High-voltage DC–DC converter based on adaptive frequency conversion modulation

Lixia Zheng,Yi Zhu,Jie Ren,Changyuan Chang,Jialing Ye 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.3

With the development of electric vehicles, the demand for the high-voltage low-current DC-DC chips used in vehicle on-board equipment continues to grow. To improve the effi ciency of the switching power supply, an asynchronous buck high-voltage DC-DC converter with adaptive variable frequency modulation (AVFM) technology is designed in this paper. This work focuses on the efficiency optimization of the buck converter, and the relationship between power consumption and operating frequency under different loads. The optimal frequency range is selected during light and heavy loads, and adaptive transition of the frequency is realized during a medium load. Using a threshold voltage ( V th_cs ) circuit with an adjustable current inside the chip, the on-time of the switch is changed to realize frequency conversion. The whole chip design is based on 0.35 μm BCD process, in which the integrated LDMOS can withstand 200 V. System simulations are completed in Cadence. The results show that when the input voltage is 30–60 V and the output specifi cation is 5 V/0.5 A, the system realizes adaptive frequency conversion in the entire load range, and the efficiency reaches 88.9%. The actual performance of the chip meets the design requirements and has good EMI characteristics.

Isolation and Characterization of a Novel Bacterium Burkholderia gladioli Bsp-1 Producing Alkaline Lipase

( Jing Zhu ),( Yanjing Liu ),( Yanqin ),( Lixia Pan ),( Yi Li ),( Geliang ),( Qingyan Wang ) 한국미생물·생명공학회 2019 Journal of microbiology and biotechnology Vol.29 No.7

Active lipase-producing bacterium Burkholderia gladioli Bps-1 was rapidly isolated using a modified trypan blue and tetracycline, ampicillin plate. The electro-phoretically pure enzyme was obtained by purification using ethanol precipitation, ion-exchange chromatography, and gel filtration chromatography. The molecular weight was 34.6 kDa and the specific activity was determined to be 443.9 U/mg. The purified lipase showed the highest activity after hydrolysis with p-NPC₁₆ at a pH of 8.5 and 50°C, and the K_m, k_cat, and k_cat/K_m values were 1.05 mM, 292.95 s^-1 and 279 s^-1mM^-1, respectively. The lipase was highly stable at 7.5 ≤ pH ≤ 10.0. K⁺ and Na⁺ exerted activation effects on the lipase which had favorable tolerance to short-chain alcohols with its residual enzyme activity being 110% after being maintained in 30% ethanol for 1 h. The results demonstrated that the lipase produced by the strain B. gladioli Bps-1 has high enzyme activity and is an alkaline lipase. The lipase has promising chemical properties for a range of applications in the food-processing and detergent industries, and has particularly high potential for use in the manufacture of biodiesel.

Investigating Impacts of CoronaVac Vaccination in Males on In Vitro Fertilization: A Propensity Score Matched Cohort Study

Wang Meng,Yang Qiyu,Zhu Lixia,Jin Lei 대한남성과학회 2022 The World Journal of Men's Health Vol.40 No.4

Purpose: This study aimed to evaluate the influences of SARS-CoV-2 vaccination (CoronaVac) on male fertility and investigate the impact of a history of the CoronaVac vaccination in males on gamete and embryo development and in vitro fertilization (IVF) outcomes. Materials and Methods: A prospective cohort study enrolled couples undergoing IVF cycles between June and August 2021 at Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology in China. According to the history of SARS-CoV-2 vaccination in males, the participants were divided into the vaccination group and the non-vaccination group. A self-controlled study of semen analyses for males before and after CoronaVac vaccination was conducted. Baseline characteristics were matched using propensity score matching. Participants were categorized into the unexposed group (non-vaccination) and exposed group (vaccination), and the population was 271 for each. Semen parameters and IVF outcomes were the main outcomes. Results: Generally, no statistically significant differences were exhibited between the matched cohorts regarding embryo developmental parameters, including fertilization rate, cleavage rate, high-quality embryo rate, blastocyst formation rate, and available blastocyst rate, as well as clinical outcomes, such as implantation rate, biochemical pregnancy rate, and clinical pregnancy rate. Moreover, males after vaccination seemed to have fluctuating semen parameters including increased semen volume, lower motility, and decreased normal forms of sperm, while the motile sperm counts were similar. In addition, all semen parameters were above the lower reference limits. Conclusions: Our findings suggested that CoronaVac vaccinations in males may not have adverse effects on patient performance or the gamete and embryonic development potential during assisted reproductive technology (ART) treatments.

THE USE OF DAPHNIA CARINATA FOR ECOTOXICOLOGICAL ASSESSMENT OF ACID MINE DRAINAGE-AFFECTED STREAMS IN SUBTROPICAL CHINA

WU YONGGUI,LIN CHUXIA,ZHU LIXIA 한국수자원학회 2005 한국수자원학회 학술대회 Vol.2005 No.1

UBE2W Interacts with FANCL and Regulates the Monoubiquitination of Fanconi Anemia Protein FANCD2

Yingying Zhang,Peitang Huang,Xiaowei Zhou,Lixia Zhao,Chao Li,Hengqi Zhu,Long Xu,Liran Shan,Xiang Liao,Zekun Guo 한국분자세포생물학회 2011 Molecules and cells Vol.31 No.2

Fanconi anemia (FA) is a rare cancer-predisposing ge-netic disease mostly caused by improper regulation of the monoubiquitination of Fanconi anemia complementation group D2 (FANCD2). Genetic studies have indicated that ubiquitin conjugating enzyme UBE2T and HHR6 could regulate FANCD2 monoubiquitination through distinct mechanisms. However, the exact regulation mechanisms of FANCD2 monoubiquitination in response to different DNA damages remain unclear. Here we report that UBE2W, a new ubiquitin conjugating enzyme, could regulate FANCD2 monoubiquitination by mechanisms different from UBE2T or HHR6. Indeed, UBE2W exhibits ubiquitin conjugating enzyme activity and catalyzes the monoubiquitination of PHD domain of Fanconi anemia complementation group L (FANCL) in vitro. UBE2W binds to FANCL, and the PHD domain is both necessary and sufficient for this interaction in mammalian cells. In addition, over-expression of UBE2W in cells promotes the monoubiquitination of FANCD2 and down-regulated UBE2W markedly reduces the UV irradia-tion-induced but not MMC-induced FANCD2 monoubiquiti-nation. These results indicate that UBE2W regulates FANCD2 monoubiquitination by mechanisms different from UBE2T and HRR6. It may provide an additional regulatory step in the activation of the FA pathway.

The relevance of ABCA1 R219K polymorphisms and serum ABCA1 protein concentration to Parkinson’s disease pathogenesis and classification: a case–control study

Xiaoliu Dong,Tiejun Liu,Shijun Xu,Lixia Zhu,Panpan Zhang,Aibin Cheng,Qingqiang Qian 한국유전학회 2016 Genes & Genomics Vol.38 No.3

To investigate the relevance of ABCA1 R219K polymorphisms and serum ABCA1 protein concentration to Parkinson’s disease (PD) pathogenesis and classification in Chinese population. Between June 2013 to January 2014, 108 patients diagnosed with PD at Department of Neurology, Tangshan People’s Hospital, Tangshan were enrolled in the PD group, and 123 healthy individuals, from Health Screening Center of the same hospital, with matched age, gender, and education were enrolled in the control group. Polymerase chain reaction–restriction fragment length polymorphism method was used to detect ABCA1 R219K polymorphisms and enzyme-linked immunosorbent assay used to measure serum ABCA1 concentrations. Frequencies of R/K and K/K genotypes, and K allele of ABCA1 R219K polymorphisms were significantly lower in the PD group than the control group (all P\0.05). Significant differences existed in distributions of genotype frequencies, including R/R, R/K and K/K, between PD and control group of each classification (all P\0.05). ABCA1 concentrations were significantly different in the PD and control group (P\0.05); also ABCA1 concentrations were very different among PD patients with different genotypes (all P\0.05). Serum concentrations of ABCA1were significantly different among PD patients in different classifications (all P\0.05), suggesting the negative correlation between ABCA1 serum concentration and PD classification (r = -0.776, P\0.05). And serum concentrations of ABCA1 showed obvious differences among cases with three different genotypes in each classification (all P\0.05). ABCA1 R219K polymorphisms and serum concentration were associated with pathogenesis and classification of PD, and K allele may be a protective genetic factor.

Capacitors Energy Strategy Based Cascaded H-Bridge Converter for DC Port Failures

Xu Peng,Xiaohan Liu,Guolong Yang,Xijun Liu,Lixia Gao,Xinyu Zhu 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.5

In this paper, a capacitors energy strategy based Cascaded H-bridge Converter (CHBC) for steady DC link voltage is proposed, which allow the CHBC to work while DC power fails. The topology of the CHBC is analyzed to construct the proposed strategy. The capacitors energy strategy is deduced based on the principle that the DC link voltage should be steady, the switch state should be smooth and the switch frequency should be normal. Experiments based on a three-module prototype, including static experiment, start experiment and step change experiment, proves the correctness of the strategy. They also verified the excellent fault tolerance ability and good dynamic performance of the proposed strategy.

Glia maturation factor beta deficiency protects against diabetic osteoporosis by suppressing osteoclast hyperactivity

Shi Si,Gu Huijie,Xu Jinyuan,Sun Wan,Liu Caiyin,Zhu Tong,Wang Juan,Gao Furong,Zhang Jieping,Ou Qingjian,Jin Caixia,Xu Jingying,Chen Hao,Li Jiao,Xu Guotong,Tian Haibin,Lu Lixia 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

Excessive osteoclast activation, which depends on dramatic changes in actin dynamics, causes osteoporosis (OP). The molecular mechanism of osteoclast activation in OP related to type 1 diabetes (T1D) remains unclear. Glia maturation factor beta (GMFB) is considered a growth and differentiation factor for both glia and neurons. Here, we demonstrated that Gmfb deficiency effectively ameliorated the phenotype of T1D-OP in rats by inhibiting osteoclast hyperactivity. In vitro assays showed that GMFB participated in osteoclast activation rather than proliferation. Gmfb deficiency did not affect osteoclast sealing zone (SZ) formation but effectively decreased the SZ area by decreasing actin depolymerization. When GMFB was overexpressed in Gmfb-deficient osteoclasts, the size of the SZ area was enlarged in a dose-dependent manner. Moreover, decreased actin depolymerization led to a decrease in nuclear G-actin, which activated MKL1/SRF-dependent gene transcription. We found that pro-osteoclastogenic factors (Mmp9 and Mmp14) were downregulated, while anti-osteoclastogenic factors (Cftr and Fhl2) were upregulated in Gmfb KO osteoclasts. A GMFB inhibitor, DS-30, targeting the binding site of GMFB and Arp2/3, was obtained. Biocore analysis revealed a high affinity between DS-30 and GMFB in a dose-dependent manner. As expected, DS-30 strongly suppressed osteoclast hyperactivity in vivo and in vitro. In conclusion, our work identified a new therapeutic strategy for T1D-OP treatment. The discovery of GMFB inhibitors will contribute to translational research on T1D-OP.

Capacitors Energy Strategy Based Cascaded H-Bridge Converter for DC Port Failures

Peng, Xu,Liu, Xiaohan,Yang, Guolong,Liu, Xijun,Gao, Lixia,Zhu, Xinyu The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.5

In this paper, a capacitors energy strategy based Cascaded H-bridge Converter (CHBC) for steady DC link voltage is proposed, which allow the CHBC to work while DC power fails. The topology of the CHBC is analyzed to construct the proposed strategy. The capacitors energy strategy is deduced based on the principle that the DC link voltage should be steady, the switch state should be smooth and the switch frequency should be normal. Experiments based on a three-module prototype, including static experiment, start experiment and step change experiment, proves the correctness of the strategy. They also verified the excellent fault tolerance ability and good dynamic performance of the proposed strategy.

Voltage balance evaluation strategy for DC-port faults in centralized aircraft ground power unit based on three-level neutral point clamped cascaded converter

Peng, Xu,Yu, Le,Gong, Kaiyue,Liu, Xiaohan,Yang, Guolong,Xu, Jiangjun,Zhou, Chao,Gao, Lixia,Zhu, Xinyu The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.8

An aircraft ground power unit (GPU) can replace the auxiliary power unit (APU) in an aircraft while the aircraft is parked at an airport. Therefore, the problems associated with the oil consumption and air pollution of the APU are solved. However, the GPU is faced with challenges in terms of utilization, power quality, and fault tolerance. Thus, a novel centralized aircraft GPU based on a three-level neutral point clamped cascaded converter (3LNPC-CC) is introduced in this paper to improve utilization and power quality. Furthermore, an evaluation voltage balance strategy is proposed for the DC-port fault tolerance of the 3LNPC-CC. In addition, both the modulation of the phase shift pulse width modulation (PSPWM) and the control of the double closed loop are used in the 3LNPC-CC. A simulation platform including the control, modulation, and fault tolerance of the system is established to verify the feasibility and performance of the proposed GPU. In particular, it is used to evaluate the voltage balance strategy for DC-port faults. Moreover, a prototype of the GPU and relevant experiments are completed to verify the correctness and feasibility of the system and the strategy.