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Liu Genshen,Wei Peitang,Liu Huaiju,Du Xuesong,Hu Rui,He Huilin,Zhou Pengliang,Tan Xiaoqing 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.6
The planetary roller screw mechanism (PRSM) is an advanced linear transmission device. The relationship between tolerance allocation and performance risk still remains elusive, which is a challenge for its future applications. This work proposes a novel transmission accuracy–axial backlash–fatigue life-driven tolerance optimization method for the screw, roller, and nut of PRSM. A computational framework for PRSM transmission accuracy, axial backlash, and fatigue life calculation is developed to work on the parametric variation of design parameters including the eccentric, pitch, nominal diameter, and flank angle. Combinations of parametric variation are obtained by the Latin hypercube sampling-based tolerance statistical model to rapidly evaluate PRSM performance risk under operation conditions and tolerance parameters. The optimal tolerance parameters with the expanded width of tolerance interval and the minimum PRSM performance risk probability are obtained using the non-dominated sorting genetic algorithm. Results reveal that PRSM performance risk probabilities change from 89.25 to 68.72% and 58.1 to 56.86%, with 29.94 and 17.38% tolerance interval width increase under the high-precision and heavy-loading operation cases studied, respectively.
Jianqiao Liu,Guohua Jin,Zhaoxia Zhai,Faheema Fairuj Monica,Xuesong Liu 대한금속·재료학회 2015 ELECTRONIC MATERIALS LETTERS Vol.11 No.3
The grain size effects on tin oxide gas-sensitive elements are numerically described by the model of gradient-distributed oxygen vacancies, which extends the receptor function of semiconductors to the condition of inhomogeneous donor density in grains. The sensor resistance and the response to the reducing gas are formulated as functions of the grain size and the depletion layer width. The simulations show good agreement with the experimental results. The depletion layer width is estimated as 4 nm for the undoped SnO2 element, whereas the values are 2 and 7 nm for Sb-doped and Al-doped samples, respectively. The results are experimentally verified by the donor-doped SnO2 thin films, the depletion layer widths of which are evaluated on the basis of the correlation between the electrical resistance and the Sb-doping amount. The location of the Fermi level is found to be a crucial factor that dominates the evaluation results.
The Role of Tumor Microenvironment in Mycosis Fungoides and Sézary Syndrome
( Zhaorui Liu ),( Xuesong Wu ),( Sam T. Hwang ),( Jie Liu ) 대한피부과학회 2021 Annals of Dermatology Vol.33 No.6
Mycosis fungoides (MF) and Sezary syndrome (SS) are the most common subtypes of cutaneous T-cell lymphomas (CTCLs). Most cases of MF display an indolent course during its early stage. However, in some patients, it can progress to the tumor stage with potential systematic involvement and a poor prognosis. SS is defined as an erythrodermic CTCL with leukemic involvements. The pathogenesis of MF and SS is still not fully understood, but recent data have found that the development of MF and SS is related to genetic alterations and possibly to environmental influences. In CTCL, many components interacting with tumor cells, such as tumor-associated macrophages, fibroblasts, dendritic cells, mast cells, and myeloid-derived suppressor cells, as well as with chemokines, cytokines and other key players, establish the tumor microenvironment (TME). In turn, the TME regulates tumor cell migration and proliferation directly and indirectly and may play a critical role in the progression of MF and SS. The TME of MF and SS appear to show features of a Th2 phenotype, thus dampening tumorrelated immune responses. Recently, several studies have been published on the immunological characteristics of MF and SS, but a full understanding of the CTCL-related TME remains to be determined. This review focuses on the role of the TME in MF and SS, aiming to further demonstrate the pathogenesis of the disease and to provide new ideas for potential treatments targeted at the microenvironment components of the tumor.
Jianqiao Liu,Zhaoxia Zhai,Guohua Jin,Yuan Li,Faheema Fairuj Monica,Xuesong Liu 대한금속·재료학회 2015 ELECTRONIC MATERIALS LETTERS Vol.11 No.1
The model of gradient-distributed oxygen vacancies is utilized in simulatingthe grain size effects of gas-sensitive SnO2 thin films. The distribution profileof oxygen vacancies has a grain size effect and the profile gradient correlatespositively with the radius of the grains. The simulation results show that thegrain size is a fundamental factor dominating the gas-sensing properties ofthin films. The potential barrier height and resistivity have significant grainsize effects when m is between 0.1 and 0.5 nm−1. The size effects on sensorresponse to stimulant gases can be enhanced by increasing the value of m orthe absolute value of α. Two expressions are used to simulate the grain sizeeffect of the sensor response. The expressions act similarly when α < 0.2. The simplified response provides a neat function to quantitatively explain thesensor performance on gases with low partial pressure. Although the accurate response is complicated, it is applicable to theentire concentration range. A small power-law exponent n is calculated from the accurate response expression when a high gasconcentration is employed, illustrating a “saturation effect” of the response.
Performance Research of Counter-rotating Tidal Stream Power Unit
Xuesong Wei,Bin Huang,Pin Liu,Toshiaki Kanemoto 한국유체기계학회 2016 International journal of fluid machinery and syste Vol.9 No.2
An experimental investigation was carried out to improve the performance of a counter-rotating type horizontal-axis tidal stream power unit. Front and rear blades were designed separately based on modified blade element momentum (BEM) theory, and their performances at different conditions of blade tip speed ratio were measured in a wind tunnel. Three different groups of blades were designed successively, and the results showed that Group3 possessed the highest power coefficient of 0.44 and was the most satisfactory model. This experiment shows that properly increasing diameter and reducing chord length will benefit the performance of the blade.
Xuesong Feng,Yuanpeng Jie,Haidong Liu,Xun Sun,Bin Xu 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.6
Utilizing a computer-aided simulation approach, this work studies the impacts of different inter-stop transport distances on the transport efficiency evaluated by the transport time cost intensity of a typically composed Chinese freight train hauled by representative types of locomotives in view of different target speeds. It is found that the decelerated decrease of the transport time cost intensity with improving the target speed is much traded off by decreasing the stop-spacing especially below approximately 20.00 km. Moreover, the decrease of the inter-stop transport distance especially shorter than about 20.00 km obviously increases the transport time cost intensity in an accelerated way for the same target speed. Such a trend is more apparent when the target speed becomes relatively high. Therefore, it is suggested that the inter-stop transport distance of a freight train ought to be over 20.00 km for relatively high transport efficiency.
Performance Research of Counter-rotating Tidal Stream Power Unit
Wei, Xuesong,Huang, Bin,Liu, Pin,Kanemoto, Toshiaki Korean Society for Fluid machinery 2016 International journal of fluid machinery and syste Vol.9 No.2
An experimental investigation was carried out to improve the performance of a counter-rotating type horizontal-axis tidal stream power unit. Front and rear blades were designed separately based on modified blade element momentum (BEM) theory, and their performances at different conditions of blade tip speed ratio were measured in a wind tunnel. Three different groups of blades were designed successively, and the results showed that Group3 possessed the highest power coefficient of 0.44 and was the most satisfactory model. This experiment shows that properly increasing diameter and reducing chord length will benefit the performance of the blade.