Numerical and experimental investigations on the cavitation characteristics of a high-speed centrifugal pump with a splitter-blade inducer

XiaoMei Guo,Linhang Zhu,ZuChao Zhu,BaoLing Cui,Yi Li 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.1

A high-speed centrifugal pump with a splitter-blade inducer is investigated in this work. The flow with rotating cavitation is numericallysimulated, external characteristics are subjected to experimental tests, and the internal flow is visualized. These procedures are conductedto obtain the pressure, velocity, and vapor volume fraction distribution in the inducer and the impeller of the centrifugal pump. Bubble occurrence, development, and collapse are also observed. The predicted H-Q and η-Q curves agree with the experimental resultsof external characteristics. The calculated vapor volume fraction also agrees with the experimental results obtained from the visualizationsystem. The mechanism of bubble evolution and the anti-cavitation performance of the high-speed centrifugal pump with a splitter-bladeinducer are clearly elucidated.

Effects of the number of inducer blades on the anti-cavitation characteristics and external performance of a centrifugal pump

XiaoMei Guo,ZuChao Zhu,BaoLing Cui,GaoPing Shi 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.7

Installing an inducer upstream of the main impeller is an effective approach for improving the anti-cavitation performance of a highspeed centrifugal pump. For a high-speed centrifugal pump with an inducer, the number of inducer blades can affect its internal flow and external performance. We studied the manner in which the number of inducer blades can affect the anti-cavitation characteristics and external performance of a centrifugal pump. We first use the Rayleigh-Plesset equation and the mixture model to simulate the vaporliquid flow in a centrifugal pump with an inducer, and then predict its external performance. Finally, we tested the external performance of a centrifugal pump with 2-, 3- and 4-bladed inducers respectively. The results show that the simulations of external performance in a centrifugal pump are in accordance with our experiments. Based on this, we obtained vapor volume fraction distributions for the inducer, the impeller, and in the corresponding whole flow parts. We discovered that the vapor volume fraction of a centrifugal pump with a 3-bladed inducer is less than that of a centrifugal pump with 2- or 4-bladed inducers, which means that a centrifugal pump with a 3-bladed inducer has a better external and anti-cavitation performance.

On China’s Alibaba’s Success

Guo-An Wang,Xiaomei Qi,Shan Zheng 중앙대학교 한국전자무역연구소 2009 전자무역연구 Vol.7 No.3

지난 10년간의 개발기간동안 알리바바는 고유의 비즈니스 방식을 만들었는데 즉, 기업과 개인에게 시간과 공간의 단절 없이 운영하고 그 자체와 수백만의 중소기업들에게 전례가 없는 사업 기회를 제공하고 있는 국경 없는 전자무역 시장이다. 알리바바의 혁신적인 마케팅 전략은 그들의 개발을 가속화시켰고 세계의 전자상거래 분야에서 두드러졌다. 이 논문은 알리바바의 성공 경로에 대해 처음으로 연구되는 것이며 McCarthy 교수의 4Ps 이론에 기초한 효과적인 마케팅 전략에 대해 살펴본다. 마지막으로 2008년에 있었던 세계 금융 위기에 맞선 마케팅 전략의 향상에 관한 제안을 제공한다. During the 10 years of development, Alibaba has established a unique business mode, a borderless e-trade market running around the clock on the Internet for enterprises and individuals without limit in time and space and providing itself and millions of small and medium-sized enterprises(SME) with unprecedented business opportunities. The innovative marketing strategies of Alibaba has accelerated its development and distinguished itself in the field of e-commerce in the world. This paper at first offers an overview of Alibaba’s path of development, and then discusses its effective marketing strategies based on Professor McCarthy’s 4Ps theory. Finally it provides some suggestions on the improvement of its marketing strategies regarding the fight against the financial crisis worldwide which began in 2008.

Efficacy of lymph node dissection on stage IIICr of cervical cancer before CCRT: study protocol for a phase III, randomized controlled clinical trial (CQGOG0103)

Misi He,Mingfang Guo,Qi Zhou,Ying Tang,Lin Zhong,Qing Liu,Xiaomei Fan,Xiwa Zhao,Xiang Zhang,Gang Chen,Yuanming Shen,Qin Xu,Xiao-jun Chen,Yuancheng Li,Dongling Zou 대한부인종양학회 2023 Journal of Gynecologic Oncology Vol.34 No.3

Background: Cervical cancer is still present a major public health problem, especially in developing countries. In International Federation of Gynaecology and Obstetrics 2018, allowing assessment of retroperitoneal lymph nodes by imaging and/or pathological findings and, if deemed metastatic, the case is designated as stage IIIC (with r and p notations). Patients with lymph node metastases have lower overall survival (OS), progression free survival (PFS), and survival after recurrence, especially those who have unresectable macroscopical positive lymph nodes. Retrospective analysis suggests that there may be a benefit to debulking macroscopic nodes that would be otherwise difficult to sterilize with standard doses of radiation therapy. However, there are no prospective study reporting that resecting macroscopic nodes before concurrent chemoradiation therapy (CCRT) would improve PFS or OS of cervical cancer and no guidelines for surgical resection of bulky lymph nodes. The CQGOG0103 study is a prospective, multicenter and randomized controlled trial (RCT) evaluating lymph node dissection on stage IIICr of cervical cancer. Methods: Eligible patients are histologically confirmed cervical squamous cell carcinoma, adenocarcinoma, adeno-squamous cell carcinoma. Stage IIICr (confirmed by computed tomography [CT]/magnetic resonance imaging/positron emission tomography/CT) and the short diameter of image-positive lymph node ≥15 mm. 452 patients will be equally randomized to receive either CCRT (pelvic external-beam radiotherapy [EBRT]/extended-field EBRT + cisplatin [40 mg/m2] or carboplatin [the area under curve=2] every week for 5 cycles + brachytherapy) or open/minimally invasive pelvic and para-aortic lymph node dissection followed by CCRT. Randomization is stratified by status of para-aortic lymph node. The primary endpoint is PFS. Secondary endpoints are OS and surgical complications. A total of 452 patients will be enrolled from multiple hospitals in China within 4 years and followed up for 5 years.

Expression, Purification, and Characterization of a Recombined Fibrinolytic Enzyme from Endophytic Paenibacillus polymyxa EJS-3 in Escherichia coli

Fengxia Lv,Chong Zhang,Fangfang Guo,Yingjian Lu,Xiaomei Bie,Hui Qian,Zhaoxin Lu 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.1

The gene encoding the fibrinolytic enzyme (PPFE-I) from Paenibacillus polymyxa EJS-3 was cloned and sequenced (Genbank No. KC176802). The 1773 bp gene encoded 590 amino acids and had low homology with other known fibrinolytic enzymes. PPFE-I was soluble and expressed in E. coli BL21 to enhance the activity. The recombinant enzyme (rPPFE-I) was purified to homogeneity, and enzymatic properties were characterized. The optimal temperature and pH for rPPFE-I were 37℃ and 7.5, respectively. Observed activities of rPPFE-I were highest in the presence of Zn2+, Mg2+, and Fe2+ and the lowest in the presence of Ca2+ and Cu2+. The rPPFE-I activity was strongly inhibited by PMSF. The α-chain was affected by the rPPFE-I cleavage speed of fibrinogen, followed by the b and γ chains. The inhibitory effects of rPPFE-I against ADP-induced human platelet aggregation were dosedependent with an IC50 value of 1.54 μM.

Ultrastructural changes of Haematococcus pluvialis (Chlorophyta) in process of astaxanthin accumulation and cell damage under condition of high light with acetate

He, Bangxiang,Hou, Lulu,Zhang, Feng,Cong, Xiaomei,Wang, Zhendong,Guo, Yalin,Shi, Jiawei,Jiang, Ming,Zhang, Xuecheng,Zang, Xiaonan The Korean Society of Phycology 2020 ALGAE Vol.35 No.3

Haematococcus pluvialis is a commercial microalga that can produce high quantities of astaxanthin. Under induced conditions, some important changes in the subcellular structures related to astaxanthin accumulation were observable. For example, a large number of astaxanthin granules, oil structures and starch granules appeared in the thick-walled cells; Astaxanthin granules gradually dissolved into the oil structures and spread throughout the entire cell with the fusion and diffusion process of oil structures during the middle and late stages of induction; The plastoglobules were closed to the newly formed structures, and some plastoglobules would abnormally increase in size under stress. Based on observations of cell damage, the degradation of membrane structures, such as chloroplasts, was found to be the primary form of damage during the early stage of induction. During the middle stage of induction, some transparent holes were exposed in the dissolving astaxanthin granules in the cytoplasm. In thick-walled cells, these transparent holes were covered by oil substances dissolving astaxanthin, thereby avoiding further damage to cells. Given the relatively few oil structures, in non-thick-walled cells, the transparent holes expanded to form multiple transparent areas, eventually resulting in the rupture and death of cells. These results suggested that the high level of synthesis and the wide range diffusion of oil explained the expansion of astaxanthin in H. pluvialis.