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Chunsheng Zhu,Xiaoping Li,Bing Zhang,Zhijian Lin 한국한의학연구원 2017 Integrative Medicine Research Vol.6 No.1
In order to achieve the comprehensive quality control of Chinese herbal medicine (CHM), the conventional practice of selecting a single marker for testing has been gradually replaced by the determination of multiple active components based on the characteristics of the synergistic interaction of CHM and applicability of sophisticated analytical techniques. However, with a huge number of CHM in the market and more complex preparations, the limited availability of various standard substances for quantitative analysis has been a major bottleneck in realizing the goal. To overcome these uprising problems, quantitative analysis of multi-components by single marker (QAMS) was proposed and accepted as a new method to reflect the internal quality of CHM. In this review, the current knowledge about QAMS is systematically summarized, including the general content of QAMS, current status, and general procedure. Additionally, speculation is proposed about the future applications of QAMS approaches in the modernization and standardization of CHM.
Numerical and statistical analysis of permeability of concrete as a random heterogeneous composite
Kefei Li,Chunsheng Zhou 사단법인 한국계산역학회 2010 Computers and Concrete, An International Journal Vol.7 No.5
This paper investigates the concrete permeability through a numerical and statistical approach. Concrete is considered as a random heterogeneous composite of three phases: aggregates, interfacial transition zones (ITZ) and matrix. The paper begins with some classical bound and estimate theories applied to concrete permeability and the influence of ITZ on these bound and estimate values is discussed. Numerical samples for permeability analysis are established through random aggregate structure (RAS) scheme, each numerical sample containing randomly distributed aggregates coated with ITZ and dispersed in a homogeneous matrix. The volumetric fraction of aggregates is fixed and the size distribution of aggregates observes Fuller’s curve. Then finite element method is used to solve the steady permeation problem on 2D numerical samples and the overall permeability is deduced from flux-pressure relation. The impact of ITZ on overall permeability is analyzed in terms of ITZ width and contrast ratio between ITZ and matrix permeabilities. Hereafter, 3680 samples are generated for 23 sample sizes and 4 contrast ratios, and statistical analysis is performed on the permeability dispersion in terms of sample size and ITZ characteristics. By sample theory, the size of representative volume element (RVE) for permeability is then quantified considering sample realization number and expected error. Concluding remarks are provided for the impact of ITZ on concrete permeability and its statistical characteristics.
Junction temperature measurement method for IGBTs using turn-on miller plateau duration
Guo, Chunsheng,Zhang, Shiwei,Wei, Lei,Li, Hao,Wang, Sijin,Zhu, Konggang The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.9
A new method is proposed for the measurement of the junction temperature of insulated gate bipolar transistors (IGBTs) during operation. The application of this method overcomes the problems arising from the complexity of measurement circuits or the difficulty of tests. The proposed measurement method uses the turn-on Miller plateau duration (t<sub>mon</sub>), i.e., the duration from the first rising edge to the second rising edge of the gate-emitter voltage, of an IGBT. The obtained results show that t<sub>mon</sub> is strongly linear with respect to temperature. For comparison, the temperature-sensitive electrical parameters (TSEPs) turn-off Miller plateau duration (i.e., the duration between the two falling edges of the V<sub>ge-off</sub> curve) were also measured. The obtained results show that t<sub>mon</sub> exhibits a high sensitivity that permits accurate determination of the junction temperatures of IGBTs.
Investigation on Spraying Uniformity in Etching Process of FPCB with 18 μm Line Pitch
Ruijian Ming,Hui Li,Aojie Chen,Jiazheng Sheng,Bin Sun,Jian Wang,Chunsheng Huang,Jie Yang 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.5
In the wet etching process of the flexible printed circuit board (FPCB), to obtain a symmetrical and stable circuit structure and improve the yield, it is necessary to control the uniformity of the etchant velocity and pressure on the surface of the FPCB as far as possible. In this paper, a numerical method implemented with Euler multiphase flow model is proposed to study the spraying uniformity of the wet etching process of the FPCB. A 3D full model of the multi-nozzle array is established to study the velocity distribution of the etchant in the spraying domain. The FPCB sample is manufactured based on the process parameters obtained by the parametric study. In the experiment, pressure sensors are applied to monitor the etchant pressure on the surface of the FPCB and the cross-section of the FPCB circuit is observed, which validates the numerical simulation method. The results of simulations demonstrate that when the nozzle rotation angle θ is 1.3°, the distribution of the low-speed flow zone on the surface of the FPCB is about 60 mm along the X axis direction, and the standard deviation of the pressure is reduced by 67.6% compared to 0°. The cross-section of the FPCB circuit is close to an isosceles trapezoid with an 18 μm line pitch, which is the center-to-center distance between the adjacent circuit lines.
Type synthesis for lower-mobility decoupled parallel mechanism with redundant constraints
Shuwei Qu,Ruiqin Li,Chunsheng Ma,Hong Li 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6
A novel method for type synthesis of lower-mobility decoupled parallel mechanism with redundant constraints is proposed. Firstly, the definition of the redundant constraints is put forward. Then, number and topology structure synthesis is carried out based on the redundant constraints between the closed loop structure of parallel configuration. Next, the specific procedure for type synthesis of lower-mobility decoupled parallel mechanism is derived. Furthermore, the local freedom of the limbs was established through the relationship of motion-screw and constraint-screw between limbs. Finally, type synthesis of 2R1T decoupled parallel mechanism is established. The synthesized configuration theoretical output characteristics is a decoupled Jacobin matrix. The output characteristics are analyzed based on theoretical calculation and ADAMS simulation software. The simulation results and the theoretical calculation results are consistent. The proposed method can be applied to type synthesis of lower-mobility decoupled parallel mechanisms.
Yi Zuo,Yaonan Wang,Lihong Huang,Chunsheng Li 대한수학회 2009 대한수학회지 Vol.46 No.5
This paper considers the problem of existence and exponential stability of almost periodic solution for shunting inhibitory cellular neural networks with distributed delays and large impulses. Based on the contraction principle and Gronwall-Bellman's inequality, some sufficient conditions are obtained. The results of this paper are new and they complement previously known results. This paper considers the problem of existence and exponential stability of almost periodic solution for shunting inhibitory cellular neural networks with distributed delays and large impulses. Based on the contraction principle and Gronwall-Bellman's inequality, some sufficient conditions are obtained. The results of this paper are new and they complement previously known results.
Test Research on Influence Rule of Subsoiling Pressure to Subsoiling Quality
Zuo Shengjia,Kong Degang,Liu Chunsheng,Li Zhihui,Zhao Yongchao 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.10
Pneumatic subsoiling is a new subsoiling technology which uses the pneumatic fracturing principle. To conduct a research on the influence rules of subsoiling pressure to subsoiling quality, the method combining the soil resistivity test and CFD simulation test will be adopted to carry out a pneumatic subsoiling test through taking the increasing rate of soil porosity and soil surface uplift as evaluation index. The test results indicate that after pneumatic subsoiling, the soil porosity of plow pan increases obviously under different subsoiling pneumatic, effective break the plow pan; with the increase of bulk density of plow pan, the spread of the high pressure gas upwards in the plow pan shows a weakening trend and its spread towards horizontal direction shows a enhancing trend; for the plow pan with larger bulk density, the increasing rate of soil porosity and soil surface uplift will increase with the increasing of subsoiling pneumatic accordingly and for the plow pan with smaller bulk density, its regularity is not obvious. Simultaneously, the subsoiling pneumatic and its technical parameters fit for plow pan with different bulk density will be obtained to provide a basis for in-depth research of pneumatic subsoiling technology and development of Pneumatic subsoiling machine.
Zuo, Yi,Wang, Yaonan,Huang, Lihong,Li, Chunsheng Korean Mathematical Society 2009 대한수학회지 Vol.46 No.5
This paper considers the problem of existence and exponential stability of almost periodic solution for shunting inhibitory cellular neural networks with distributed delays and large impulses. Based on the contraction principle and Gronwall-Bellman's inequality, some sufficient conditions are obtained. The results of this paper are new and they complement previously known results.