Single-Phase Improved Auxiliary Resonant Snubber Inverter that Reduces the Auxiliary Current and THD

Zhang, Hailin,Kou, Baoquan,Zhang, He,Zhang, Lu The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.6

An LC filter is required to reduce the output current ripple in the auxiliary resonant snubber inverter (ARSI) for high-performance applications. However, if the traditional control method is used in the ARSI with LC filter, then unnecessary current flows in the auxiliary circuit. In addressing this problem, a novel load-adaptive control that fully uses the filter inductor current ripple to realize the soft-switching of the main switches is proposed. Compared with the traditional control implemented in the ARSI with LC filter, the proposed control can reduce the required auxiliary current, contributing to higher efficiency and DC-link voltage utilization. In this study, the detailed circuit operation in the light load mode (LLM) and the heavy load mode (HLM) considering the inductor current ripple is described. The characteristics of the improved ARSI are expressed mathematically. A prototype with 200 kHz switching frequency, 80 V DC voltage, and 8 A maximum output current was developed to verify the effectiveness of the improved ARSI. The proposed ARSI was found to successfully operate in the LLM and HLM, achieving zero-voltage switching (ZVS) of the main switches and zero-current switching (ZCS) of the auxiliary switches from zero load to full load. The DC-link voltage utilization of the proposed control is 0.758, which is 0.022 higher than that of the traditional control. The peak efficiency is 91.75% at 8 A output current for the proposed control, higher than 89.73% for the traditional control. Meanwhile, the carrier harmonics is reduced from -44 dB to -66 dB through the addition of the LC filter.

Theoretical and experimental investigations of gear transmission with geometric elements constructed tooth pairs having triple contact points

Lu-he Zhang,Shi-xuan Li,Jian Huang,Bingkui Chen 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.7

A novel gear transmission with geometric elements constructed tooth pairs having triple contact points is proposed in this study. Based on the equidistance enveloping method, the generation principle and method of the tooth surface are presented. Three types of contact pattern of tooth profiles are generated: convex to convex, convex to plane, convex to concave. A calculation example for convex to concave tooth profiles of gears is provided. Performance experiment is carried out based on the developed gear prototype, and a comparison with involute gear drive is also shown. Theoretical and numerical results demonstrate the feasibility and correctness and it lays the foundation for the design of high performance gear transmission.

Single-Phase Improved Auxiliary Resonant Snubber Inverter that Reduces the Auxiliary Current and THD

Hailin Zhang,Baoquan Kou,He Zhang,Lu Zhang 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.6

An LC filter is required to reduce the output current ripple in the auxiliary resonant snubber inverter (ARSI) for high-performance applications. However, if the traditional control method is used in the ARSI with LC filter, then unnecessary current flows in the auxiliary circuit. In addressing this problem, a novel load-adaptive control that fully uses the filter inductor current ripple to realize the soft-switching of the main switches is proposed. Compared with the traditional control implemented in the ARSI with LC filter, the proposed control can reduce the required auxiliary current, contributing to higher efficiency and DC-link voltage utilization. In this study, the detailed circuit operation in the light load mode (LLM) and the heavy load mode (HLM) considering the inductor current ripple is described. The characteristics of the improved ARSI are expressed mathematically. A prototype with 200 ㎑ switching frequency, 80 V DC voltage, and 8 A maximum output current was developed to verify the effectiveness of the improved ARSI. The proposed ARSI was found to successfully operate in the LLM and HLM, achieving zero-voltage switching (ZVS) of the main switches and zero-current switching (ZCS) of the auxiliary switches from zero load to full load. The DC-link voltage utilization of the proposed control is 0.758, which is 0.022 higher than that of the traditional control. The peak efficiency is 91.75% at 8 A output current for the proposed control, higher than 89.73% for the traditional control. Meanwhile, the carrier harmonics is reduced from –44 ㏈ to –66 ㏈ through the addition of the LC filter.

Glabridin Liposome Ameliorating UVB-Induced Erythema and Lethery Skin by Suppressing Inflammatory Cytokine Production

( Chijian Zhang ),( Yongjie Lu ),( Yong Ai ),( Xian Xu ),( Siyang Zhu ),( Bing Zhang ),( Minghui Tang ),( Lanyue Zhang ),( Tinggang He ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.4

Glabridin, a compound of the flavonoid, has shown outstanding skin-whitening and anti-aging properties, but its water insolubility limits its wide application. Therefore, glabridin liposome (GL) has been developed to improve its poor bioavailability, while there are few studies to evaluate its amelioration of UVB- induced photoaging. This study is performed to investigate the amelioration of GL against UVB- induced cutaneous photoaging. The prepared GL has a spheroidal morphology with an average diameter of 200 nm. The GL shows lower cytotoxicity than glabridin, but it has a more effective role in inhibition of melanin. Moreover, the application of GL can effectively relieve UV radiation induced erythema and leathery skin, associated with the down-regulated expression of inflammatory cytokines (TNF-α, IL-6 and IL-10). Taken together, these results demonstrate that GL has potentials as topical therapeutic agents against UVB radiation induced skin damage through inhibiting inflammation.

Cloning and Biochemical Characterization of a Hyaluronate Lyase from Bacillus sp. CQMU-D

Wang Lu,Liu Qianqian,Gong Xue,Jian Wenwen,Cui Yihong,Jia Qianying,Zhang Jibei,Zhang Yi,Guo Yanan,Lu He,Tu Zeng 한국미생물·생명공학회 2023 Journal of microbiology and biotechnology Vol.33 No.2

Hyaluronidase (HAase) can enhance drug diffusion and dissipate edema by degrading hyaluronic acid (HA) in the extracellular matrix into unsaturated HA oligosaccharides in mammalian tissues. Microorganisms are recognized as valuable sources of HAase. In this study, a new hyaluronate lyase (HAaseD) from Bacillus sp. CQMU-D was expressed in Escherichia coli BL21, purified, and characterized. The results showed that HAaseD belonged to the polysaccharide lyase (PL) 8 family and had a molecular weight of 123 kDa. HAaseD could degrade chondroitin sulfate (CS) -A, CS-B, CSC, and HA, with the highest activity toward HA. The optimum temperature and pH value of HAaseD were 40°C and 7.0, respectively. In addition, HAaseD retained stability in an alkaline environment and displayed higher activity with appropriate concentrations of metal ions. Moreover, HAaseD was an endolytic hyaluronate lyase that could degrade HA to produce unsaturated HA oligosaccharides. Together, our findings indicate that HAaseD from Bacillus sp. CQMU-D is a new hyaluronate lyase and with excellent potential for application in industrial production.

Characterization of Ecdysteroid UDP-Glucosyltransferase Gene Promoter from Bombyx mori Nucleopolyhedrovirus

Zhang, Zhi-Fang,Shen, Xing-Jia,Yi, Yong-Zhu,Tang, Shun-Ming,Li, Yi-Ren,He, Jia-Lu,Wu, Xiang-Fu Korean Society of Sericultural Science 2004 International Journal of Industrial Entomology Vol.8 No.2

Bombyx mori nucleopolyhedrovirus(BmNPV) ecdysteroid UDP-glucosyltransferase gene (egt) promoter fragments of different lengths were amplified from BmNPV ZJ-8 genomic DNA by PCR. Reporter plasmids pBmegt542-luc, pBmegt309-luc and pBmegtl59-luc with luciferase (lue) driven by egt promoters were constructed. Both in vitro and in vivo expressions showed that BmNPV egt promoter activity requires the transactivation of viral factor(s), and expression of luc was detected earliest at 24 hrs post infection (pi). BmNPV ZJ-8 homologous region 3 (hr3) increased the expression of luc by over 1,600-fold. Molting hormone of 1.0 - 2.0 $\mu\textrm{g}$/$m\ell$ can dramatically down regulate expression of luc. Juvenile hormone analogue of 0.5-2.0 ${\mu}g$/$m\ell$ increased expression of luc by 145.8% to 75.7%. Deletion assay revealed that the promoter fragment of 159 bp contains the basal promoter structure; Promoter fragments of 309 bp and 542 bp showed similar but much higher transcriptional activities than that of 159 bp, suggesting that nucleotide from -159 to -309 nt upstream the translation initiation site harbors the main cis-acting elements.

COMPLEXITY OF CONTINUOUS SEMI-FLOWS AND RELATED DYNAMICAL PROPERTIES

Zhang, Feng,He, Lian-Fa,Lu, Qi-Shao Korean Mathematical Society 2009 대한수학회지 Vol.46 No.2

The equicontinuity and scattering properties of continuous semi-flows are studied on a compact metric space. The main results are obtained as follows: first, the complexity function defined by the spanning set is bounded if and only if the system is equicontinuous; secondly, if a continuous semi-flow is topologically weak mixing, then it is pointwise scattering; thirdly, several equivalent conditions for the time-one map of a continuous semi-flow to be scattering are presented; Finally, for a minimal continuous map it is shown that the "non-dense" requirement is unnecessary in the definition of scattering by using open covers.

Carpooling Service for Large-Scale Taxicab Networks

Zhang, Desheng,He, Tian,Zhang, Fan,Lu, Mingming,Liu, Yunhuai,Lee, Haengju,Son, Sang H. Association for Computing Machinery 2016 ACM transactions on sensor networks Vol.12 No.3

<P>Carpooling has long held the promise of reducing gas consumption by decreasing mileage to deliver coriders. Although ad hoc carpools already exist in the real world through private arrangements, little research on the topic has been done. In this article, we present the first systematic work to design, implement, and evaluate a carpool service, called coRide, in a large-scale taxicab network intended to reduce total mileage for less gas consumption. Our coRide system consists of three components, a dispatching cloud server, passenger clients, and an onboard customized device, called TaxiBox. In the coRide design, in response to the delivery requests of passengers, dispatching cloud servers calculate cost-efficient carpool routes for taxicab drivers and thus lower fares for the individual passengers. To improve coRide's efficiency in mileage reduction, we formulate an NP-hard route calculation problem under different practical constraints. We then provide (1) an optimal algorithm using Linear Programming, (2) a 2-approximation algorithm with a polynomial complexity, and (3) its corresponding online version with a linear complexity. To encourage coRide's adoption, we present a win-win fare model as the incentive mechanism for passengers and drivers to participate. We test the performance of coRide by a comprehensive evaluation with a real-world trial implementation and a data-driven simulation with 14,000 taxi data from the Chinese city Shenzhen. The results show that compared with the ground truth, our service can reduce 33% of total mileage; with our win-win fare model, we can lower passenger fares by 49% and simultaneously increase driver profit by 76%.</P>

The Effects of Multi-minerals on Susceptibility to Lead Toxicity in Rats

Lu, Jing,Zhang, Jun,Zhang, Lili,Cui, Tao,Xie, Guangyun,He, Xiwen The Korean Society of Toxicology Korea Environment 2001 Toxicological Research Vol.17 No.-

Female Wistar rats were randomly divided into 5 groups: Control, received distilled water; Low lead, received 0.5 g/ιlead (as acetate) in drinking water; High lead, received 2.0 g/ιlead; Low lead + Minerals, received 0.5 g/ιlead in drinking water and received minerals (Ca$^{2+}$, 25 mg/kg/day; Fe$^{3+}$, 0.47 mg/ kg/day; Zn$^{2+}$, 0.33 mg/kg/day; Se, 0.83 $\mu\textrm{g}$/kg/day) by gavage; High lead + Minerals, received 2.0 g/ιlead and received the same minerals. Animals exposure to lead was from 10 days before mating till postnatal day 21; and the minerals was administered from the first day of pregnancy and during lactation. No statistical difference was found either in body weights or in blood lead levels between the pups received minerals and those only exposed to lead at the same dose. The developmental and behavioral teratological effects of lead on pups, such as time-lag of eye opening, pinna detachment, fur developing, incisor eruption, ear unfolding, and surface righting were observed in this study; and the minerals decreased the toxicity of lead either in low or in high lead exposure pups. The numbers of step-down were significantly increased in lead exposed animals, and the effect of intervention by the minerals was appeared only in the pups exposed to low lead. The ChAT activity and levels of glutamate and aspartate in hippocampus decreased in treated animals compared to control animals, no effect of intervention by the minerals was found. The results of this study indicate that the applied multi-minerals can alter the outcome of develop-mental lead poisoning in rats.s.s.s.

Changing patterns of Serum CEA and CA199 for Evaluating the Response to First-line Chemotherapy in Patients with Advanced Gastric Adenocarcinoma

He, Bo,Zhang, Hui-Qing,Xiong, Shu-Ping,Lu, Shan,Wan, Yi-Ye,Song, Rong-Feng Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.8

Background: This study was designed to investigate the value of CEA and CA199 in predicting the treatment response to palliative chemotherapy for advanced gastric cancer. Materials and Methods: We studied 189 patients with advanced gastric cancer who received first-line chemotherapy, measured the serum CEA and CA199 levels, used RECIST1.1 as the gold standard and analyzed the value of CEA and CA199 levels changes in predicting the treatment efficacy of chemotherapy. Results: Among the 189 patients, 80 and 94 cases had increases of baseline CEA (${\geq}5ng/ml$) and CA199 levels (${\geq}27U/ml$), respectively. After two cycles of chemotherapy, 42.9% patients showed partial remission, 33.3% stable disease, and 23.8% progressive disease. The area under the ROC curve (AUC) for CEA and CA199 reduction in predicting effective chemotherapy were 0.828 (95%CI 0.740-0.916) and 0.897 (95%CI 0.832-0.961). The AUCs for CEA and CA199 increase in predicting progression after chemotherapy were 0.923 (95%CI 0.865-0.980) and 0.896 (95%CI 0.834-0.959), respectively. Patients who exhibited a CEA decline ${\geq}24%$ and a CA199 decline ${\geq}29%$ had significantly longer PFS (log rank p=0.001, p<0.001). With the exception of patients who presented with abnormal levels after chemotherapy, changes of CEA and CA199 levels had limited value for evaluating the chemotherapy efficacy in patients with normal baseline tumor markers. Conclusions: Changes in serum CEA and CA199 levels can accurately predict the efficacy of first-line chemotherapy in advanced gastric cancer. Patients with levels decreasing beyond the optimal critical values after chemotherapy have longer PFS.