检索结果-南通市图书馆

“Redistribution” Effect of Lumpy Zone for Gas Flow in BF

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2007年第6期14卷 1-7页

作者： ZHU Qing-tian CHENG shu-sen School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China

The gas flow from tuyere to raceway zone by blasting involves three distributional zones, such as dripping, cohesive, and lumpy zone. The gas flow distribution in lumpy zone directly affects the gas utilization ration and smooth operation in the blast furnace. However, the furnace closeness brings about great difficulty in the study of high-temperature gas flow. The charging and blasting system affecting the gas flow and whether the top gas flow distribution could reflect its inner condition as well as the furnace state, such as hanging or scaffolding, which have become the main problems for the research on gas flow. Recently, several researches overseas studied gas flow distribution using the numerical simulation method; however, such a research was rare amongst the natives. In this study, the flow model of gas in cohesive and lumpy zone was established using the numerical simulation software and the gas flow distributions with uniform distribution of burden permeability, scaffolding of wall, and nonuniform charge level were analyzed. As a result, the effects of cohesive zone and lower parts on the gas flow are very limited and the charge level largely affects the distribution of top gas flow. Therefore, it was found that the distribution of top gas flow could hardly reflect the inner gas flow. The process is called ＂redistribution＂ effect, which means that the gas flow after passing through the raceway, dripping, and cohesive zone is distributed when it flows into the lumpy zone.

关键词： blast furnace gas flow lumpy zone numerical simulation

Analysis of Effect of Gas Temperature on Cooling Stave of Blast Furnace

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2010年第1期17卷 1-6页

作者： XIE Ning-qiang CHENG shu-sen School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China

In order to study the effect of gas temperature variation on cooling stave, temperature, stress and displacement distributions of cooling stave were analyzed respectively when gas temperature inside- blast furnace increases from 1000 to 1 600 ℃. The results show that the temperature field on cold side is under control of cooling pipes and hardly changes when gas temperature increases. The temperature gradient and change rate with time near hot sides are greater than those in other regions and the later can reach 100 ℃/s. The stress intensity near middle area of hot surface is up to 400 MPa and that＇s why there are lots of cracks at this place. The edge of stave is bent to cold side and middle regions between fixed bolts and pin moves to hot side. The displacement around fixed pin is smaller but larger on the edge and the maximum is located on hot side of top surface. The maximum displacement in z direction is about 4 mm and 3 mm in y direction. If the expansion coefficient of packing layer is 1/4, the thickness of packing layer between the cooling staves is 32 mm and 24 mm between sides up and down.

关键词： temperature variation displacement temperature change rate stress intensity packing layer

Postoperative outcomes after open splenectomy versus laparoscopic splenectomy in cirrhotic patients:a meta-analysis

在线全文

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2016年第1期15卷 14-20页

作者： Khaled Al-raimi shu-sen Zheng Division of Hepatobiliary Pancreatic Surgery First Affiliated HospitalZhejiang University School of Medicine

BACKGROUND： Laparoscopic splenectomy is considered the gold standard for resecting normal-to-moderately bigger spleens in benign conditions, and in addition could be tried for patients with malignant splenic disorders. However, the safety of laparoscopic splenectomy in patients with hyper- splenism is not well-known. This study aimed to investigate the efficacy and safety of laparoscopic splenectomy for pa- tients with hypersplenism secondary to liver cirrhosis by com- paring with the open splenectomy.

关键词： open splenectomy laparoscopic splenectomy cirrhosis

Effects of high-pressure rheo-squeeze casting on the Fe-rich phases and mechanical properties of Al-17Si-(1,1.5)Fe alloys

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2018年第9期25卷 1018-1026页

作者： Chong Lin shu-sen Wu shu-lin Lü Ping An He-bao Wu State Key Laboratory of Materials Processing and Die & Mould Technology Huazhong University of Science and Technology Hubei Provincial Key Laboratory of Chemical Equipment Intensification and Intrinsic Safety Wuhan Institute of Technology

The effects of high pressure rheo-squeeze casting(HPRC) on the Fe-rich phases(FRPs) and mechanical properties of Al-17 Si-(1,1.5)Fe alloys were investigated. The alloy melts were first treated by ultrasonic vibration(UV) and then formed by high-pressure squeeze casting(HPSC). The FRPs in the as-cast HPSC Al-17 Si-1 Fe alloys only contained a long, needle-shaped β-Al5 Fe Si phase at 0 MPa. In addition to the β-Al5 Fe Si phase, the HPSC Al-17 Si-1.5 Fe alloy also contained the plate-shaped δ-Al4 Fe Si2 phase. A fine, block-shaped δ-Al4 Fe Si2 phase was formed in the Al-17 Si-1 Fe alloy treated by UV. The size of FRPs decreased with increasing pressure. After UV treatment, solidification under pressure led to further refinement of the FRPs. Considering alloy samples of the same composition, the ultimate tensile strength(UTS) of the HPRC samples was higher than that of the HPSC samples, and the UTS increased with increasing pressure. The UTS of the Al-17 Si-1 Fe alloy formed by HPSC exceeded that of the Al-17 Si-1.5 Fe alloy formed in the same manner under the same pressure. Conversely, the UTS of the Al-17 Si-1 Fe alloy formed by HPRC decreased to a value lower than that of the Al-17 Si-1.5 Fe alloy formed in the same manner.

关键词： high pressure rheo-squeeze casting Al-17Si-(1,1.5)Fe alloys Fe-rich phases mechanical properties

Study on the early warning mechanism for the security of blast furnace hearths

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2013年第4期20卷 345-353页

作者： Hong-bo Zhao Shou-feng Huo shu-sen Cheng State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing North Billion Technology Co. LTD.

The campaign life of blast furnace （BF） hearths has become the limiting factor for safety and high efficiency production of modern BFs. However, the early warning mechanism of hearth security has not been clear. In this article, based on heat transfer calculations, heat flux and erosion monitoring, the features of heat flux and erosion were analyzed and compared among different types of hearths. The primary detecting elements, mathematical models, evaluating standards, and warning methods were discussed. A novel early warning mechanism with the three-level quantificational standards was proposed for BF hearth security.

关键词： blast furnaces hearths erosion heat flux warning

Characteristics of shell thickness in a slab continuous casting mold

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2009年第1期16卷 25-31页

作者： Di-feng Wu shu-sen Cheng Zi-jian Cheng School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China Steelmaking Plant Jiuquan Iron and Steel Co. Ltd. Jiayuguan 735100 China

The key to reduce shell breakout in the continuous casting process is to control shell thickness in the mold. A numerical simulation on the turbulent flow and heat transfer coupled with solidification in the slab mold using the volume of fluid （VOF） model and the enthalpy-porosity scheme was conducted and the emphasis was put upon the flow effect on the shell thickness profiles in longitudinal and transverse directions. The results show that the jet acts a stronger impingement on the shell of narrow face, which causes a zero-increase of shell thickness in a certain range near the impingement point. The thinnest shell on the slab cross-section locates primarily in the center of the narrow face, and secondly near the comer of the wide face. Nozzle optimization can obviously increase the shell thickness and make it more uniform.

关键词： continuous casting slab mold shell thickness nozzle optimization

Microstructure,Mechanical Properties and Die-Filling Behavior of High-Performance Die-Cast Al-Mg-Si-Mn Alloy

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2015年第11期28卷 1344-1353页

作者： Zu-Qi Hu Xin-Jian Zhang shu-sen Wu Institute of Materials China Academy of Engineering Physics State Key Lab of Materials Processing and Die & Mould Technology Huazhong University of Science and Technology

This work aims to reveal the relationships between the microstructure, mechanical properties and flow behavior of die-casting AlMg5Si2Mn alloy. Results indicated that the microstructure of the die-cast AlMgsSi2Mn consists of α1-Al grains, fine-size α2-Al grains and （Al ＋ Mg2Si） eutectic. The surface layer observed has the thickness in a range of 120-135 μm, while an ellipse-like surface layer edge is observed in the corner of the plateqike sample. Tensile strength and elongation （3） of the specimens are slightly decreased along the die-filling direction due to the backflow of melt. Pure （Al ＋ Mg2Si） eutectic layer and ultra-fine-size α2-Al grains observed are around the overflow channels. Mass feeding is predominantly responsible for the superior mechanical properties of the round bars as compared to those of plate-like samples.

关键词： High-pressure die casting Aluminum alloy Microstructure segregations Mechanicalproperties Die-filling behavior Numerical simulation

Epigenetic changes of pituitary tumor-derived transforming gene 1 in pancreatic cancer

在线全文

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2008年第3期7卷 313-317页

作者： Zhang, Mang-Li Lu, sen Zheng, shu-sen Zhejiang Univ Sch Med Affiliated Hosp 1 Dept Hepatobiliary & Pancreat Surg Hangzhou 310003 Zhejiang Peoples R China

BACKGROUND: Pancreatic cancer is a devastating disease with abnormal genetic changes. The pituitary tumor-derived transforming gene (PTTG) is considered to be implicated in the tumorigenesis of cancers when the gene is epigenetically transformed. In this study, we investigated the relationships between aberrant expression and epigenetic changes of the PTTG1 gene in pancreatic cancer. METHODS: We chose 4 cell lines (PANC-1, Colo357, T3M-4 and PancTu I) and pancreatic ductal adenocarcinoma (PDAC) tissues. After using restriction isoschizomer endonucleases (Msp I /Hpa II) to digest the DNA sequence (5'-CCGG-3'), we performed PCR reaction to amplify the product. And RT-PCR was applied to determine the gene expression. RESULTS: The mRNA expression of the PTTG1 gene was higher in pancreatic tumor than in normal tissue. The gene was also expressed in the 4 PDAC cell lines. The methylation states of the upstream regions of the PTTG1 gene were almost identical in normal, tumor pancreatic tissues and the 4 PDAC cell lines. Some (5'-CCGG-3') areas in the upstream region of PTTG1 were methylated, while some others were unmethylated. CONCLUSIONS: The oncogene PTTG1 was overexpressed in pancreatic tumor tissues and verified by RT-PCR detection. The methylation status of DNA in promoter areas was involved in the gene expression with the help of other factors in pancreatic cancer.

关键词： pancreatic neoplasms pituitary tumor-derived transforming gene epigenesis, genetic

Glucagonoma syndrome with necrolytic migratory erythema as initial manifestation

在线全文

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2021年第6期20卷 598-600页

作者： Wei-Fang Zhu shu-sen Zheng Department of Dermatology the First Affiliated HospitalZhejiang University School of MedicineHangzhou 310003China Department of Hepatobiliary and Pancreatic Surgery the First Affiliated HospitalZhejiang University School of MedicineHangzhou 310003China

To the Editor:Necrolytic migratory erythema(NME)is a group of cutaneous lesions characterized by periodic episodes of annular or figurative dark red plaques,which are typically accompanied by blisters,erosions,and *** is often associated with *** is an extremely rare neuroendocrine tumor that arises from pancreatic isletαcells and manifests as elevated glucagon,with an incidence of about 1 in 20 million per year[1,2].

关键词： erythema elevated islet