检索结果-南通市图书馆

Effect of cooling rate and forced convection on as-cast structure of 2205 duplex stainless steel

在线全文

学校读者我要写书评

暂无评论

China Foundry 2015年第1期12卷 32-38页

作者： Cheng Zhang Hong-gang Zhong Cong-sen wu Jie Ni Qi-jie Zhai Shanghai Key Laboratory of Modern Metallurgy & Materials Processing Shanghai University

To forecast the as-cast structure and ferrite-austenite phase ratio of 2205 duplex stainless steel(DSS), the effects of cooling rate and forced convection were observed in a high-vacuum resistance furnace in which the forced convection was created by the rotation of the crucible. The as-cast structure of all 2205 DSS samples is full equiaxed grains, and the microstructure consists of a great amount of desirable intra-granular austenite inside the continuous ferrite grain matrix, besides Widmanstatten austenite and grain boundary austenite. The ferrite grain size decreases gradually with the increase in the cooling rates(20 to 60 oC·min-1) or the forced convection, while the ferrite grains of the samples solidified with a strong convection are barely changed when the cooling rate is below 50 oC·min-1. Moreover, a small grain size is beneficial for the austenite formation but the influence is not very obvious under the cooling rates in the range of 5 to 50 oC·min-1. Compared with grain size, the cooling rate has a greater influence on the final ferrite content. A model based on the experimental results is established to predict the ferrite content, which could be approximated by δ(%) = 20.5·exp(c/80.0) + 0.34 d +34.1, where cis the cooling rate in oC·min-1 and d is the grain size in mm. By using this model, the dependence of the final ferrite content on cooling rate and grain size is well described.

关键词： duplex stainless steel cooling rate grain size forced convection ferrite content

A new heuristics model of simulating pedestrian dynamics based on Voronoi diagram

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第1期30卷 623-639页

作者： Xin-sen wu Hao Yue Qiu-Mei Liu Xu Zhang Chun-Fu Shao Key Laboratory of Transport Industry of Big Data Application Technologies for Comprehensive Transport Ministry of TransportBeijing Jiaotong UniversityBeijing 100044China College of Civil Engineering and Architecture Henan University of TechnologyZhengzhou 450001China

A new heuristics model based on the Voronoi diagram is presented to simulate pedestrian dynamics with the noncrowded state, in which these mechanisms of preference demand evading and surpassing, microscopic anti-deadlock, and site-fine-tuning are considered. The preference demand describes the willingness determination of detouring or following other pedestrians. In the evading and surpassing mechanisms, in order to achieve a balance between avoiding conflicts and minimizing detour distances, a new pair of concepts: "allow-areas and denial-areas" are introduced to divide the feasible region for pedestrians detour behaviors, in which the direction and magnitude of detour velocity are determined.A microscopic anti-deadlock mechanism is inserted to avoid deadlock problem of the counter-directional pedestrian. A site-fine-tuning mechanism is introduced to describe the behavior of avoiding getting too close to the neighbors in pedestrian movement. The presented model is verified through multiple scenarios, including the uni-or bi-direction pedestrian flow in the corridor without obstacles, the uni-direction pedestrian flow in the corridor with obstacles, and the pedestrian evacuation from a room with single-exit. The simulation results show that the velocity–density relationship is consistent with empirical data. Some self-organizing phenomena, such as lanes formation and arching are observed in the *** pedestrians detour an obstacle, the avoiding area before the obstacle and the unoccupied area after the obstacle can be observed. When pedestrians evacuate through a bottleneck without panic, the fan-shaped crowd can be found, which is consistent with the actual observation. It is also found that the behavior of following others in an orderly manner is more conducive to the improvement of the overall movement efficiency when the crowd moves in a limited space.

关键词： pedestrian dynamics pedestrian simulation heuristics rules Voronoi diagram

A brief review of genome editing technology for generating animal models

在线全文

学校读者我要写书评

暂无评论

Frontiers of Agricultural Science and Engineering 2020年第2期7卷 123-128页

作者： Haoyi WANG sen wu Mario R.CAPECCHI Rudolf JAENISCH State Key Laboratory of Stem Cell and Reproductive Biology Institute of ZoologyChinese Academy of SciencesBeijing 100101China University of the Chinese Academy of Sciences Beijing 100049China Institute for Stem Cell and Regeneration Chinese Academy of SciencesBeijing 100101China Beijing Advanced Innovation C enter for Food Nutrition and Human Health China Agricultural UniversityBeijing 100193China State Key L aboratory of Agrobiotechnology College of Biological SciencesChina Agricultural UniversityBeijing 100193China Departm ent of Human Genetics University of Utah School of MedicineSalt Lake CityUT 84112USA Whitehead Institute for Biomedical Research CambridgeMA 02142USA Departm ent of Biology Massachusetts Institute of TechnologyCambridgeMA 02142USA

The recent development of genome editing technologies has given researchers unprecedented power to alter DNA sequences at chosen genomic loci,thereby generating various genetically edited animal *** mini-review briefly summarizes the development of major genome editing tools,focusing on the application of these tools to generate animal models in multiple species.

关键词： animal model CRISPR genome editing TALEN ZFN

Primary splenic angiosarcoma with liver metastasis: A case report and literature review

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2016年第12期22卷 3506-3510页

作者： Kai-Feng Yang Yong Li De-Long Wang Jun-wu Yang sen-Yan wu Wei-Dong Xiao Department of General Surgery The First Affiliated Hospital of Nanchang University

Primary splenic angiosarcoma(PSA) is an unusual and highly malignant vascular tumour with a high rate of metastatic. Moreover, the research on prognosis of the disease is poor. The epidemiology, etiology, clinical diagnosis and treatment of the disease remain challenging, because case reports of the disease are few in number. In accordance with other malignant tumors, PSA is very aggressive, and the majority of patients in which this disease is found are at an advanced stage. Almost all patients die within 12 mo of diagnosis irrespective of treatment. We report here a woman who had complained of upper bellyache and anorexia for 10 d. Magnetic resonance imaging showed enlargement of the spleen with multiple heterogeneous masses in the lower pole of the spleen. A hand-assisted laparoscopic splenectomy was performed which allowed histopathologic diagnosis. The patient was diagnosed with PSA and liver metastasis, and succumbed to the disease 35 d after surgery. The literature was finished combined with the clinical features, diagnosis and management of PSA.

关键词： Angiosarcoma Immunohistochemistry Spleen Splenectomy Metastasis

A new fast heat treatment process for cast A356 alloy motorcycle wheel hubs

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Foundry 2018年第1期15卷 11-16页

作者： Shi-ping Lu Rui Du Jian-ping Liu Lin-can Chen Shu-sen wu Zhejiang Wanfeng Motorcycle Wheel Co. Ltd. Xinchang 312500. Zhejiang. China State Key Lab of Materials Processing and Die &Mould Technology Huazhong University of Science and Technology Wuhan 430074 China

The normal T6 heat treatment process for cast A356 alloy generally requires about 15 h. This longperiod procedure increases greatly the manufacturing cost and decreases the productivity in practical production. In this study, a new short-time heat treatment process with only 30 min solution time at 540℃ was developed for the production of motorcycle wheel hubs in order to reduce heat treatment time. Comparisons on microstructure evaluation and mechanical properties, such as tensile strength and ductility, were made between this new fast process and the conventional T6 heat treatment. The results revealed that this new heat treatment process enabled the spheroidization of the eutectic silicon thoroughly, while minimizing the growth of eutectic silicon. The A356 alloy after this new short-time heat treatment shows nearly equal mechanical properties compared with the same alloy heat treated in a normal T6 heat treatment. This investigation makes it possible to significantly improve the efficiency of heat treatment on A356 alloy and, at the same time, improve the mechanical properties of the alloy.

关键词： A356 alloy short-time heat treatment microstructure evaluation mechanical properties

Effect of electrical contact on performance of WSe_(2) field effect transistors

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第6期30卷 684-690页

作者： Yi-Di Pang En-Xiu wu Zhi-Hao Xu Xiao-Dong Hu sen wu Lin-Yan Xu Jing Liu State Key Laboratory of Precision Measurement Technology and Instruments School of Precision Instruments and Opto-electronics EngineeringTianjin UniversityTianjin 300072China

Two-dimensional(2 D) transition metal dichalcogenides(TMDCs) such as tungsten diselenide(WSe_(2)) have spead many interesting physical properties, which may become ideal candidates to develop new generation electronic and optoelectronic devices. In order to reveal essential features of 2 D TMDCs, it is necessary to fabricate high-quality devices with reliable electrical contact. We systematically analyze the effect of graphene and metal contacts on performance of multilayered WSe_(2) field effect transistors(FETs). The temperature-dependent transport characteristics of both devices are *** graphene-contacted WSe_(2) FETs are observed with the metal-insulator transition phenomenon which mainly attributes to the ultra-clean contact interface and lowered contact barrier. Further characterization on contact barrier demonstrates that graphene contact enables lower contact barrier with WSe_(2) than metal contact, since the Fermi level of graphene can be modulated by the gate bias to match the Fermi level of the channel material. We also analyze the carrier mobility of both devices under different temperatures, revealing that graphene contact can reduce the charge scattering of the device caused by ionized impurities and phonon vibrations in low and room temperature regions, respectively. This work is expected to provide reference for fabricating 2 D material devices with decent performances.

关键词： two-dimensional materials tungsten diselenide metal-insulator transition Schottky barrier contact

Genome-wide piggyBac transposon mediated screening reveals genes related to reprogramming

在线全文

学校读者我要写书评

暂无评论

Protein & Cell 2017年第2期8卷 134-139页

作者： Xi Zhang Xinglin Wei Yuanyuan wu Yuzhe Wang Cheng Tan Xiaoxiang Hu Ning Li Mario R. Capecchi sen wu State Key Laboratory of Agrobiotechnology College of Biological Sciences China Agricultural University Beijing 100193 China Department of Human Genetics University of Utah School of Medicine Salt Lake City UT 84112 USA

iPSCs are typically derived using four transcription factors Oct4 （also known as Pou5f1）, Klf4, Sox2 and c-Myc （OKSM）（Takahashi and Yamanaka, 2006）. Major directions in this field are focused on understanding the reprogramming mechanism, optimizing reprogramming methods to improve iPS cell （iPSC） quality, and applications of the cells for regenerative medicine.

关键词： transposon piggyBac Genome-wide

Recurrent thrombosis in the lower extremities after thrombectomy in a patient with polycythemia vera:A case report

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2020年第24期8卷 6473-6479页

作者： Bu-Ping Jiang Guo-Bing Cheng Qiang Hu Jia-Wen wu Xiao-Yang Li Sheng Liao sen-Yan wu Wei Lu Department of Vascular Surgery People’s Hospital of QuzhouQuzhou 324000Zhejiang ProvinceChina

BACKGROUND Acute arterial embolism of the extremities is a surgical emergency. Atrialfibrillation is the major etiology of acute arterial embolism of the *** femoral artery thrombectomy can successfully treat this ***, polycythemia vera (PV) may sometimes explain this medicalemergency. Recurrent thrombosis in the lower extremities after thrombectomycan be found in patients with PV, and reoperation is needed for this *** SUMMARY A 68-year-old man in China suffered from sudden pain in the left lower extremityfor 14 h. The examination in the emergency department showed a diagnosis ofacute arterial embolism of the extremities combined with PV. The patient’scomplaint disappeared after repeat emergency *** Patients with acute arterial embolism of the extremities should be treatedcarefully, especially those who have recurrent thrombosis after emergencythrombectomy. Clinicians should be aware of PV, a rare cause of acute arterialembolism of the extremities. The combination of thrombectomy, phlebotomy, andantiplatelet and anticoagulant drugs may be a suitable therapeutic regimen forthese patients.

关键词： Thrombosis Thrombectomy Polycythemia vera Case report

Effect of transient space-charge perturbation on carrier transport in high-resistance CdZnTe semiconductor

维普期刊数据库评论

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11期28卷 304-307页

作者： Yu Guo Gang-Qiang Zha Ying-Rui Li Ting-Ting Tan Hao Zhu sen wu MIIT Key Laboratory of Radiation Detection Materials and Devices State Key Laboratory of Solidification ProcessingSchool of Materials Science and EngineeringNorthwestern Polytechnical University(NWPU)Xi’an 710072China

The polarization effect introduced by electric field deformation is the most important bottleneck of CdZnTe detector in x-ray imaging. Currently, most of studies focus on electric field deformation caused by trapped carriers;the perturbation of electric field due to drifting carriers has been rarely reported. In this study, the effect of transient space-charge perturbation on carrier transport in a CdZnTe semiconductor is evaluated by using the laser-beam-induced current(LBIC) *** appear in the current curves of CdZnTe detectors with different carrier transport performances under intense excitation, indicating the deformation of electric field. The current signals under different excitations are compared. The results suggest that with the increase of excitation, the amplitude of cusp increases and the electron transient time gradually decreases. The distortion in electric field is independent of carrier transport performance of detector. Transient space-charge perturbation is responsible for the pulse shape and affects the carrier transport process.

关键词： CdZnTe transient space-charge perturbation laser-beam-induced current(LBIC) technique carrier transport