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Wide input/output control strategy for multiphase series capacitor bidirectional DC-DC converters
Guo, Zheng,Wang, Yubin,Wang, Fan,Tian, Xinna,Dong, Yuxiang The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.5
The series capacitor converter is one kind of high-gain bidirectional DC-DC converter based on interleaved and switched capacitor techniques. For the n-phase series capacitor converter, n times voltage gain when compared with the traditional boost converter under a specific duty cycle, as well as automatic current sharing among phases can be achieved. The specific duty cycle is (n - 1)/n to 1 in the boost mode and 0 to 1/n in the buck mode, which means that it is not suitable for wide input and/or wide output applications. To solve this issue, an 180° interleaved switching strategy is proposed in this paper. The proposed strategy is more suitable for converters to widen the working duty cycle range. The working principle, voltage gain and current distribution/sharing characteristics with the duty cycle ranging from 0 to 1 are analyzed and calculated in greater detail. In addition, as one of the n-phase series capacitor converters, a small signal model of a three-phase series capacitor converter is built, and a dual closed-loop controller is studied and designed. Finally, an experimental prototype with an input voltage that varies from 10 to 30 V and an output voltage of 100 V is built and tested. Results obtained with the prototype verify the correctness of the proposed switching strategy.
Yanfeng Wang,Xudong Guo,Zhigang Wang,Zhixin Guo,Mingtao Liu,Keyu Zhao,Xue Feng,Xu Zheng,Xiaojing Wang,Huifang Hao 한국통합생물학회 2017 Animal cells and systems Vol.21 No.5
PSMB1 (proteasome subunit beta type 1) is a core component of the 20S proteasome, and based on its structure, it might have a crucial function in the transcription of certain genes. Rheb (Ras homolog enriched in brain) is a Ras-like small GTPase that acts as an upstream positive regulator of the mechanistic target of rapamycin complex 1 (mTORC1) pathway. We cloned and characterized PSMB1 (KY310590.1) to determine its function in cell cycle progression and proliferation of goat fetal fibroblasts (GFbs). Further, by yeast two-hybrid screen and coimmunoprecipitation, we conformed that PSMB1 interacts directly with Rheb. An siRNA was designed and expressed targeting PSMB1 mRNA in GFbs and inducing cell cycle arrest. Rheb overexpression in GFbs significantly increased the number of S phase cells and growth efficiency compared with control cells. These data indicate that PSMB1 and Rheb have important functions in the cell cycle and proliferation of GFbs, indicating that their interaction governs many processes in GFbs.
Hu, Wei-Guo,Hu, Jia-Jia,Cai, Wei,Zheng, Min-Hua,Zang, Lu,Wang, Zheng-Ting,Zhu, Zheng-Gang Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.5
The association between the NAD(P)H:quinone oxidoreductase 1 (NQO1) gene C609T polymorphism (rs1800566) and gastric cancer has been widely evaluated, but a definitive answer is so far lacking. We first conducted a case-control study to assess this association in a large Han Chinese population, and then performed a meta-analysis to further address this issue. Although our case-control association study indicated no significant difference in the genotype and allele distributions of C609T polymorphism between gastric cancer patients and controls, in the meta analysis involving 4,000 subjects, comparison of alleles 609T and 609C indicated a significantly increased risk (46%) for gastric cancer (95% confidence interval (95%CI) for odds ratio (OR)=1.20-1.79) in individuals with the T allele. The tendency was similar to the homozygote (OR=1.81, 95%CI: 1.16-2.84), dominant models (OR=1.41, 95%CI: 1.12-1.79), as well as recessive model (OR=1.58, 95%CI: 1.06-2.35). Stratified analysis by study design demonstrated stronger associations in population-based than in hospital-based studies. And ethnicity-based analysis demonstrated a significant association in Asians. We conclude that the NQO1 gene C609T polymorphism increases the risk for gastric cancer, especially in Asian populations.
Guo-Hua Feng,Fu-Sheng Wang,Ji-Yuan Zhang,Qing-Lei Zeng,Lei Jin,Junliang Fu,Bin Yang,Ying Sun,Tianjun Jiang,Xiangsheng Xu,Zheng Zhang,Jinhong Yuan,Liyuan Wu 한국분자세포생물학회 2013 Molecules and cells Vol.36 No.4
Interleukin-21 (IL-21)+CD4+ T cells are involved in the immune response against hepatitis B virus (HBV) by secreting IL-21. However, the role of IL-21+CD4+ T cells in the immune response against chronic hepatitis C (CHC) virus infection is poorly understood. This study aimed to investigate the role of IL-21+CD4+ T cells in CHC patients and the potential mechanisms. The study subjects in-cluded nineteen CHC patients who were grouped by viral load (low, < 106 RNA copies/ml, n = 8; high, > 106 RNA copies/ml, n = 11). The peripheral frequency of HCV-specific IL-21+CD4+ T cells was higher in the low viral load group and was negatively correlated with the serum HCV RNA viral load in all CHC patients. Meanwhile, IL-21+ cells accumulated in the liver in the low viral load group. In vitro, IL-21 treatment increased the expression of proliferation markers and cytolytic molecules on HCV-specific CD8+ T cells. In summary, these findings suggest that HCV-specific IL-21+CD4+ T cells might contribute to HCV control by rescuing HCV-specific CD8+ T cells in CHC patients.
( Guo Hong Gong ),( Zhi Ming Zheng ),( Hui Liu,Li Wang ),( Jin Shan Diao ),( Peng Wang ),( Gen Hai Zhao ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.6
An extracellular β-glucosidase from Aspergillus niger Au0847 was purified to homogeneity by precipitation with ammonium sulfate, anion exchange, and gel filtration. The purified protein was composed of two subunits with molecular masses of 110 and 120 kDa. Au0847 β-glucosidase exhibited relatively high thermostability and pH stability, and its highest activity was obtained at 65°C and pH 4.6, respectively. As a potential metalloprotein, its enzymatic activity was potently stimulated by manganese ion and DTT. The β-glucosidase displayed avid affinity and high catalytic efficiency for geniposide. Au0847 β-glucosidase has potential value as an industrial enzyme for the hydrolysis of geniposide to genipin.
Traveling Wave Type Multi‑Degree‑of‑Freedom Spherical Ultrasonic Motor with Built‑in Stators
Zheng Li,Liang Zhao,Zhe Wang,Peng Guo 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.4
A multi-degree-of-freedom spherical ultrasonic motor with built-in traveling wave stators is proposed, and each traveling wave stator can be controlled independently, the three-degree-of-freedom movement of the spherical rotor is realized by the coordinated control of the three traveling wave stators and the spatial arrangement of the support structures. The motor also has a built-in pre-pressure adjustment structure, which can adjust the pre-pressure of three stators at the same time and make them the same size. The structure and working principle of the motor are expounded in detail. The structure and working principle of the motor are expounded in detail. The fnite element method is used to analyze the modal of the traveling wave stator, and the transient trajectory of the driving part is simulated. Finally, the working principle was verifed on the prototype, and the mechanical output performance of the prototype was tested: when the excitation voltage of the motor is 400 V and the preload is 100 N, the maximum speed is 45.6 rad/min, the maximum speed output torque is 1.265 Nm; the maximum defection angle is 43°, and the maximum defection speed is 56.3 rad/min, the maximum defection torque is 1.76 Nm, achieves high torque and multiple-degrees-of-freedom. The motor has the advantages of large output force, high integration, and adjustable preload.
Zheng Chen,Xiang Wu,Li-Hua Hang,Hong Wang,Dong-Hua Shao,Yi-Guo Xu,Wei Cui 연세대학교의과대학 2016 Yonsei medical journal Vol.57 No.4
Purpose: Intranasal dexmedetomidine is an effective sedative for premedication and is regularly used to reduce preoperative tension and anxiety in children. This study aimed to assess the effect of intranasally adjunctive dexmedetomidine on perioperativesedative and analgesic requirements in adults. Materials and Methods: Patients were randomly divided into four groups to receive preoperative administration of saline, intranasaldexmedetomidine 1 μg/kg and 2 μg/kg, and intravenous dexmedetomidine 1 μg/kg, respectively. Propofol and remifentanil were target-controlled infused to maintain intraoperative bispectral index at 45–55 and blood pressure at baseline value±20%. Sufentanil was administered to maintain postoperative visual analogue scale ≤3. Perioperative anesthetics requirements were compared using nonparametric tests. Results: Intranasal dexmedetomidine significantly attenuated propofol requirements for anesthesia induction and maintenance in a dose-dependent manner. Patients given intranasal dexmedetomidine 2 μg/kg required less remifentanil for anesthesia maintenance. The first postoperative request for sufentanil analgesia was delayed in patients given intranasal dexmedetomidine 2 μg/kg. The anesthetics-sparing effect of intranasal dexmedetomidine was significantly weaker than intravenous dexmedetomidine at the same dose of 1 μg/kg. The incidences of adverse events, including hemodynamic instability and delayed recovery, were comparablewith and without intranasal dexmedetomidine. Conclusion: Intranasal administration of dexmedetomidine can reduce perioperative anesthetic requirements, and a dose of dexmedetomidine 2 μg/kg produces a better effect in adults. The anesthetics-sparing effect of intranasal dexmedetomidine 1 μg/kg is less than that with the same intravenous dose of dexmedetomidine.
Guo-zheng Quan,Chao An,Hui-min Qiu,Le Zhang,Xuan Wang 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.7
In the hot stamping process of ultra-high-strength steel sheets, it is a significant issue to reveal the nonuniformity of cooling rate in space–time domain by finite element method and even uncover the inner cause, which contributes to the further adjustment of the phase transformation. In this work, a series of heat transfer experiments between dies and sheets were conducted on the self-developed experimental apparatus. The temperature evolution curves of die and BR1500HS ultra-high-strength steel sheets under different pressures and holding time were obtained. Moreover, the transient heat transfer coefficients (HTC) under different mean interface temperatures and pressures were calculated by the inverse heat transfer algorithm. Subsequently, based on the HTC curves, a thermal–mechanical-phase dynamic coupling finite element model was developed for modeling the hot stamping process, and a series of simulations for analyzing the non-uniform microstructures distribution in hot stamping parts were implemented. Finally, the simulation results were validated by actual hot stamping experiments. Two significant influence factors on the nonuniform distribution of microstructures were summarized as follows: the existence of incomplete contact between steel sheets and dies due to the sheet thickness reduction in sidewall and circular bead regions, and the temperature differences between dies and steel sheets.
Wang, Yuan-Shan,Xu, Jian-Miao,Zheng, Ren-Chao,Zheng, Yu-Guo,Shen, Yin-Chu The Korean Society for Microbiology and Biotechnol 2008 Journal of microbiology and biotechnology Vol.18 No.12
The R-amidase production by a newly isolated strain of Delftia tsuruhatensis ZJB-05174 was optimized in this paper. Effects of factors such as carbon sources, nitrogen sources, and inducers on amidase production were investigated. The medium composition was optimized using central composite designs and response surface analysis. The optimal medium components for enhanced amidase production were found to be as follows: glucose, 8.23 g/l; yeast extract, 11.59 g/l; 2,2-(R,S)-dimethylcyclopropane carboxamide, 1.76 g/l; NaCl, 1 g/l; ${KH_2}{PO_4}$ 1 g/l; and ${K_2}{HPO_4}$ 1 g/l. A maximum enzyme production of 528.21 U/l was obtained under the optimized conditions, which was 4.7 times higher than that obtained under initial conditions.