检索结果-南通市图书馆

Compound jet generated from an impacted concave dual-layer liquid surface

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2021年第2期33卷 390-394页

作者： Xiang-gang cheng xiao-peng chen School of Marine Science and Technology Northwestern Polytechnical UniversityXi'an 710072China

By impacting a concave dual-layer liquid(with the oil and the dyed water)surface in a test tube,a compound jet with a water core and an oil shell is *** velocities of the jet's head(Vj)and the oil-water interface(Vj')are experimentally determined against the initial thickness and the viscosity of the upper layer *** results show that the oil-water interface can be roughly regarded as a pure material surface,whose velocity can be determined from the jet velocity and the initial location(or the film thickness).Furthermore,the effective density,viscosity and surface tension of the compound jet are used to evaluate the jetting *** previous scaling relation for a single liquid jet can be used to give a good prediction with the effective *** results of this paper can be used for the compound jet/droplet preparation.

关键词： Compound jet dual-layer liquid viscosity interface tension

Wetting failure condition on rough surfaces

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2019年第4期28卷 242-246页

作者： Feng-Chao Yang xiao-peng chen School of Mechanics Civil Engineering and Architecture Northwestern Polytechnical University School of Marine Science Northwestern Polytechnical University

Wetting states and processes attract plenty of interest of scientific and industrial societies. Air entrainment, i.e.,wetting failure, on smooth plate in wetting process has been investigated carefully before. Liquid bath entries of "rough"silicon wafers are studied experimentally in the present work, and the air entrainment condition is analyzed specially with the lubrication theory. The roughness effects on the moving contact lines are therefore explored. The contact line pinning is found to be the main reason for the dynamically enhanced hydrophobicity of rough surface, which implies an effective microscopic contact angle of θ_e = θ_Y + 90° where θY is the Young's contact angle of the material. Our results suggest that the solid surfaces can be considered as hydrophobic ones for a wide range of dynamic process, since they are normally rough. The work can also be considered as a starting point for investigating the high-speed advancing of moving contact line on rough surfaces.

关键词： wetting failure roughness lubrication theory contact angle

A numerical study of the early-stage dynamics of a bubble cluster

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2020年第5期32卷 845-852页

作者： Ya-zhen Shi Kai Luo xiao-peng chen Dai-jin Li School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an 710072China School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an 710129China

The dynamics of multiple cavitating bubbles is numerically simulated,with the ambient pressure lower than the saturated vapor pressure,using a pseudopotential lattice Boltzmann method(LBM)coupled with the Camahan-Starling equation of ***-bubble and multi-bubble systems are tested,and the method for the bubble cluster is *** is found that the bubble can either grow or collapse in the early stage,depending on the configuration of the bubble cluster,characterized by the bubble number,the inter-bubble distance and the initial *** the induced flow,the bubbles are mutually *** relations of the interaction are proposed according to the numerical *** consideration of the interactions,the simplified Rayleigh-Plesset equations(RPEs)for multiple bubbles can describe the evolution of the bubbles *** results may serve as the basis for improved cavitation models.

关键词： Cavitation bubble dynamics interaction lattice Boltzmann method(LBM) Rayleigh-Plesset equation(RPE)

Study on vibration of dragon wash basin and free surface waves inside

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2019年第1期35卷 15-23,I0001页

作者： Zi-Yu Guo xiao-peng chen Lai-Bing Jia Bin Xu School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710129China School of Marine Science and Technology Northwestern Polytechnical UniversityXi'an 710072China

We conducted experimental and numerical studies on the vibrating modes of a dragon wash basin (DWB) and the free surface waves inside the DWB. Both the vibration of the DWB and the sound produced were studied carefully. It was found that the DWB can be excited at different intrinsic modes under different excitation, including striking and rubbing it fast/slowly. However, with gentle rubbing, the DWB will be excited mainly at the first vibrating mode. We showed that the concave side wall of a DWB decreases the intrinsic frequencies (compared with a straight side wall), and the ears of a DWB lead to breaking of the vibrating-axisymmetry and cause the separation of modes I/II and IV/V as well. A theoretical model, in which the water is assumed to be incompressible and inviscid, is applied to the first order vibration and predicts the relation of vibrating frequency versus water depth in the system. The measurement shows that both the radial and azimuthal waves are produced as DWB is working. The frequency of the first component of the surface wave is twice as large as the second one induced by non-linear effects. For both the radial and azimuthal waves, the dispersion relation is presented in the framework of capillary wave theory.

关键词： Dragon wash basin Eigen-mode vibration Surface wave

On the Factors Influencing the High Stretch-Flangeability of a Low-Density 1180 MPa Fe-Mn-Al-C-Nbδ-QP Steel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2024年第8期37卷 1291-1300页

作者： Dan‑Dan Cui peng chen peng‑Fei Wang xiao‑Wu Li Department of Materials Physics and Chemistry School of Materials Science and Engineeringand Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education)Northeastern UniversityShenyang 110819China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China

Low-densityδ-quenching and partitioning(δ-QP)steels with excellent strength and ductility have been recently ***,there are still rare reports on the formability of δ-QP steels,which are critical for satisfying the manufacture of structural parts during the application in automotive *** the present work,an 1180 MPa Fe–Mn–Al–C–Nbδ-QP steel with a high ductility was adopted for the stretch–flangeability ***δ-QP steel was developed by separated quenching and partitioning processes.A good hole expansion ratio(HER)of 34.9±0.9%was obtained in the quenched steel,but it has been further increased to 52.2%by the tempering *** improved stretch–flangeability was attributed to the enhanced austenite stability and deformation *** the one hand,the stability of austenite was increased by carbon partitioning during tempering,which reduced crack possibility via the suppression of the fresh martensite *** the other hand,the tempering treatment released the internal stress caused by martensitic transformation and reduced the difference in strength among different phases,resulting in an increase in the resistance to crack initiation and propagation.

关键词： Hole expansion ratio Low-densityδ-quenching and partitioning(δ-QP)steel Stretch-flangeability Austenite stability Deformation uniformity

Inhibitory effect of interferon-α-2b on expression of cyclooxygenase-2 and vascular endothelial growth factor in human hepatocellular carcinoma inoculated in nude mice

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2008年第44期14卷 6802-6807页

作者： Bin Cao xiao-Ping chen peng Zhu Lei Ding Jian Guan Zuo-Liang Shi Hepatic Surgery Center Affiiiated Tongji Hospital Tongji Medical College Huazhong University of Science and Technology Wuhan 430030 Hubei Province China

AIM： To evaluate the effects of interferon-α-2b （IFN- α-2b） on expression of cyclooxygenase-2 （COX-2） and vascular endothelial growth factor （VEGF） in human hepatocellular carcinoma （HCC） inoculated in nude mice and to study the underlying mechanism of IFN-α- 2b against HCC growth. METHODS： Thirb/-two nude mice bearing human HCC were randomly divided into four groups （n = 8）. On the 10th day after implantation of HCC cells, the mice in test groups （groups A, B and C） received IFN-α- 2b at a serial dose （10000 IU for group A, 20000 IU for group B, 40000 IU for group C sc daily） for 35 d. The mice in control group received normal saline （NS）. The growth conditions of transplanted tumors were observed. Both genes and proteins of COX-2 and VEGF were detected by RT-PCR and Western blot. Apoptosis of tumor cells in nude mice was detected by TUNEL assay after treatment with IFN-α-2b. RESULTS： Tumors were significantly smaller and had a lower weight in the IFN-α-2b treatment groups than those in the control group （P 〈 0.01）, and the tumor growth inhibition rate in groups A, B and C was 27.78%, 65.22% and 49.64%, respectively. The expression levels of both genes and proteins of COX-2 and VEGF were much lower in the IFN-α-2b treatment groups than in the control group （P 〈 0.01）. The apoptosis index （AI） of tumor cells in the IFN-α-2b treatment groups was markedly higher than that in the control group （P 〈 0.01）. Group B had a higher inhibition rate of tumor growth, a lower expression level of COX-2 and VEGF and a higher AI than groups A and C （P 〈 0.05）, but there was no significant difference between groups A and C. CONCLUSION： The inhibitory effects of IFN-α-2b on implanted tumor growth and apoptosis may be associated with the down-regulation of COX-2 and VEGF expression. There is a dose-effect relationship. The medium dose of IFN-α-2b for inhibiting tumor growth is 20 000 IU/d.

关键词： Hepatocellular carcinoma Interferon-α-2b Cyclooxygenase-2 Vascular endothelial growth factor Apoptosis

Experimental study on operative methods of pancreaticojejunostomy with reference to anastomotic patency and postoperative pancreatic exocrine function

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2008年第3期14卷 441-447页

作者： Ming-Dong Bai Liang-Qun Rong Lian-chen Wang Hai Xu Rui-Fang Fan Pei Wang xiao-peng chen Liu-Bin Shi Shu-You peng Department of General Surgery The Second Affiliated HospitalXuzhou Medical College Xuzhou 221006 Jiangsu Province China Department of Hepatobiliary Surgery Lanzhou General Hospital Lanzhou Command PLA Lanzhou 730050Gansu Province China Second Department of Health Care Lanzhou General Hospital Lanzhou Command PLA Lanzhou 730050 GansuProvince China Department of General Surgery Affiliated Yijishan Hospital Wannan Medical College Wuhu 241001 AnhuiProvince China Department of General Surgery Affiliated Huashan Hospital College of Medicine Fudan University Shanghai 200433China Department of General Surgery Second Affiliated Hospital College of Medicine Zhejiang University Hangzhou310016 Zhejiang Province China

AIM:To assess the patency of pancreaticoenterostomy and pancreatic exocrine function after three surgical methods. METHODS: A pig model of pancreatic ductal dilation was made by ligating the main pancreatic duct. After 4 wk ligation, a total of 36 piglets were divided randomly into four groups. The piglets in the control group underwent laparotomy only; the others were treated by three anastomoses: (1) end-to-end pancreaticojejunostomy invagination (EEPJ); (2) end-to-side duct-to- mucosa sutured anastomosis (ESPJ); or (3) binding pancreaticojejunostomy (BPJ). Anastomotic patency was assessed after 8 wk by body weight gain, intrapancreatic ductal pressure, pancreatic exocrine function secretin test, pancreatography, and macroscopic and histologic features of the anastomotic site. RESULTS: The EEPJ group had significantly slower weight gain than the ESPJ and BPJ groups on postoperative weeks 6 and 8 (P < 0.05). The animals in both the ESPJ and BPJ groups had a similar body weight *** ductal pressure was similar in ESPJ and BPJ. However, pressure in EEPJ was significantly higher than that in ESPJ and BPJ (P < 0.05). All three functional parameters, the secretory volume, the flow rate of pancreatic juice, and bicarbonate concentration, were significantly higher in ESPJ and BPJ as compared to EEPJ (P < 0.05). However, the three parameters were similar in ESPJ and BPJ. Pancreatography performed after EEPJ revealed dilation and meandering of the main pancreatic duct, and the anastomotic site exhibited a variable degree of occlusion, and even blockage. Pancreatography of ESPJ and BPJ, however, showed normal ductal patency. Histopathology showed that the intestinal mucosa had fused with that of the pancreatic duct, with a gradual and continuous change from one to the other. For EEPJ, the portion of the pancreatic stump protruding into the jejunal lumen was largely replaced by cicatricial fibrous tissue. CONCLUSION: A mucosa-to-mucosa pancreatico- jejunostomy

关键词： Pancreaticojejunostomy Animal model anastomotic patency Pancreatic exocrine function Histopathology Pancreatography

Dynamic steric confinement effect expands the frontier of Cu-catalyzed asymmetric propargylic aminations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第10期67卷 3181-3183页

作者： peng chen Mao-Mao Zhang Wen-Jing xiao Liang-Qiu Lu Engineering Research Center of Photoenergy Utilization for Pollution Control and Carbon Reduction Ministry of EducationCollege of ChemistryCentral China Normal UniversityWuhan 430079China Wuhan Institute of Photochemistry and Technology Wuhan 430082China State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics(LICP)Chinese Academy of SciencesLanzhou 730000China School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiang 453007China

Chiralα-tertiary amines and related azacycles are commonly found in many natural products,pharmaceuticals and agrochemicals[1].Copper-catalyzed asymmetric propargylic amination(APA)reactions have been established as a reliable method to access enantio-enriched propargylic amines,largely due to the seminal contribution of Nishibayashi et al.[2]and van Maarseveen et al.[3]in 2008.

关键词： catalyzed asymmetric amines

Experimental investigation on using CO_(2)/H_(2)O emulsion with high water cut in enhanced oil recovery

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第2期21卷 974-986页

作者： Xi-Dao Wu peng xiao Bei Liu Guang-Jin chen Jian-Hua Pang State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China Ocean Intelligence Technology Center Shenzhen Institute of Guangdong Ocean UniversityShenzhen518120GuangdongChina

CO_(2) emulsions used for EOR have received a lot of interest because of its good performance on CO_(2)mobility ***,most of them have been focusing on the high quality CO_(2) emulsion(high CO_(2) fraction),while CO_(2) emulsion with high water cut has been rarely *** this paper,we carried out a comprehensive experimental study of using high water cut CO_(2)/H_(2)O emulsion for enhancing oil ***,a nonionic surfactant,alkyl glycosides(APG),was selected to stabilize CO_(2)/H_(2)O emulsion,and the corresponding morphology and stability were evaluated with a transparent PVT ***,plugging capacity and apparent viscosity of CO_(2)/H_(2)O emulsion were measured systematically by a sand pack displacement apparatus connected with a 1.95-m long capillary ***,a high water cut(40 vol%) CO_(2)/H_(2)O emulsion was selected for flooding experiments in a long sand pack and a core sample,and the oil recovery,the rate of oil recovery,and the pressure gradients were *** results indicated that APG had a good performance on emulsifying and stabilizing CO_(2) *** inversion from H_(2)O/CO_(2) emulsion to CO_(2)/H_(2)O emulsion with the increase in water cut was ***_(2)/H_(2)O emulsions with lower water cuts presented higher apparent viscosity,while the optimal plugging capacity of CO_(2)/H_(2)O emulsion occurred at a certain water ***,the displacement using CO_(2)/H_(2)O emulsion provided 18.98% and 13.36% additional oil recovery than that using pure CO_(2) in long sand pack and core tests,*** work may provide guidelines for EOR using CO_(2) emulsions with high water cut.

关键词： CO_(2)/H_(2)O emulsion High water cut CO_(2) mobility control Enhanced oil recovery