New Dioscin-Glycosidase Hydrolyzing Multi-Glycosides of Dioscin from Absidia Strain

( Yao Yao Fu ),( Hong Shan Yu ),( Si Hui Tang ),( Xiang Chun Hu ),( Yuan Hao Wang ),( Bing Liu ),( Chen Xu Yu ),( Feng Xie Jin ) 한국미생물 · 생명공학회 2010 Journal of microbiology and biotechnology Vol.20 No.6

Low Specific On-resistance SOI LDMOS Device with P⁺P-top Layer in the Drift Region

Yao, Jia-Fei,Guo, Yu-Feng,Xu, Guang-Ming,Hua, Ting-Ting,Lin, Hong,Xiao, Jian The Institute of Electronics and Information Engin 2014 Journal of semiconductor technology and science Vol.14 No.5

In this paper, a novel low specific on-resistance SOI LDMOS Device with P+P-top layer in the drift region is proposed and investigated using a two dimensional device simulator, MEDICI. The structure is characterized by a heavily-doped $P^+$ region which is connected to the P-top layer in the drift region. The $P^+$ region can modulates the surface electric field profile, increases the drift doping concentration and reduces the sensitivity of the breakdown voltage on the geometry parameters. Compared to the conventional D-RESURF device, a 25.8% decrease in specific on-resistance and a 48.2% increase in figure of merit can be obtained in the novel device. Furthermore, the novel $P^+P$-top device also present cost efficiency due to the fact that the $P^+$ region can be fabricated together with the P-type body contact region without any additional mask.

Investigating the load–displacement restorative force model for steel slag self stressing concrete–filled circular steel tubular columns

Feng Yu,Bo Xu,Chi Yao,Alei Dong,Yuan Fang 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.49 No.6

To investigate the seismic behavior of steel slag self-stressing concrete–filled circular steel tubular (SSSCFCST) columns, 14 specimens were designed, namely, 10 SSSCFCST columns and four ordinary steel slag (SS) concrete (SSC)–filled circular steel tubular (SSCFCST) columns. Comparative tests were conducted under low reversed cyclic loading considering various parameters, such as the axial compression ratio, diameter–thickness ratio, shear–span ratio, and expansion ratio of SSC. The failure process of the specimens was observed, and hysteretic and skeleton curves were obtained. Next, the influence of these parameters on the hysteretic behavior of the SSSCFCST columns was analyzed. The self stress of SS considerably increased the bearing capacity and ductility of the specimens. Results indicated that specimens with a shear–span ratio of 1.83 exhibited compression bending failure, whereas those with shear–span ratios of 0.91 or 1.37 exhibited drum-shaped cracking failure. However, shear–bond failure occurred in the nonloading direction. The stiffness of the falling section of the specimens decreased with increasing shear–span ratio. The hysteretic curves exhibited a weak pinch phenomenon, and their shapes evolved from a full shuttle shape to a bow shape during loading. The skeleton curves of the specimens were nearly complete, progressing through elastic, elastoplastic, and plastic stages. Based on the experimental study and considering the effects of the SSC expansion rate, shear–span ratio, diameter–thickness ratio, and axial compression ratio on the seismic behavior, a peak displacement coefficient of 0.91 was introduced through regression analysis. A simplified method for calculating load– displacement skeleton curves was proposed and loading and unloading rules for SSSCFCST columns were provided. The load– displacement restorative force model of the specimens was established. These findings can serve as a guide for further research and practical application of SSSCFCST columns.

Carbon coated porous nickel phosphides nanoplates for highly efficient oxygen evolution reaction

Yu, Xin-Yao,Feng, Yi,Guan, Buyuan,(David) Lou, Xiong Wen,Paik, Ungyu The Royal Society of Chemistry 2016 Energy & environmental science Vol.9 No.4

<P>Electrochemical splitting of water provides an attractive way to produce hydrogen fuel. Unfortunately, the efficient and large-scale H-2 production is still hindered by the sluggish kinetics of the oxygen evolution reaction (OER) at the anode side of a water electrolyzer. Starting from metal-organic frameworks (MOFs), we demonstrate a template-engaged strategy to transformNi-Ni Prussian blue analogue (PBA) nanoplates into porous carbon coated nickel phosphides nanoplates with mixed phases of Ni5P4 and Ni2P. For comparison, NiO and Ni(OH)(2) porous nanoplates with the similar morphology have also been synthesized from the same precursor. Benefitting from their structural merits and the in situ formed catalytically active oxidized nickel species, the as-derived nickel phosphides manifest excellent electrocatalytic activity for OER superior to NiO and Ni(OH)(2).</P>

Nickel cobalt phosphides quasi-hollow nanocubes as an efficient electrocatalyst for hydrogen evolution in alkaline solution

Feng, Yi,Yu, Xin-Yao,Paik, Ungyu The Royal Society of Chemistry 2016 Chemical communications Vol.52 No.8

<P>A template-engaged strategy is used to synthesize nanostructured metal phosphides with different compositions. Among the as-synthesized metal phosphides, nickel cobalt phosphides quasi-hollow nanocubes exhibit the best electrocatalytic activity for hydrogen evolution reaction in terms of lower overpotential and smaller Tafel slope in alkaline solution.</P>

Reasearch on the main factors for changes in pressure based on turbulent circulating fluidized bed coal gasification technology

Duan Feng,Jin Bao-Sheng,Huang Ya-Ji,Li Bin,Sun Yu,Wu Yiming,Zhang Ming-Yao 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.6

High temperature preheated air and steam as gasifying agent and coal gasification was performed in a pressurized turbulent circulating fluidized bed (CFB) gasification pilot plant to investigate the pressurized gasification process and estimate its potential. Within the scope of this paper this test facility as well as its operation behavior was described. Furthermore, the parameter pressure has been investigated regarding its influence on the syngas composition and was presented and discussed in the following. The results show that the gasification quality is improved at higher pressure because of the better fluidization in the reactor. Coal gasification at a higher pressure shows advantages in lower heat value and carbon conversion. With the gasifier pressure increased from 0.1MPa to 0.3MPa, the gas heating value is increased by 15%. Increasing the gasifier pressure would increase the carbon conversion from 57.52% to 76.76%. Also, the dry gas yield and efficiency of cold gas increase little with the increase of the gasifier pressure. The operating parameter of pressure exists at optimum operating range for this specific CFB coal gasification process.

Incidence and relative risk factors in posttransplant diabetes mellitus patients: a retrospective cohort study

Ching-Yao Cheng,Yu-Tung Feng,Hue-Yu Wang 대한이식학회 2020 Korean Journal of Transplantation Vol.34 No.4

Background: Posttransplant diabetes mellitus (PTDM) has a long-term impact on kidney transplantation outcomes, such as graft and patient survival. The incidence and risk factors of PTDM are well studied, but long-term follow-up results remain unavailable. We examined the long-term incidence and relative risk factors of PTDM. Methods: A hospital information system database for kidney transplant recipients (KTRs) for a transplantation center between 1983 and 2018 was used to perform this retrospective cohort study. KTRs with DM diagnosis and continuous use of hypoglycemic agents for more than 3 months were defined as having PTDM. Demographics and comorbidities before transplantation were also collected. Kaplan-Meier analyses were used to determine the cumulative incidence and relative risk factors. Results: A total of 296 PTDM cases were confirmed (28.46%) in this study. An increased cumulative incidence associated with age was noted, which was significantly increased in those aged ≥40 years. Male sex, hypertension, hyperlipidemia before transplantation, cytomegalovirus (CMV) infection, and tacrolimus-based regimens were also risk factors. No significant correlation was found between the development of PTDM and the increase of human leukocyte antigen mismatches, the primary causes of end-stage renal disease, and acute rejection. Conclusions: PTDM incidence was high in this cohort study. Characteristics such as age ≥40 years, tacrolimus use, comorbidity of hypertension and hyperlipidemia before transplantation, and CMV infection were associated with a high risk of PTDM. Monitoring and adjusting preventable risk factors such as CMV infection might be useful to prevent PTDM.

Direct Adaptive Fuzzy Sliding Mode Control for Under-actuated Uncertain Systems

Shun-Feng Su,Yao-Chu Hsueh,Cio-Ping Tseng,Song-Shyong Chen,Yu-San Lin 한국지능시스템학회 2015 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.15 No.4

The development of the control algorithms for under-actuated systems is important. Decoupled sliding mode control has been successfully employed to control under-actuated systems in a decoupling manner with the use of sliding mode control. However, in such a control scheme, the system functions must be known. If there are uncertainties in those functions, the control performance may not be satisfactory. In this paper, the direct adaptive fuzzy sliding mode control is employed to control a class of under-actuated uncertain systems which can be regarded as a combination of several subsystems with one same control input. By using the hierarchical sliding control approach, a sliding control law is derived so as to make every subsystem stabilized at the same time. But, since the system considered is assumed to be uncertain, the sliding control law cannot be readily facilitated. Therefore, in the study, based on Lyapunov stable theory a fuzzy compensator is proposed to approximate the uncertain part of the sliding control law. From those simulations, it can be concluded that the proposed compensator can indeed cope with system uncertainties. Besides, it can be found that the proposed compensator also provide good robustness properties.

Mechanical behavior of rock-coal-rock specimens with different coal thicknesses

Guo, Wei-Yao,Tan, Yun-Liang,Yu, Feng-Hai,Zhao, Tong-Bin,Hu, Shan-Chao,Huang, Dong-Mei,Qin, Zhe Techno-Press 2018 Geomechanics & engineering Vol.15 No.4

To explore the influence of coal thickness on the mechanical behavior and the failure characteristics of rock-coal-rock (RCR) mass, the experimental investigation of uniaxial compressive tests was conducted first and then a systematic numerical simulation by particle flow code (PFC2D) was performed to deeply analyze the failure mechanical behavior of RCR specimens with different coal thicknesses in conventional compression tests. The overall elastic modulus and peak stress of RCR specimens lie between the rock and the coal. Inter-particle properties were calibrated to match the physical sample strength and the stiffness response. Numerical simulation results show that the deformation and strength behaviors of RCR specimens depend not only on the coal thickness, but also on the confining pressure. Under low confining pressures, the overall failure mechanism of RCR specimen is the serious damage of coal section when the coal thickness is smaller than 30 mm, but it is shear failure of coal section when the coal thickness is larger than 30 mm. Whereas under high confining pressures, obvious shear bands exist in both the coal section and the rock section when the coal thickness is larger than 30 mm, but when the coal thickness is smaller than 30mm, the failure mechanism is serious damage of coal section and shear failure of rock section.

Direct Adaptive Fuzzy Sliding Mode Control for Under-actuated Uncertain Systems

Su, Shun-Feng,Hsueh, Yao-Chu,Tseng, Cio-Ping,Chen, Song-Shyong,Lin, Yu-San Korean Institute of Intelligent Systems 2015 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.15 No.4

The development of the control algorithms for under-actuated systems is important. Decoupled sliding mode control has been successfully employed to control under-actuated systems in a decoupling manner with the use of sliding mode control. However, in such a control scheme, the system functions must be known. If there are uncertainties in those functions, the control performance may not be satisfactory.In this paper, the direct adaptive fuzzy sliding mode control is employed to control a class of under-actuated uncertain systems which can be regarded as a combination of several subsystems with one same control input. By using the hierarchical sliding control approach, a sliding control law is derived so as to make every subsystem stabilized at the same time. But, since the system considered is assumed to be uncertain, the sliding control law cannot be readily facilitated. Therefore, in the study, based on Lyapunov stable theory a fuzzy compensator is proposed to approximate the uncertain part of the sliding control law. From those simulations, it can be concluded that the proposed compensator can indeed cope with system uncertainties. Besides, it can be found that the proposed compensator also provide good robustness properties.