检索结果-南通市图书馆

Approach for Polishing Diamond Coated Complicated Cutting Tool: Abrasive Flow Machining(AFM)

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2018年第6期31卷 154-168页

作者： Xin-Chang Wang Cheng-Chuan Wang Chang-Ying Wang fang-hong sun School of Mechanical Engineering Shanghai Jiao Tong University

Lower surface roughness and sharper cutting edge are beneficial for improving the machining quality of the cut?ting tool, while coatings often deteriorate them. Focusing on the diamond coated WC?Co milling cutter, the abrasive flow machining(AFM) is selected for reducing the surface roughness and sharpening the cutting edge. Comparative cutting tests are conducted on di erent types of coated cutters before and after AFM, as well as uncoated WC?Co one, demonstrating that the boron?doped microcrystalline and undoped fine?grained composite diamond coated cutter after the AFM(AFM?BDM?UFGCD) is a good choice for the finish milling of the 6063 Al alloy in the present case, because it shows favorable machining quality close to the uncoated one, but much prolonged tool lifetime. Besides, compared with the micro?sized diamond films, it is much more convenient and e cient to finish the BDM?UFGCD coated cutter covered by nano?sized diamond grains, and resharpen its cutting edge by the AFM, owing to the lower initial surface roughness and hardness. Moreover, the boron incorporation and micro?sized grains in the underly?ing layer can enhance the film?substrate adhesion, avoid the rapid film removal in the machining process, and thus maximize the tool life(1040 m, four times more than the uncoated one). In general, the AFM is firstly proposed and discussed for post?processing the diamond coated complicated cutting tools, which is proved to be feasible for improving the cutting performance

关键词： Abrasive flow machining Diamond coated complicated cutting tool Surface roughness Radius of the cutting edge Machining quality Tool lifetime

Effect of deposition temperature on properties of boron-doped diamond films on tungsten carbide substrate

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2018年第4期28卷 729-738页

作者： Bin SHEN Su-lin CHEN fang-hong sun School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Boron-doped diamond(BDD)films were deposited on the tungsten carbide substrates at different substrate temperatures ranging from 450 to 850°C by hot filament chemical vapor deposition(HFCVD)*** effect of deposition temperature on the properties of the boron-doped diamond films on tungsten carbide substrate was *** is found that boron doping obviously enhances the growth rate of diamond films.A relatively high growth rate of 544 nm/h was obtained for the BDD film deposited on the tungsten carbide at 650°*** added boron-containing precursor gas apparently reduced activation energy of film growth to be 53.1 kJ/mol,thus accelerated the rate of deposition chemical ***,Raman and XRD analysis showed that heavy boron doping(750 and 850°C)deteriorated the diamond crystallinity and produced a high defect density in the BDD ***,600-700°C is found to be an optimum substrate temperature range for depositing BDD films on tungsten carbide substrate.

关键词： hot filament chemical vapor deposition diamond film boron doping substrate temperature tungsten carbide

Fabrication and application of nano/microcrystalline composite diamond coated drawing dies using alternative carbon sources

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2018年第8期28卷 1602-1610页

作者： Cheng-chuan WANG Xin-chang WANG fang-hong sun School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Nano/microcrystalline composite diamond films were deposited on the holes of WC-6%Co drawing dies by a two-step procedure using alternative carbon sources, i.e., methane for the microcrystalline diamond（MCD） layer and acetone for the nanocrystalline diamond（NCD） layer. Moreover, the monolayer methane-MCD and acetone-NCD coated drawing dies were fabricated as comparisons. The adhesion and wear rates of the diamond coated drawing dies were also tested by an inner hole polishing apparatus. Compared with mono-layer diamond coated drawing die, the composite diamond coated one exhibits better comprehensive performance, including higher adhesive strength and better wear resistance than the NCD one, and smoother surface（Ra=65.3 nm） than the MCD one（Ra=95.6 nm） after polishing at the same time. Compared with the NCD coated drawing die, the working lifetime of the composite diamond coated one is increased by nearly 20 times.

关键词： microcrystalline nanocrystalline composite diamond film WC Co drawing die alternative carbon source

Cutting performance of multilayer diamond coated silicon nitride inserts in machining aluminum-silicon alloy

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2013年第7期23卷 1985-1992页

作者：陈乃超孙方宏上海交通大学机械与动力工程学院上海200240

Aluminum-silicon （Al-Si） alloy is very difficult to machine and diamond tools are considered by far the best choice for the machining of these materials. Experimental results in the machining of the Al-Si alloy with diamond coated inserts are presented. Considering the fact that high adhesive strength and fine surface morphology play an importance role in the applications of chemical vapor deposition （CVD） diamond films, multilayer technique combining the hot filament CVD （HFCVD） method is proposed, by which multilayer diamond-coating on silicon nitride inserts is obtained, microcrystalline diamond （MCD）/ nanocrystalline diamond （NCD） film. Also, the conventional monolayer NCD and MCD coated inserts are produced for comparison. The as-deposited diamond films are characterized by field emission scanning electron microscopy （FE-SEM） and Raman spectrum. All the CVD diamond coated inserts and uncoated insert endure the aluminum-silicon alloy turning to estimate their cutting performances. Among all the tested inserts, the MCD/NCD coated insert exhibits the perfect behavior as tool wear due to its very low flank wear and no diamond peeling.

关键词： aluminum-silicon alloy multilayer diamond films silicon nitride cutting performance

Co evolutions for WC-Co with different Co contents during pretreatment and HFCVD diamond film growth processes

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2018年第3期28卷 469-486页

作者： Xin-chang WANG Cheng-chuan WANG Wei-kai HE fang-hong sun State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China School of Physics and Technology University of Ji’nanJi’nan 250022China

Systematical researches were accomplished on WC-Co with different Co contents(6%,10%and 12%,mass fraction).Based on the XPS and EDX,from orthogonal pretreatment experiments,it is indicated that the acid concentration,the time of the acid pretreatment and the original Co content have significant influences on the Co-removal depth(D).Moreover,the specimen temperature,original Co content and Co-removal depth dependences of the Co evolution in nucleation,heating(in pure H2 atmosphere)and growth experiments were discussed,and mechanisms of Co evolutions were summarized,providing sufficient theoretical bases for the deposition of high-quality diamond films on WC-Co substrates,especially Co-rich WC-Co *** is proven that the Co-rich substrate often presents rapid Co *** high substrate temperature can promote the Co diffusion in the pretreated substrate,while acts as a Co-etching process for the untreated *** is finally found that the appropriate Co-removal depth for the WC-12%Co substrate is 8-9μm.

关键词： HFCVD diamond film WC-Co Murakami-acid pretreatment Co content Co evolution

scRNA-seq reveals that origin recognition complex subunit 6 regulates mouse spermatogonial cell proliferation and apoptosis via activation of Wnt/β-catenin signaling

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2024年第1期26卷 46-56页

作者： Shi-Wei Liu Jia-Qiang Luo Liang-Yu Zhao Ning-Jing Ou Chao-Yang Yu-Xiang Zhang Hao-Wei Bai hong-fang sun Jian-Xiong Zhang Chen-Cheng Yao Peng Li Ru-Hui Tian Zheng Li Zi-Jue Zhu Department of Andrology Center for Men's HealthUrologic Medical CenterShanghai General HospitalShanghai Jiao Tong University School of MedicineShanghai 200080China State Key Lab of Reproductive Medicine Nanjing Medical UniversityNanjing 211166China Shanghai Key Lab of Reproductive Medicine Shanghai Jiao Tong University School of MedicineShanghai 200080China Department of Urology Guangdong Provincial Key Laboratory of Biomedical ImagingThe Fifth Affiliated HospitalSun Yat-sen UniversityZhuhai 519000China Department of Urology First Affiliated Hospital of Nanjing Medical UniversityNanjing 210029China

The regulation of spermatogonial proliferation and apoptosis is of great significance for maintaining *** single-cell RNA sequencing(scRNA-seq)analysis of the testis was performed to identify genes upregulated in *** scRNAseq analysis,we identified the spermatogonia upregulated gene origin recognition complex subunit 6(Orc6),which is involved in DNA replication and cell cycle regulation;its protein expression in the human and mouse testis was detected by western blot and *** explore the potential function of Orc6 in spermatogonia,the C18-4 cell line was transfected with control or Orc6 ***,5-ethynyl-2-deoxyuridine(EdU)and terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL)assays,flow cytometry,and western blot were used to evaluate its effects on proliferation and *** was revealed that ORC6 could promote proliferation and inhibit apoptosis of C18-4 *** RNA sequencing and bioinformatics analysis indicated that Orc6 was involved in the activation of wingless/integrated(Wnt)/β-catenin *** blot revealed that the expression ofβ-catenin protein and its phosphorylation(Ser675)were significantly decreased when silencing the expression of *** findings indicated that Orc6 was upregulated in spermatogonia,whereby it regulated proliferation and apoptosis by activating Wnt/β-catenin signaling.

关键词： cell proliferation ORCG scRNA-seq analysis spermatogonia Wnt/β-catenin signaling

Amorphous SiO_2 interlayers for deposition of adherent diamond films onto WC-Co inserts

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

Transactions of Nonferrous Metals Society of China 2015年第9期25卷 3012-3022页

作者：崔雨潇赵天奇孙方宏沈彬上海交通大学机械与动力工程学院机械系统与振动国家重点实验室上海200240

Amorphous Si O2（a-Si O2） films were synthesized on WC-Co substrates with H2 and tetraethoxysilane（TEOS） via pyrolysis of molecular precursor.X-ray diffraction（XRD） pattern shows that silicon-cobalt compounds form at the interface between a-Si O2 films and WC-Co ***,it is observed by transmission electron microscope（TEM） that the a-Si O2 films are composed of hollow mirco-spheroid a-Si O2 ***,the a-Si O2 films are used as intermediate films and chemical vapor deposition（CVD） diamond films are deposited on *** tests were performed to evaluate the adhesion of bi-layer（a-Si O2 ＋ diamond） films on cemented carbide *** the cutting performance of bi-layer（a-Si O2 ＋ diamond） coated inserts was evaluated by machining the glass fiber reinforced plastic（GFRP）.The results show that a-Si O2 interlayers can greatly improve the adhesive strength of diamond films on cemented carbide inserts;furthermore,thickness of the a-Si O2 interlayers plays a significant role in their effectiveness on adhesion enhancement of diamond films.

关键词： hot filament chemical vapor deposition(HFCVD) diamond film WC-Co substrate interlayer adhesion

Effects of deposition parameters on HFCVD diamond films growth on inner hole surfaces of WC-Co substrates

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2015年第3期25卷 791-802页

作者：王新昶林子超沈彬孙方宏上海交通大学机械与动力工程学院上海200240

Deposition parameters that have great influences on hot filament chemical vapor deposition (HFCVD) diamond films growth on inner hole surfaces of WC?Co substrates mainly include the substrate temperature (t), carbon content (φ), total pressure (p) and total mass flow (F). Taguchi method was used for the experimental design in order to study the combined effects of the four parameters on the properties of as-deposited diamond films. A new figure-of-merit (FOM) was defined to assess their comprehensive performance. It is clarified thatt,φandp all have significant and complicated effects on the performance of the diamond film and the FOM, which also present some differences as compared with the previous studies on CVD diamond films growth on plane or external surfaces. Aiming to deposit HFCVD diamond films with the best comprehensive performance, the key deposition parameters were finally optimized as:t=830 °C,φ=4.5%,p=4000 Pa,F=800 mL/min.

关键词： hot filament chemical vapor deposition diamond film inner hole surface Taguchi method deposition parameter optimization

The interaction between KIF21A and KANK1 regulates dendritic morphology and synapse plasticity in neurons

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第1期20卷 209-223页

作者： Shi-Yan sun Lingyun Nie Jing Zhang Xue fang hongmei Luo Chuanhai Fu Zhiyi Wei Ai-Hui Tang Hefei National Research Center for Physical Sciences at the Microscale CAS Key Laboratory of Brain Function and DiseaseMinistry of Education Key Laboratory for Membrane-less Organelles and Cellular DynamicsDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefeiAnhui ProvinceChina Institute of Artificial Intelligence Hefei Comprehensive National Science CenterHefeiAnhui ProvinceChina CAS Center for Excellence in Molecular Cell Sciences Division of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefeiAnhui ProvinceChina Department of Neurobiology School of Life SciencesSouthern University of Science and TechnologyShenzhenGuangdong ProvinceChina Brain Research Center Southern University of Science and TechnologyShenzhenGuangdong ProvinceChina

Morphological alterations in dendritic spines have been linked to changes in functional communication between neurons that affect learning and ***-4 KIF21A helps organize the microtubule-actin network at the cell cortex by interacting with KANK1;however,whether KIF21A modulates dendritic structure and function in neurons remains *** this study,we found that KIF21A was distributed in a subset of dendritic spines,and that these KIF21A-positive spines were larger and more structurally plastic than KIF21A-negative ***,the interaction between KIF21A and KANK1 was found to be critical for dendritic spine morphogenesis and synaptic *** of either KIF21A or KANK1 inhibited dendritic spine morphogenesis and dendritic branching,and these deficits were fully rescued by coexpressing full-length KIF21A or KANK1,but not by proteins with mutations disrupting direct binding between KIF21A and KANK1 or binding between KANK1 and *** down KIF21A in the hippocampus of rats inhibited the amplitudes of long-term potentiation induced by high-frequency stimulation and negatively impacted the animals’cognitive *** together,our findings demonstrate the function of KIF21A in modulating spine morphology and provide insight into its role in synaptic function.

关键词： actin cytoskeleton dendrite KANK1 KIF21A microtubule spine morphology spine synaptic plasticity talin1