Experimental study on the combined effects of obstacles and local water mist on gas explosion for maritime safety

Zhang Bin,Li Zhuoran,Xia Yuanchen,Shi Jihao,Zhang Jinnan,Wang Boqiao,Yu Jiahang,Qu Yanxu,Chen Li,Lin Yejin,Wu Wanqing 대한조선학회 2022 International Journal of Naval Architecture and Oc Vol.14 No.1

A variety of experimental configurations including different water mist obstacles, are used to investigate the combined effects of obstacles and water mist upon the gas explosion. The results demonstrate the 8 mm water mist can significantly inhibit the deflagration, while both 45 mm and 80 mm water mists exhibit the opposite effect under all the locally distributed positions of water spray nozzle without obstacles inside the vessel. When considering the obstacles, the 45 mm water mist starts to mitigate the deflagration and its mitigation effect is more significant than that induced by the 8 mm water mist. What's more, the 80 mm water mist can slow down the flame propagation speed while it would still lead to the gas explosion. Additionally, there remains unchanged about the effect of locally spraying 8 mm water mist upon deflagration at the initial stage of flame development as varying the position of obstacles, while the effects of mitigating deflagration by 45 mm and 80 mm water mist are decreased. The results will make contributions to design the arrangement of equipment and water mist configuration on the offshore platform or NG-fueled ship's engine room so as to mitigate the gas explosion accident.

An Improved SoC Balancing Strategy for Battery Energy Storage System in All-Electric Propulsion Ships Current Sharing Effect

Zhang Qinjin,Qu Tengda,Liu Yancheng,Zeng Yuji,Hu Wangbao,Zhang Hanwen 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.3

A dynamic state of charge (SoC) balancing strategy for parallel battery energy storage units (BESUs) based on dynamic adjustment factor is proposed under the hierarchical control framework of all-electric propulsion ships, which can achieve accurate power distribution, bus voltage recovery, and SoC balance accuracy. In the primary control layer, the arccot function is introduced into the improved balancing strategy, and the bus voltage drop is effectively limited while the SoC balancing speed is quickly achieved by adjusting the SoC convergence factors. In the secondary control layer, power and voltage compensation controllers are designed individually to improve the SoC balance accuracy and compensate the bus voltage. Furthermore, neighbor-to-neighbor communication network is constructed by using dynamic consensus algorithm to reduce the communication burden as well as its error rate. Finally, the simulation and StarSim HIL experimental results show that the proposed control strategy can achieve accurate power distribution, bus voltage recovery, and has a faster SoC convergence speed than advanced methods.

Potent Anticancer Effects of Lentivirus Encoding a Drosophila Melanogaster Deoxyribonucleoside Kinase Mutant Combined with Brivudine

Zhang, Nian-Qu,Zhao, Lei,Ma, Shuai,Gu, Ming,Zheng, Xin-Yu Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5

Objective: Deoxyribonucleoside kinase of Drosophila melanogaster (Dm-dNK) mutants have been reported to exert suicide gene effects in combined gene/chemotherapy of cancer. Here, we aimed to further evaluate the capacity of the mutanted enzyme and its potential for inhibiting cancer cell growth. Methods: We altered the sequence of the last 10 amino acids of Dm-dNK to perform site-directed mutagenesis and constructed active site mutanted Dm-dNK (Dm-dNKmut), RT-PCR and western bloting studies were used to reveal the expression of lentivirus mediated Dm-dNKmut in a breast cancer cell line (Bcap37), a gastric cancer cell line (SGC7901) and a colorectal cancer cell line (CCL187). [3H]-labeled substrates were used for enzyme activity assays, cell cytotoxicity was assessed by MTT assays, cell proliferation using a hemocytometer and apoptosis induction by thenannexin-V-FITC labeled FACS method. In vivo, an animal study was set out in which BALB/C nude mice bearing tumors were treated with lentivirus mediated expression of Dm-dNKmut with the pyrimidine nucleoside analog brivudine (BVDU, (E)-5-(2-bromovinyl)-(2-deoxyuridine). Results: The Dm-dNKmut could be stably expressed in the cancer cell lines and retained its enzymatic activity. Moreover, the cells expressing Dm-dNKmut exhibited increased sensitivity in combination with BVDU, with induction of apoptosis in vitro and in vivo. Conclusion: These findings underlined the importance of BVDU phosphorylated by Dm-dNKmut in transduced cancer cells and the potential role of Dm-dNKmut as a suicide gene, thus providing the basis for future intensive research for cancer therapy.

Phytoestrogen Intake and Risk of Ovarian Cancer: a Meta-Analysis of 10 Observational Studies

Qu, Xin-Lan,Fang, Yuan,Zhang, Ming,Zhang, Yuan-Zhen Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.21

Background: Epidemiology studies have shown an inconclusive relationship between phytoestrogen intake and ovarian cancer risk and there have been no relevant meta-analyses directly regarding this topic. The purpose of the present meta-analysis was therefore to investigate any association between phytoestrogen intake and ovarian cancer in detail. Materials and Methods: We conducted a search of PubMed, EMBASE, EBSCO, the Cochrane Library, CNKI and Chinese Biomedical Database (up to April 2014) using common keywords for studies that focused on phytoestrogen and ovarian cancer risk. Study-specific risk estimates (RRs) were pooled using fixed effect or random-effect models. Results: Ten epidemiologic studies were finally included in the meta-analysis. The total results indicated higher phytoestrogen intake was associated with a reduced ovarian cancer risk (RR, 0.70; 95%CI: 0.56-0.87). The association was similar in sensitivity analysis. Meta regression analysis demonstrated sources and possibly types and regions as heterogeneous factors. Subgroup analysis of types, sources and regions showed that isoflavones (RR: 0.63; 95%CI: 0.46, 0.86), soy foods (RR: 0.51; 95%CI: 0.39, 0.68) and an Asian diet (RR: 0.48; 95%CI: 0.37, 0.63) intake could reduce the incidence of ovarian cancer. Conclusions: Our findings show possible protection by phytoestrogens against ovarian cancer. We emphasize specific phytoestrogens from soy foods, but not all could reduce the risk. The habit of plentiful phytoestrogen intake by Asians is worthy to recommendation. However, we still need additional larger well designed observational studies to fully characterize underlying associations.

Multi-objective Fuzzy-optimization of Crowbar Resistances for the Low-Voltage Ride-through of Doubly Fed Induction Wind Turbine Generation Systems

Zhang, Wenjuan,Ma, Haomiao,Zhang, Junli,Chen, Lingling,Qu, Yang The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.4

This study investigates the multi-objective fuzzy optimization of crowbar resistance for the doubly fed induction generator (DFIG) low-voltage ride-through (LVRT). By integrating the crowbar resistance of the crowbar circuit as a decision variable, a multi-objective model for crowbar resistance value optimization has been established to minimize rotor overcurrent and to simultaneously reduce the DFIG reactive power absorbed from the grid during the process of LVRT. A multi-objective genetic algorithm (MOGA) is applied to solve this optimization problem. In the proposed GA, the value of the crowbar resistance is represented by floating-point numbers in the GA population. The MOGA emphasizes the non-dominated solutions and simultaneously maintains diversity in the non-dominated solutions. A fuzzy-set-theory-based is employed to obtain the best solution. The proposed approach has been evaluated on a 3 MW DFIG LVRT. Simulation results show the effectiveness of the proposed approach for solving the crowbar resistance multi-objective optimization problem in the DFIG LVRT.

Potential Therapeutic Targets for the Primary Gallbladder Carcinoma: Estrogen Receptors

Zhang, Ling-Qiang,Zhang, Xiu-De,Xu, Jia,Wan, Yong,Qu, Kai,Zhang, Jing-Yao,Wang, Zhi-Xin,Wei, Ji-Chao,Meng, Fan-Di,Tai, Ming-Hui,Zhou, Lei,Liu, Chang Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.4

Gallbladder carcinoma, the most frequent malignant neoplasm of the biliary tract system, has always been considered to feature late clinical presentation and diagnosis, limited treatment options and an extremely poor prognosis. In recent years, while the incidence of gallbladder cancer has appeared to be on the increase, the available treatment methods have not greatly improved survival of the affected patients. Thus, exploring new therapeutic targets for this devastating disease is an urgent matter at present. Epidemical studies have demonstrated that the incidence of gallbladder carcinoma exhibits a distinct gender bias, affecting females two to three times more than males, pointing to crucial roles of estrogen. It is well known that estrogen acts on target tissues by binding to estrogen receptors (ERs), which are mainly divided into three subtypes, $ER{\alpha}$, $ER{\beta}$ and $ER{\gamma}$. $ER{\alpha}$ and $ER{\beta}$ appear to have overlapping but also unique even opposite biological effects. As important pathogenic mediators, ERs have been considered to relate to several kinds of tumors. In gallbladder carcinoma tissue, ERs have been shown to be positively expressed, and ERs expression levels are associated with differentiation and prognosis of this cancer. Nevertheless, the exact mechanisms of estrogen inducing growth of gallbladder carcinoma remain poorly understood. On the base of the current investigations, we deduce that estrogen participates in promotion of gallbladder carcinoma by influencing the formation of gallstones, stimulating angiogenesis, and promoting abnormal proliferation. Since ERs mediate the carcinogenic actions of estrogen in gallbladder, and therapy targeting ERs may provide new directions for gallbladder carcinoma. Therefore, it should be stressed that ERs are potential therapeutic targets for gallbladder carcinoma.

The evaluation of online course of Traditional Chinese Medicine for Medical Bachelor, Bachelor of Surgery international students during the COVID-19 epidemic period

Zhang Qing,He Yi-Jing,Zhu Yu-Hang,Dai Min-Chen,Pan Man-Man,Wu Jia-Qi,Zhang Xian,Gu Ying-Er,Wang Fang-Fang,Xu Xiang-Rong,Qu Fan 한국한의학연구원 2020 Integrative Medicine Research Vol.9 No.3

Background: During the COVID-19 epidemic period, Traditional Chinese Medicine (TCM) course for international students of Medical Bachelor, Bachelor of Surgery (MBBS) program in Zhejiang University has shifted from traditional classroom to online environment. This study aimed to investigate MBBS international students’ perception on online TCM course, and to assess the online learning efficacy. Methods: A total of 84 MBBS international students attending course of “Basic Traditional Chinese Medicine” during 2020 academic years at Zhejiang University were enrolled in this study. A quantitative questionnaire was respectively completed before and after the TCM course using a pretest–post-test design. By means of two online learning platforms, Learning in ZJU and DingTalk, TCM course was broadcast in both live and archived format to students. Results: A total of 48 participants completed both baseline and follow-up questionnaires. The majority of participants preferred face-to-face classroom learning (26, 54.17% of total) when compared with online learning. Students felt that the course had brought in much benefits (mean 3.88, SD 0.87), and they were satisfied with the course content (mean 3.83, SD 0.95). Students’ TCM related knowledge and their behaviors of discussion and consulting were significantly improved by online TCM course (all P < 0.001). Students’ awareness of the necessity of TCM education and their feeling of difficulty in learning TCM were significantly strengthened (P = 0.042, 0.025, respectively). Conclusion: Online learning is a good alternative for TCM course of MBBS international students when classroom learning is suspended, whereas it cannot replace the need for onsite and face-to-face learning.

A field determination method of D-T neutron source yields based on oxygen prompt gamma rays

Xiongjie Zhang,Bin Tang,Geng Nian,Haitao Wang,Lijiao Zhang,Yan Zhang,Rui Chen,Zhifeng Liu,Jinhui Qu Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.7

A field determination method for small D-T neutron source yield based on the oxygen prompt gamma rays was established. A neutron-gamma transport equation of the determination device was developed. Two yield field determination devices with a thickness of 20 mm and 50 mm were made. The count rates of the oxygen prompt gamma rays were calculated using three energy spectra processing approaches, which were the characteristic peak of 6.13 MeV, the overlapping peak of 6.92 MeV and 7.12 MeV, and the total energy area. The R-square of the calibration curve is better than 94% and the maximum error of the yield test is 5.21%, demonstrating that it is feasible to measure the yield of D-T neutron source by oxygen prompt gamma rays. Additionally, the results meet the requirements for field determination of the conventional D-T neutron source yield.

An Innovative Rotor Position Detection at Stand-Still and Low Speed with Carrier Phase-Shifted PWM Method

Kewang Qu,Guoqing Xu,차석원,Yanhui Zhang,Wei Feng,Junci Cao,Weili Li,Yihuang Zhang,Zhigang Wu 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.9

An innovative permanent magnet synchronous motor rotor position detection method using d-q reference-frames derived from PWM inverter switching is presented based on carrier phase-shift PWM method. It also gives the development the polarity identification at standstill for permanent magnet synchronies motor in the rotary frame with position detected of the neutral voltage. The new technique detects the motor position from simple measurements of the neutral point voltage of the motor influenced by the variation of inductances with respect to rotor position. The transfer is derived with constant element and 2nd harmonic element of selfinductance and mutual-inductance between three phase inductances and the inductance of d-axis and q-axis. Theoretical studies are carried out and verified using experiment results with variation rotor position over one electrical cycle at standstill. Rotor position estimation from stator inductance variation with rotor position is effective in zero speed and low speed.

Towards understanding the carbon catalyzed CO2 reforming of methane to syngas

Guojie Zhang,Jiangwen Qu,Aiting Su,Yongfa Zhang,Ying Xu 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1

In this paper, a fixed-bed reactor is used to study the influence of different conditions on carboncatalyzed CO2–CH4 reforming. The surface structure and functional groups of carbonaceous materialhave been characterized through SEM, XPS, XRD, BET and chemical titration before and after the reaction. Studies have revealed that under non-catalytic condition, methane pyrolysis happens first, followed bythe gasification reaction between CO2 and carbon deposit produced from the pyrolysis. While withcarbonaceous material, CO2 gasification, methane pyrolysis and CO2–CH4 reforming can take place at thesame time, with the reforming as the main reaction, CO2 gasification and methane pyrolysis as the sidereaction. Catalytic activity varies from one carbonaceous material to another, but their reaction trend isthe same on the whole. Those high specific surface area carbonaceous materials show higher catalyticactivity. The increase in reaction temperature and residence time of the reforming can improve theconversion of reactant gas. Adjusting the partial pressure of methane can control carbon–hydrogen ratio ofthe synthesis gas. XPS and XRDcharacterizationsdemonstrate that the structural ordering of carbonaceousmaterials becomes a little messier after the reforming reaction, and the number and content of oxygenfunctional groups decrease. That means these oxygen functional groups on the surface of carbonaceousmaterials are involved in the reforming and these groups along with pore structure on the surface are themajor factors influencing the catalytic properties. Different oxygen species make the nature of electricalenergy on the surface different; the catalytic activity depends on the polarity of oxygen from differentspecies. Those whose polarity is strong have strong activity. The dipole force can be associated withmethane in the form of hydrogen bond, so that the material can display strong activity. Those whosepolarity is weak have weak activity, the catalytic activity is weak too. The results of chemical titration andXPS characterization show that the oxygen in the anhydride and lactone structures on the surface ofcarbonaceous materials are active oxygen, and which is the main active component, it can reduce theactivation energy of methane dehydrogenation.