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Search Results: 1 - 10 of 52270 matches for " Cheng Zhu "
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Modeling for Collapsing Cavitation Bubble near Rough Solid Wall by Mulit-Relaxation-Time Pseudopotential Lattice Boltzmann Model  [PDF]
Minglei Shan, Yipeng Zhu, Cheng Yao, Qingbang Han, Changping Zhu
Journal of Applied Mathematics and Physics (JAMP) , 2017, DOI: 10.4236/jamp.2017.56106
Abstract: Cavitation bubble collapse near rough solid wall is modeled by the multi-relaxation-time (MRT) pseudopotential lattice Boltzmann (LB) model. The modified forcing scheme, which can achieve LB model’s thermodynamic consistency by tuning a parameter related with the particle interaction range, is adopted to achieve desired stability and density ratio. The bubble collapse near rough solid wall was simulated by the improved MRT pseudopotential LB model. The mechanism of bubble collapse is studied by investigating the bubble profiles, pressure field and velocity field evolution. The eroding effects of collapsing bubble are analyzed in details. It is found that the process and the effect of the interaction between bubble collapse and rough solid wall are affected seriously by the geometry of solid boundary. At the same time, it demonstrates that the MRT pseudopotential LB model is a potential tool for the investigation of the interaction mechanism between the collapsing bubble and complex geometry boundary.
Regulation of ovarian function by the matrix metalloproteinase system
Donglin Liu,Cheng Zhu
Chinese Science Bulletin , 2002, DOI: 10.1007/BF02907597
Environmental archaeology of the dachang region in the Daning Valley, the Three Gorges reservoir region of the Yangtze River, China
Yun Zhang,Cheng Zhu
Chinese Science Bulletin , 2008, DOI: 10.1007/s11434-008-5012-9
Abstract: Environmental archaeology of archaeological sites on both sides of the Dachang section in the Daning River, the Three Gorges of the Yangtze River, shows that riverbed evolution has a great influence on the distribution of archaeological sites during the prehistorical and historical period, and it restricts human activity and the development of ancient culture. Field investigation, dating data, paleocurrent analysis of 100 gravels on the riverbed and archaeological excavation reveal that the riverbed of the Dachang section developed in the Shuangyantang region during the early stage, after about 30 kaBP it shifted westward gradually and reached the present place. Along with the westward shift, the focus of ancient culture changed for several times. In the Western Zhou Dynasty’s period, the east riverbank of the Daning River was the main residential area. During the Han Dynasty, along with the westward shift, the living space of ancient people was no longer confined to the east riverbank and the focus of culture moved westward. Then the Zhangjiawan site became the main dwelling district. In the late Han Dynasty, the villages were flooded and the ancients had to immigrate to a high place. Tombs of the Han and the Jin Dynasties outcropped on the flood plain of the east bank because their surface sediments were eroded by several flood events and the westward shift of the riverbed.
Bearingless motor’s radial suspension force control based on flux equivalent with virtual winding current analysis method
HuangQiu Zhu,QiuLiang Cheng
Chinese Science Bulletin , 2009, DOI: 10.1007/s11434-009-0151-1
Abstract: A bearingless motor has two sets of intercoupling stator windings, namely torque windings and suspension force windings. The decoupling control of the two sets is difficult and a key technology to stable operation for a bearingless motor. In this paper, a simple, reliable and accurate analysis method is put forward using the concept of flux equivalent with virtual winding currents. By this method, the suspension operation condition P B=P M±1 for bearingless motors is testified, and under the rotation condition of the motor, it is also proved that currents in suspension force windings must have the same phase sequence and frequency as torque windings to generate a stable single direction radial force in the rotor’s whole circumference. On this basis, the control strategy of realizing the suspension operation of the bearingless motor is presented, and a prototype of the bearingless surface-mounted permanent magnet synchronous motor is tested. The research results have indicated that the experimental results correspond with theoretical analysis adopting this method, a stable and reliable radial suspension force can be generated, and the validity and feasibility of this control strategy are confirmed.
Functions of VEGF in female reproductive system
Qian Dong,Zhu Cheng
Chinese Science Bulletin , 2003, DOI: 10.1007/BF03183286
Abstract: As a homodimeric glycoprotein, vascular endothelial growth factor (VEGF) is a highly specific mitogen of vascular endothelial cells. It can induce proliferation and migration, and inhibit apoptosis of endothelial cell. VEGF is involved in many processes in the female reproductive system, such as ovulation, periodical changes of endometrium, embryo implantation and development. VEGF plays important roles in some reproductive diseases, including preeclampsia and fetal hypoevolutism in uterus. Based on our studies on angiogenesis and its relevant factors in the female reproductive system these years, the functions of VEGF in female reproductive system are reviewed, and the research prospect and application of VEGF are also discussed.
Expression and regulation of mRNAs for insulin-like growth factor (IGF-I), IGF-binding protein-2, and LH receptor in the process of follicular atresia
Wenxiang Luo,Cheng Zhu
Science China Life Sciences , 2000, DOI: 10.1007/BF02879286
Abstract: Expression of mRNAs for IGF-I, IGF-binding protein-2 (IGFBP-2), and LH receptor (LHR) as well as their regulations during induced follicular atresia was determined. 26-day-old female rats received 15 IU pregnant mare serum gonadotropins (PMSG). Through detection, it was demonstrated that apoptosis occurred in some small antral follicles after 48 h of PMSG treatment. At 96 h, apoptosis occurred in preovulatory follicles. At 120 h, numerous apoptotic cells appeared in preovulatory follicles. IGF-I was mainly expressed in preantral and small antral follicles from 48 to 120 h. At 48 and 96 h, the theca cells of preantral and antral follicles expressed high level of IGFBP-2 mRNA. At 48 h, there were strong signals of LHR mRNA in granulosa cells, but the LHR signals in granulosa cells significantly decreased at 96 and 120 h (p<0.001). Both epidermal growth factor (EGF) and IGF-I inhibited apoptosis in preantral and antral follicles. Meanwhile, it was observed that EGF promoted IGF-I mRNA expression, and in preovulatory follicles, IGF-I stimulated LHR mRNA expression. These results show that the interaction between ECF and IGF-I may be involved in the regulation of atresia of follicles at different stages of development.
Angiogenesis in female reproductive system
Longjiang Shao,Cheng Zhu
Chinese Science Bulletin , 2001, DOI: 10.1007/BF02900588
Nitric oxide in female reproductive system
Xuan Zhang,Cheng Zhu
Chinese Science Bulletin , 2002, DOI: 10.1360/02tb9293
Expression and regulation of mRNAs for insulin-like growth factor-I receptor and LH receptor in corpora lutea
Wenxiang Lou,Cheng Zhu
Science China Life Sciences , 2000, DOI: 10.1007/BF02879127
Abstract: Relationship between insulin-like growth factor-I receptor (IGF-IR) and luteinizing hormone receptor (LHR) mRNA expression as well as their regulation was determined in rat corpora lutea (CL). In the CL of estrous cycle rat, LHR mRNA positive CL expressed high level of mRNA of IGF-IR. While the expression of LHR mRNA decreased on estrus, the CL still expressed relatively high level of IGF-IR mRNA. In pseudopregnant rat CL, the expression level of LHR mRNA was low on day 1, the most intense signals were detected on day 8, the signals of LHR mRNA became undetectable on day 14. In contrast to LHR expression, the high level of IGF-IR mRNA was observed in pseudopregnant CL of day 1, and thereafter its signals were detected from day 2 to day 14. Pregnant rat CL expressed both LHR and IGF-IR mRNAs. IGF-I stimulated LHR expression in CL. PGF2α inhibited expression of IGF-IR and LHR. PGE2 negated the inhibiting effects of PGF2α. These data suggest that IGF-I may be involved in regulating CL function, and maintaining CL structure through changes in expression of its receptors. Inhibited expression of IGF-IR by PGF2α may be part of mechanisms for regression of CL.
Shuiming Cheng,Shengdong Zhu
BioResources , 2008,
Abstract: Traditional chemical industry depends on non-renewable fossil resources and is now facing great challenges. Lignocellulosic materials are the most abundant renewable resources in the world, and their efficient utilization provides a practical route to maintain sustainable development of chemical industry. Modern chemical technology as well as industrial biotechnology will play an important role in comprehensive utilization of lignocellulosic materials in an environmentally friendly way. Bio-refinery is a useful concept in use when considering lignocellulosic materials for a sustainable chemical industry.
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