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Evolution of Grain Selection in Spiral Selector during Directional Solidification of Nickel-base Superalloys

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Journal of Materials Science & Technology 2011年第2期27卷 118-126页

作者： Xiangbin Meng Jinguo Li Tao Jin Xiaofeng sun Changbo sun Zhuangqi Hu Institute of Metal Research Chinese Academy of SciencesShenyang 00China Graduate School of Chinese Academy of Sciences Beijing 000China Shenyang Liming Aero-engine(Group) Corporation Ltd. Aviation Industry Corporation of China(AVIC)Shenyang 110043China

The process of grain selection in the spiral selector was investigated by both a ProCAST simulation based on a cellular automaton finite element（CAFE） model and experimental *** results show that the height of starter block,the spiral diameter and initial angle play an important role in grain *** dimension of selector should be maintained in a stable range to optimize the grain orientation and select a single crystal efficiently.A selector which can efficiently select a single crystal had been successfully *** orientation fluctuation in the spiral part was also studied by means of the variation of thermal condition.

关键词： Ni-base single crystal superalloys Grain selection Directional solidification

Zn–Ca–Al mixed oxide as efficient catalyst for synthesis of propylene carbonate from urea and 1,2-propylene glycol

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Chinese Journal of Chemical Engineering 2017年第5期25卷 609-616页

作者： Sen Liu Suhong sun Xuehui Tian Peiyong sun Shenghong Zhang Zhilong Yao College of Chemical Engineering Sichuan University Beijing Key Laboratory of Enze Biomass Fine Chemicals College of Chemical EngineeringBeijing Institute of Petrochemical Technology

A series of Zn–Ca–Al oxides with different cao and ZnO contents have been prepared and evaluated in the synthesis of propylene carbonate(PC) from 1,2-propylene glycol(PG) and urea in a batch reactor. The effect of catalyst composition, basicity and reaction process parameters such as temperature, catalyst dose, molar ratio of PG to urea, purge gas flow and reaction time has been studied to find suitable reaction conditions for the PC synthesis. The PC selectivity and yield under the desired conditions could reach 98.4% and 90.8%, respectively. The best performing catalyst also exhibited a good reusability without appreciable loss in the PC selectivity and yield after five consecutive reaction runs. In addition, a stepwise reaction pathway involving a 2-hydroxypropyl carbamate intermediate was proposed for the urea alcoholysis to PC in the presence of Zn–Ca–Al catalysts, according to the time dependences of reaction intermediates and products.

关键词： Propylene carbonate 1 2-Propylene glycol Urea Catalysis Alcoholysis

Two-layer Lagrange-based relay network topology and trajectory design for solar system explorations

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Science China(Information Sciences) 2024年第6期67卷 342-358页

作者： Jun cao Jian JIAO Hao LIU Rongxing LU Qinyu ZHANG Guangdong Provincial Key Laboratory of Aerospace Communication and Networking Technology Harbin Institute of Technology (Shenzhen) Faculty of Computer Science (FCS) University of New Brunswick

Exploration targeting outer planets and even the edge of the solar system is an emerging direction for the deep-space exploration in the next decades. To address this challenge, a novel two-layer Lagrangebased relay network topology is proposed in this study. Specifically, we utilize the sun-Mars and sun-Saturn Lagrange points(LPs) L4 and L5 to build a two-layer backbone relay network, which ensures continuous and high-efficiency communication capability for the exploration of the solar system. Furthermore, we utilize the planetary gravity assist and design the transfer trajectory of backbone relays with the help of planetary celestial body motion equations and Kepler's laws. Moreover, we conduct link budget analysis for multihop relay transmission under Gamma-Gamma distribution, shadowed Rician fading, and additive white Gaussian noise channels in several typical exploration scenarios and validate that the LP relays can effectively support future deep-space exploration missions.

关键词： deep-space communication Lagrangian points backbone relay network transfer trajectory relay selection

Effect of Surface Hydrogen Coverage on Field Emission Properties of DiamondFilms Investigated by High-Resolution Electron Energy Loss Spectroscopy

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Chinese Physics Letters 2000年第4期17卷 294-295页

作者： WANG yu-Guang GU Chang-Zhi JIN Zeng-sun XIONG Yan-yun LIN Zhang-Da FENG Ke-An State Key Laboratory of Surface Physics Institute of PhysicsChinese Academy of SciencesBeijing 100080 State Key Laboratory of Superhard Materials Jilin UniversityChangchun 130023

The influence of surface hydrogen coverage on the electron field emission of diamond films was investigated by high-resolution electron energy loss *** was found that hydrogen plasma treatment increased the surface hydrogen coverage while annealing caused hydrogen desorption and induced surface *** electron emission measurements manifested that increase of surface hydrogen coverage could improve the field emission properties,due to the decrease of electron affinity of the *** hy hvdrogen adsorption.

关键词： spectroscopy. surface Diamond

Multi-neighboring grids schemes for solving PDE eigen-problems

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Science China Mathematics 2013年第12期56卷 2677-2700页

作者： sun JiaChang Laboratory of Computational Sciences Institute of Software Chinese Academy of Sciences

Instead of most existing postprocessing schemes, a new preprocessing approach, called multi- neighboring grids （MNG）, is proposed for solving PDE eigen-problems on an existing grid G（A）. The linear or multi-linear element, based on box-splines, are taken as the first stage Khuh -λh/1Mh/1Uh. In this paper, the j-th stage neighboring-grid scheme is defined as Khuh λh/j Mh/j Uh = λh/j Mh/j Uh , where gh ：- Mh/j-1 Kh/1 and Mhuh is to be found as a better mass distribution over the j-th stage neighboring-grid G（/k）, and Kh/1 can be seen as an expansion of Kh on the j-th neighboring-grid with respect to the （j - 1）-th mass distribution Mh_l. It is shown that for an ODE model eigen-problem, the j-th stage scheme with 2j-th order B-spline basis can reach 2j-th order accuracy and even （2j ＋ 2）-th order accuracy by perturbing the mass matrix. The argument can be extended to high dimensions with separable variable cases. For Laplace eigen-problems with some 2-D and 3-D structured uniform grids, some 2j-th order schemes are presented for j ≤ 3.

关键词： PDE eigen-problem discrete Rayleigh quotient multi-neighboring grids schemes B-splines

Karyomorphology of three endemic plants(Brassicaceae:Euclidieae and Arabideae)from the Qinghai-Tibet Plateau and its significance

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Plant Diversity 2020年第3期42卷 135-141页

作者： Wenguang sun Haixia Wang Rui Wu Hang sun Zhimin Li CAS Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China School of Life Science Engineering Research Center of Sustainable Development and Utilization of Biomass EnergyYunnan Normal UniversityKunming 650500.China University of the Chinese Academy of Sciences Beijing 100049China

In the paper,chromosome number and karyotype of three endemic genera from China are reported for the first *** results show that Anzhengxia yechengnica has a karyotype formula2 n=2 x=14=6 m+8 sm and belongs to Stebbins-3 A;Shangrilaia nana karyotype formula is2 n=2 x=14=10 m+4 sm(2 sat) and belongs to Stebbins-1 A;Baimashania pulvinata karyotype formula is 2 n=2 x=16=12 m(2 sat)+4 sm and belongs to Stebbins-1 *** and Shangrilaia are monospecific genera belonging to tribe Euclidieae and both have a basic chromosome x=***,which belongs to tribe Arabideae,has two species which have a basic chromosome x=*** implications of these cytological data are compared with morphological support and the implications for each tribe are *** also summarize chromosomal number variation and its systematic implications of two tribes from the Qinghai-Tibet Plateau.

关键词： Karyotype Endemic species Anzhengxia Shangrilaia Baimashania Qinghai-Tibet Plateau

Autoimmune enteropathy and primary biliary cholangitis after proctocolectomy for ulcerative colitis:A case report and review of the literature

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World Journal of Gastroenterology 2021年第29期27卷 4929-4938页

作者： Qing-Yang Zhou Wei-Xun Zhou Xi-yu sun Bin Wu Wei-Yang Zheng yue Li Jia-Ming Qian Department of Gastroenterology Peking Union Medical College HospitalPeking Union Medical College and Chinese Academy of Medical SciencesBeijing 100730China Department of Pathology Peking Union Medical College HospitalPeking Union Medical College and Chinese Academy of Medical SciencesBeijing 100730China Department of General Surgery Peking Union Medical College HospitalPeking Union Medical College and Chinese Academy of Medical SciencesBeijing 100730China

BACKGROUND Autoimmune enteropathy(AIE)and primary biliary cholangitis(PBC)are both immune-mediated *** or PBC complicated with ulcerative colitis(UC)are *** are no cases of AIE and PBC diagnosed after proctocolectomy for UC reported before,and the pathogenesis of these comorbidities has not been *** SUMMARY A middle-aged woman diagnosed with UC underwent subtotal colectomy and ileostomy due to the steroid-resistant refractory disease,and a restorative proctectomy with ileal pouch-anal anastomosis and proximal neoileostomy was postponed due to active residual rectal inflammation in January 2016.A few months after the neoileostomy,she began to suffer from recurrent episodes of watery *** was diagnosed with postcolectomy enteritis and stoma closure acquired a good therapeutic ***,her symptoms of diarrhea relapsed in 2019,with different histological features of endoscopic biopsies compared with 2016,which showed apoptotic bodies,a lack of goblet and Paneth cells,and villous blunting.A diagnosis of AIE was established,and the patient’s stool volume decreased dramatically with the treatment of methylprednisolone 60 mg/d for 1 wk and tacrolimus 3 mg/d for 4 ***,her constantly evaluated cholestatic enzymes and high titers of antimitochondrial antibodies indicated the diagnosis of PBC,and treatment with ursodeoxycholic acid(16 mg/kg per day)achieved satisfactory *** Some immune-mediated diseases may be promoted by operation due to microbial alterations in UC *** follow-up is essential for UC patients with postoperative complications.

关键词： Autoimmune enteropathy Primary biliary cholangitis Ulcerative colitis Proctocolectomy Bacterial translocation Case report

Characteristics of High Temperature Rupture of a Cast Ni-Based Superalloy M963

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Journal of Materials Science & Technology 2001年第4期17卷 425-428页

作者： Chao yuAN , Xaofeng sun,Fengshi YIN,Hengrong GUAN,Zhuangqi HU, Qi ZHENG and Yang yu Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110015, China Chinese Acad Sci Inst Met Res Shenyang 110015 Peoples R China

The rupture behavior of a cast Ni-base superalloy M963 at high temperature has been investi- gated. The microstructure examination shows that there exists a large amount of the carbide and γ-γ' eutectic, which is very harmful to the mechanical properties of M963 superalloy. The tensile strength of M963 superalloy both at room temperature and at high temperatures is higher than that of K17G alloy, but the tensile ductility of the former is much lower than that of the latter. In tensile fracture process with the high strain rate, the open carbides are the initiation site and the carbide/matrix interface is the propagation path of cracks. But in fracture process with the low strain rate, the carbide/matrix interface and cast microvoids are the initiation sites, and the carbide/matrix interface is the propagation path of cracks. The effective ways to improve ductility of M963 superalloy are also suggested.

关键词： Characteristics of High Temperature Rupture of a Cast Ni-Based Superalloy M963 Cast high Ni

烧结温度对La0.67Ca0.33-xSrxMnO3结构及电学性能的影响

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无机材料学报 2016年第9期31卷 943-947页

作者：孙淑苗于洋米乐于云曹韫真宋力昕中国科学院上海硅酸盐研究所中国科学院特种无机涂层重点实验室上海200050

采用传统固相反应法合成了双掺杂La_(0.67)Ca_(0.33-x)Sr_xMnO_3(x=0,0.05,0.15)粉体,研究了烧结温度对La_(0.67)Ca_(0.33-x)Sr_xMnO_3(x=0,0.05,0.15)结构、微观形貌和金属-绝缘体相转变温度的影响规律。结果表明:烧结温度的升高对微观形貌及结构影响较小,双掺杂有效改善了材料体系的相转变温度。当烧结温度为1400℃,掺杂量x=0增加至x=0.05时,材料体系为正交相,相转变温度从–20℃升高至6℃。掺杂量继续增加至x=0.15,材料体系从正交相转变为六方相,相转变温度升高至17℃。当掺杂量相同时,相转变温度随烧结温度的升高而升高。具有上述智能相变特性的材料体系可以作为长寿命卫星主动热控技术的重要候选材料。

关键词： La0.67Ca0.33-xSrxMnO3陶瓷烧结温度相转变温度