welding robot. On the penetration, the weld width and the reinforcement, the influence of welding parameters is analyzed by generalized regression neural network （GRNN） fitting.

关键词： arc-welding robot Al-alloy shaping welding parameters

A New shaping Model for Green Ceramic Balls

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厦门大学学报（自然科学版） 2002年第S1期41卷 35-36页

作者： REN Cheng-zu, WU Zhen-yong, JIN Xin-ming, WANG Chun-jie, XU Qiang (Institute of Mechanical Engineering, Tianjin University, Tianjin 300072, China)

The shaping quality of green ceramic balls is directly related to the efficiency and cost of later machining for the ceramic balls. Until now the shaping for green ceramic balls is still conducted by handwork. In this paper, a new shaping model for green ceramic balls was designed. In the new model, two grinding wheels with the same generator line as circular arc are mounted on symmetry, and their axes are parallel. The green ball can be put in the enveloping space formed by the two grinding wheels. The radius of generator line must be equal to or slightly greater than the final radius of the green balls, which can ensure that an ideal sphere can be enveloped by the generator of grinding wheel as grinding the green body surface with the wheels. One of the two wheels rotates in upward direction at high speed v 1, conversely, the other wheel rotates in downward direction at low speed v 2, and a cluster of compressed air is exerted on the green ball above for canceling out the force acting upon the green ball created by the action of the grinding wheel revolving at high speed and avoiding that the green ball jumps off its station. Because of the randomness of the distributions of abrasive grains on the surface of grinding wheels, the size and shape of the abrasive grains, and the posture of green body when falling into the grinding space, the values and directions of the resultant forces and torques exerted on the body, caused by the tow wheels, are random, the rotation of green body is irregular under the actions of the compressed air and the wheels. The irregularity of rotation can ensure an ideal sphere in theory. Experiment researches indicate that the new shaping model can improve the spherical deviations and the size distribution of the green ceramic balls, raise the production, and reduce the costs. The spherical deviations can be improved to 0.04 mm easily. It can be observed by SEM that there is no crack in the surface of sintered ceramic balls shaped with the

关键词： ceramic balls green shaping spherical deviation