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Uncertainty analysis and probabilistic design optimization of hybrid rocket motors for manned lunar landing

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Science China(Technological Sciences) 2015年第7期58卷 1234-1241页

作者： zhu Hao TIAN Hui CAI GuoBiao BAO WeiMin School of Astronautics Beihang University China Aerospace Science and Technology Corporation

To obtain a conceptual design for a hybrid rocket motor(HRM)to be used as the Ascent Propulsion System in the Apollo lunar module,the deterministic design optimization(DDO)method is applied to the HRM *** on the results of an uncertainty analysis of HRMs,an uncertainty-based design optimization(UDO)method is also adopted to improve the design *** HRM design process,which is a multidisciplinary system,is analyzed,and a mathematical model for the system design is established to compute the motor performance from the input parameters,including the input variables and model *** input parameter uncertainties are quantified,and a sensitivity analysis of the model parameter uncertainties is conducted to identify the most important model parameter uncertainties for *** DDO and probabilistic UDO methods are applied to conceptual designs for an HRM to be used as a substitute for the liquid rocket motor(LRM)of the Ascent Propulsion *** conceptual design results show that HRMs have several advantages as an alternative to the LRM of the Ascent Propulsion System,including nontoxic propellant combination,small motor volume,and comparable functions,such as restarting and *** of the DDO and UDO results indicate that the UDO method achieves more robust and reliable optimal designs than the DDO *** probabilistic UDO method can be used to develop better conceptual designs for HRMs.

关键词： hybrid rocket motor deterministic design optimization uncertainty-based design optimization sensitivity analysis manned lunar landing

Hierarchical porous MgBO_2(OH) microspheres: Hydrothermal synthesis,thermal decomposition, and application as adsorbents for Congo red removal

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Chinese Journal of Chemical Engineering 2018年第7期26卷 1561-1569页

作者： Panpan Sun Liyuan Chen Lin Xu Wancheng zhu Department of Chemical Engineering Qufu Normal University

A facile eco-friendly hydrothermal route （180 ℃, 12.0 h） has been developed for the first time to the uniform hierarchical porous MgBO2（OH） microspheres without the aid of any organic additive, surfactant or template, by using the abundant MgCl2·6H2O, H3BO3 and NaOH as the raw materials. The as-obtained porous microspheres exhibit a specific surface area of 94.752 mg·g-1, pore volume of 0.814 cm3.g-1, and ca. 84.0% of which have a diameter of 2.25-3.40 μm. The thermal decomposition of the porous MgBO2（OH） microspheres （650 ℃, 2.5 ℃. min-l） leads to the porous Mg2B2O5 rnicrospheres with well-retained morphology. When utilized as the adsorbents for the removal of CR from mimic waste water, the present porous MgBO2（OH） microspheres exhibit satisfactory adsorption capacity, with the maximum adsorption capacity qm of 309.1 mg-g-1, much higher than that derived from most of the referenced adsorbents. This opens a new window for the facile green hydrothermal synthesis of the hierarchical porous MgBO2（OH） microspheres, and extends the potential application of the 3D hierarchical porous metal borates as high-efficiency adsorbents for organic dyes removal.

关键词： Hierarchical porous microspheres Magnesium borate hydroxide Adsorption Congo red Hydrothermal

Multipliers on weighted Hardy spaces over locally compact Vilenkin groups

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Chinese Science Bulletin 1999年第18期44卷 1649-1653页

作者： Yueping zhu Weixing Zheng Nanjing Univ Dept Math Nanjing 210093 Peoples R China

A weighted Hpω(G) multiplier theorem on the multiplier operator T associated with a function m∈ L∞ (Γ) is shown and the atomic decomposition of functions fin Hp*(G) is obtained, where G is a Vilenkin group, r its ... 详细信息

关键词： multipliers Vilenkin group atom-decomposition.

Arsenic prepared by Chinese alchemist-pharmacists

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Science China(Life Sciences) 2016年第10期59卷 1086-1089页

作者： Jing zhu Dingcheng Ren Department of Philosophy East China Normal UniversityShanghai 200241China Department of History University of Chinese Academy of SciencesBeijing 100049China Center for Social Studies of Science Peking UniversityBeijing 100871China

Dear Editor, The discovery of artemisinin is just one of the gifts from traditional Chinese medicine to the world. Clinical studies have shown that arsenic trioxide, an ancient drug used in Chinese medicine, is an effective and relatively safe treat- ment for acute promyelocytic leukemia （APL）. In particular, Chinese alchemy has attracted attention as it gave rise to a wealth of innovations in the medical and chemical field,

关键词：三氧化二砷中国急性早幼粒细胞白血病炼丹术化学领域中医药青蒿素 APL

Improvement on the Oxidation Resistance of a Ti_3Al Based Alloy by Cr1-xAl_xN (0≤x≤0.47) Coatings

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Journal of Materials Science & Technology 2007年第3期23卷 373-378页

作者： Ming zhu Meishuan LI Shuwang DUO Yanchun ZHOU Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Jiangxi Key Laboratory of Surface Engineering Jiangxi Science ＆ Technology Normal University Nanchang 330013 China

Cr1-xAlxN coatings have been deposited on a Ti3Al based alloy by reactive sputtering method. The results of the isothermal oxidation test at 800-900℃ showed that Cr1-xAlxN coatings could remarkably reduce the oxidation rate of the alloy owing to the formation of Al2O3＋Cr2O3 mixture oxide scale on the surface of the coatings. No spallation of the coatings or oxide scales took place during the cyclic oxidation at 800℃. Ti was observed to diffuse into the coatings, the diffusion distance of which was very short, and the diffusion ability of it was proportional to the AI content in the coatings. Compared to Ti, Nb can diffuse much more easily through the whole coatings and oxide scales.

关键词： Cr1-xAlxN coatings Oxidation Interdiffusion Ti3Al based alloy

Size distributions of aerosol and water-soluble ions in Nanjing during a crop residual burning event

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Journal of Environmental Sciences 2012年第8期24卷 1457-1465页

作者： Honglei Wang Bin zhu Lijuan Shen Hanqing Kang Key Laboratory of Meteorological Disaster of Ministry of Education Nanjing University of Information Science and TechnologyNanjing 210044China.

To investigate the impact on urban air pollution by crop residual burning outside Nanjing, aerosol concentration, pollution gas concentration, mass concentration, and water-soluble ion size distribution were observed during one event of November 4-9, 2010. Results show that the size distribution of aerosol concentration is bimodal on pollution days and normal days, with peak values at 60- 70 and 200-300 nm, respectively. Aerosol concentration is 104 ***-1 on pollution days. The peak value of spectrum distribution of aerosol concentration on pollution days is 1.5-3.3 times higher than that on a normal day. Crop residual burning has a great impact on the concentration of fine particles. Diurnal variation of aerosol concentration is trimodal on pollution days and normal days, with peak values at 03：00, 09：00 and 19：00 local standard time. The first peak is impacted by meteorological elements, while the second and third peaks are due to human activities, such as rush hour traffic. Crop residual burning has the greatest impact on SO2 concentration, followed by NO2, 03 is hardly affected. The impact of crop residual burning on fine particles （〈 2.1 μm） is larger than on coarse particles （〉 2.1 μm）, thus ion concentration in fine particles is higher than that in coarse particles. Crop residual burning leads to similar increase in all ion components, thus it has a small impact on the water-soluble ions order. Crop residual burning has a strong impact on the size distribution of K^＋, Cl^-, Na^＋, and F- and has a weak impact on the size distributions of NH4^＋, Ca^2＋, NO3^- and SO4^2-.

关键词： crop residual burning atmospheric aerosol number concentration mass concentration water-soluble ions size distribution

THE EIGENVALUE PROBLEM AND SAINT-VENANT DECAY RATE FOR A NONHOMOGENEOUS SEMI-INFINITE STRIP

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Acta Mechanica Solida Sinica 2014年第6期27卷 588-596页

作者： Qing Yang Bailin Zheng Kai Zhang Jianxin zhu School of Aerospace Engineering and Applied Mechanics Tongji University

The eigenvalue problem about a nonhomogeneous semi-infinite strip is investigated using the methodology proposed by Papkovich and Fadle for homogeneous plane problems. Two types of nonhomogeneity are considered：（i） the elastic modulus varying with the thickness coor- dinate x exponentially, （ii） it varying with the length coordinate y exponentially. The eigenvalues for the two cases are obtained numerically in plane strain and plane stress states, respectively. By considering the smallest positive eigenvalue, tile Saint-Venant Decay rates are estimated, which indicates material nonhomogeneity has a signifcant influence on the Saint-Venant end effect.

关键词： eigenvalue Saint-Venant decay rate nonhomogeneous semi-infinite strip

Evaluation of the SMOS and SMAP soil moisture products under different vegetation types against two sparse in situ networks over arid mountainous watersheds, Northwest China

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Science China Earth Sciences 2019年第4期62卷 703-718页

作者： Lanhui ZHANG Chansheng HE Mingmin ZHANG Yi zhu Key Laboratory of West China’s Environmental System (Ministry of Education) College of Earth and Environmental Sciences Lanzhou University Department of Geography Western Michigan University

Assessment of the suitability of satellite soil moisture products at large scales is urgently needed for numerous climatic and hydrological researches, particularly in arid mountainous watersheds where soil moisture plays a key role in landatmosphere exchanges. This study presents evaluation of the SMOS(L2) and SMAP(L2_P_E and L2_P) products against ground-based observations from the Upstream of the Heihe River Watershed in situ Soil Moisture Network(UHRWSMN) and the Ecological and Hydrological Wireless Sensor Network(EHWSN) over arid high mountainous watersheds, Northwest *** show that all the three products are reliable in catching the temporal trend of the in situ observations at both point and watershed scales in the study area. Due to the uncertainty in brightness temperature and the underestimation of effective temperature, the SMOS L2 product and both the SMAP L2 products show "dry bias" in the high, cold mountainous area. Because of the more accurate brightness temperature observations viewing at a constant angle and more suitable estimations of single scattering albedo and optical depth, both the SMAP L2 products performed significantly better than the SMOS ***, comparing with station density of in situ network, station representation is much more important in the evaluation of the satellite soil moisture products. Based on our analysis, we propose the following suggestions for improvement of the SMOS and SMAP product suitability in the mountainous areas: further optimization of effective temperature; revision of the retrieval algorithm of the SMOS mission to reduce the topographic impacts; and, careful selection of in situ observation stations for better representation of in situ network in future evaluations. All these improvements would lead to better applicability of the SMOS and SMAP products for soil moisture estimation to the high elevation and topographically complex mountainous areas in arid regions.

关键词： SMOS SMAP Evaluation Different vegetation types Sparse in situ networks Arid mountainous watershed

Co-conversion of methanol and n-hexane into aromatics using intergrown ZSM-5/ZSM-11 as a catalyst

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Frontiers of Chemical Science and Engineering 2020年第5期14卷 783-792页

作者： Shumei Wei Yarong Xu Zhaoyang Jin Xuedong zhu UNILAB State Key Laboratory of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China Research Institute of Urumqi Petrochemical Company Petrochina Company LimitedUrumqi 830019China

The conversion of n-hexane and methanol into value-added aromatic compounds is a promising method for their industrially relevant *** this study,intergrown ZSM-5/ZSM-11 crystals were synthesized and their resulting catalytic performance was investigated and compared to those of the isolated ZSM-5 and ZSM-1I *** physicochemical properties of ZSM-5/ZSM-l1 intergrown zeolite were analyzed using X-ray diffrac-tion,N2 isothermal adsorption-desorption,the tempera-ture-programmed desorption of ammonium,scanning clectron microscopy,Fourier transform infrared spectra of adsorbed pyridine,and nuclear magnetic resonance of 27AI,and compared with those of the ZSM-5 and ZSM-11 *** catalytic performances of the materials were evaluated during the co-feeding reaction of methanol and n-hexane under the fixed bed conditions of 400℃,0.5 MPa(N2),methanol:n-hexane=7:3(mass ratio),and weight hourly space velocity=1 h 1(methanol).Com-pared to the ZSM-5 and ZSM-11 zeolites,the ZSM-5/ZSM-11 zeolite exhibited the largest specific surface area,a unique crystal structure,moderate acidity,and suitable Brensted/Lewis acid *** evaluation results showed that ZSM-5/ZSM-11 catalyst exhibited better catalytic reactivity than the ZSM-5 and ZSM-11 catalysts in terms of methanol conversion rate,n-hexane conversion rate,and aromatic *** outstanding catalytic property of the intergrown ZSM-5/ZSM-11 was attributed to the enhanced diffusion associated with its unique *** benefit of using zeolite intergrowth in the co-conversion of methanol and alkanes offers a novel route for future catalyst development.

关键词： ZSM-5/ZSM-11 methanol w-hexane cofeeding aromatics