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Unsteady flow structures in the tip region for a centrifugal compressor impeller before rotating stall

Science China(Technological Sciences) 2017年第6期60卷 924-934页

作者： zhao huijing WANG ZhiHeng XI Guang School of Energy and Power Engineering Xi 'an Jiaotong University Xi'an 710049 China

To get an insight into the occurrence and the mechanism of flow unsteadiness in the tip region of centrifugal compressor impellers, the flow in Krain’s impeller is investigated by using both steady and unsteady RANS solver techniques. It is found that the flow unsteadiness on the pressure side is much stronger than that on the suction side. The periodical frequency of the unsteady flow is around half of the blade passing frequency. The originating mechanism of the flow unsteadiness is illustrated with the time-dependent tip leakage flow and blade loading at the tip region. Due to the blockage caused by the joint effects of broken-downed tip leakage vortex, separated fluids and tip leakage flow at downstream, a low pressure region is formed on the pressure side, consequently the blade loadings is altered. In turn, the changed blade loadings will alter the intensity of tip leakage flow. Such alternative behavior finally results in the periodic process. By comparing the calculated flow field in the cases of single-passage and four-passage models, it is confirmed that the investigated flow unsteadiness is confined in each single passage, as no phase differences are found in the model of four passages. This is different from the situation in axial compressor when the rotating instability is encountered. The flow unsteadiness only occurs at the working conditions with small mass flow rates, and the oscillation intensity will be enhanced with the decrease of mass flow rate. When the mass flow rate is too small, the flow unsteadiness in a single passage may trigger rotating stall, as the disturbance propagates in the circumferential direction.

关键词： centrifugal compressor impeller flow unsteadiness tip leakage flow blade loading

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多孔聚四氟乙烯人工血管制备及功能化改性研究的进展

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中国组织工程研究 2024年第5期28卷 759-765页

作者：徐溶王豪杰耿梦想孟凯王卉张克勤赵荟菁苏州大学纺织与服装工程学院江苏省苏州市215021 现代丝绸国家工程实验室(苏州) 江苏省苏州市215123

背景:中、大口径的聚四氟乙烯人工血管已被广泛应用于临床,但主要依赖进口;小口径的聚四氟乙烯人工血管易形成血栓和内膜增生,存在远期通畅率低的问题,难以满足临床应用要求。目的:梳理并总结聚四氟乙烯在人工血管领域的研究进展,为小... 详细信息

背景:中、大口径的聚四氟乙烯人工血管已被广泛应用于临床,但主要依赖进口;小口径的聚四氟乙烯人工血管易形成血栓和内膜增生,存在远期通畅率低的问题,难以满足临床应用要求。目的:梳理并总结聚四氟乙烯在人工血管领域的研究进展,为小口径聚四氟乙烯人工血管的功能化改性及提高其远期通畅率提供参考。方法:由第一作者检索CNKI、Web of Science、Wiley Online Library、SpringerLink、Science Direct和IOP Science数据库中的相关文献,检索时间为2022年10月至2023年3月,中文检索词为“多孔聚四氟乙烯,人工血管,电纺,医学应用和功能化改性”,英文检索关键词为“ePTFE,Porous polytetrafluoroethylene,vascular graft,electrospinning,medical application,functional modification”,检索国内外有关聚四氟乙烯人工血管制备及其改性的相关文献。结论与结论:多孔聚四氟乙烯人工血管的制备和功能性改性仍是研究的热点与难点,从近几年的国内外研究进展来看,多孔聚四氟乙烯人工血管的制备主要采用快速热拉伸法,但静电纺丝法制备聚四氟乙烯人工血管是一种很有前景的新型方法;其次,通过分析和总结不同的功能化改性方法发现,多孔聚四氟乙烯人工血管的远期通畅率得到改善,但小口径聚四氟乙烯人工血管的功能化改性仍需进一步探索和优化。

关键词：人工血管多孔聚四氟乙烯孔隙电纺制备医学应用功能化改性综述

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Silicon and Oxygen Isotopic Composition of Igneous Rocks from the Eastern Manus Basin

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Journal of Ocean University of China 2014年第3期13卷 421-427页

作者： zhao huijing ZENG Zhigang YIN Xuebo CHEN Shuai Seafloor Hydrothermal Activity Laboratory of the Key Laboratory of Marine Geology and Environment Institute of Oceanology Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

This paper reports silicon and oxygen isotopes of 20 kinds of igneous rocks and their major elements from the eastern Manus Basin. Combining silicon and oxygen isotopic data from other studies, we suppose that both δ30Si and δ18O values increase with the increasing of SiO2 content. It means that the fractionation of silicon and oxygen isotopes are affected by the silica content. The positive correlation between CaO/Al2O3 ratios and MgO and that between Si/Al and SiO2 content indicate that clinopyroxene is the predominant mineral phase in our samples. We suppose that the fractionation of silicon and oxygen isotopes are influenced by mineral fractional crystallization. Probably, it is due to their different silicon and oxygen bridges. In this study, the δ30Simean value=-0.17‰±0.17‰ and δ18Omean value= +6.07‰±0.57‰ are higher than normal δ30Si and δ18O values of mantle, and we propose that these igneous rocks in the eastern Manus Basin are affected by hydrothermal alteration.

关键词： Si isotope O isotope igneous rocks eastern Manus Basin

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Characteristics of silicon and oxygen isotopic compositions of basalts near East Pacific Rise 13°N

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Acta Oceanologica Sinica 2013年第12期32卷 104-108页

作者： WANG Xiaoyuan zhao huijing ZENG Zhigang YIN Xuebo CHEN Shuai MA Yao Seafloor Hydrothermal Activity Laboratory of the Key Laboratory of Marine Geology and Environment Institute of OceanologyChinese Academy of Sciences Graduate University of Chinese Academy of Sciences

In this study, 13 groups of silicon and oxygen isotopes and major elements of the basalts near the East Pacific Rise 13°N are used to study the fractionation of silicon and oxygen isotopes. Among these data, δ30Si values of basalts vary from -0.4%o to 0.2%o with a mean value of δ30Si of （-0.18±0.22）%o. The δ180 values range from 4.1%o to 6.4%o with a mean δ180 value of （＋5.35±0.73） %0. Since the δ30Si values increase in the series of basalt-basaltic andesite- andesite, and δ180 values display a positive correlation with the SiO2 content, we propose that the fractionation of silicon and oxygen isotopes is influenced by the SiO2 content in igneous rocks. Compared with the igneous rocks from Manus Basin with clinopyroxene as their dominant mineral phase, MORBs in this study containing olivine and plagioclase as primary minerals have lower δ180 and δ30Si values, indicating that the fractionation of silicon and oxygen isotopes is also affected by different Si-O bridges in silicate minerals. Furthermore, our samples from the EPR are defined as E-MORB based on K/Ti ratios. Probably, the difference in δ30Si and δ30O between our samples and a normal MORB are cause by the enriched components in E-MORBs.

关键词： silicon and oxygen isotopes basalt East Pacific Rise near 13°N

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PTFE Electrospun Stent Graft—Preparation,Properties and Its Industrialization Prospect

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Chemical Research in Chinese Universities 2021年第3期37卷 589-597页

作者： LUO Yu GONG Xiaoyan Shawn XU Zhiwei MENG Kai ZHANG Ke-Qin zhao huijing National Engineering Laboratory for Modern Silk College of Textile and Clothing EngineeringSoochow UniversitySuzhou215123China Suzhou Innomed Medical Device Co. Ltd.Suzhou215123China Nantong Textile&Silk Industrial Technology Research Institute Nantong226001China

Stent graft(SG),isolating the diseased vessels from the normal blood circulation and preventing the rupture of the aneurysm wall in minimally invasive surgery,is normally composed of a metallic stent and a cover with a textile *** this study,the electrospinning method was used to prepare a new type of cover,and the preparing conditions and the performance of the SG were *** polytetrafluoroethylene(PTFE)and polyethylene oxide(PEO)were blended at the ratios of 99:1,98:2,97:3 and electrospun to form precursor *** they were dried in a vacuum and sintered at different temperatures under different time periods to obtain PTFE membrane,which was compounded with a *** morphology,mechanical properties,water permeability and biological properties were *** results showed that when the membrane was sintered at 380℃ for 10 min,it had the best tensile *** integral water permeability of the PTFE electrospun SG was close to *** hemolysis rate of the SG was 2.84%,and human umbillical vein endothelial cells(HUVECs)can adhere and proliferate well on the surface of the PTFE *** PTFE electrospun SG had great potential for clinical application and industrialization.

关键词： Polytetrafluoroethylene(PTFE) Electrospinning Stent graft Water permeability Biocompatibility

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Component characteristics of organic matter in hydrothermal barnacle shells from Southwest Indian Ridge

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Acta Oceanologica Sinica 2013年第12期32卷 60-67页

作者： HUANG Xin ZENG Zhigang CHEN Shuai YIN Xuebo WANG Xiaoyuan zhao huijing YANG Baoju RONG Kunbo MA Yao Key Laboratory of Marine Geology and Environment Institute of OceanologyChinese Academy of Sciences University of Chinese Academy of Sciences

In 2008-2009, hydrothermal barnacle and sediment samples were collected from the Southwest Indian Ridge during a survey of the China Ocean Mineral Resources R＆D Association （COMRA）. Samples were ana- lyzed by gas chromatography-mass spectrometer （GC-MS）, revealing the main organic constituents of hy- drothermal barnacle and sediment to be fatty acids and alkylbenzenes. N-alkanes which possessed obvious even carbon advantage were also detected in hydrothermal sediment. The high concentrations of aromatic compounds might be the result of macromolecular thermal alteration. Microorganism in the submarine hydrothermal ecosystem, especially those related to sulfur metabolism, might be the source of the high con- centrations of fatty acids detected in these samples. In high temperature and high pressure hydrothermal environments, n-alkanes which possessed obvious even carbon advantage might originate from thermal alteration of carboxylic acids and other lipid compounds.

关键词： Southwest Indian Ridge hydrothermal barnacle shell hydrothermal sediment organic matter

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Silk Fibroin/Poly-L-lactide Lactone Bi-layered Membranes for Guided Bone Regeneration

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Journal of Donghua University(English Edition) 2019年第6期36卷 564-572页

作者： WANG Linbo REN Xiangxiang JIANG Ziyi MENG Kai zhao huijing National Engineering Laboratory for Modern Silk College of Textile and Clothing EngineeringSoochow UniversitySuzhou 215123China Nantong Textile&Silk Industrial Technology Research Institute Nantong 226001China

After removal of the caries or diseased teeth,the alveolar ridge will undergo absorption and *** the amount of alveolar bone is insufficient,it will cause an inability to perform effective dental implant *** order to control the absorption and promote the repair and regeneration of alveolar ridge,a method of implanting guided bone regeneration(GBR)membranes at the extraction site is often *** this study,silk fibroin(SF)and poly-L-lactide lactone(PLCL)were used to prepare bilayered guided bone regeneration membranes,and its morphology,hydrophilicity,surface roughness and mechanical properties were *** the same time,the drug release behaviors and cell compatibility of the bilayered membranes were *** results showed that SF/PLCL bi-layered membranes had good mechanical properties and surface hydrophilicity,and the drug-loaded bi-layered membranes had good cell *** bilayered membranes fabricated in this study are of potential for applying in the oral health field to promote bone regeneration.

关键词： silk fibroin(SF) poly-L-lactide lactone(PLCL) guided bone regeneration(GBR) oral health

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Simulation and preparation of novel medium convex artificial blood vessel for reducing compliance mismatch

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Medicine in Novel Technology and Devices 2023年第2期18卷 247-257页

作者： Ziyi Jiang huijing zhao Ke-Qin Zhang Kai Meng College of Textile and Clothing Engineering Soochow UniversityNo.178 Ganjiang RoadSuzhou215006PR China National Engineering Laboratory for Modern Silk(Suzhou) No.199 Ren'ai RoadIndustrial ParkSuzhou215123PR China

Compliance mismatch between artificial blood vessel and host vessel can cause abnormal hemodynamics and is the main mechanical trigger of intimal hyperplasia(IH)after *** explore the specific effects of the degree of compliance mismatch on hemodynamics,the concept of“compliance mismatch degree”was defined in this *** results showed that when the compliance mismatch degree was less than-22.21%or more than 3.16%,the minimum WSS in the anastomotic site was less than the safety threshold of 0.5 Pa,which is easy to induce *** addition,the compliance mismatch caused different radial displacements first,which in turn affected the *** by this,a novel medium convex artificial blood vessel was proposed,and the simulation results theoretically validated its desired effect on reducing the compliance *** increase of 0.22 mm in the diameter of the artificial blood vessel corresponded to a decrease of 0.88%in compliance mismatch *** feasibility of preparing real medium convex artificial blood vessel was also *** PLCL medium convex artificial blood vessel with good mechanical properties was prepared by dip-coating and electrospinning composite *** findings are valuable for the design and preparation of novel artificial blood vessel which can make up for the mismatch of compliance.

关键词： Artificial blood vessel Compliance mismatch Numerical simulation Hemodynamics Wall shear stress

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Determination of total fl avonoids content in buckwheat and inhibition ofα-amylase activity

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Journal of Polyphenols 2024年第3期6卷 98-105页

作者： huijing Chao Rong Yang Ming Yang Beijie Xu Xu zhao Faculty of Functional Food and Wine Shenyang Pharmaceutical UniversityShenyang 110016China

Diabetes is one of the most diffi cult chronic diseases to cure in the world,which seriously aff ects people’s health and quality of *** in buckwheat can regulate blood glucose levels by inhibitingα-amylase ***,sweet buckwheat produced in Inner Mongolia was used as the research object,and buckwheat fl avonoids were extracted by ultrasonic-assisted extraction *** fl avonoids content was determined by ultraviolet-visible *** acarbose as the positive control,the inhibition test ofα-amylase was carried out by DNS colorimetry to study the inhibition behavior of fl avonoids onα-amylase *** results showed that the extraction process of fl avonoids was stable and reliable,and the established method for the determination of flavonoids was simple,accurate and *** total fl avonoids content of buckwheat samples was 2.706 mg/g,buckwheat total fl avonoids extraction solution had an inhibitory eff ect onα-amylase,and its median inhibition concentration(IC_(50))was 38.53 mg/*** results of this experiment provide a technical reference for the development and utilization of fl avonoids in Inner Mongolia sweet buckwheat,and provide a theoretical reference for the development and application of fl avonoid-rich hypoglycemic food.

关键词： buckwheat total fl avonoids content α-amylase activity inhibition

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Numerical simulation to study the impact of compliance mismatch between artificial and host blood vessel on hemodynamics

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Medicine in Novel Technology and Devices 2022年第3期15卷 115-123页

作者： Ting Cao Ziyi Jiang huijing zhao Ke-Qin Zhang Kai Meng College of Textile and Clothing Engineering Soochow University.No.178 Ganjiang RoadSuzhou215006PR China National Engineering Laboratory for Modern Silk(Suzhou).No.199 Ren'ai Road Industrial ParkSuzhou215123PR China

Small-diameter artificial blood vessels are prone to cause intimal hyperplasia(IH)after transplantation,which leads to restenosis and low long-term patency *** main biomechanical factor for IH formation is the compliance mismatch between the artificial and host blood vessels which can cause abnormal *** there have been many studies on vascular compliance mismatches,however,little attention has been paid to the effect of the degree of compliance mismatch between graft and the host vessel on *** present,the research on compliance mismatch between the artificial and host blood vessels is still very limited,especially with regard to the specific impact of the compliance mismatch degree on ***,three end-to-end anastomosis models(the compliance of the artificial blood vessel is lower than,similar to,and higher than that of the host blood vessel,called model 1,model 2,model 3,respectively)were constructed and simulated in this *** results showed that the radial displacement difference between the artificial and host blood vessels were 0.281 mm,0.183 mm and 0.485 mm in model 1,model 2 and model 3,respectively.A low-velocity recirculation zone near the distal anastomosis was formed in model 1 which resulted in excessively low TAWSS(9.261 E-5Pa)and high OSI(0.497).Similarly,a low-velocity recirculation zone near the proximal anastomosis was formed in model 3 and lead to low TAWSS(6.007 E-4Pa)and high OSI(0.480).However,there was no low-velocity recirculation zone near the anastomosis stoma in model *** results are instructive for the design and preparation of artificial blood vessels.

关键词： Numerical simulation Artificial blood vessel Compliance mismatch Wall shear stress Oscillatory shear index

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