摘要：
This study utilises the transfer matrix method (TMM) to address the acoustic characteristics of multilayered cylindrical shells lined with porous materials. The TMM theoretical model for the sound transmission loss of composite cylindrical shells with internal porous materials is derived by establishing transfer matrices for the air/composite material interface, composite material/foam interface, foam/air interface and boundary interfaces. The accuracy of the TMM model is validated through a comparison and analysis with experimental results. Building upon this, the impact of porous foam material parameters and types on the structural sound transmission loss is discussed. The results indicate that the use of TMM accurately reflects the acoustic performance of composite structures. Additionally, this model allows for the determination of the influence patterns of porous foam material parameters and types on the acoustic performance of composite structures. In the frequency range of 100-10,000 Hz, the sound transmission loss of the melamine foam-lined composite structure increases with the increase in flow resistance and porosity and the decrease of the tortuosity factor. The use of the porous lining material significantly enhances the structural sound insulation performance.
摘要：
Polystyrene (PS) is a widely used matrix material in selective laser sintering (SLS). Polystyrene is inexpensive and its powdered form, used as a matrix material in selective laser sintering, enables high accuracy in prototype production, similar to the casting process of wax molds. However, the performance of polystyrene varies significantly due to the differences in its synthetic process and added fillers of different grades available in the market, leading to varying outcomes when used in selective laser sintering technology. Therefore, it is necessary to study the polystyrene materials available in the market to identify the most suitable ones for selective laser sintering technology. In this study, three different grades of polystyrene powder (75-100 mu m) were selected as research objects and treated to sintering experiments using a "selective laser sintering" rapid prototyping machine. The research results indicated that the molecular weight affects the quality of selective laser sintering parts by influencing the melt viscosity of polystyrene, which in turn affects the density and accuracy of the fabricated parts. Guided by these research findings, two 75-100 mu m polystyrene powder materials were selected, and their sintering performance and thermal weight loss characteristics were investigated. Under optimized processing parameters, the test specimens with high accuracy were fabricated by selective laser sintering, and its mechanical property was further reinforced through epoxy resin post-processed, and the microstructure of the tensile fracture surface was examined using electron microscopy. In conclusion, the PS1 type polystyrene material and its process parameters, suitable in selective laser sintering and its post-processing, were determined. The research findings presented in this paper provided a methodology for the selection of selective laser sintering materials.
摘要：
To verify whether the results of rapid thermal fatigue of solder joint are consistent with that of the conventional fatigue method, the repeated thermal cycling condition of alternating temperature should be created. In this paper, an experiment, which heat rapidly a metal boss under the single solder joint in 10 seconds by the induced eddy current effect of electromagnetic field and then stop to heat it at the same time in sequence, was implemented. That is to say, the single solder joint above the boss was heated and cooled through heat conduction of the boss where the heat quantity is generated by the electromagnetic induction heating. The condition of rapid thermal cycle was realized by this method. When the single solder joint was subjected to rapid thermal cycling, the interfacial microstructure between the solder ball and Cu substrate was observed and analyzed by SEM. The results indicated that this method supplying rapid heat source by induction heating is feasible to investigate the rapid thermal fatigue behavior of single solder joint. This method can provide more experience for fatigue failure to effectively improve the reliability of the electronic packaging devices.
摘要：
LEDs have the advantages of high efficiency, low power consumption, environmental friendliness and long life. Nowadays with brightness of LEDs increasing rapidly, it has various applications such as street light, flat panel backlighting, vehicle forward lamp and general illumination. The increasing demand for light emitting diodes (LEDs) has been absorbed by a number of application fields, including display backlighting, communications, medical services, signage, and general illumination. When high power LEDs are applied under complex service conditions, especially encounter thermal fluctuations and off and on duty cycles, the cyclical strain and stress are imposed upon its chip, which eventually leads to chip failure. In particular, with the trend that LEDs are expected to service in more dynamic environments where the temperature distribution change with time, not only the luminous flux and thermal resistance but also the fatigue resistance of the chip become of great significance for reliability.
摘要：
Aiming at the current SLS forming metal parts with poor performance, low accuracy, and cannot be directly used, etc., in this paper, Having studied a formula of SLS forming material with good formability, simple preparation and low cost for laser sintering. Using the orthogonal cut-and-try method to study and optimize the influence of SLS forming craft parameter on the shape semi-finished product intensity and the precision. By analyzing the high temperature sintering process of the degraded billet, the high temperature sintering process of the composite metal powder material was established. Having studied The mechanical strength of metal parts after the post-treatment process such as degreasing and high-temperature sintering, as well as its internal microscopic organization appearance characteristic, obtain the compared effect.
期刊：
International Journal of Hydrogen Energy,2019年44(38):21080-21089 ISSN：0360-3199
通讯作者：
Tu, Zhengkai
作者机构：
[Shu, Shuiming; Chang, Huawei; Xu, Xiangxiang; Tu, Zhengkai] Huazhong Univ Sci & Technol, Sch Energy & Power Engn, Wuhan 430074, Hubei, Peoples R China.;[Duan, Chen] Wuhan Second Ship Design & Res Inst, Wuhan 430064, Hubei, Peoples R China.;[Pei, Houchang] Wuhan Polytech Univ, Sch Mech Engn, Wuhan 430048, Hubei, Peoples R China.
通讯机构：
[Tu, Zhengkai] H;Huazhong Univ Sci & Technol, Sch Energy & Power Engn, Wuhan 430074, Hubei, Peoples R China.
会议名称：
13th International Symposium on HYdrogen POwer THeoretical and Engineering Solutions (HYPOTHESIS)
会议时间：
JUL 24-27, 2017
会议地点：
Singapore, SINGAPORE
会议主办单位：
[Chang, Huawei;Xu, Xiangxiang;Shu, Shuiming;Tu, Zhengkai] Huazhong Univ Sci & Technol, Sch Energy & Power Engn, Wuhan 430074, Hubei, Peoples R China.^[Duan, Chen] Wuhan Second Ship Design & Res Inst, Wuhan 430064, Hubei, Peoples R China.^[Pei, Houchang] Wuhan Polytech Univ, Sch Mech Engn, Wuhan 430048, Hubei, Peoples R China.
关键词：
CCHP;Economic performance;Environmental performance;High temperature PEMFC;Solar energy;Thermal performance
摘要：
A solar energy and high temperature proton exchange membrane fuel cell (PEMFC)-based micro-combined cooling, heating and power (CCHP) system (named system I) is proposed in this work. This system mainly consists of a PEMFC subsystem, an organic Rankine cycle (ORC) subsystem and a vapor compression cycle (VCC) subsystem. System I would reduce to a high temperature PEMFC-based CCHP system (named system II) if there was no solar energy. With the technical performance analysis models developed, the effects of the current density, operating temperature, solar radiation intensity and ambient temperature on the thermal, economic and environmental performances of the systems are theoretically analyzed. The results show that the current density and solar radiation intensity are the main impact factors that can significantly affect the thermal, economic and environmental performances, while the operating temperature and ambient temperature only have remarkable influences on the thermal performance. The coefficient of performance (COP) of system II is approximately 1.19 in summer and 1.42 in winter, which is always higher than that of system I under the same working conditions. The exergy efficiency of system I and system II are approximately 49.7% and 47.4%, respectively. The primary energy saving rates (PESRs) of system I and system II are 64.9% and 31.8% in summer, and 60.0% and 36.2% in winter, respectively. The payback periods of system I and system II are 9.6 yr and 6.0 yr without government subsidy, respectively. Compared with system II, the pollutant emission reduction rates (ERRs) of system I can be increased by approximately 8.4%–23.5% with the addition of solar energy, which indicates that the development and utilization of clean and renewable energy such as solar energy can significantly reduce pollutant emissions.
摘要：
A variety of recovered-edible-oil identification models were established by using Raman combined with near-infrared spectroscopy (NIR). Eight types of 156 edible vegetable oil samples were collected to acquire their Raman and NIR spectra. The spectral data were processed for modeling. The preprocessing methods for the Raman spectra included the moving average method (11 points), adaptive iterative reweighted-penalty least squares method, and the normalization method based on the intensity of the characteristic peak at 1454 cm-1 (MA11-airPLS-Nor). The preprocessing method for the NIR spectra was the standard normal variable transformation algorithm combined with a detrending technique (SNV_DT). The Raman and NIR spectra were fused at the feature level by using independently the serial fusion and wavelet fusion approaches. The results showed that with the serial-fusion-and wavelet-fusion-based models, the identification of recovered oils can be achieved very rapidly. Furthermore, the comprehensive performances of the models based on fused Raman and NIR data were better than those of models based on separate Raman or NIR data.
摘要：
Aiming at the adulteration of sesame oil, our research is focused on using near-infrared spectroscopy combined with chemometrics to achieve rapid detection. The near-infrared spectrum of the sample was collected, and the data analysis and modeling were conducted on MATLAB. The raw spectral data was pretreated using multiplicative scatter correction (MSC) and standard normal variate (SNV). Support vector machine (SNM) model was established by using competitive adaptive reweighed sampling (CARS) and combined synergy interval partial least squares (SiPLS) to select characteristic spectral data. The highest correct recognition rate of the qualitative model is 100%, the mean square error MSE of the quantitative model is 0.0829, and the correlation error R is 99.0772%. The results prove that the support vector machine classification model established by near-infrared spectroscopy combined with chemometrics can qualitatively detect whether sesame oil is adulterated. In the meanwhile, the SNM model can quantitatively predict the content of active components.
摘要：
LEDs (Light Emitting Diodes) Light source due to conform to the low carbon, green and environmental protection and social development requirements, has been widely used in the field of information field, lighting, display, is the incandescent lamp, fluorescent lamp, gas discharge lamp after a new type of Light source. Many research institutions have developed with high level of LED testing equipment, but overall, the high cost of the equipment. At present, our country's national standards in the field of LED and related products is still a blank, no unified standards and test methods to regulate the industry, making the industry products are good and bad are intermingled. In the design of test system, this paper first introduces the basic theory about LED photometric measurement and measurement standards and the status quo at home and abroad, and the main optical parameters of traditional measurement methods are summarized. Then, according to the principle of digital imaging, the overall scheme of the two kinds of measurement system is presented. Therefore, this article USES the by a CCD camera and a lambert scattering screen composition, light from the LED light to the front of the screen surface, and CCD camera filmed illuminated screen. Experiment, he measured data for the system parameters in a calibration scheme. Since then, we can use two other LED light intensity distribution measurement system plan, this completes the LED the design and development of the spatial light intensity distribution measuring device, the set of instrument system can complete the LED light intensity and photometric parameters of rapid measurement, suitable for LED production testing and research.
摘要：
This experiment mainly study the influence of the thermal fatigue of solder joint, solder was - Cu and Sn, Pb, Sn - Ag is 760 microns in diameter, welding plate of 560 microns. Internationally accepted tin-lead solder is most likely to replace the Sn Ag - Cu alloy series. In order to study the temperature and stress under the dual function of single substrate BGA solder joint in the process of thermal fatigue deformation process, organizational structure evolution, establishing the model of fatigue study solder joint fatigue mechanism; Find out fast cyclic heating and fast cooling the coupling mechanism of solder joint fatigue and solder joint interface evolution process. First of all, experimental apparatus mainly has a high frequency current box, catheter, relay and thermocouple. Under the condition of rapid heating and rapid cooling, the thermal fatigue behavior of single substrate.
摘要：
Covalent compounds have strong covalent bond, thus showing high melting point, high hardness, high temperature resistance, corrosion resistance, wear resistance and other excellent performance, is widely applied to the field of refractory materials and wear-resistant materials.But at the same time this kind of material also has the problem of poor toughness and difficulty in sintering.In this article, by adding the nonstoichiometric ratio to the AlN titanium nitride, a new method were studied to improve the sintering property and reduce the sintering temperature through vacancy diffusion and to study the sintering of micro forming mechanism. The experimental results show that after sintering at the interface between TiN0.3 and AlN two-phase, the TiN0.3 / AlN layer have apparent diffusion zone, AlN in N, Al atom diffusion in TiN0.3 via the vacancy diffusion mechanism. As a result of the existence of a large amount of N of TiN0.3 space, when the diffusion of N atomic migration in TiN0.3 is absorbed by vacancy,and approaches stoichiometric ratio TiN layer AlN substrate;Al atoms crystallized out of the TiN layer in the hexagonal AlN structure in TiN0.3 matrix.
会议论文集名称：
The 1st International Symposium on Application of Materials Science and Energy Materials (SAMSE 2017) 论文集
摘要：
Abnormal grain growth of single phase AZ31 Mg alloy in the spatio-temporal process has been simulated by phase field models,and the influencing factors of abnormal grain growth are studied in order to find the ways to control secondary recrystallization in the microstructure.The study aims to find out the mechanisms for abnormal grain growth in real alloys.It is shown from the simulated results that the abnormal grain growth can be controlled by the strain restored energy.Secondary recrystallization after an annealing treatment can be induced if there are grains of a certain orientation in the microstructure with local high restored energy.However,if the value of the local restored energy at a certain grain orientation is not greater than 1.1E0,there may be no abnormal grain growth in the microstructure.
摘要：
To identify the type of edible oil, we proposed a near-infrared (NIR) spectral analysis method based on the contents of four characteristic components: iodine value, palmitic acid, oleic acid, and linoleic acid. Built support vector machine qualitative models that can identify eight kinds of oil. The four characteristic component values of 129 oil samples from 8 kinds of oil were collected and detected. Established three SVC identification models by using three parameter optimization methods including genetic algorithm, grid search and particle swarm optimization. The results showed that the prediction sets' accuracy rates of all the three models were up to 100%. Especially, both the accuracy rates of the correction and prediction sets of the particle-swarm-optimization-support-vector-machine classification (PSO-SVC) model reached 100%. The results indicate that it is effective and feasible to use the contents of characteristic components to identify the type of edible oil, and this method is fast, convenient, and accurate.
会议名称：
2nd International Conference on Applied Mathematics, Simulation and Modelling (AMSM)
会议时间：
AUG 06-07, 2017
会议地点：
Adv Sci & Ind Res Ctr, Phuket, THAILAND
会议主办单位：
Adv Sci & Ind Res Ctr
会议论文集名称：
DEStech Transactions on Engineering and Technology Research
关键词：
Near infrared;Saponification value;Parameter optimization;SVR
摘要：
Regression prediction methods of the saponification value of edible oils,which were based on different parameter optimization algorithms combined with near infrared spectroscopy(NIR) were studied.The
关键词：
Continuous casting;The Finite Element Method;Temperature Field;Crystallizer;Casting Blank
摘要：
Crystallizer is the most important equipment of continuous casting process, and its structure is complex. In this paper, we analyze the mathematical model of heat transfer in caster crystallizer and c
关键词：
Alkaline noodle;Automatic production line;Wrapper cutting and rolling device;Dough wrapper;Roller die
摘要：
The production technology research of alkaline noodles is of instructive significance to existing noodle industry. As the key device of alkaline noodle automatic production line, the wrapper cutting and rolling device is designed in detail in this paper. On the basis of determining the overall layout of the device and relative position relations between modules, we research the key components, such as dough wrapper conveyer, the fixed-length cutting device, the dough wrapper rolling device, the roller die storage device and the rack, This paper emphasis on the parametric design of wrapper cutting and rolling device, using the MATLAB software to solve the cam profile curve of rising curve of roller die.
摘要：
BGA micro-joint with double substrates used by SAC305 lead-free solder is fabricated by reflowing process based on substrate FR-4. The microstructures of the solder joints are studied through the method of rapid thermal cycling (RPC). The double-based plate Cu/SAC305/Cu solder joint was tested at extreme temperature 60-180 degrees C by rapid thermal cycling 48 hours and 72 hours respectively, it was found the IMC grow by the zigzag shape, and fatigue cracks greatly appear at the interface of IMC/Cu, they are initiating and propagating along the boundary, and thread through the cross section of solder joint in the end, which lead to the failure of solder joint.
摘要：
The purpose of this study is to conduct qualitative analysis on the adulteration in peanut oil by combining data fusion of Raman and near infrared (NIR) spectral characteristics with chemometrics methods. With laser Raman and NIR spectrometer, the spectra of 134 adulterated oil samples and 24 pure peanut oil were collected. The spectra data of Raman and NIR were preprocessed. Competitive adaptive reweighted sampling(CARS) were used to extract the characteristic wavelengths of the spectra data. Combining data fusion technique and partial least squares linear discriminant analysis (PLS-LDA) method, the Ram-PLS-LDA model, NIR-PLS-LDA model and Ram-NIR-PLS-LDA model were established by using the obtained feature layer data. The calibration set and prediction set accuracy of the SG9-airPLS-Nor-CARS-SNV_DTCARS-PLS-LDA model are 100%. According to the analysis, the prediction accuracy of Ram-NIR-PLS-LDA model is better than that of single spectral model, data fusion technology can enhance the ability to identify the model, which is conducive to practical application. It shows that the two kinds of spectra are complementary, and the using of spectral analysis and data fusion technology has great application value in the identification of edible oil.
