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Environment and economic feasibility of municipal solid waste central sorting strategy： a case study in Beijing

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Frontiers of Environmental Science & Engineering 2016年第4期10卷 115-125页

作者： hua ZHANG Zongguo wen Yixi chen School of Humanities and Economic Management China University of Geosciences Beijing 100083 China State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC) School of Environment Tsinghua University Beijing 100084 China

Although Beijing has carried out municipal solid waste （MSW） source separation since 1996, it has largely been ineffective. In 2012, a ＂Green House＂ program was established as a new attempt for central sorting. In this study, the authors used material flow analysis （MFA） and cost benefit analysis （CBA） methods to investigate Green House＇s environment and economic feasibility. Results showed that the program did have significant environmental benefits on waste reduction, which reduced the amount of waste by 34%. If the Green House program is implemented in a residential community with wet waste ratio of 66%, the proportion of waste reduction can reach 37%. However, the Green House is now running with a monthly loss of 1982 CNY. This is mainly because most of its benefits come from waste reduction （i.e., 5878 CNY per month）, which does not turn a monetary benefit, but is instead distributed to the whole of society as positive environmental externalities. Lack of government involvement, small program scale, and technical/managerial deficiency are three main barriers of the Green House. We, thus, make three recommendations： involve government authority and financial support, expand the program scale to separate 91.4 tons of waste every month, and use more professional equipment/technologies. If the Green House program can successfully adopt these suggestions, 33.8 tons of waste can be reduced monthly, and it would be able to flip the loss into a profit worth 35034 CNY.

关键词： Environment and economic feasibility Municipal solid waste (MSW)Waste central sorting Green House

Dynamic response characteristics of a circular lined tunnel under anisotropy frost heave of overlying soil at the tunnel portal section in cold regions

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Journal of Mountain Science 2023年第5期20卷 1424-1440页

作者： ZHANG Shuo-cheng chen wen-hua School of Civil Engineering Beijing Jiaotong UniversityBeijing 100044China

The rapid development of traffic engineering in cold regions and its consequent problems need to be *** this paper,the dynamic response characteristics of the tunnel portal section in cold regions with harmonic load acting on the lining were studied in the frequency *** lining is in close contact with the frozen soil,and there is relative movement between the frozen and unfrozen soil due to the phase *** analytical solution of the vibration of tunnel portal section caused by the harmonic load acting on the lining was derived under the consideration of the anisotropy frost heave of overlying *** on the continuity conditions and boundary conditions,the undetermined coefficients were obtained,and the analytical solutions for different medium displacements and stresses of the cold-region tunnel system were *** vertical pressure coefficient was equivalently simplified as a variable that could be used to replace the thickness of the overlying soil above the *** analysis of the parameter model shows that the change of the medium parameters(lining,frozen,and unfrozen soil)affects the circumferential stresses,the radial displacements and their peak frequencies of the *** example,the increase of density ratio of tunnel lining to frozen soil decreases the radial stresses of the frozen and unfrozen soil;the increase of volumetric frost heaving strain of the frozen soil increases the radial displacements of the frozen surface and decreases the stability of the frozen surface;the increasing of thickness of the frozen soil significantly reduces the radial displacement of unfrozen soil at dimensionless radius η=4.5 compared with that of frozen soil at η=1.5.

关键词： Frost heave Tunnel portal section Relative movement Dynamic response characteristics Cold region

Shape Memory Effect Induced by Stress-induced α' Martensite in a Metastable Fe–Cr–Ni Austenitic Stainless Steel

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Acta Metallurgica Sinica(English Letters) 2017年第6期30卷 513-520页

作者： Yong-Ning Wang Jie chen hua-Bei Peng Yu-hua wen School of Manufacturing Science and Engineering Sichuan UniversityChengdu 610065China School of Aeronautics and Astronautics Sichuan UniversityChengdu 610065China

It is not clear whether a shape memory effect （SME） can be realized by stress-induced α＇ martensite in metastable austenitic stainless steels although the stress-induced ε martensite in these materials can result in the SME. To clarify this problem, the relationship between the shape recovery and the reverse transformation of the stress-induced ε and α＇ martensite in a 304 stainless steel was investigated. The results show that the stress-induced α＇ martensite can result in the SME when heating above 773 K. After deformation at 77 K and step heating or directly holding at 1073 K, two-stage shape recoveries below 440 K and above 773 K can be obtained due to the reverse transformation of the stress-induced ε martensite and α＇ martensite, respectively. After deformation at room temperature, the α＇ martensite produced can result in the SME only when directly holding at 1073 K. The intrusion of more dislocations before the formation of the α＇ martensite at room temperature than at 77 K is the reason that the α＇ martensite induced at room temperature cannot result in the SME in the case of slow heating. The recovered strains resulting from the stress-induced ε and α＇ martensite are proportional to the amounts of their reverse transformation, respectively.

关键词： Austenitic stainless steel Shape memory effect Alpha prime martensite Epsilon martensite Two-stage recoveries

一种基于柱面镜聚焦系统的高灵敏度全谱光谱仪

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光谱学与光谱分析 2025年第1期45卷 222-230页

作者：陈吉文陈作儿赵迎北方工业大学电气与控制工程学院北京100144

很多元素的最灵敏谱线主要分布在紫外波段。一些常被作为检测对象的重要元素,例如C、P和S,其谱线甚至位于200 nm以下的真空紫外波段。然而真空紫外波段内的辐射极易受空气吸收而无法在空气中传输。因此为了适用于紫外波段各谱线的检测,... 详细信息

很多元素的最灵敏谱线主要分布在紫外波段。一些常被作为检测对象的重要元素,例如C、P和S,其谱线甚至位于200 nm以下的真空紫外波段。然而真空紫外波段内的辐射极易受空气吸收而无法在空气中传输。因此为了适用于紫外波段各谱线的检测,常使用光程短、系统精简的罗兰圆光学系统作为光谱仪的色散系统,并且在进行检测分析时,还需对设备腔体内部建立相对真空的环境进行实验,进而减小实验环境对真空紫外波段内各谱线强度的削弱作用。然而即使在该条件下,P和S这两种元素在真空紫外波段的谱线灵敏度仍然较弱。为此为了实现真空紫外波段范围内的高灵敏度,本研究在距离像面前30 mm处位置设计了一个柱面镜聚焦系统。其采用了材料为CaF_(2)、中心厚度为5 mm以及弧矢面曲率半径为22.06 mm的柱面镜作为核心部件。并利用仿真软件Zemax对设计的光学系统进行仿真与优化,以及从非序列模式下的辐射照度仿真结果可知,柱面镜聚焦系统在几乎不影响分辨率的情况下对各波长成像灵敏度有较大的提升。最后以中低合金钢为检测样品,使用电火花激发光源对样品中各元素在紫外波段内的各谱线进行激发,进而验证光谱仪的各项性能:通过一次拟合、参比拟合以及二次拟合,建立每个元素谱峰强度和实际含量之间的数学模型,并算得各元素的拟合优度R^(2)均在0.99以上;柱面镜聚焦系统显著提高了设备在真空紫外波段的灵敏度,响应提高了1倍以上。实验结果表明,柱面镜聚焦系统的设计方法对于提升罗兰圆色散系统的灵敏度具有一定的参考价值。

关键词：紫外光谱罗兰圆光学系统柱面镜灵敏度拟合优度

Quantitative rescattering theory for nonsequential double ionization

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Chinese Physics B 2019年第12期28卷 14-32页

作者： Zhangjin chen Fang Liu hua wen Department of Physics College of ScienceShantou University UniversityShantou 515063China

We review the recently improved quantitative rescattering theory for nonsequential double ionization, in which the lowering of threshold due to the presence of electric field at the time of recollision has been taken into account. First,we present the basic theoretical tools which are used in the numerical simulations, especially the quantum theories for elastic scattering of electron as well as the processes of electron impact excitation and electron impact ionization. Then,after a brief discussion about the properties of the returning electron wave packet, we provide the numerical procedures for the simulations of the total double ionization yield, the double-to-single ionization ratio, and the correlated two-electron momentum distribution.

关键词： laser-induced recollision nonsequential double ionization quantitative rescattering model

MR全脊柱移床扫描在快速诊断急性脊柱创伤中的应用

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实用放射学杂志 2007年第5期23卷 631-632页

作者：黄文华陈金勇姜楠彭浩王明炎南方医科大学临床解剖学研究所南方医科大学临床解剖学研究所广东广州510515

目的探讨MR全脊柱移床扫描对急性脊柱创伤后多水平椎体及脊髓损伤的应用价值。方法回顾性分析71例急性脊柱创伤患者,应用MR全脊柱移床扫描技术,行颈、胸及腰骶3段脊柱扫描后,采用对接的方法完成全脊柱全程图像。结果71例均获得直观、清... 详细信息

目的探讨MR全脊柱移床扫描对急性脊柱创伤后多水平椎体及脊髓损伤的应用价值。方法回顾性分析71例急性脊柱创伤患者,应用MR全脊柱移床扫描技术,行颈、胸及腰骶3段脊柱扫描后,采用对接的方法完成全脊柱全程图像。结果71例均获得直观、清晰地显示椎管内全段脊髓、全部脊椎及周围韧带的连续全脊柱MR图像。2例表现正常,69例表现椎骨骨折(36例表现单发椎骨骨折,33例表现多发椎骨骨折)。69例椎骨骨折患者中伴有椎体滑脱12节,伴有脊髓损伤15段,伴有韧带挫裂伤19处。结论MR全脊柱移床扫描,可以很好显示椎体骨折的部位、数目,周围软组织损伤情况以及有无脊髓损伤,大大提高了定位及定性诊断的准确性。

关键词：磁共振成像脊柱创伤脊髓损伤

Preparation of Mesoporous Bi_4(GeO_4)_3 Microspheres from Na_4Ge_9O_(20) Template Microspheres for Photodegradation of Reactive Brilliant Red X-3B

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Acta Metallurgica Sinica(English Letters) 2015年第9期28卷 1156-1161页

作者： hua chen Guo-hua Jiang Yong-Kun Liu Lei Li Qin huang wen-Xing chen Department of Materials Engineering Zhejiang Sci-Tech University National Engineering Laboratory for Textile Fiber Materials and Processing Technology (Zhejiang) Key Laboratory of Advanced Textile Materials and Manufacturing Technology (ATMT) Ministry of Education

Mesoporous materials have attracted increasing attention due to their wide application. In this paper, the Na4Ge9020 microspheres were firstly prepared by solvothermal method. Then, the as-prepared Na4Ge9020 microspheres were dispersed into Bi（NO3）3 solution, and the Bi4（GeO4）3 microspheres with mesoporous structure were formed due to the solid-state reaction between bismuth nitrate and Na4Ge9020. The morphology, structure and optical properties were characterized by SEM, EDS, XRD, FITR, BET and UV-Vis diffuse reflectance analysis. The as-prepared products exhibited excellent photocatalytic performance for degradation of reactive brilliant red X-3B under the UV light irradi- ation. A possible photocatalytic mechanism was discussed as well.

关键词： Mesoporous Microspheres Photocatalysis

Electronic structure and optical properties of plutonium dioxide from first-principles calculations

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Rare Metals 2016年第8期35卷 643-648页

作者： Jun chen Da-qiao Meng Qiu-Yun chen wen-hua Luo Science and Technology on Surface Physics and Chemistry Laboratory Mianyang 621907China

The electronic structure and optical properties of plutonium dioxide were calculated using the generalized gradient approximation with a Hubbard parameter U （GGA ＋ U） for considering the strong coulomb correlation between localized Pu of electrons based on the first-principles density functional theory. The calculated results show that PuO2 is a semiconductor material with the band gap of 1.8 eV, which is in good agreement with the corresponding experimental data. Furthermore, the dielectric function, reflectivity, refractive index, and extinction coefficient were calculated and analyzed using the Kramers-Kronig relationship for PuO2. The calculated results were compared with the experimental data from the published literature.

关键词： PuO2 Generalized gradientapproximation + U Electronic structure Optical properties

Power duality for multi-antenna OFDM system in broadcast channel with user scheduling

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第2期9卷 215-224页

作者： Feng SHE Han-wen LUO Lei chen hua XIA Department of Electronic Engineering Shanghai Jiao Tong University Shanghai 200240 China Datang Microelectronics Technology Co. Ltd. Beijing 100083 China

This paper deals with design and analysis of user scheduling and power allocation for multi-antenna OFDM systems with DPC,ZF-DPC,ZF-BF and TDMA transmit *** consider the general multi-user downlink scheduling problem and power minimization with multi-user rate *** to the channel state,it is shown that there is a power optimal policy which selects a subset of users in each scheduling *** present user selection algorithms for DPC,ZF-DPC,ZF-BF and TDMA for multi-antenna OFDM system in broadcast channels,and we also present the practical water-filling solution in this *** the selected users with the consideration of fairness,we derive the power optimization algorithm with multi-user rate *** also analyze the power duality of uplink-downlink for the transmit strategies of DPC,ZF-DPC and *** results show that the present user-scheduling algorithm and power minimization algorithm can achieve good power performance,and that the scheduling algorithm can guarantee fairness.

关键词： Multiple-input multiple-output (MIMO) Orthogonal frequency division multiplexing (OFDM) Broadcast channel Multi-user diversity Dirty paper coding (DPC) Downlink scheduling