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Unsteady-state Grinding technology (III) Studies on the Surface Quality

厦门大学学报（自然科学版） 2002年第S1期41卷 42-43页

作者： XU Yan-shen, HU Jun, LIN Bin, LI Zhi-chao (The state Education Ministry key {2. of High Temperature Structure Ceramics and Machining technology of Engineering Ceramics, tianjin university, tianjin 300072. China)

In conventional grinding theory, the chief removed mode of ceramic coprocessor by diamond tools was brittle removal. In order to perform the plastic removal or ductility processing of engineering ceramics the high degree of accuracy and high rigidity grinner must be using micro grain size diamond grinding wheel to direct the processing of micron below rank depth to prevent form the occurring of the brittle processing zone. This will resulted in the high expense of grinding. The expense of grinding could even reach the 80% of the total manufacture cost of the ceramic part. Ultra-precision grinding for advanced ceramics has been achieved by the unsteady-state grinding technique. In this paper, we mainly deals with observing and analyzing the surface quality of the silicon nitride ground by pink fused alumina wheel in different grinding parameters. To optimize the grinding parameters in the process of the unsteady-state grinding, the experiments of X-ray diffraction, energy spectrum analysis, SEM observation and roughness measurement were performed. The results show that: 1. In the process of unsteady state grinding, high line speed (rotational speed) of the grind wheel can improve the roughness of the silicon nitride apparently. It was also evident that the larger the grain mesh size, the better the surface quality. 2. There exists an optimum combination of grinding conditions such as grinding wheel speed, rotational speed of the workpiece, feed rate between the grinding wheel and the workpiece, grinding times and cutting coolant. The surface quality of the silicon nitride can be up to the standard of mirror finishing. 3. By analyzing the finished surface with X-ray diffraction and energy spectrum, the existence of some new phases including titanium and alumina was proved. 4. By utilizing the unsteady state grinding technique, the surface roughness of Ra ≤ 0.030 μm can be achieved by grinding the silicon nitride with the pink fused alumina wheel in low cost. Based on

关键词： unsteady state grinding theory engineering ceramics grinding surface quality

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Unsteady-state Grinding technology (I) Theoretical Generalization and Research on Grinding Mechanism

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厦门大学学报（自然科学版） 2002年第S1期41卷 46-47页

作者： LIN Bin, LI Zhi-chao, XU Yan-shen, HU Jun (The state Education Ministry key {2. of High Temperature Structure Ceramics and Machining technology of Engineering Ceramics, tianjin university, tianjin 300072. China)

In conventional grinding theory, it is obvious that there must be a very high hardness difference between grains of the grinding wheel and workpieces. The best grinding wheels are those giving the lowest "natural limiting surface roughness" while cutting at appreciable plunge velocities. With the development of new materials and new machining processes, conventional theories of grinding techniques are no longer suitable to explain many phenomena in the course of grinding procedures. In dealing with precision or ultra-precision grinding processes of advanced ceramics, many results of experiments and practical production have shown that grinding with super hard materials wheels is not the only method to machine advanced ceramics. This paper is intended to propose a new grinding theory named as unsteady-{2. grinding technique evolved from some phenomena that can not be explained by conventional grinding theory. Unsteady-{2. grinding technique means the technique which can make the surface roughness of the materials, especially hard and brittle, be up to the standard of ultra-precision machining by utilizing common wheels characteristic of inferior self-sharpening and wear-resistance. In the process of machining, the common wheel need to be redressed about 3～5 times and the time between two redressings is about 3～5 minutes. As a validation of the new grinding technology, experimental work was performed to prove the existence of the unsteady {2. in the process of ultra-precision grinding with common abrasive wheel-pink fused alumina wheel. From the results of the observation of the wheel topography, the whole grinding process in unsteady {2. was separated into three stages namely cutting by grains peaks, micro-cutting by micro edges of the broken grains and rubbing without material removal, which is different from conventional grinding theory. For the difference of hardness between grinding wheel and workpiece material is not so apparent, some people have doubts

关键词： unsteady state grinding theory grinding mechanism common abrasive wheel ceramic

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Recognition System for Pipeline Typical Abnormal Events Based on DSP

Recognition System for Pipeline Typical Abnormal Events Base...

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2.09 9th International Conference on Electronic Measurement & instruments（ICEMI’2.09）

作者： Jian Li Guoxing Jiang Ping Lai Shijiu Jin ( state key {2. of precision measuring technology and instruments tianjin university No.92.Nankai District 300072.tianjin China)

A new technique of designing a recognition system for pipeline typical abnormal events based on DSP is introduced in this paper. The pipeline has been widely used to transport oil and gas in the world. The abnormal events such as man digging and machine digging may cause pipeline leakage or other pipeline damage, which not only causes great loss of economy, but also leads to serious pollution to the environment. The hardware and software of the system are introduced in detail. The information entropy value of abnormal events signal is calculated to identify the event’s type. The experiment proves that the system can recognize pipeline typical abnormal events effectively.

关键词： pipeline abnormal event DSP information entropy.

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Effect of Tool Geometry in Nanometric Cutting

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厦门大学学报（自然科学版） 2002年第S1期41卷 16-17页

作者： HAN Xue-song, LIN Bin, YU Si-yuan, LIN Mon-xia (The state Education Ministry key {2. of High Temperature Structure Ceramics and Machining technology of Engineering Ceramics, tianjin university, tianjin 300072. China)

With the development of science and technology, the ultra-precision manufacturing of the brittle and hard materials with superior quality have become a new attractive subject. Brittle materials (such as engineering ceramics, optical glass, semiconductor and so on) are widely used in electronics, optics, aeronautics and other high technology fields, so there are important theory significance and practical value to systematically study its machining mechanism and technology. Single crystal silicon is one of the typical brittle materials. Single crystal silicon wafer is a basic component of large and ultralarge integrated the circuit, its surface roughness and flatness are the key factor of improving its integration. With the successfully producing of the large diameter single crystal silicon wafer, its manufacturing technology became attractive subject again. This paper carries out computer simulation of nanometer cutting on single crystal silicon. Molecular Dynamics method which is different from continuous mechanics is employed to investigate the features of grinding energy dissipation, grinding force, stress state and grinding temperature, constructs the atom model of tool and work piece, and explains the microscale mechanism of material remove and surface generation of nanometer(subnanometer) manufacturing. This paper also investigates the variation of cutting force, thrust force, specific energy and surface deformation with different tool edge radius, different depth of cut.

关键词： single crystal silicon ultraprecision machining manufacturing mechanism molecular dynamics computer simulation

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不同强度工频磁场对皮层神经元瞬时外向钾离子通道的影响

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生物化学与生物物理进展 2011年第11期38卷 1036-1042页

作者：李刚李丹丹李媛媛林凌天津大学精密测试技术及仪器国家重点实验室天津300072 天津工业大学计算机科学与软件学院天津300387

人们对电磁辐射越来越关注,但是工频磁场产生的生物效应并不确定.选用1、5、10 mT的工频磁场照射急性分离的小鼠皮层神经元(15 min),应用全细胞膜片钳技术离线记录瞬时外向钾通道电流,研究工频磁场对离子通道的影响.结果显示:工频磁场... 详细信息

人们对电磁辐射越来越关注,但是工频磁场产生的生物效应并不确定.选用1、5、10 mT的工频磁场照射急性分离的小鼠皮层神经元(15 min),应用全细胞膜片钳技术离线记录瞬时外向钾通道电流,研究工频磁场对离子通道的影响.结果显示:工频磁场抑制通道的电流密度,并且1 mT、5 mT及10 mT工频磁场的抑制率分别为(63.0±2.2.%、(55.0±1.7)%和(38.0±1.8)%.工频磁场影响离子通道的激活和失活特性,半数激活电压和半数失活电压变小.不同强度工频磁场对离子通道产生的影响程度不同,其中1 mT工频磁场对通道电流的抑制率最大,5 mT工频磁场对通道的半数激活电压和半数失活电压影响最大,10 mT工频磁场增大了通道的失活斜率因子.研究结果表明,工频磁场影响了细胞膜上离子通道蛋白质构象的变化,进一步影响了离子通道的正常功能.

关键词：工频磁场瞬时外向钾通道神经元

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Optimization of a synthetic medium for ethanol production by xylose-fermenting Zymomonas mobilis using response surface methodology

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Science Bulletin 2012年第Z2期 3782-3789页

作者： DONG HuiNa 1,2.4,5,ZHAO XueMing 2.4,5,MA YuanYuan 1* & ZHANG MinHua 1,3 1 tianjin university R&D Center for Petrochemical technology,{2. university,{2. 300072.China 2.Department of Biochemical Engineering,School of Chemical Engineering and technology,{2. university,{2. 300072.China 3 state {12. laboratory of Engines,{2. university,{2. 300072.China 4 {12. laboratory of Systems Bioengineering,Ministry of Education,{2. university,{2. 300072.China 5 Edinburgh-{2. Joint Research Centre for Systems Biology and Synthetic Biology,{2. university,{2. 300072.China

A synthetic medium for ethanol production by recombinant xylose-fermenting Zymomonas mobilis was optimized using Plackett-Burman(PB) design and response surface methodology(RSM).The effects of 19 medium components were investigated by PB *** of these components were determined to have significant effects on ethanol *** statistical model was constructed via central composite design(CCD) using five selected variables,including xylose,trisodium citrate,choline chloride,pyridoxine,and *** validity of the developed model was *** ethanol concentration in the optimized medium was 6.7% higher than in the RM *** optimized medium was then simplified to give the final synthetic medium(S2.,in which the ethanol concentration was 2..7% higher than in the RM *** and trisodium citrate were the key medium components influencing ethanol production,while calcium pantothenate was the only growth factor required by recombinant *** production and growth response were directly proportional to the logarithm of the concentration of trisodium citrate in the range of 0.1-1.6 g/L.

关键词： recombinant Zymomonas mobilis synthetic medium ethanol production response surface methodology trisodium citrate xylose

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Anode Simulation and Cathode Design for Electrolytic Dressing of Diamond Profile Wheel

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Transactions of tianjin university 2005年第3期11卷 172-175页

作者：邹峰于爱兵谭业发 key laboratory for Advanced Ceramics and Machining {2. of Education Ministry School of Mechanical Engineering Tianjin University Tianjin 300072 China Nanjing Engineering Institute Nanjing 210007 China

The design methods of anode and cathode are proposed for precision profile grinding. Based on the electrolytic machining theory, electrolytic equilibrium condition and Faraday′s law of electrolysis are applied to establishing the mathematical model of profile diamond dressing process- es. A finite element method (FEM) program is developed to solve the inverse boundary problem of Laplace′s equation. Desired anode contour or cathode shape is determined by computing the distribution of electric potential layer by layer. Electrolytic machining experiment is carried out to verify the simulated anode shape. The research result shows that shape deviation between designed cathode and profile wheel increases with the value of angle between feed rate and the normal to anode surface. The shape of simulated anode is consistent with the contour of metal-bonded diamond profile wheel for a given cathode. Based on the anode contour, cathode shape can also be designed accurately.

关键词： profile wheel dressing electrolysis FEM diamond

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Evaluation of Diesel Engine Noise Reduction Measures Based on Hierarchy Diagnosis

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Transactions of tianjin university 2007年第3期13卷 205-210页

作者：梁兴雨舒歌群卫海桥陈达亮 state key {2. of Engines Tianjin University

Effect of different noise reduction measures for diesel engines was evaluated based on hierarchy diagnosis. The hierarchy diagnosis chart and hierarchy judgment matrix were given. Through evaluation of noise reduction measures, the main strategies of noise reduction were found. The result shows that the noise reduction level of different frequency belts varies from measure to measure. The reduction capacity of different measures could not add simply, which relates to the problem of parameter matching.

关键词： diesel engine hierarchy diagnosis noise reduction power spectrum

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用电容传感器进行相对测量的实验装置设计

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实验技术与管理 2010年第1期27卷 50-53页

作者：孙长库肖旭王鹏天津大学精密测试技术及仪器国家重点实验室

电容测量技术具有非接触、稳定性好、测量微位移时具有高分辨率等特点,广泛应用于缓慢变化和微小位移的非接触测量。设计了一套用于教学的电容传感器进行相对测量的实验装置,系统介绍了电容传感器进行相对测量的原理及电路,给出了电容... 详细信息

电容测量技术具有非接触、稳定性好、测量微位移时具有高分辨率等特点,广泛应用于缓慢变化和微小位移的非接触测量。设计了一套用于教学的电容传感器进行相对测量的实验装置,系统介绍了电容传感器进行相对测量的原理及电路,给出了电容传感器的标定方法,并进行了标定实验。设计了容易操作的传感器现场标定和相对测量的软件。该装置旨在帮助学生深入理解电容传感器的工作原理、相对测量概念、仪器标定及数据处理方法。

关键词：电容传感器相对测量标定

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Multistage Extractive Reaction for Hydrogen Peroxide Production by Anthraquinone Process

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Transactions of tianjin university 2005年第4期11卷 245-249页

作者：王莅吕树祥王亚权米镇涛 key laboratory of Green Chemistry and {2. Tianjin University Tianjin 300072 China

The extractive reaction process of oxygen-working solution-water three-phase system for the production of hydrogen peroxide by the anthraquinone method was investigated in a sieve plate column of 50 mm in internal diameter. The oxidation reaction of anthrahydroquinone in the working solution with oxygen and the extraction of hydrogen peroxide from the working solution into aqueous phase occurred simultaneously in the countercurrent mode. The agitating effect caused by gaseous phase made the droplets of the dispersed phase become smaller, thus, increasing the liquid-liquid interfacial contact areas and resulting in the improvement of the mass transfer velocity. Results showed that the gas-agitation had a beneficial effect on the extraction of hydrogen peroxide from the working solution into the aqueous phase; the concentration of hydrogen peroxide in the raffinate decreased with the increase of the gaseous superficial velocities; and the concentration of H2.2.in the raffinate increased with the increase of the dispersed phase superficial velocity at the same superficial velocity of the gaseous phase. In the G-L-L extractive reaction process, with the increase of the gaseous superficial velocities, both the conversion of the anthrahydroquinone oxidation and the extraction efficiency of hydrogen peroxide first increased significantly, then increased gradually.

关键词： hydrogen peroxide anthraquinone working solution extractive reaction

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