First Sagittarius A* Event Horizon Telescope Results. VIII. Physical Interpretation of the Polarized Ring

In a companion paper, we present the first spatially resolved polarized image of Sagittarius A* on event horizon scales, captured using the Event Horizon Telescope, a global very long baseline interferometric array operating at a wavelength of 1.3 mm. Here we interpret this image using both simple analytic models and numerical general relativistic magnetohydrodynamic (GRMHD) simulations. The large spatially resolved linear polarization fraction (24%–28%, peaking at ∼40%) is the most stringent constraint on parameter space, disfavoring models that are too Faraday depolarized. Similar to our studies of M87*, polarimetric constraints reinforce a preference for GRMHD models with dynamically important magnetic fields. Although the spiral morphology of the polarization pattern is known to constrain the spin and inclination angle, the time-variable rotation measure (RM) of Sgr A* (equivalent to ≈46° ± 12° rotation at 228 GHz) limits its present utility as a constraint. If we attribute the RM to internal Faraday rotation, then the motion of accreting material is inferred to be counterclockwise, contrary to inferences based on historical polarized flares, and no model satisfies all polarimetric and total intensity constraints. On the other hand, if we attribute the mean RM to an external Faraday screen, then the motion of accreting material is inferred to be clockwise, and one model passes all applied total intensity and polarimetric constraints: a model with strong magnetic fields, a spin parameter of 0.94, and an inclination of 150°. We discuss how future 345 GHz and dynamical imaging will mitigate our present uncertainties and provide additional constraints on the black hole and its accretion flow

工业乳化废液破乳剂研究趋势与进展

针对工业中乳化废液的破乳除油需求与难题,首先分析了各类工业乳化废液的水质情况,然后探讨了近年来主流化学破乳剂的破乳机理,并讨论了机理间的协同作用。对近年来关注度较高的聚醚类破乳剂、星型/超支化破乳剂、天然破乳剂及其改性破乳剂和磁性纳米颗粒破乳剂的结构和性能特点进行了综述,并对不同类型的破乳剂的优缺点进行评价与总结。在此基础上,提出了各类破乳剂在研究及应用过程中存在的某些共性问题,如不具有普遍适用性、缺乏对实际乳化废液使用情况的精确分析测试、在研发与应用方面存在局限性。因此,为了提高破乳效能,除了研究破乳剂本身以外,更要针对各领域的实际乳化废液进行破乳分析测试,以获得效率更高、普适性更强的高效破乳剂

工业乳化废液破乳剂研究趋势与进展

针对工业中乳化废液的破乳除油需求与难题,首先分析了各类工业乳化废液的水质情况,然后探讨了近年来主流化学破乳剂的破乳机理,并讨论了机理间的协同作用。对近年来关注度较高的聚醚类破乳剂、星型/超支化破乳剂、天然破乳剂及其改性破乳剂和磁性纳米颗粒破乳剂的结构和性能特点进行了综述,并对不同类型的破乳剂的优缺点进行评价与总结。在此基础上,提出了各类破乳剂在研究及应用过程中存在的某些共性问题,如不具有普遍适用性、缺乏对实际乳化废液使用情况的精确分析测试、在研发与应用方面存在局限性。因此,为了提高破乳效能,除了研究破乳剂本身以外,更要针对各领域的实际乳化废液进行破乳分析测试,以获得效率更高、普适性更强的高效破乳剂

新型絮凝剂在焦化废水中的应用

混凝作为处理水处理过程中的一种手段,因其具有操作简单、可操作性强和经济性等优点而被广泛应用。本文主要从考察新型絮凝剂(IPE-ZH)混凝性能,并将其应用于处理焦化废水中。通过考察助凝剂、IPE-ZH投加量等因素对混凝过程影响以及IPE-ZH系列絮凝剂对焦化废水生化出水的混凝效果。同时与现有絮凝剂的混凝效果进行对比

Experimental study on laser water-jet machining of metal material

金属材料的激光加工目前正向着低表面粗糙度、小热影响区及大深径比结构的趋势发展。新近发展了一种基于激光-水射流耦合原理的水导激光加工技术,本文阐述了水导激光加工技术的基本原理及其相对于传统激光加工方法的优势,基于激光-水射流耦合原理构建了一套水导激光加工设备,对多种金属材料进行了水导激光加工实验。利用超景深显微镜对加工工件表面进行了观测与分析,发现两种金属材料加工得到的盲孔边缘规则圆滑,切槽的边缘平直无毛刺,没有热影响区。实验结果说明对金属材料的水导激光精密加工具有可行性且有重要的应用价值。</p

Friedel盐对废水中低浓度Cd2＋的吸附动力学

以合成的Friedel盐（FS,3CaO·A12O3·CaCl2·10H2O）为吸附剂,研究了FS去除废水中Cd2＋的反应动力学和等温吸附特性.考察了FS盐用量、温度及Cd2＋初始浓度对Cd2＋去除的影响.结果表明,FS用量为0.03g/L时,在室温下对废水中初始浓度为10mg/L的Cd2＋的去除率大于94.34%,吸附容量可达301.9mg/g,吸附主要以离子交换吸附为主,最终形成Cd4Al2（OH）12Cl2（H2O）4xH2O及Cd4Al2（OH）12Cl24H2O化合物.利用一级动力学模型关联了反应动力学数据,得到速率常数k=0.049min-1,吸附行为较符合Langmuir等温吸附方程

CuO-modified LiNi_0.5Mn_1.5O_4 cathode materials for lithium ion batteries

本文首先通过共沉淀法和固相球磨法制备了纳米级的lInI0.5Mn1.5O4高电压正极材料,然后通过溶胶-凝胶法制备了表面包覆CuO的CuO-lInI0.5Mn1.5O4复合材料.通过对CuO包覆量为1%,3%和5%的复合材料的电化学性能对比,发现当包覆量为1%时,材料的性能最佳.在1 C下,材料的放电比容量高达126.1 MA H g？1,循环100次后容量保持率在99.5%.CuO包覆在纳米lInI0.5Mn1.5O4材料表面,阻止电解液与活性颗粒的直接接触,削弱了电解液与lInI0.5Mn1.5O4的相互作用,进而在一定程度上减缓了电解液的分解;CuO的包覆同时还缓解了电解液中Hf对材料的攻击,阻止了锰的溶解和由此带来的结构改变,进而提高了材料的循环稳定性.The CuO-coated LiNi0.5Mn1.5O4 has been synthesized to be used as a cathode material for lithium ion batteries via a sol-gel method.The coating of CuO on the material does not have significant effect on the basic spinel structure of LNMO, but effectively reduces the interaction between electrolyte and LNMO, and prevent further the dissolution of manganese.The results show that LNMO with 1% CuO coating has the better electrochemical performance, for example, its discharge specific capacity at a rate of 0.2, 0.5, 1, 2, 5 and 10 C is 123.1, 122.8, 127.8, 125.9, 120 and 113.9 mA h g?1, respectively, and its capacity retention at 1 C cycle is up to 99.5% after 100 cycles.Even cycling at 5C rate, the cell with 1% CuO-LNMO cathode can has 99.4% of capacity retention after 200 cycles, indicating that it is a promising cathode material for lithium ion batteries.国家高技术研究发展计划(2012AA110204); 福建省厦门市科技局重大计划(2013H6022); 国家基础科学人才培养基金(J1310024)的资

Friedel盐对废水中低浓度Cd2＋的吸附动力学

以合成的Friedel盐（FS,3CaO·A12O3·CaCl2·10H2O）为吸附剂,研究了FS去除废水中Cd2＋的反应动力学和等温吸附特性.考察了FS盐用量、温度及Cd2＋初始浓度对Cd2＋去除的影响.结果表明,FS用量为0.03g/L时,在室温下对废水中初始浓度为10mg/L的Cd2＋的去除率大于94.34%,吸附容量可达301.9mg/g,吸附主要以离子交换吸附为主,最终形成Cd4Al2（OH）12Cl2（H2O）4xH2O及Cd4Al2（OH）12Cl24H2O化合物.利用一级动力学模型关联了反应动力学数据,得到速率常数k=0.049min-1,吸附行为较符合Langmuir等温吸附方程

Research Progress in High-voltage LiNi_(0.5)Mn_(1.5)O_4 for Lithium-ion Batteries

lInI0.5Mn1.5O4作为一种新型的锂离子电池高电压正极材料,具有低成本、低毒性和对环境友好等特点,是锂离子电池正极材料的研究热点之一.本文综述了lInI0.5Mn1.5O4正极材料的结构、制备方法、改性方法和存在的问题,比较了各种制备方法的优缺点,分析和总结了近年来国内外对于改善lInI0.5Mn1.5O4电化学性能所进行的研究工作进展,阐述了其作为锂离子电池高电压正极材料的应用前景.As a new type of lithium ion battery of high voltage cathode material,LiNi0.5Mn1.5O4 possesses some excellent characteristics such as low cost,low toxicity,environment friendly,etc.In this paper,the structure,preparation methods,modification methods and the existing problems of LiNi0.5Mn1.5O4 were introduced and summarized.The advantages and disadvantages of various preparation methods were compared and discussed at the same time.The research progress in improving electrochemical properties of LiNi0.5Mn1.5O4 at home and abroad in recent years was discussed,and the developing trend of LiNi0.5Mn1.5O4 was also predicted.国家高技术研究发展计划(863计划)(2012AA110204); 国家基础科学人才培养基金(J1310024); 厦门市重大科技计划项目(2013H6022