含盐水池沸腾特性及盐分影响因素研究

水资源在工业生产中不可或缺,在地球的水资源中,仅有2.5%为淡水,超过97%的水为含盐水。全球每年约4000多亿立方米含污水排放,造成严重的环境污染和经济治理成本问题。深入理解含盐水沸腾传热特性对于保证核电站、注汽锅炉、海水淡化中的传热安全具有重要意义。本文搭建了基于不同材质加热表面的核态池沸腾实验系统,通过热电偶梯度测温和可视化高速摄像技术测量得到热流密度、加热面温度、气泡脱离直径、脱离频率、生长速率等沸腾传热过程的关键参数。研究结果表明盐分的存在对沸腾传热起着一定程度的强化作用。     

Resistive switching memory for high density storage and computing

The resistive random access memory (RRAM) has stimulated a variety of promising applications including programmable analog circuit, massive data storage, neuromorphic computing, etc. These new emerging applications have huge demands on high integration density and low power consumption. The cross-point configuration or passive array, which offers the smallest footprint of cell size and feasible capability of multi-layer stacking, has received broad attention from the research community. In such array, correct operation of reading and writing on a cell relies on effective elimination of the sneaking current coming from the neighboring cells. This target requires nonlinear I-V characteristics of the memory cell, which can be realized by either adding separate selector or developing implicit build-in nonlinear cells. The performance of a passive array largely depends on the cell nonlinearity, reliability, on/off ratio, line resistance, thermal coupling, etc. This article provides a comprehensive review on the progress achieved concerning 3D RRAM integration. First, the authors start with a brief overview of the associative problems in passive array and the category of 3D architectures. Next, the state of the arts on the development of various selector devices and self-selective cells are presented. Key parameters that influence the device nonlinearity and current density are outlined according to the corresponding working principles. Then, the reliability issues in 3D array are summarized in terms of uniformity, endurance, retention, and disturbance. Subsequently, scaling issue and thermal crosstalk in 3D memory array are thoroughly discussed, and applications of 3D RRAM beyond storage, such as neuromorphic computing and CMOL circuit are discussed later. Summary and outlooks are given in the final.     

基于DEA-Malmquist模型的西北地区能源空间转运格局效率及其变化分析

西北地区有着丰富的能源资源,对其能源空间转运格局进行效率评价及全要素生产率时空演变分析,对推动整个地区的发展有着重要意义.运用DEA中的BCC模型,对2016年西北地区的铁路和公路货运效率进行研究.利用Malmquist指数方法及ArcGIS软件,进一步分析2010-2016年西北地区铁路、公路货运全要素生产率的时空演变和地区差异.研究表明:1)2016年西北地区铁路货运效率总体水平较高,公路中等;存在地区差异性,东部整体高于西部;规模效率决定其有效性.2) 2010-2016年铁路和公路的Malmquist指数整体较稳定,技术进步变化对该指数影响最大.从时空演变来看,2010-2016西北地区铁路货运的Malmquist指数先升后降,地区差异先减小后增大;公路货运的Malmquist指数先降后升,地区差异先减小后增大最后又减小.     

多星测控调度效能评价指标体系研究

分析了建立多星测控调度问题评价指标体系的工程需求.从测控网管理方的角度,定义了反映测控系统服务能力、利用效率和资源配置合理性的指标;针对航天器拥有方的需求,建立了反映接受测控服务情况和反映航天任务满足程度的指标.通过两大部分指标构建了多星测控调度问题的指标体系.通过算例说明了利用该指标体系进行多星测控系统效能分析的可行性.     

原子吸收光谱法测定金矿石中金的不确定度

针对聚氨酯泡塑吸附-原子吸收光谱法测定金矿石中金的分析测定过程和数学模型,找出了影响测量不确定度的主要来源,对各不确定度分量进行了评定,并计算得到了合成标准不确定度和扩展不确定度,给出了相应的测定结果表示法.     

环境规制对出口产品质量的影响研究——基于行业面板数据的实证分析

本文以环境规制作为解释变量,基于2003~2010年中国19个行业出口产品质量和环境规制数据,采用固定效用模型实证检验了环境规制对出口产品质量的影响。研究结果表明,环境规制对出口产品质量的影响呈“U”型,即环境规制增强前期成本效应大于创新效应,经营成本提高导致产品质量下降;环境规制增强后期创新效应大于成本效应,研发创新促使产品质量提高。不同行业对环境规制的敏感度不一样,将样本数据中涉及的19个部门,分为重污染行业和轻污染行业进行分类回归,回归结果显示环境规制对轻度污染行业出口产品质量的影响呈倒“U”型,即具有先促进后抑制的作用;环境规制对重度污染行业出口产品质量的影响呈“U”型,即具有先抑制后促进的作用。据此,提出有效利用环境规制以提高出口产品质量和发展绿色贸易的政策启示。     

α-Fe_2O_3空心球的水热法制备及其对苯酚的吸附性能

以铁氰化钾、磷酸二氢铵等为反应物,采用水热法合成了α-Fe2O3空心球,并用XRD,TEM,FESEM(场发射扫描电镜)、UV-Vis和低温氮吸附脱附对其进行了表征。结果表明,α-Fe2O3空心球直径在200～560nm之间,其BET比表面积为80m2·g-1,平均孔径为8.5nm。考察了反应时间、反应物用量和反应温度等对α-Fe2O3空心球形貌和大小的影响,提出了其可能的形成机理。研究了室温下α-Fe2O3空心球吸附苯酚的性能,吸附达平衡时,其吸附苯酚的量达97mg·g-1。     

配合物[Co(O_2CC_6HF_4)_2(Phen)_2]的合成、晶体结构和电化学性质(O_2CC_6HF_4=2,3,5,6-四氟苯甲酸根;Phen=1,10-邻菲咯啉)(英文)

利用四氟苯甲酸(H2tfbdc),1,10-邻菲咯啉与四水醋酸钴在甲醇和水混合溶剂中的反应,得到了标题配合物[Co(O2CC6HF4)2(Phen)2]。用元素分析、红外光谱、热重分析、循环伏安、X-衍射单晶结构分析等对其进行了表征。晶体结构表明,标题配合物的晶体属单斜晶系,空间群为P21/c,晶胞参数:a=1.3719(8)nm,b=1.5956(10)nm,c=1.5849(10)nm,β=106.327(10)°;每个钴离子与来自2个2,3,5,6-四氟苯甲酸分子的2个氧原子和2个1,10-邻菲咯啉分子的4个氮原子配位,形成变形的八面体配位构型。[Co(O2CC6HF4)2(Phen)2]独立结构单元通过两种氢键(C-H…F和C-H…O)形成三维的超分子网络结构。     

污泥的热解提油-半焦燃烧工艺的实验研究

本文提出了双流化床中污泥的热解提油-半焦燃烧工艺,组织实验论证并进行了探索研究。结果表明,双流化床中可以实现污泥热解提油工艺和半焦燃烧工艺的耦合,即获得了污泥热解产生的油和气,又实现了污泥的焚烧无害化处理。污泥在双流化床中发生热解反应时,干燥无灰基污泥的油产率为24.1%,是煤的2.4倍,干燥无灰基污泥的轻油产率为8.44%,是煤的9倍。该工艺中,污泥中热量的43.1%转化为油,10.4%转化为热值10.54MJ/m~3的气体燃料,46.5%的热量残留在污泥半焦中,在燃烧炉内燃烧放热。     

Syntheses and Crystal Structures of Two Supramolecular Architectures:(H_2tfbdc)·(tfbdc)·(Hbipy)_2 and (tfbdc)·(H_2pz)(tfbdc=Tetrafluoroterephthalate,bipy=4,4'-Bipyridine,pz=Pyrazine)

Two new supramolecular compounds,2C 10 H 9 N 2 + ·C 8 HF 4 O 4 2-·C 8 H 2 F 4 O 4 /(H 2 tfbdc)· (tfbdc)·(Hbipy) 2 (1) and C 4 H 6 N 2 2+ ·C 8 HF 4 O 4 2-/(tfbdc)·(H 2 pz) (2),were synthesized and characterized by elemental analysis,IR spectra,and single-crystal X-ray diffraction.Compound 1 crystallizes in the triclinic system,space group P1,with a=8.3453(12),b=10.1798(15),c=10.6626(16),α=87.591(2),β=74.047(2),γ=69.006(2)°,V=834.53(12) 3,D c=1.614 g/cm 3,F(000)=400,u=1.45 cm-1,Z=2,the final R=0.0353 and wR=0.1005 for 5882 observed reflections with I > 2σ(I);and compound 2 crystallizes in the monoclinic system,space group P2 1 /c,with a=10.471(4),b=5.4419(19),c=12.249(4),β=114.909(6)°,V=633(4)3,D c=1.669 g/cm 3,F(000)=320,u=1.63 cm-1,Z=2,the final R=0.0794 and wR=0.2923 for 3213 observed reflections with I > 2σ(I).Both compounds 1 and 2 crystallize as charge-transfer organic salts with the dianionic or neutral acid components lying at the inversion centers.Hbipy + cations and anionic acid in compound 1 are linked to form a chain by means of C-H···O hydrogen bonds.Adjacent chains are further extended into a two-dimensional layer network via N-H···O and O-H···N hydrogen bonds.In compound 2,the acid and base subunits are arranged alternately to generate a linear tape motif via N-H O hydrogen bonds;these tapes are further combined into a three-dimensional array with CdSO 4 topology via C-H O intermolecular hydrogen bonds.