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Reduction of die roll height in duplex gears through a sheet-bulk metal forming method

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Advances in Manufacturing 2019年第1期7卷 42-51页

作者： Xiao-Long Sun Xin-Cun Zhuang feng-chun Yang Zhen Zhao Institute of Forming Technology and Equipment School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200030 People's Republic of China National Engineering Research Center of Die & Mold CAD Shanghai Jiao Tong University Shanghai 200030 People's Republic of China

In the existing shearing processes for fabricating parts such as duplex gears, die roll is difficult to avoid. Accordingly, a method based on sheet-bulk metal forming for fabricating a duplex gear with extremely small die roll in one stroke is proposed in the current work. The process could be divided into three stages according to the forming features: upsetting and shearing stage, lateral extrusion stage, and local filling stage. The die roll appeared in the shearing stage, which could be reduced in the subsequent extrusion and local filling stages. To reveal the underground mechanism, material flows under two situations, as a key factor to influence the forming quality, were compared and investigated. The results revealed that by controlling material flow, one could avoid the defects and reduce the die roll.

关键词： Die roll Duplex gear part Sheet-bulk metal forming Lateral extrusion Material flow

Progress in Polymer-Ceramic Hybrid Antifouling Coatings

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Chinese Journal of Polymer Science 2023年第7期41卷 995-1001页

作者： Zhen-Qiang Zhang Yin-Jie Huang chun-feng Ma Guang-Zhao Zhang Faculty of Materials Science and Engineering South China University of TechnologyGuangzhou510640China

Simultaneous realization of superior mechanical and antifouling properties is critical for a coating. The use of stereoscopic polysiloxanes in place of linear polysiloxanes to fabricate antifouling coatings can combine properties of organic and inorganic materials, i.e., they can exhibit both high hardness and wear resistance from inorganic components as well as the flexibility and tunability from organic components. This strategy is used to prepare hard yet flexible antifouling coatings or polymer-ceramic hybrid antifouling coatings. In this mini-review, we report the recent advances in this field. Particularly, the effects of stereoscopic polysiloxane structures on their mechanical and antifouling properties are discussed in detail.

关键词： Antifouling coating Organic-inorganic hybrid Sol-gel Hard yet flexible

Living Crystallization-Driven Self-Assembly of Oligo(p-phenylene vinylene)-Containing Block Copolymers:Impact of Branched Structure of Alkyl Side Chain ofπ-Conjugated Segment

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Chinese Journal of Polymer Science 2023年第4期41卷 574-584,I0008页

作者： Yang Song Bo Xiang Xiao-Yu Huang Guo-Lin Lu chun feng School of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai200093China Shanghai Key Laboratory of Advanced Polymeric Materials School of Materials Science and EngineeringEast China University of Science and TechnologyShanghai200237China Key Laboratory of Synthetic and Self-Assembly Chemistry for Organic Functional Molecules Shanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai200032China

The structure of side chains ofπ-conjugated segments is a critical factor determining living crystallization-driven self-assembly(CDSA),a versatile platform to generate fiber-like nanostructures with precise length and ***,we design and synthesize three block copolymers(BCPs)containing same corona-forming poly(N-isopropyl acrylamide)(PNIPAM)segment,but different core-formingπ-conjugated oligo(p-phenylene vinylene)(OPV)with linear pentyl(l-OPV),racemic 2-methyl butyl(r-OPV)and stereo-regular chiral(S)-2-methyl butyl(c-OPV)side chains,*** using these BCPs of l-OPV-b-PNIPAM_(47),r-OPV-b-PNIPAM_(47)and c-OPV-b-PNIPAM_(47)as model,we aim to get a deep insight into how steric and stereo-regular effect induced by branched alkyl side chains of OPV segment affects the living *** results showed that l-OPV-b-PNIPAM_(47)exhibits typical characteristics of self-seeding and seeded growth of living CDSA to give uniform fiber-like micelles of controlled *** the contrary,r-OPV-b-PNIPAM_(47)and c-OPV-b-PNIPAM_(47)with branched racemic and stereo-regular chiral alkyl side chains are more prone to self-nucleation during the micellar elongation to give short and polydisperse fiber-like *** obvious selfnucleation during the micellar elongation of r-OPV-b-PNIPAM_(47)and c-OPV-b-PNIPAM_(47)is due to the increase of steric repulsion with OPV units induced by branched alkyl side chains,not the stereo-irregular effect of racemic alkyl side chains.

关键词： π-Conjugated polymer Nanofiber Living crystallization-driven self-assembly Structure effect

Adamantiades-Behcet's disease-complicated gastroenteropathy

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World Journal of Gastroenterology 2012年第7期18卷 609-615页

作者： Qing-Jun Wu feng-chun Zhang Xuan Zhang feng-chun Zhang Xuan ZhangDepartmentof RheumatologyPeking Union Medical College HospitalPe-king Union Medical CollegeChinese Academy of Medical Sci-encesBeijing 100730China

Adamantiades-Behcet's disease (ABD) is a chronic,relapsing,systemic vasculitis of unknown *** is more prevalent in populations along the ancient Silk Road from Eastern Asia to the Mediterranean Basin,and most frequently affects young adults between the second and fourth decades of ***-complicated gastroenteropathy is a significant cause of morbidity and mortality,with abdominal pain as the most common *** ileocecal region is affected predominantly,with ulcerations that may lead to penetration and/or perforation,whereas other parts of the gastrointestinal system including the esophagus and stomach can also be *** is useful to locate the site and extent of the lesions,and tissue biopsy is often warranted to examine the histopathology that is often suggestive of underlying vasculitis of small veins/venules or,alternatively in some cases,nonspecific *** wall thickening is the most common finding on computed tomography *** is largely empirical since well-controlled studies are difficult to conduct due to the heterogeneity of the disease,and the unpredictable course with exacerbation and *** with or without other immunosuppressive drugs,such as cyclophosphamide,azathioprine,sulfasalazine,tumor necrosis factor α antagonist or thalidomide should be applied before surgery,except in emergency.

关键词： Adamantiades-Behcet's disease Gastro-enteropathy Ulceration Vasculitis

Optimal Portfolio and Consumption Rule with a CIR Model Under HARA Utility

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Journal of the Operations Research Society of China 2018年第1期6卷 107-137页

作者： chun-feng Wang Hao Chang Zhen-Ming Fang College of Management and Economics Tianjin UniversityTianjin 300072China School of Science Tianjin Polytechnic UniversityTianjin 300387China

In the real-world environments,different individuals have different risk *** paper investigates the optimal portfolio and consumption rule with a Cox–Ingersoll–Ross(CIR)model in a more general utility *** consumption,an individual invests his wealth into the financial market with one risk-free asset and multiple risky assets,where the short-term rate is driven by the CIR model and stock price dynamics are simultaneously influenced by random sources from both stochastic interest rate and stock market *** individual hopes to optimize their portfolios and consumption rules to maximize expected utility of terminal wealth and intermediate *** preference of individual is assumed to satisfy hyperbolic absolute risk aversion(HARA)utility,which contains power utility,logarithm utility,and exponential utility as special *** using the principle of stochastic optimality and Legendre transform-dual theory,the explicit expressions of the optimal portfolio and consumption rule are *** sensitivity of the optimal strategies to main parameters is analysed by a numerical *** addition,economic implications are also *** research results show that Legendre transform-dual theory is an effective methodology in dealing with the portfolio selection problems with HARA utility and interest rate risk can be completely hedged by constructing specific portfolios.

关键词： CIR model Optimal portfolios and consumption rules HARA utility Legendre transform-dual theory Stochastic optimal control Economic implicati

A Solvable Decorated Ising Lattice Model

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Communications in Theoretical Physics 2006年第3期45卷 555-557页

作者： SUN chun-feng KONG Xiang-Mu YIN Xun-Chang Department of Physics Xiaogan University Xiaogan 432100 China Department of Physics Qufu Normal University Qufu 273165 China Interdisciplinary Center of Theoretical Studies the Chinese Academy of Sciences Beijing 100080 China

A decorated lattice is suggested and the Ising model on it with three kinds of interactions K1, K2, and K3 is studied. Using an equivalent transformation, the square decorated Ising lattice is transformed into a regular square Ising lattice with nearest-neighbor, next-nearest-nelghbor, and four-spin interactions, and the critical fixed point is found at K1 = 0.5769, K2= -0.0671, and K3 = 0.3428, which determines the critical temperature of the system. It is also found that this system and the regular square Ising lattice, and the eight-vertex model belong to the same universality class.

关键词： Ising model square decorated lattice critical point universality class

Clinical Significance of REM Sleep Behavior Disorders and Other Non-motor Symptoms of Parkinsonism

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Neuroscience Bulletin 2017年第5期33卷 576-584页

作者： Hong Jin Jin-Ru Zhang Yun Shen chun-feng Liu Department of Neurology and Sleep Center The Second Affiliated Hospital of Soochow University Institute of Neuroscience Soochow University

Rapid eye movement sleep behavior disorder （RBD） is one of the most common non-motor symptoms of parkinsonism, and it may serve as a prodromal marker of neurodegenerative disease. The mechanism underlying RBD is unclear. Several prospective studies have reported that specific non-motor symptoms predict a conversion risk of developing a neurodegenerative disease, including olfactory dysfunction, abnormal color vision, autonomic dysfunction, excessive daytime sleepiness, depression, and cognitive impairment. Parkinson＇s disease （PD） with RBD exhibits clinical heterogeneity with respect to motor and non-motor symptoms compared with PD without RBD. In this review, we describe the main clinical and pathogenic features of RBD, focusing on its association with other non-motor symptoms of parkinsonism.

关键词： Parkinson's disease · Rapid eye movement sleep behavior disorder · Risk factors ·Parkinsonism

Connexin:a potential novel target for protecting the central nervous system?

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Neural Regeneration Research 2015年第4期10卷 659-666页

作者： Hong-yan Xie Yu Cui Fang Deng Jia-chun feng Departmet of Neurology the First Hospital of Jilin University Department of Neurosurgery the First People’s Hospital of Xianyang

Connexin subunits are proteins that form gap junction channels, and play an important role in communication between adjacent cells. This review article discusses the function of connexins/hemichannels/gap junctions under physiological conditions, and summarizes the findings re-garding the role of connexins/hemichannels/gap junctions in the physiological and pathological mechanisms underlying central nervous system diseases such as brain ischemia, traumatic brain and spinal cord injury, epilepsy, brain and spinal cord tumor, migraine, neuroautoimmune disease, Alzheimer’s disease, Parkinson’s disease, X-linked Charcot-Marie-Tooth disease, Peli-zaeus-Merzbacher-like disease, spastic paraplegia and maxillofacial dysplasia. Connexins are considered to be a potential novel target for protecting the central nervous system.

关键词： connexin gap junction biosynthetic pathways biodegradation brain central nervous system diseases

Numerical Analysis of Perforation during Hydraulic Fracture Initiation Based on Continuous-Discontinuous Element Method

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Computer Modeling in Engineering & Sciences 2024年第8期140卷 2103-2129页

作者： Rui Zhang Lixiang Wang Jing Li chun feng Yiming Zhang School of Civil and Transportation Engineering Hebei University of TechnologyTianjin300401China Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing100190China School of Civil Engineering and Architecture Zhejiang Sci-Tech UniversityHangzhou310018China Jinyun Institute Zhejiang Sci-Tech UniversityLishui321400China

Perforation is a pivotal technique employed to establish main flow channels within the reservoir formation at the outset of hydraulic fracturing *** perforation designs is critical for augmenting the efficacy of hydraulic fracturing and boosting oil or gas *** this study,we employ a hybrid finite-discrete element method,known as the continuous–discontinuous element method(CDEM),to simulate the initiation of post-perforation hydraulic fractures and to derive enhanced design *** model incorporates the four most prevalent perforation geometries,as delineated in an engineering technical ***-world perforations deviate from the ideal cylindrical shape,exhibiting variable cross-sectional profiles that typically manifest as an initial constriction followed by an expansion,a feature consistent across all four perforation *** simulations take into account variations in perforation hole geometries,cross-sectional diameters,and perforation *** findings show that perforations generated by the 39g DP3 HMX perforating bullet yield the lowest breakdown pressure,which inversely correlates with increases in sectional diameter and perforation ***,this study reveals the relationship between breakdown pressure and fracture degree,providing valuable insights for engineers and designers to refine perforation strategies.

关键词： Hydraulic fracturing real perforation shape breakdown pressure perforation layout design CDEM