Structural phase transition and metallization in compressed SrC_2

The structural, dynamical, and electronic properties of compressed Sr C2 were systematically investigated up to 200 GPa by using ab initio method. Three new phases are obtained by means of evolutionary algorithm. The confirmed most stable structure has C2/c symmetry at zero pressure, which transforms into an orthorhombic Cmcm phase at 4.5 GPa, followed by another orthorhombic Immm phase, which is stabilized at wide pressure range of 21.5–123.5 GPa, and then transformed into Mg B2-type phase（space group, P6/mmm）. Although Sr C2 has similar structural transformation to that of compressed Ca C2, Sr C2 holds small electron–phonon coupling,which leads to its low superconducting critical temperature（only 1.8 K）.     

Ferromagnetic and ferroelectric properties of Aurivillius phase Bi9Fe4.7Me0.3Ti3O27（Me 5 Fe,Co, Ni,Mn）

New Aurivillius phase Bi9Fe4.7Me0.3Ti3O27（Me = Fe, Co, Ni, Mn） oxides have been prepared using a citrate combustion method. X-ray diffraction on powders and high-resolution transmission electron microscopy investigation confirmed that the Bi9Fe4.7Me0.3Ti3O27 samples are with an eight-layer structure. Both ferromagnetic and ferroelectric investigations suggested that Co or Ni substitution could enhance their multiferroic properties,while Mn substitution depressed them. Among all the samples, Bi9Fe4.7Co0.3Ti3O27 sample exhibits the largest remnant polarization of Pr＊3.8 l C/cm2, and the largest remnant magnetization of Mr＊0.06 lB/f.u. with a Curie temperature about 764 K, while the Bi9Fe4.7Ni0.3Ti3O27 sample has the largest spontaneous magnetization（0.26 lB/f.u.）. The improved ferromagnetic properties ofboth Bi9Fe4.7Co0.3Ti3O27 and Bi9Fe4.7Ni0.3Ti3O27 can be ascribed to the spin canting of magnetic ion-based sublattices via the Dzyaloshinskii–Moriya interaction and also the magnetic ions exchanging interactions（Fe3–O–Co3or Fe3–O–Ni3）.     

Multiferroic and magnetoelectric properties of La0.1Ba0.9Fe12O19 ceramics

La0.1Ba0.9Fe12O19 powders with similar hexagonal crystal structure to Ba Fe12O19 have been successfully synthesized using polymer precursor method. The powders were suppressed into pellets, which were sintered into ceramics at 1,300 °C for 1 h. The structure and morphology of the ceramics have been determined by X-ray diffraction（XRD） and field emission scanning electron microscopy（FESEM）. Clear electric hysteresis loops upon different amplitude of external fields indicates that La0.1Ba0.9Fe12O19 is a kind of possible ferroelectric compound. The maximum remnant polarization of La0.1Ba0.9Fe12O19 ceramic is estimated to be ＊9.6 l C/cm2. The Fe O6 octahedron in its perovskite-like hexagonal unit cell as well as the shift of Fe3？off the center of octahedron are proposed to be the origin of electric polarization in La0.1Ba0.9Fe12O19. Simultaneous occurrence of large ferroelectricity and strong ferromagnetism has been observed in La0.1Ba0.9Fe12O19 ceramics. More interestingly, this compound demonstrates electronic polarization behavior being actuated by an applied magnetic field, indicating the existence of magnetoelectric（ME） coupling effect in the La0.1Ba0.9Fe12O19 ceramics. Our results may lead to new device applications such as magnetically recorded ferroelectric memory.     

浅议我国网上银行的金融监管

网上银行作为21世纪一种新兴的金融业,其低廉的成本和广阔的前景,已越来越得到人们的重视。货币数字化和网络支付体系已经成为当今银行业的操作基础。随着信息化的飞速发展,网上银行在带给人们优质、快捷、全面服务的同时,这种以信息流为主的模式,也对实施金融监管提出了强有力的挑战。本文从网上银行的特征及我国网上银行的发展现状出发,深入分析我国网上银行发展对金融监管的冲击,并提出适时地金融监管对策。     

超硬膜β-C_3N_4的研究进展

理论分析认为β－Ｃ３Ｎ４可能是一种比金刚石还要硬的材料，它的研究成为当今材料科学的一个热点。文章论述了β－Ｃ３Ｎ４问题的由来和研究进展，以及今后的研究趋势。     

“家电下乡”活动的分销渠道建设思考——以湖北省为例

该文在全国开展的“家电下乡”活动的背景下,以湖北省为例,认为农村家电市场消费具有注重经济实用性、消费时间集中、市场分布广、品牌意识逐渐增强等特征,预测了活动持续期间农村家电市场的需求,对目前较成熟的区域代理分销模式、大型连锁终端分销模式、企业自建渠道分销模式、直销模式等四种家电产品分销渠道进行了分析,并给出了针对农村市场的分销渠道创新建议。     

SBR工艺中DO和C/N对同步硝化反硝化的影响

采用SBR工艺处理氨氮废水,研究不同的DO和C/N对同步硝化反硝化的影响,探索硝化反硝化一体化工艺的规律和特性.发现当DO=1.60～1.80mg/L、CODCr/CNH+4-N=6.5或BOD5/NH+4-N=4时,TN的去除率分别达到最大.     

动态催化聚合C3N4膜的研究

自Ｃｏｈｅｎ等人[1] 揭示β Ｃ3Ｎ4 的结构和性质以来 ,实验聚合沉积 β Ｃ3Ｎ4 膜的工作一直继续进行着 .早期的工作[2～ 10 ] 大多数采用气相沉积 ,工作气体一般是ＣＨ4 Ｎ2 或ＣＨ4 ＮＨ3,由于金刚石、石墨和Ｃ3Ｎ4 中Ｃ( 1ｓ)的结合能非常接近 ,在聚合反应时因相互竞争 ,其沉积产物常常是无定形碳、石墨、金刚石和Ｃ3Ｎ4 的混合物 .而在Ｃ3Ｎ4 聚合物中 ,常常包含有β Ｃ3Ｎ4 ,α Ｃ3Ｎ4 和石墨结构型Ｃ3Ｎ4 .Ｃｈｅｎ等人[11] 提出 ,采用适宜的有机分子预聚体 ,ＹｏｕＪｉ ｔａｎｉ等人[10 ] 提出采用不含Ｃ≡Ｎ的有机分子预聚体 ,…     

Preparation,thermal stability and biocompatibility studies of gelatin-induced hydroxyapatite co-substituted with essential physiological trace elements

Gelatin-induced hydroxyapatite with combined substitution of essential physiological trace elements(G-FAP)was prepared by a precipitation method.Pure hydroxyapatite(HAP)and ion-substituted hydroxyapatite(FAP)were also prepared for comparison.The characteristics of the precipitated powders were determined using X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Fourier transform infrared spectroscopy(FT-IR),specific surface area measurement(SSA),X-ray fluorescence spectroscopy(XRF),and thermogravimetric(TG)analysis.The biocompatibility was also determined by an in vitro investigation with MC3T3-E1 cells.SEM and TEM results showed that the G-FAP powders were composed of dense aggregates of agglomerated whisker-like crystals of200–300 nm in length and 10–20 nm in width.XRD and FT-IR analyses indicated the formation of pure apatite phase,and the substituted ions and gelatin did not change the diffraction pattern of the precipitated powders.The SSAs of the precipitated powder were 64.741,72.492,and107.745 m2/g,for HAP,FAP,and G-FAP,respectively.XRF analysis showed that Na+,Mg2+,and F-were substituted into the crystal lattice.TG results showed a reduced thermal stability of the precipitated G-FAP powders,with an advanced phase transformation beginning at800°C and a serious phase transformation from hexagonal apatite phase to rhombohedral b-TCP phase at 1,200°C in comparison with HAP and FAP.In vitro biological tests showed non-cytotoxic effects for all powders.However,G-FAP stimulated the proliferation of MC3T3-E1 cells earlier than HAP and FAP.The present G-FAP will therefore be a promising primary biomaterial for bone regeneration,tooth filling,or as a coating for metal artificial limbs.     

绿色人才培养中存在的问题及解决对策

随着可持续观念的发展,环境教育已成为提高我国全民族思想道德素质和文化素质的基本手段之一,绿色人才应运而生。本文概括了绿色人才的含义,在分析绿色人才培养中存在问题的基础上,提出了建立专业化绿色学校、培养知识型绿色人才、争取政府的引导与支持、重视网络信息的传播作用等解决对策。     

论翻译批评对读者的关注

我国当前的翻译批评“量少质次”,主要囿于“文本批评”,对作为翻译接受主体的读者关注不够。本文首先指出关注读者乃翻译批评的固有之义,接着探讨了翻译批评理应对待读者的态度以及关注读者的主要方面。     

可控环境因素对沼气产量的影响

探讨发酵条件对产沼气的影响。以新鲜猪粪为原料,研究pH、接种量、C/N三个因素在三个水平上对厌氧发酵的启动、产气量的影响。不同水平都能启动发酵,以pH=6.5、接种量=29%、C/N=30%启动最快。接种量是启动的关键因素,pH次之。以pH=7.0、接种量=34%、C/N=35%产气量最高。pH是产气量的关键因素,接种量次之。pH与接种量在启动和产沼气中都无显著差异。说明人为可控的三个因素综合影响发酵过程,pH=6.5、接种量=24%—29%加速厌氧发酵启动。随发酵中间产物的形成和产甲烷菌对原料的利用,接种量=29%,pH=6.5—7.0,利于提高沼气产量,且三因素呈同步变化趋势。     

Entransy: its physical basis,applications and limitations

In this paper, the physical basis and application conditions of the entransy theory are reviewed and discussed. Entransy can be obtained from the analogy between heat and electrical conductions. It is a state value and the‘‘potential energy’’ of heat. From the viewpoint of thermomass, it reflects the thermal energy of the thermomass in an object. Furthermore, it was also related to the microstate number and is a single value function of the microstate number. The concepts of entransy, entransy flux and entransy dissipation can be used to express the least action of heat transfer. The entransy balance equations for heat transfer and thermodynamic processes and their applications to thermal systems are also reviewed. The differences between the entransy theory, constructal theory, entropy generation minimization, exergy analyses method, principle of uniformity of temperature difference field and field synergy（coordination） principle are also discussed. The entransy theory is different from the other discussed theories. The limitations of the entransy theory are also discussed.     

架空输电线路应用摄影测量技术分析

随着摄影测量技术的成熟和发展,在架空输电线路工程中的应用摄影测量技术得到广泛重视。本文对摄影测量在架空输电线路中的应用现状进行分析和总结,并对其发展趋势提出一点看法。     

The path toward prognostication and prediction in stage Ⅱ colon cancer

Currently, there are several newer biomarkers that may be clinically useful in colon cancer. This paper focuses on a few of these biomarkers, namely microsatellite instability, loss of heterozygosity at chromosome 18q （LOH18q） and multi-gene assays, and discusses the clinical evidence behind their predictive or prognostic abilities. The results show that although there have been several newer prognostic factors identified, such as LOH18q and multi-gene assays, none of these factors can predict benefit from treatment. Therefore, ongoing prospective clinical trials are still needed to further assess the role and optimal use of these tests.     

浅议配电系统中供电可靠性

配电系统是直接连接用户的系统,其供电可靠性对用户有着重要的影响。本文对配电系统的影响供电可靠性的因素、可靠性分析内容以及提高系统供电可靠性的措施等方面进行了研究。     

一个IP建多个Web站点——TCP端口法

气象网站是气象部门对外气象服务的一个窗口。在这个高度信息化的社会里,建立县级台站自己的网站是最直接、最有效的服务及宣传手段。目前当地网络运营商只为县级台站提供了一个固定的IP地址,且在中小型局域网中,县级台站服务器往往只有一台,但是一个Web站点显然又无法满足工作需要。那么,能否在一台服务器上设置多个Web站点呢？答案是肯定的,并有多种途径可以达到这一目的。我们知道,网络上的每一个Web站点都有一个惟一的身份标识,从而使客户机能够准确地访问。这一标识由三部分组成,即TCP端口号、IP地址和主机头名,要实现＂一机多站＂就需要在这三个方面下工夫。本文将以例子的形式介绍＂TCP端口号＂法。     

High-performance lithium–sulfur battery based on porous N-rich g-C3N4 nan-otubes via a self-template method

The commercial development of lithium–sulfur batteries (Li–S) is severely limited by the shuttle effect of lithium polysulfides (LPSs) and the non-conductivity of sulfur. Herein, porous g-C3N4 nanotubes (PCNNTs) are synthesized via a self-template method and util-ized as an efficient sulfur host material. The one-dimensional PCNNTs have a high specific surface area (143.47 m2·g?1) and an abundance of macro-/mesopores, which could achieve a high sulfur loading rate of 74.7wt%. A Li–S battery bearing the PCNNTs/S composite as a cathode displays a low capacity decay of 0.021% per cycle over 800 cycles at 0.5 C with an initial capacity of 704.8 mAh·g?1. PCNNTs with a tubular structure could alleviate the volume expansion caused by sulfur and lithium sulfide during charge/discharge cycling. High N contents could greatly enhance the adsorption capacity of the carbon nitride for LPSs. These synergistic effects contribute to the excellent cycling stability and rate performance of the PCNNTs/S composite electrode.     

晶粒尺寸和热处理对Sm2Fe17N3/Fe3N/BN软磁/硬磁复合材料的合成及磁性能影响

采用高能球磨和真空热处理方法制备Sm2Fe17N3/Fe3N/BN复合材料, 并研究球磨过程中晶粒尺寸变化对固态相变和磁性能的影响.  结果表明: Sm2Fe17N3和Fe3N相产生的条件是Fe的晶粒尺寸达到纳米量级（D＜80 nm）并形成Fe(Sm)固溶体; 随着退火时间的增加, 300 ℃真空退火的球磨样品中Sm2Fe17N3的结晶物增多, 矫顽力提高, 表明样品的磁性能与Sm2Fe17N3的结晶程度有关.     

职业教育教学探析

我是一名在教学一线工作的专任教师,本人认为教学模式及教学方法应该与时俱进,首先我认为应该强调每一个老师要从单纯注重传授知识转变为引导学生学会学习,学会合作,学会做人。其次要着重培养学生具有社会责任感、实践能力和良好的综合素养等。第三要关注学生思想品德等多方面的发展。