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Experimental and Three-Dimensional Numerical Study on Under-Expanded Impinging Jets

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Journal of Thermal Science 2000年第4期9卷 316-321页

作者： MinoruYaga KenshiUeda 等 DepartmentofMechanicalSystemsEngineering FacultyofEngineeringUniversityoftheRyukyusSenbaru1Okinawa903－0213JAPAN DepartmentofMechanicalSystemsEngineering FacultyofEngineeringUniv

In this paper, under-expanded impinging jets issued from converging circular and rectangular nozzles were investigated. The ratio of the distance between the nozzle exit and the plate L to the diameter D was set at 2, 3, 4 for the circular nozzle and 2, 3 for the rectangular nozzle. Two-dimensional temperature and static pressure distributions on the impinging plate were measured using an infrared camera and a semi-conductor pressure sensor and flow fields were visualized by means of schlieren method. Three-dimensional numerical calculations were also conducted by solving the three-dimensional compressible Euler equations and compared to the experimental results. As a result, it is found that the numerical calculations for the circular and the rectangular nozzles are in good agreement with the experiments. In the experiments, it is found that the stagnation temperature on the plate depends on the pressure in the settling chamber and the distance between the nozzle exit and the plate. The temperature and pressure distributions in the experiments illustrate that even in the case of the circular nozzle, the distributions on the impinging plate are non-axisymmetric, which is confirmed by the three dimensional calculations. The calculation for the rectangular nozzle indicates that two circulating regions occur immediately upstream of the plate.

关键词： compressible flow shock wave under-expanded impinging jet CFD surface temperature.

Large and Fast Resonant Third-Order Optical Nonlinearities of Silicon 2,3-Napht halocyanine Bis （trihexylsilyloxide）

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Chinese Physics Letters 2005年第7期22卷 1687-1690页

作者：付刚 KazuoKasatani HiroakiOkamoto ShunsukeTakenaka DepartmentofAdvancedMaterialsScienceandEngineering FacultyofEngineeringYamaguchiUniversityTokiwadaiUbe755-8611Japan

Third-order optical nonlinearities of silicon 2,3-naphthalocyanine bis(trihexylsilyloxide) (SiNc) were measured by femtosecond degenerate four-wave mixing technique under resonant conditions. The time dependence of the signals indicates that the electronic response dominates the mechanism. The electronic molecular hyperpolarizability γe of SiNc was determined to be as high as 2×10−28 esu, which is the largest value reported so far to our knowledge. The electronic third-order susceptibility for a pure SiNc film has been measured to be 4×10−7esu. The large nonlinear susceptibility was discussed in terms of J-type molecular arrangement.

关键词： DFWM THF PMMA

Mechanical Properties of Sialic Foamed Ceramic and Applications in Defense Structure

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Chinese Physics Letters 2014年第8期31卷 106-110页

作者：李煦阳李永池赵凯高光发 DepartmentofModernMechanics UniversityofScienceandTechnologyofChinaHefei230027 facultyofengineering NationalUniversityofSingaporeSingapore120425Singapore

Mechanical properties of a closed-cellular sialic foamed ceramic are investigated by compressive tests. The sialic foamed ceramic under uniaxial stress compression shows brittleness and the flow stress increases with the strain rate. The engineering stress-engineering strain curve under uniaxial strain compression could be divided into three stages： linear elasticity, collapsed plateau and densification. The unloading elastic modulus, Poisson ratio and energy absorption ability are discussed. Shelly cellular material made by sialic foamed ceramic is applied into the stress distribution layer in the defense structure. Field explosion experiments are performed for the sand based stress distribution layer and shelly cellular material based layer. Compared with sand, the shelly cellular material reduces the peak stress of the blast wave.

关键词： MATERIALS -- Mechanical properties RESEARCH CERAMICS -- Research BRITTLENESS POISSON'S ratio BLAST waves

Stabilization effects of surplus soft clay with cement and GBF slag

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Journal of Environmental Sciences 2004年第3期16卷 397-403页

作者： LUJiang ChirdchaninMODMOLTIN KatsutadaONITSUKA DepartmentofCivilEngineering SagaUniversitySagaJapan840-8502 facultyofengineering SiamUniversityBangkok10163Thailand

Utilization of industrial waste and surplus construction soft clay as construction material was recommended, and many attempts at geotechnical waste utilization were undertaken. This study aimed at the application of cement and a kind of industrial wastes, i.e. granulated blast furnace slag, on stabilization of surplus soft clay. The results showed that the cement and slag can successfully stabilize Ariake clays even though this high organic clay fails to be stabilized by lime and cement. Addition of slag in cement for stabilization induces higher strength than cement alone for longer curing time. The application of the cement with slag is more suitable than cement alone for stabilization because of economical consideration.

关键词： surplus soft clay stabilization GBF slag cement organic matter lime humic acid

Enhancement of Gain in L-Band Bismuth-Based Erbium-Doped Fibre Amplifier Using an Un-pumped EDF and Midway Isolator

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Chinese Physics Letters 2004年第12期21卷 2452-2453页

作者： W.Y.Chong S.W.Harun H.Ahmad PhotonicsLaboratory DepartmentofPhysicsUniversityofMalaya50603KualaLumpur facultyofengineering MultimediaUniversityJalanMultimedia63100CyberjayaSelangorMalaysia

A hybrid L-band erbium-doped fibre amplifier (EDFA) with enhanced gain characteristic is demonstrated without a significant noise figure penalty. It uses a backward C-band amplified stimulated emission from both the ends of a bismuth-based EDFA system to pump an unpumped erbium-doped fibre (EDF) for gain enhancing. The maximum gain enhancement of 4.0dB is obtained at wavelength 1604nm with EDF length of 20m. The gain spectrum is reasonably flat in this amplifier compared with the amplifier without an EDF. The gain varies from 27.4dB to 30.2dB at wavelength region 1564--1608nm with incorporation of 20m EDF. Noise figure also varies from 6.0 to 7.7dB at this wavelength region.

关键词： Erbium doped fiber amplifiers

Finding of Gray Points on the Surface of the Sn-Fe Alloy Layer and Its Effects on the Corrosion Resistance of the Alloy Layer

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Journal of Materials Science & Technology 2003年第2期19卷 174-176页

作者：王长钰 JiuguiHUANG DeriZHOU DeyuLI KurachiMitsuo DepartmentofAppliedChemistry HarbinInstituteofTechnologyHarbin150001China facultyofengineering KyotoUniversityKyoto606-8283Japan

After removing tin coating of tinplates offered by some steel works, we discovered massive, highly disperse gray points outspreading along rolling direction on the surface of the alloy layer. Morphology of the alloy layer was observed by scanning electron microscope (SEM), and many cavities of the alloy layer were found out in the gray point. After analyzing the composition of the alloy layer, we found that content of Fe in the gray points was more than that in the normal alloy layer. Moreover, corrosion resistance of the alloy layer declines with increase of amount of gray points. In addition, the hot-humidity testing was carried out for some plates whose surface has many gray points. After 14 days, there were many rust points occurring in the edge of gray points and in the small gray points. The morphology of rust points was observed by atomic force microscope (AFM). The reason why rust points generated in the edge of gray points and in the small gray points was discussed.

关键词： Sn-Fe alloy Gray point SEM AFM Corrosion resistance

Pneumatic active suspension system for a one-wheel car model using fuzzy reasoning and a disturbance observer

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Journal of Zhejiang University Science 2004年第9期5卷 1060-1068页

作者： YOSHIMURAToshio TAKAGIAtsushi DepartmentofMechanicalEngineering FacultyofEngineeringTheUniversityofTokushimaMinamijosanjima-cho2-1Tokushima770-8506Japan

This paper presents the construction of a pneumatic active suspension system for a one-wheel car model using fuzzy reasoning and a disturbance observer. The one-wheel car model can be approximately described as a nonlinear two degrees of freedom system subject to excitation from a road profile. The active control is composed of fuzzy and disturbance controls, and the active control force is constructed by actuating a pneumatic actuator. A phase lead-lag compensator is inserted to counter the performance degradation due to the delay of the pneumatic actuator. The experimental result indicates that the proposed active suspension improves much the vibration suppression of the car model.

关键词： One-wheel car model Active suspension system Fuzzy reasoning Pneumatic actuator Disturbance observer

Comparison and application of different empirical correlations for estimating the hydrate safety margin of oil-based drilling fluids containing ethylene glycol

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Journal of Natural Gas Chemistry 2011年第1期20卷 25-33页

作者： Fulong Ning Ling Zhang Guosheng Jiang Yunzhong Tu Xiang W u Yibing Yu facultyofengineering ChinaUniversityofGeosciencesWuhan430074HubeiChina DepartmentofChemistry NorwegianUniversityofScienceandTechnologyTrondheimNO-7491Norway NationalLaboratoryonScientificDrilling ChinaUniversityofGeosciencesatBeijingBeijing100083China

As the oil and gas industries continue to increase their activity in deep water, gas hydrate hazards will become more serious and challenging, both at present and in the future. Accurate predictions of the hydrate-free zone and the suitable addition of salts and/or alcohols in preparing drilling fluids are particularly important both in preventing hydrate problems and decreasing the cost of drilling operations. In this paper, we compared several empirical correlations commonly used to estimate the hydrate inhibition effect of aqueous organic and electrolyte solutions using experiments with ethylene glycol （EG） as a hydrate inhibitor. The results show that the Najibi et al. correlation （for single and mixed thermodynamic inhibitors） and the Ostergaard et al. empirical correlation （for single thermodynamic inhibitors） are suitable for estimating the hydrate safety margin of oil-based drilling fluids （OBDFs） in the presence of thermodynamic hydrate inhibitors. According to the two correlations, the OBDF, composed of 1.6 L vaporizing oil, 2% emulsifying agent, 1% organobentonite, 0.5% SP-1, 1% LP-1, 10% water and 40% EG, can be safely used at a water depth of up to 1900 m. However, for more accurate predictions for drilling fluids, the effects of the solid phase, especially bentonite, on hydrate inhibition need to be considered and included in the application of these two empirical correlations.

关键词： oil-based drilling fluid gas hydrates ethylene glycol inhibition prediction

Two stages kinetics of municipal solid waste inoculation composting processes

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Journal of Environmental Sciences 2004年第3期16卷 520-524页

作者： XIBei-dou HUANGGuo-he QINXiao-sheng LIUHong-liang ChineseResearchAcademyofEnviromnentalScience Beijing100012China EVSE FacultyofEngineeringUniversityofReginaReginaSKCanadaS4S0A2

In order to understand the key mechanisms of the composting processes, the municipal solid waste(MSW) composting processes were divided into two stages, and the characteristics of typical experimental scenarios from the viewpoint of microbial kinetics was analyzed. Through experimentation with advanced composting reactor under controlled composting conditions, several equations were worked out to simulate the degradation rate of the substrate. The equations showed that the degradation rate was controlled by concentration of microbes in the first stage. The degradation rates of substrates of inoculation Run A, B, C and Control composting systems were 13 61 g/(kg·h), 13 08 g/(kg·h), 15 671 g/(kg·h), and 10 5 g/(kg·h), respectively. The value of Run C is around 1 5 times higher than that of Control system. The decomposition rate of the second stage is controlled by concentration of substrate. Although the organic matter degradation rates were similar to all Runs, inoculation could reduce the values of the half velocity coefficient K \-m and could be more efficient to make the composting stable. Particularly, for Run C, the degradation rate is high in the first stage, and K \-m is low in the second stage. The results indicated that the inoculation was efficient for the composting processes.

关键词： municipal solid waste inoculation complex microbial community oxygen consumption two stages kinetics equations