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Changsheng Zhang,Jiahong Zhang,Zhengang Zhao 한국광학회 2020 Current Optics and Photonics Vol.4 No.4
An approach based on an integrated photonic Ti: LiNbO 3 Y branch has been proposed, designed, and analyzed for the microwave instantaneous frequency measurement (IFM). By designing the Y branch with length L = 6545 µm and refractive index N TE - N TM = 0.0764, a complementary optical filter with free spectral range (FSR) of 600 GHz is constituted, which results in a maximum measureable frequency of 300 GHz being obtained. Theoretical analysis on the temperature stability of the Ti: LiNbO 3 Y branch shows that the FSR variation of the complementary filter is 0.3% for the temperature change of 100 K, which indicates that the IFM approach will have a better stability. All these results demonstrate that the proposed IFM approach has potential capability to be used for the increasingly higher microwave IFM with better stability.
Zhang Jian,Yan Bin,Chen Zhe,Zheng Zhaomin,Yang Changsheng 대한척추외과학회 2021 Asian Spine Journal Vol.15 No.5
Study Design: This was a retrospective clinical study. Purpose: This study aimed to evaluate the effect of combination therapy with zoledronic acid and teriparatide on the risk of new vertebral fracture (NVF) in type 2 diabetes mellitus (T2DM) patients after percutaneous kyphoplasty (PKP). Overview of Literature: Although T2DM had been associated with bone fragility and increased fracture risk, it remains unknown whether patients with T2DM could expect similar benefit from the combination therapy with zoledronic acid and teriparatide following PKP. Methods: Total 106 diabetic patients who had undergone PKP and had received anti-osteoporosis treatment for osteoporotic vertebral compression fracture were enrolled and allocated into the following two groups: group I (n=52, zoledronic acid) and group II (n=54, zoledronic acid plus teriparatide). The operating time, bone cement volume, and complications related to anti-osteoporosis treatment or PKP, if any, were recorded. The Visual Analog Scale (VAS) score and Oswestry Disability Index (ODI) were assessed at admission, at discharge, and at the final follow-up. Dual-energy X-ray absorptiometry scan of the hip for the measurement of the bone mineral density (BMD) was performed preoperatively and at the final follow-up for all the patients. Results: There was no significant difference in the age, body mass index, bone cement volume, or follow-up time of the groups. The mean follow-up duration was 22.5±1.6 months. All the patients had improved VAS and ODI, and group II had significantly better clinical outcomes than group I. All the patients had increased BMD at the latest follow-up, while group II exhibited significantly more improvement. The prevalence of NVF was lower in group II (11.5% vs. 7.4%, p=0.523). Male patients had a higher prevalence of NVF although the difference was not statistically significant. Conclusions: Combination therapy with zoledronic acid and teriparatide could improve the clinical outcomes, and BMD and had the potential to reduce NVF in diabetic patients following PKP.
Xuepeng Zhang,Yujing Jiang,Gang Wang,Jiankang Liu,Dong Wang,Changsheng Wang,Satoshi Sugimoto 한국지질과학협의회 2019 Geosciences Journal Vol.23 No.3
The physical and mechanical change processes of rock are closely related to energy transformation, and its deformation and failure is an instability phenomena driven by energy exchange. This study investigated mechanism of shear deformation, failure and energy dissipation of joint using both physical and numerical direct shear tests under constant normal load (CNL) condition. Three kinds of joint surface were artificially prepared. An acoustic emission system was employed to monitor acoustic emission in physical test, and rupture frequency was recorded in numerical test to represent micro-crack development. By research of numerical micro-crack development accompanied with physical acoustic emission results, mechanism of shear deformation and failure of joints were illustrated schematically. By definition of dissipation energy, captured using the particle flow code (PFC2D), energy releasing and dissipation were discussed with microscopic damage evolution of joints. Results showed that joints under shearing present a dissipation trend of four stages including a slow rise stage, a rapid rise stage, a shock rise stage and a rapid decline stage.
Qian Wang,Changsheng Shao,Qing Liu,Zhourong Zhang,Zhixia He 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.4
Effects of Injection rates on combustion process and emissions of engines operating with directly injected natural gas and pilot diesel were numerically investigated. Injection rates of natural gas and diesel were investigated separately utilizing five types of injection rates. An impact factor was defined to present the effects of the initial and terminal injection rates of diesel and natural gas on the combustion and emissions more intuitionally. Based on the simulation results, cylinder pressure and temperature were more sensitive to terminal injection rates of pilot diesel than initial injection rates, and lower terminal injection rates of pilot diesel can achieve lower NO and Soot emission level. However, there is a trade-off between NO and Soot emissions affected by different natural gas injection rates. The impact factors of pilot diesel injection rates on pressure show a double-peak trend. However, the impact factors of natural gas injection rates on pressure show a single-peak trend.
Guoxing Qiu,Dongping Zhan,Changsheng Liu,Min Qi,Zhouhua Jiang,Huishu Zhang 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.6
In this paper, the CLAM steel strengthened by micro-scale YeZreO was prepared by vacuum inductionmelting followed by electroslag remelting (VIM-ESR). Yttrium (Y) and zirconium (Zr) were easy to aggregatesinto massive yttrium-zirconium-rich inclusions in the steel melted by vacuum inductionmelting (VIM), which would interrupt the continuity of the matrix and reduce the mechanical propertiesof steel. Micron-sized YeZreO inclusions would be produced with the removal of original blocky YeZrrichinclusions and the submicron-sized inclusions smaller than 0.2 mm could be retained in the steel. The small grain size and the better refinement and distribution uniformity of YeZreO inclusions afterremelting would be responsible for the better yield strength and toughness. For VIM-ESR alloy, the ultimatetensile strength is 749 MPa and the yield strength is 642 MPa at room temperature, meanwhilethey are 391 MPa and 367 MPa at 600 C, respectively. Meanwhile, the ductile-brittle transition temperature(DBTT) reduced from 43 C (VIM) to-76 C (VIM-ESR).
Bo Li,BaoXing Bai,Changsheng Zhang,Yixue Jiang 보안공학연구지원센터 2016 International Journal of Database Theory and Appli Vol.9 No.8
Prediction of network public opinion is a complicated prediction featuring poor information, small samples and uncertainty. A prediction model of network public opinion based on grey support vector machine (SVM) is specified to increase prediction accuracy. First, network data are preprocessed by text clustering, hotpot extraction and data aggregation. Then a time series model GM(1,1) is established and SVM is used to modify prediction outcomes of GM(1,1). At last, simulation experiment is conducted to test performance of the model. Simulation results indicate that grey SVM improves the prediction accuracy of network public opinion compared with traditional prediction models. The predictions have certain practical values.
FUEL-SAVING CONTROL STRATEGY FOR FUEL VEHICLES WITH DEEP REINFORCEMENT LEARNING AND COMPUTER VISION
Han Ling,Liu Guopeng,Zhang Hui,Fang Ruoyu,Zhu Changsheng 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.3
This study uses deep reinforcement learning (DRL) combined with computer vision technology to investigate vehicle fuel economy. In a driving cycle with car-following and traffic light scenarios, the vehicle fuel-saving control strategy based on DRL can realize the cooperative control of the engine and continuously variable transmission. The visual processing method of the convolutional neural network is used to extract available visual information from an on-board camera, and other types of information are obtained through the vehicle’s inherent sensor. The various detected types of information are further used as the state of DRL, and the fuel-saving control strategy is built. A Carla–Simulink co-simulation model is established to evaluate the proposed strategy. An urban road driving cycle and highway road driving cycle model with visual information is built in Carla, and the vehicle power system is constructed in Simulink. Results show that the fuel-saving control strategy based on DRL and computer vision achieves improved fuel economy. In addition, in the Carla–Simulink co-simulation model, the fuel-saving control strategy based on DRL and computer vision consumes an average time of 17.55 ms to output control actions, indicating its potential for use in real-time applications.
Guoxing Qiu,Dongping Zhan,Changsheng Liu,Min Qi,Zhouhua Jiang,Huishu Zhang 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.5
The effects of Y and Ti on the microstructure stability and tensile properties of the reduced activationferritic/martensitic steel have been investigated. The addition of Y and Ti affected the prior austenitegrain size due to the pinning of the inclusions. Ti addition of 0.008 wt% to the steel was intended topromote the precipitation of nano-sized carbides with a high resistance to coarsening. 8Ti14Y exhibited ahigher yield strength and a lower DBTT than the other alloys due to the fine grain size and additionalprecipitation hardening by (Ti, Ta)-rich MX. After thermal exposure at 550 C for 1500 h, yield strengthwas dropped significantly in exposed 0Ti13Y. On the contrary, a lower reduction of YS was observed in8Ti14Y. The M23C6 in 0Ti13Y and 8Ti14Y and MX in 25Ti14Y and 39Ti15Y coarsened seriously duringageing, which could be responsible for the reduction of the tensile properties of alloys.
Fangjie Mo,Erdong Wu,Changsheng Zhang,Hong Wang,Zhengye Zhong,Jian Zhang,Bo Chen,Michael Hofmann,Weimin Gan,Guangai Sun 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.5
The present work attempts to reveal the correlation between the microstructural defects and residual stress in the singlecrystal nickel-based superalloy, both of which play the signifi cant role on properties and performance. Neutron diff ractionwas employed to investigate the microstructural defects and residual stresses in a single crystal (SC) nickel-based superalloy,which was subjected to creeping under 220 MPa and 1000 °C for different times. The measured superlattice andfundamental lattice refl ections confi rm that the mismatch and tetragonal distortions with c / a > 1 exist in the SC superalloy. At the initially unstrained state, there exists the angular distortion between γ and γ’ phases with small triaxial compressivestresses, ensuring the structural stability of the superalloy. After creeping, the tetragonal distortion for the γ phase is largerthan that for the γ’ phase. With increasing the creeping time, the mismatch between γ and γ’ phases increases to the maximum,then decreases gradually and fi nally remains unchanged. The macroscopic residual stress shows a similar behaviorwith the mismatch, indicating the correlation between them. Based on the model of shear and dislocations, the evolution ofmicrostructural defects and residual stress are reasonably explained. The effect of shear is dominant at the primary creepstage, which greatly enlarges the mismatch and the residual stress. The dislocations weaken the effect of shear for the furthercreep stage, resulting in the decrease of the mismatch and relaxation of the residual stress. Those fi ndings add some helpfulunderstanding into the microstructure-performance relationship in the SC nickel-based superalloy, which might provide theinsight to materials design and applications.