Mineralogical alteration of thermally treated siderite in air: Mössbauer spectroscopy results

Mineralogical alternation of thermally treated siderite in air atmosphere has been systematically analyzed by Mössbauer effects. It was preliminarily estimated from the area of subspectra that 4%, 39% and 62% of magnetite were formed at 410 °C, 490 °C and 510 °C respectively. After being incrementally heated at 530 °C the spectra consist of two sextets of Fe₃O₄. Sextet of γ-Fe₂O₃ with hyperfine field of 50T was observed at 550 °C. Spectra at 580 °C consisted of two sextets with hyperfine fields caused by γ-Fe₂O₃ and α-Fe₂O₃. Fe₃O₄ disappeared and the amount of γ-Fe₂O₃ decreased, while the quantity of α-Fe₂O₃ increased to 34% and 77% at 640 °C and 690 °C, respectively. During the early stage of decomposition and oxidation, FeO was probably produced but quickly oxidized to magnetite and unidentified in our experiment. These results, in good agreement with the X-ray diffraction analyses and microscopic observation, provide an interpretation to anomalous magnetic property changes of siderite-bearing rock samples.     

混合低温送风方式的测试及分析

对低温蓄冷低温送水中央空调系统中采用回风、新风、露点风混合调节到合适的温、湿度的混合空气送风方式进行了能耗实验测试，测试结果证明混合送风的方式有较好的节能效果．     

拓扑相变与物质拓扑相的理论发现——2016年度诺贝尔物理学奖成果简介

 美国物理学家索利斯（David J.Thouless）、霍尔丹（F.Duncan M.Haldane）、科斯德里茨（J.Michael Kosterlitz）因“关于拓扑相变和物质拓扑相的理论发现”获得2016年度诺贝尔物理学奖。介绍了这3位诺贝尔物理学奖获得者的学术经历,并从拓扑与拓扑相变、量子霍尔效应中的拓扑、1维量子反铁磁与对称性保护的拓扑态等方面探析拓扑相变和物质拓扑相理论发现的科学意义。     

Characteristics of U-pattern distribution of highconcentration ^210pb in surface air at central Guizhou, China

In recent thirty years, with deep-going studies of the problems of regional environmental quality and global climate change, 210Pb has been found to have wide appli-cations in tracing the aquatic sedimentation, catchment’s erosion and the path of atmospheric transfer. 222Rn pro-duced from decay of the U-Ra series in surface rocks and soils diffuses in the atmosphere and continues to decay into 210Pb. This part of the 210Pb, due to separation from its parent 226Ra, is generally referred to a…     

Er_2Fe_(17)C_xN_y系稀土化合物Er_2Fe_(17)CN自旋重定转换温度的穆斯堡尔谱分析

在温度为２９５Ｋ～８０Ｋ范围内，应用穆斯堡尔效应方法，测量了Ｅｒ２Ｆｅ１７ＣｘＮｙ系稀土化合物Ｅｒ２Ｆｅ１７ＣＮ的穆斯堡尔谱．结果表明，用Ｃ，Ｎ原子掺杂渗入Ｅｒ２Ｆｅ１７化合物替换Ｅｒ３＋离子后形成的Ｅｒ２Ｆｅ１７ＣＮ化合物，影响了Ｅｒ２Ｆｅ１７化合物原来的自旋重定转换温度ＴＣ，并使自旋重定转换角度θ也发生了变化，出现了两个自旋重定转换温度ＴＣ１，ＴＣ２．ＴＣ１２００Ｋ，ＴＣ２８０Ｋ．这说明稀土化合物Ｅｒ２Ｆｅ１７ＣＮ磁矩是突变的（一级相变）．     

Influence of magnetic current on the ground state entanglement in an isotropic transverse XY chain

We study the ground state entanglement in a three-qubit XY chain under the influence of a magnetization current. It is found that the ground state changes from a W state to a disentangled state as the magnetic field varies. When the Lagrange multiplier λ> , namely under a strong magnetic current, the ground state holds onto a W state for a large range of the magnetic field strength. A phase transition to the magnetization-current phase occurs under a certain condition.     

Influence of magnetic current on the ground state entanglement in an isotropic transverse XY chain

We study the ground state entanglement in a three-qubit XY chain under the influence of a magnetization current. It is found that the ground state changes from a W state to a disentangled state as the magnetic field varies. When the Lagrange multiplier λ> , namely under a strong magnetic current, the ground state holds onto a W state for a large range of the magnetic field strength. A phase transition to the magnetization-current phase occurs under a certain condition.     

水泵变频技术在空调系统中的应用

在对空调系统中冷冻水泵变水量调节分析的基础上，阐述了水泵变频技术的节能原理、控制方法及其在中央空调系统中的应用，并对其节能效果进行了评价．     

YBa_2Cu_3O_（6＋x）高温超导体的临界温度与氧含量关系的逾渗理论分析

本文提出了一种局域氧有序的限制通渗模型，从理论上计算出了ＴＢａ２Ｃｕ３Ｏ６＋ｘ高温超导体临界温度Ｔｃ与氧含量之间的关系曲线，与实验曲线符合得非常好．并对Ｔｃ～ｘ实验曲线上出现的＂台阶＂现象进行了分析．随着ｘ的增加出现了两种结构相变：四方相到正交相、正交（Ⅰ）相到正交（Ⅱ）相的转变．这些转变有逾渗机制．     

等离子体中准周期混沌的实验观察

本实验研究了非驱动放电等离子体中趋向混沌的准周期道路。从实验信号的功率谱分析和Lyapunov指数计算定量地描述了准周期到混沌的转变。同时在这种等离子体混沌中还发现了低维奇怪吸引子。     

压力脉动固态发酵微生物蛋白质及机理的初步研究

研究了固态发酵微生物蛋白质的提取、纯化条件以及压力脉动对固态发酵微生物蛋白质的影响，并初步探讨了压力脉动固态发酵的作用机理。结果表明在发酵后的酶曲中，加入Tris-HCl提取液，可得胞内蛋白质，FPA酶活与CMCase酶活回收率分别为83.6%与67%,纯化效果较好。从压力脉动外界周期刺激固态发酵干酶曲中提取的胞内蛋白质与从未加周期刺激的微生物中提取的相比，胞外蛋白质的质量、FPA酶活和CMCase酶活分别提高了17.75%、60.08%和21.17%。压力脉动固态发酵5d的微生物胞外蛋白质的酶活,与静态固态发酵6d的相当，发酵周期缩短。压力脉动外界周期刺激使蛋白质组分有所变化，减少了相对分子质量约为80400的组分，但增加了相对分子质量约为28520的组分。     

空气环境下制备相变特性VO_2薄膜

提出了一种制备相变特性VO_2薄膜的简易方法.将制备好的金属钒薄膜置于440℃空气下氧化处理,获得相变温度为60℃的单斜VO_2薄膜,薄膜方块电阻值在60～85℃范围内变化量达2.2个数量级.X射线衍射分析(XRD)表明薄膜的主要成分为单斜相VO_2.探索了此工艺的一般性规律,分析高价态钒对薄膜相变的影响.     

一次冬季暴雨转雪天气诊断分析

利用NCEP1°×1°资料和常规天气观测资料,对2010年12月15日新余市一次寒潮过程中暴雨转雪天气的环流背景、影响系统及其成因进行了分析。结果表明:1)500 h Pa横槽转竖,低层及地面的冷高压南移,使得冷空气侵入江南地区,是造成此次江南地区降温的主要原因;2)华南准静止锋的长期维持且坡度小、湿层和辐合区较薄且辐合强度较弱,导致本次降水的强度不大,但较长的持续时间使降水达到暴雨量级;3)寒潮带来的降温形成了降雪有利的温度条件,当测站上空整层温度均在0℃以下,925 h Pa温度≤-3℃,地面气温≤1℃时,降水将从雨转变为雪。     

Electronic structure and physical properties of stable and metastable phases in YN: Density-functional theory calculations

Local density functional is investigated using the full-potential linearized augmented plane wave （FP-LAPW） method for YN in the hexagonal structure and the rocksalt structure and for hexagonal structures linking a layered hexagonal phase with wurtzite structure along a homogeneous strain transition path. It is found that the wurtzite YN is unstable and the layered hexagonal phase, labeled as ho, in which atoms are approximately fivefold coordinated, is metastable, and the rocksalt ScN is stable. The electronic structure, the physical properties of the intermediate structures and the energy band structure along the transition are presented. It is noticeable that the study of ScN provides an opportunity to apply this kind of material （in wurtzite[h]-derived phase）.     

Experimental and LES investigation of flame propagation in a hydrogen/air mixture in a combustion vessel

This work presents an experimental and numerical investigation of premixed flame propagation in a hydrogen/air mixture in a closed combustion vessel. In the experiment, high-speed schlieren video photography and pressure sensor are used to examine the flame dynamics and pressure transient. In the numerical study, a large eddy simulation （LES） based on a RNG sub-grid approach and a LES combustion model is applied to reproduce experi- mental observations. The effects of four physical phenomena on the burning velocity are considered in the combustion model, and the impact of grid type on the combustion dynamics is examined in the LES calculations. The flame experiences four stages both in experiment and LES calculations with structured and unstructured grids, i.e., spherical flame, finger-shaped flame, flame with its skirt in contact with the sidewalls, and tulip-shaped flame. The flame speed and pressure in the vessel develop with periodical oscillations in both the experiment and LES simulations due to the interaction of flame front with pressure wave. The numerical simulations compare well with the detailed experimental measurements, especially in term of the flame shape and position, pressure build-up, and periodical oscillation behaviors. The LES combustion model is successfully validated against the bench-scale experiment. It is put into evidence that mesh type has an impact to a certain extent on the numerical combustion dynamics, and the LES calculation on structured grid canpredict the flame dynamics and pressure rise more accu- rately than that on unstructured grid with the same mesh resolution. The flame shape is more asymmetrical in the LES on an unstructured grid than that on a structured grid, and both the flame speed and the pressure rise at the later flame stage are underestimated in the LES on the unstructured grid.     

U型路线空气质量定量评价结果的比较与分析——以可逆加成-断裂链转移(RAFT)聚合反应为例

目的 研究不同的数据处理方法对于宝鸡市峪甘路-石陵路空气质量评价结果(CI值)的影响.方法 采用整体平均法和降维法,利用Origin 9.0软件对宝鸡市峪甘路-石陵路空气离子浓度观测结果进行统计分析,比较不同方法对于安培空气质量评价指数(CI值)以及空气质量评价等级的影响.结果 整体平均法和降序降维法计算所得CI值非常接近,而且空气质量清洁度和空气质量分级结果是一致的.但是,时序降维法计算所得CI值普遍偏高.与另外2种数据处理方法相比较,13个观测地点的CI平均值,有11个与整体平均法和降序降维法依据CI值对于空气质量分级结果是一致的,但是有2个观测点的CI计算结果出现差异,即差异率为15%.结论 降序降维法可以作为一种比较理想的空气正、负离子浓度测定结果的处理方法,而且与整体平均法相比较,因为变量少,更便于进行统计分析.