试论责任教师的岗位属性及素质要求

责任教师,又称为主持教师,因具体开展广播电视教育的学校不同,对其的职责划分略有不同,但从总体来说,还是基本一致的。一般来说,责任教师是在教学工作中起主导作用,具体负责广播电视教育的教学安排,承担具体课程,主持该课程的教学媒体设计,协调和沟通广播电视教育主编、主讲教师,媒体制作人员和学员关系的专职工作人员。责任教师在广播电视教学中起着非常重要的作用。责任教师工作的优劣直接影响远距离教学质量的高低,有时责任教师工作的疏忽会对远距离教学产生灾难性的影响。为此,本文专门论述广播电视教学责任教师的岗应属性和素质要求,以期对广播电视教育人事管理的科学化尽微薄之力。

基于属性标识位的面向对象时空数据模型

在时空数据模型发展的基础上 ,提出了一种新的基于属性标识位的面向对象时空数据模型 .将时空数据库分为一般基本属性库、有效时空属性库和历史时空属性库三部分存储 ,利用属性标识符标识数据对象在各部分库中的存在与否 。

基于属性位复用的约束性关联规则挖掘算法

在提取满足用户特定需求的关联规则时,由于现有约束性关联规则挖掘算法存在大量的冗余候选项和重复计算,故提出一种基于属性位复用的约束性关联规则挖掘算法,其适合挖掘任何长度且满足用户特定需求的关联规则。该算法通过属性位的权值组合,将交易事务转换成整数,用属性位复用技术构建候选区间,并利用其端点值双向变化,构建索引候选频繁项,同时也用布尔运算计算其支持数。实验证明其比现有算法更快速,将其应用到客户关系管理系统中分析客户关联信息,可以有效地提高系统效率。

陕西省主要城市生态活度位评价与差异分析

文章选择黄土高原地区，颇具生态地理意义的陕西省为研究对象，在借鉴杨志峰等将生态活度位理论从自然生态系统推演到社会经济生态系统这一思想基础上，结合研究区域特点，采用层次分析法，构建生态活度位评价指标体系；消除原始数据量纲的影响，拟定标准化原则，对陕西省省辖各地市的总生态活度位及其属性进行分析评价；在SPSS统计软件环境中，以各区域总生态活度位为分类实体，进行模糊动态聚类，提出市域生态活度位的三种发展模式。评价结果表明：宝鸡、咸阳、汉中的总生态活度位为优越型，其综合值界于0．774～0．847之间；西安、安康、商洛、延安的总生态活度位为过渡型，其综合值界于0．497～0．706；铜川、榆林、渭南的总生态活度位为贫乏型，其综合值界于0．295～0．427。

特征价格理论与住房价格指数编制方法

特征价格理论与住房价格指数编制方法王力宾随着中国国民经济的快速增长及产业结构的调整，房地产业正逐渐成为国民经济的重要产业。同该产业密切相关的地产和房产价格的变动，也日趋受到政府和经济界人士的关注。针对我国房地产市场信息不流通，价格资料不易收集和住房具...

免疫系统模型的优化及其应用研究

通过免疫系统模型的介绍,文章提出多属性r连续位匹配规则来优化免疫系统模型并将其应用于图像识别中。实验表明,优化的免疫系统模型不仅提高了模式识别的效率,而且算法的时间复杂度和空间复杂度令人满意。

卫星遥感与农业动态监测

农业生产是人类利用生物体生长发育机能,创造所需农产品的过程。因此其常常要受到自然环境的制约和影响。为了更好地利用农业自然资源,人们用不同的方式对土壤性状、质地、气候变化、农作物种植布局和农作物的生长发育等等进行调查监测。 农业动态监测是为了掌握农业自然资源利用状况,及时了解农业自然资源消长变化信息。为政府宏观决策,制定农业生产及农业资源利用政策和发展规划;为农业可持续发展,提供可靠的科学依据。卫星遥感技术的发展和应用,使农业动态监测工作可以从几公里甚至几万公里的高度俯视地面资源及其变化,从而开拓了人们的思路和视野。为农业资源调查、监测提供了更先进、更科学。

Effect of metallic ions on dispersibility of fine diaspore

Dispersion experiments were conducted to study the influence of metallic cations on the dispersibility of diaspore. The reaction mechanisms were investigated based on the analysis of zeta （ξ） potential and calculations of solution chemistry and DLVO theory. The results show that the valence of cations, instead of the cation type, plays an important role in the dispersibility of diaspore The impact of multivalent metallic cations is greater than that of monovalent cations. In the presence of Ca^2＋ and Mg^2＋, the dispersion of diaspore doesn＇t change in the range of pH value below 10. However, Ca^2＋ and Mg^2＋ may induce strong coagulation of particles when pH value is higher than 10. The adsorption of species of calcium and magnesium ions on diaspore can cause the compression of electric double layer, the decrease of the absolute value of zeta potential and the repulsion force between diaspore particles. The new IEP （isoelectric point） appeared at pH value of 11 may attribute to the adsorption of Mg（OH）2（s）.

Ontogeny and Metamorphic Patterns of Female Reproductive Organs of Ephedra sinica Stapf (Ephedraceae)

Ontogeny and metamorphic. development of female reproductive organs in Ephedra sinica Stapf were surveyed. At the end of April, female cones began to initialize from the vegetative buds. Pollination occurred in mid-May and seeds matured at the beginning of July. The ontogenetic pattern of female reproductive organs of E. sin ca is basically similar to that of E. distachya L. The foliar nature of the outer envelope of the ovule in Ephedra is corroborated. Reduction of ovule number as a tendency of speciation in the genus is substantiated by the occurrence of tri-ovulate cones coupled with comprehensive characters of the genus. The metamorphic patterns as well as the leaf nature of the outer envelope indicate that female cones of Ephedra are compound while the female reproductive units of the ovulate cone have been reduced from secondary reproductive shoots similar to those of cordaites by phylogenetic transformation, fusion and reduction. Each fertile bract together with its axillary female reproductive unit composed the Bract Scale and Seed Scale Complex of Ephedra.

加权社会网络低维冗余数据快速挖掘算法仿真

在进行加权社会网络低维冗余数据挖掘时,由于加权社会网络稳定性低,且挖掘聚类效果差,导致挖掘耗时长与挖掘精度较低,因此设计加权社会网络低维冗余数据快速挖掘算法。构建加权社会网络模型,提升该网络稳定性的同时对收集到的数据进行可视化分析。通过特征选择获取数据冗余特征,计算出低维冗余聚类数据的支持度,利用支持度与可信度对低维冗余数据关联规则进行评价,并按照直接属性对其限制,大幅度减少无用规则的产生。通过属性位复用方法建立候选区域,生成关联规则集,对符合关联规则集的低维冗余数据进行聚类,从而实现数据的快速挖掘。仿真结果表明:所提方法的挖掘聚类效果好、挖掘精度高、耗时短,具有可行性。

Doping-induced metal–N active sites and bandgap engineering in graphitic carbon nitride for enhancing photocatalytic H_(2 )evolution performance

Durable and inexpensive graphitic carbon nitride(g-C_(3)N_(4))demonstrates great potential for achieving efficient photocatalytic hydrogen evolution reduction(HER).To further improve its activity,g-C_(3)N_(4)was subjected to atomic-level structural engineering by doping with transition metals(M=Fe,Co,or Ni),which simultaneously induced the formation of metal-N active sites in the g-C_(3)N_(4)framework and modulated the bandgap of g-C_(3)N_(4).Experiments and density functional theory calculations further verified that the as-formed metal-N bonds in M-doped g-C_(3)N_(4)acted as an"electron transfer bridge",where the migration of photo-generated electrons along the bridge enhanced the efficiency of separation of the photogenerated charges,and the optimized bandgap of g-C_(3)N_(4)afforded stronger reduction ability and wider light absorption.As a result,doping with either Fe,Co,or Ni had a positive effect on the HER activity,where Co-doped g-C_(3)N_(4)exhibited the highest performance.The findings illustrate that this atomic-level structural engineering could efficiently improve the HER activity and inspire the design of powerful photocatalysts.

Top-down synthesis strategies: Maximum noble-metal atom efficiency in catalytic materials

Top‐down synthesis has been used to prepare catalytic materials with nanometer sizes,but fabricating atomically dispersed metal catalysts remains a challenge because surface single metal atoms are prone to aggregation or coalescence.A top‐down strategy is used to synthesize atomically dispersed metal catalysts,based on supported Ag nanoparticles.The changes of the geometric and electronic structures of the Ag atoms during the top‐down process are studied using the in situ synchrotron X‐ray diffraction technique,ex situ X‐ray absorption spectroscopy,and transmission electron microscopy.The experimental results,coupled with the density functional theory calculations,demonstrate that the electronic perturbation of the Ag frontier orbitals,induced by the Ag‐O interactions at the perimeter of the metal‐support interface,is the driving force of the top‐down process.The top‐down synthesis has two important functions:to increase the number of catalytic active sites and to facilitate the study of complex reaction mechanisms(e.g.,formaldehyde oxidation)by developing single‐site model catalysts.

Description of Properties of Triaxial Superdeformed Bands in Odd-A Lu Isotopes

Properties of the triaxial superdeformed （TSD） bands of odd-A Lu isotopes are investigated systematically within the supersymmetry scheme including many-body interactions and a perturbation possessing the S0（5） （or SU（5）） symmetry on the rotational symmetry. Quantitatively good results of the γ-ray energies, the dynamical moments of inertia and the spin of the TSD bands in odd-A Lu isotopes are obtained. The calculation shows that the competition between the pairing and anti-pairing effects exists in these TSD bands. Meanwhile, the SU（3） symmetry in TSD bands are broken more seriously than in superdeformed （SD） bands.

Recent developments in metal phosphide and sulfide electrocatalysts for oxygen evolution reaction

Oxygen evolution reaction(OER),as an important half‐reaction involved in water splitting,has been intensely studied since the last century.Transition metal phosphide and sulfide‐based compounds have attracted increasing attention as active OER catalysts due to their excellent physical and chemical characters,and massive efforts have been devoted to improving the phosphide and sulfide‐based materials with better activity and stability in recent years.In this review,the recent progress on phosphide and sulfide‐based OER electrocatalysts in terms of chemical properties,synthetic methodologies,catalytic performances evaluation and improvement strategy is reviewed.The most accepted reaction pathways as well as the thermodynamics and electrochemistry of the OER are firstly introduced in brief,followed by a summary of the recent research and optimization strategy of phosphide and sulfide‐based OER electrocatalysts.Finally,some mechanistic studies of the active phase of phosphide and sulfide‐based compounds are discussed to give insight into the nature of active catalytic sites.It is expected to indicate guidance for further improving the performances of phosphide and sulfide‐based OER electrocatalysts.

Analysis and interpretation on the concrete quality of shaft lining by elastic wave technique

The quality problem of the concrete body and backwall grouting of shaft lining must be taken into consideration during the engineering construction of the shaft. Detection and evaluation are needed to determine the parameters such as the location and depth of drilling. The record of elastic wave can be gained through laying the surveying lines of the ring and ver- tical direction in the shaft lining by the elastic wave method. And specifically, through analyzing the different parameters of seismic attribute such as the velocity of high frequency reflection wave, amplitude and frequency, the abnormal range on the wall or under the wall can be forecasted. The concrete quality of shallow layer in the shaft lining can be evaluated through the velocity of surfer wave. Using the evaluating technique of comprehensive frequency and the phase feature of waveform, the basic features such as inner construction, wall back filling and failure depth of shaft lining can be interpreted from qualitatively to half quantitatively, and the interpreting section can be drawn. The results show that the detection effect for the shaft quality is significant by elastic wave technique, and the delineation of abnormal areas is accurate. Its guidance function is better for pro- duction.

Reversible transformation between terrace and step sites of Pt nanoparticles on titanium under CO and O_(2) environments

Understanding the dynamic evolution of active sites of supported metal catalysts during catalysis is fundamentally important for improving its performance,which attracts tremendous research interests in the past decades.There are two main surficial structures for metal catalysts:terrace sites and step sites,which exhibit catalytic activity discrepancy during catalysis.Herein,by using in situ transmission electron microscopy and in situ Fourier transform infrared spectroscopy(FTIR),the transformation between surface terrace and step sites of Pt-TiO_(2) catalysts was studied under CO and O_(2) environments.We found that the{111}step sites tend to form at{111}terrace under O_(2) environment,while these step sites prefer to transform into terrace under CO environment at elevated temperature.Meanwhile,quantitative ratios of terrace/step sites were obtained by in situ FTIR.It was found that this transformation between terrace sites and step sites was reversible during gas treatment cycling of CO and O_(2).The selective adsorption of O_(2) and CO species at different sites,which stabilized the step/terrace sites,was found to serve as the driving force for active sites transition by density functional theory calculations.Inspired by the in situ results,an enhanced catalytic activity of Pt-TiO_(2) catalysts was successfully achieved through tuning surface-active sites by gas treatments.

Electrical properties of carbon nanotubes in flowing vapor

Electric potentials were generated from carbon nanotubes immersed in flowing vapors. The nanomaterials used in this study were multiwall carbon nanotubes（MWCNTs） and silver nanopowders. These nanomaterials were dispersed and densely packed on a substrate and immersed in flowing vapors generated from solution such as water, ethanol and KCI. The potentials generated from these samples were measured by a voltmeter. Experimental results showed that the electric potentials were produced at the surface of the MWCNT samlpes, and strongly dependent on the pretreatment of MWCNT and properties of the flowing vapors. The mechanism of vapor-flow induced potentials may be ascribed to ions in the flowing vapors. This property of MWCNTs can advantage their application to nanoscale sensors, detectors and power cells.

A Novel Provable Data Possession Scheme Based on Geographic Location Attribute

Increment of mobile cloud video motivates mobile users to utilize cloud storage service to address their demands, cloud storage provider always furnish a location-independent platform for managing user＇s data. However, mobile users wonder if their cloud video data leakage or dynamic migration to illegal service providers. In this paper, we design a novel provable data possession protocol based on data geographic location attribute, which allows data owner to auditing the integrity of their video data, which put forward an ideal choice for remote data possession checking in the mobile cloud storage. In our proposed scheme, we check out whether the video data dynamic migrate to an unspecified location （such as： overseas） by adding data geographic location attribute tag into provable data possession protocol. Moreover, we make sure the security of our proposed scheme under the Computational Diffic-Hellman assumption. The analysis and experiment results demonstrate that our proposed scheme is provably secure and efficient.

Heterogeneity of Adsorption Sites and Adsorption Kinetics of n-Hexane on Metal–Organic Framework MIL-101(Cr)

The heterogeneity of adsorption sites and adsorption kinetics of n-hexane on a chromium terephthalate-based metal-organic framework MIL-10^1 （Cr） were studied by gravimetric method and temperature-programmed desorption （TPD） experiments. The MIL-101 crystals were synthesized by microwave irradiation method. The ad- sorption isotherms and kinetic curves of n-hexane on the MIL-101 were measured. Desorption activation energies of n-hexane from the MIL-10^1 were estimated by TPD experiments. The resulthowed that equilibrium amount ofn-hexane adsorbed on the MIL-10^1 was up to 5.62 mmol.g- 1 at 298 K and 1.6 x10^4 Pa, much higher than that of some activated carbons, zeolltes and so on. The isotherms of n-hexane on the MIL-101 could be well fitted with Langmuir-Freundlich model. TPD spectra exhibit two types of adsorption sites on the MIL-101 with desorption activation energies of 39.41 and 86.69 kJ. mol-1. It reflects the surface energy heterogeneity on the MIL-10I frameworks for n-hexane adsorption. The diffusion coefficients of n-hexane are in the range of （1.35- 2.35 ） x 10 - 1 o cm2. s - 1 with ad sorotion activation enerv of 16.33 kl. mol - 1.