A self-powered β-Ga2O3/CsCu2I3 heterojunction photodiode responding to deep ultraviolet irradiation

Gao Ang,Jiang Weiyu,Ma Guoliang,Liu Zeng,Li Shan,Yan Zuyong,Sun Weiming,Zhang Shaohui,Tang Weihua 한국물리학회 2022 Current Applied Physics Vol.33 No.-

In this paper, a lead-free halide perovskite CsCu2I3 film with high stability was prepared by the anti-solvent assisted crystallization method. Then, we coupled it with Ga2O3 to prepare a corresponding heterojunction deep ultraviolet (UV) photodetector. After testing, we concluded that the photodetector is sensitive to 254 nm UV light. The photodetector has good reproducibility, and has an ultra-high photo-to-dark current ratio (PDCR) of more than 105. In addition, under a bias of 10 V and an illuminated intensity of 200 μW/cm2, the responsivity (R) and specific detectivity (D*) reached 20 mA/W and 107 cm Hz1/2 W 1 (Jones), and the external quantum efficiency (EQE) is 10%. Meanwhile, the prepared photodetector could operate at zero bias, i.e., self-powered operation, along with a photocurrent of about 1 nA under illumination with UV light intensity of 200 μW/cm2.

Enzymatic Desymmetrization of 3-(4-Fluorophenyl)glutaric Anhydride through Enantioselective Alcoholysis in Organic Solvents

Weiming Liu,Yi Hu,Yang Zhang,Yan Ma,He Huang 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.3

The enzymatic desymmetrization of 3-(4-fluorophenyl)glutaric anhydride (3-FGA) was investigatedthrough lipase-catalyzed enantioselective alcoholysis inorganic solvents. An immobilized Lipase B from CandidaAntarctica (Novozym 435) was found to be an efficientbiocatalyst for the enantioselective alcoholysis of 3-FGA. Methyl tert-butyl ether (MTBE) and methanol were chosenas the suitable reaction medium and acyl acceptor,respectively. The optimum reaction temperature, molarratio of methanol to 3-FGA and 3-FGA concentration were25oC, 2:1 and 100 mM, respectively. Under these conditions,complete conversion was achieved and methyl (S)-3-(4-fluorophenyl)glutarate ((S)-MFG) was obtained in a moderateee value of 80%. Furthermore, the reaction was performedon a gram scale and the ee value of (S)-MFG was enrichedto 96% after treatment with a toluene/hexane (2/1, v/v)mixture.

Plastic Deformation Mechanism of Ductile Fe50Ni30P13C7 Metallic Glass

Kangkang Geng,Weiming Yang,Jinyong Mo,Haishun Liu,Feng Wei,Zhanguo Ma,Yucheng Zhao,Akihisa Inoue 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.2

Shear band (SB) multiplication is considered as an essential characteristic of the plastic deformation in metallic glasses(MGs). In this work, the evolutionary characteristics of SBs and serrated behavior in ductile Fe50Ni30P13C7MGs werestudied by the finite element method simulation. The study demonstrated that the stress field would redistribute and becomeinhomogeneous during SB sliding, where the stress perpendicular to the original SB gradually accumulates until reachingthe magnitude of yielding strength and triggering new SBs. The results of simulation are in good agreement with the SBsintersection morphologies observed in SEM images and the serration flows on the stress–strain curves. Furthermore, severalfactors affecting stress field distribution in MGs, such as contact friction, aspect ratio, and boundary confinement, werealso analyzed and discussed. The overall results indicate that the ductility of Fe-based MGs could be achieved without anyinhomogeneous structure, and scientifically explicate the dependence of SB multiplication on both material properties andloading condition, which can provide us with a deeper understanding on plastic deformation mechanism of MGs.

Sliding Mode Control based on Disturbance Observer for Magnetic Levitation Positioning Stage

Zhang Shansi,Ma Shuyuan,Wang Weiming 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.5

Magnetic levitation system with the advantages of non-contact, no friction and no wear can satisfy the requirement of high precision and high speed positioning. In this paper, magnetic levitation positioning stage which mainly consists of planar coil and HALBACH permanent magnet array and its control and driving system are designed. Magnetic levitation system is a highly nonlinear and strongly coupled complex system and its control performance can be influenced by the uncertainty and external disturbance. So exact feedback linearization method is used to realize exact linearization and decoupling, and a strategy of sliding mode control based on disturbance observer is proposed to compensate the uncertainty and external disturbance. Detailed proofs of observer’s convergence property and system stability are derived. Both the simulation and experiment results verify the effectiveness of sliding mode control algorithm based on disturbance observer.

Coordinated Virtual Inertia Control Strategy for D-PMSG Considering Frequency Regulation Ability

Qiaoming Shi,Gang Wang,Weiming Ma,Lijun Fu,You Wu,Pengxiang Xing 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.6

In the process of virtual inertia control (VIC), the frequency regulation capability of the directly-driven wind turbine with permanent-magnet synchronous generator (D-PMSG) on wind farm is related to its rotor kinetic energy and capacity margin. This paper proposes the method for assessing the D-PMSG frequency regulation capability and defining its coefficient according to the operating state of wind power generators. In addition, the calculating method of parameters in VIC is also discussed according to the principles of primary frequency regulation and inertia response of synchronous generators. Then, by introducing the capability coefficient into the proportion-differential virtual inertia control (PD-VIC) for power coordination, a coordinated virtual inertia control (C-VIC) strategy is developed, with the consideration of the difference in frequency regulation capability between wind power generators. The proposed control method can not only give full play to the frequency regulation capability of wind power generators, decrease the movements of the pitch angle control system but also bring some self-coordination capability to different wind power generators thus to avoid a secondary drop in system frequency. The simulations and experiments prove the proposed method to be effective and practicable.

PWM-Based Sliding Mode Controller for Three-Level Full-Bridge DC-DC Converter that Eliminates Static Output Voltage Error

Liu, Jilong,Xiao, Fei,Ma, Weiming,Fan, Xuexin,Chen, Wei The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2

This paper proposes a pulse width modulation (PWM)-based sliding mode controller (SMC) for a full-bridge DC-DC converter that can eliminate static output voltage error. Hysteretic SMC in DC-DC converter does not have a fixed switching frequency, and applying hysteretic SMC to full-bridge converters is difficult. Fixed-frequency SMC, which is also called PWM-based SMC, based on equivalent control overcomes these shortcomings. However, the controller order reduction in equivalent control in PWM-based SMC causes static output voltage error. To resolve this issue, an integral item is added to the PWM-based SMC. Sliding mode coefficients are designed by applying a standard second-order system to the sliding mode surface. The effect of adding an integral item on the controller is analyzed, and an integral coefficient design method is proposed. Experiment results on a three-level full-bridge DC-DC converter verify the control scheme and design method proposed in this paper.

Coordinated Virtual Inertia Control Strategy for D-PMSG Considering Frequency Regulation Ability

Shi, Qiaoming,Wang, Gang,Ma, Weiming,Fu, Lijun,Wu, You,Xing, Pengxiang The Korean Institute of Electrical Engineers 2016 Journal of Electrical Engineering & Technology Vol.11 No.6

In the process of virtual inertia control (VIC), the frequency regulation capability of the directly-driven wind turbine with permanent-magnet synchronous generator (D-PMSG) on wind farm is related to its rotor kinetic energy and capacity margin. This paper proposes the method for assessing the D-PMSG frequency regulation capability and defining its coefficient according to the operating state of wind power generators. In addition, the calculating method of parameters in VIC is also discussed according to the principles of primary frequency regulation and inertia response of synchronous generators. Then, by introducing the capability coefficient into the proportion-differential virtual inertia control (PD-VIC) for power coordination, a coordinated virtual inertia control (C-VIC) strategy is developed, with the consideration of the difference in frequency regulation capability between wind power generators. The proposed control method can not only give full play to the frequency regulation capability of wind power generators, decrease the movements of the pitch angle control system but also bring some self-coordination capability to different wind power generators thus to avoid a secondary drop in system frequency. The simulations and experiments prove the proposed method to be effective and practicable.

PWM-Based Sliding Mode Controller for Three-Level Full-Bridge DC-DC Converter that Eliminates Static Output Voltage Error

Jilong Liu,Fei Xiao,Weiming Ma,Xuexin Fan,Wei Chen 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2

This paper proposes a pulse width modulation (PWM)-based sliding mode controller (SMC) for a full-bridge DC-DC converter that can eliminate static output voltage error. Hysteretic SMC in DC-DC converter does not have a fixed switching frequency, and applying hysteretic SMC to full-bridge converters is difficult. Fixed-frequency SMC, which is also called PWM-based SMC, based on equivalent control overcomes these shortcomings. However, the controller order reduction in equivalent control in PWM-based SMC causes static output voltage error. To resolve this issue, an integral item is added to the PWM-based SMC. Sliding mode coefficients are designed by applying a standard second-order system to the sliding mode surface. The effect of adding an integral item on the controller is analyzed, and an integral coefficient design method is proposed. Experiment results on a three-level full-bridge DC-DC converter verify the control scheme and design method proposed in this paper.

Risk factors for cancer-specific survival in elderly gastric cancer patients after curative gastrectomy

Liu Xiao,Xue Zhigang,Yu Jianchun,Ma Zhiqiang,Kang Weiming,Ye Xin,Li Zijian 한국영양학회 2022 Nutrition Research and Practice Vol.16 No.5

BACKGROUND/OBJECTIVES Previous studies have reported that protein supplementation contributes to the attenuation of inflammation. Serious trauma such as burn injury usually results in the excessive release of inflammatory factors and organs dysfunction. However, a few reports continued to focus on the function of protein ingestion in regulating burn-induced inflammation and organ dysfunction. MATERIALS/METHODS This study established the rat model of 30% total body surface area burn injury, and evaluated the function of blended protein (mixture of whey and soybean proteins). Blood routine examination, inflammatory factors, blood biochemistry, and immunohistochemical assays were employed to analyze the samples from different treatment groups. RESULTS Our results indicated a decrease in the numbers of white blood cells, monocytes, and neutrophils in the burn injury group administered with the blended protein nutritional support (Burn+BP), as compared to the burn injury group administered normal saline supplementation (Burn+S). Expressions of the pro-inflammatory factors (tumor necrosis factor-α and interleukin-6 [IL-6]) and chemokines (macrophage chemoattractant protein-1, regulated upon activation normal T cell expressed and secreted factor, and C-C motif chemokine 11) were dramatically decreased, whereas anti-inflammatory factors (IL-4, IL-10, and IL-13) were significantly increased in the Burn+BP group. Kidney function related markers blood urea nitrogen and serum creatinine, and the liver function related markers alanine transaminase, aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase were remarkably reduced, whereas albumin levels were elevated in the Burn+BP group as compared to levels obtained in the Burn+S group. Furthermore, inflammatory cells infiltration of the kidney and liver was also attenuated after burn injury administered with blended protein supplementation. CONCLUSIONS In summary, nutritional support with blended proteins dramatically attenuates the burn-induced inflammatory reaction and protects organ functions. We believe this is a new insight into a potential therapeutic strategy for nutritional support of burn patients.

Synthesis of Direct β‐to‐β Linked Porphyrin Arrays with Large Electronic Interactions: Branched and Cyclic Oligomers

Cai, Hao,Fujimoto, Keisuke,Lim, Jong Min,Wang, Chaojie,Huang, Weiming,Rao, Yutao,Zhang, Senmiao,Shi, Hui,Yin, Bangshao,Chen, Bo,Ma, Ming,Song, Jianxin,Kim, Dongho,Osuka, Atsuhiro WILEY‐VCH Verlag 2014 Angewandte Chemie Vol.126 No.41

<P><B>Abstract</B></P><P>Direct β‐to‐β linked branched and cyclic porphyrin trimers and pentamers have been synthesized by the Suzuki–Miyaura coupling of β‐borylporphyrins and β‐bromoporphyrins. The cyclic porphyrin trimer, the smallest directly linked cyclic porphyrin wheel to date, and its twined pentamer, exhibit small electrochemical HOMO–LUMO gaps, broad nonsplit Soret bands, and red‐shifted Q‐bands, thus indicating large electronic interactions between the constituent porphyrin units.</P>