浅谈地面数字广播电视发送系统的设立

在原有模拟发射台站建立数字广播电视发送系统,应尽可能考虑使用原有的模拟电视发送系统设备和用户利用原有接收天线,尽量低的经济投入来开展地面数字广播电视。采用多工器完成RF功率合成、多频道放大器合成,可使地面数字广播电视使用现有的模拟广播电视发射天线。     

中国北方地区主要树木的气候生产利研究

水资源短缺严重制约了华北高产粮区农业的可持续发展。本文对华北地区农业可持续发展的水问题况进行了阐述，对华北高产粮区的典型区域山东省桓台县农用水资源利用现状进行了分析，指出水资源浪费、污染严重，水资源管理不善是水资源利用过程中存在的最主要问题。并在区域、农中国北方地区；树木；气候生产力     

网络教育与传统教育优势互补研究

网络教育以其特有的非时空限制、个性化、多样性、灵活性、开放性等优点迅速发展,但这种教育形式也有不足部分,而这些不足部分正是传统教育的优势,网络教育与传统教育应进行优势互补,共同发展,形成一个和谐的立体的教育环境。文章在阐述了网络教育和传统教育的优势互补策略后通过教学实践证明两者优势互补是可行的和有效的。     

几种消毒剂对青霉菌消毒效果的比较

为了解常用化学消毒剂对青霉菌的消毒效果,测定了来苏儿、碘酊、84消毒液、新洁尔灭、双氧水、甲醇、高锰酸钾、硫柳汞、甲醛、氢氧化钠、苯酚和五水硫酸铜对青霉菌的杀灭效果,用显微镜观察了碘酊和甲醇对青霉菌形态的影响.结果表明:五水硫酸铜、苯酚、碘酊、来苏儿、84消毒液等对青霉菌的消毒效果较好,抑制了青霉菌菌丝的形成.研究为临床上预防青霉菌感染打下了基础.     

枫杨中两性花的发现

This paper reports the bisexual structure of the flowers of Pterocarya stenoptera. The bisexual flowers are borne at the end of a leafy shoot of the current year in many-flowered terminal pendulous catkins. They have the same structure as the general female ones. Each flower grows in the axil of a bract,  with a pair of bracteoles and four small perianths. Each flower has two or three carpels in the centre of the flower,  and upon them there are two or three styles with stigmas on the inner face. They differ from the ge- neral female ones in that each of them contains 4-6 stamens,  forming a single whorl. The stamens alternates with,  or is opposite to,  the perianth elements. Sometimes they contain 8 (-10) stamens,  forming two whorls,  with 6 in the outer whorl and 2 (-4) in the in- ner whorl, and in this case the pistil in the bisexual flower of terminal catkins often becomes a rudiment.       It is interesting that we have also found bisexual flowers in another tree,  which are borne in lateral male catkins. They have the same structure as general male ones,  and the pistils are often represented by a rudiment.       Manning (1940) points out that some female flowers of Pterocarya stenoptera and P. fraxinifolia occasionally have stamens ( ? ) opposite the sepals. In P. stenoptera we have found that both the stamens and the stigmas of bisexual flowers are functional. They are capable of producing functional fruits. This is the same case as in Myrica Gale described by Davey and Gibson (1917). Rendle (1952) points out that in the male flowers of Platycarya the pistils often appeared as a rudiment. He considers,  however,  the male flowers derived from the bisexual flowers with an indefinite number of stamens. The rudimentary pistils of later- al male catkins in P. stenoptera we found are just the same as the ones found in Platycarya by Rendle.       The discovery of the bisexual flowers in P. stenoptera may prove that the unisexual flowers of the present-day Juglandaceae are derived from ancestors with bisexual flowers.This tends to support the hypothesis that Cycadicae is the possible ancestor of the angiosperms.     

平面设计中文字的应用

在平面设计中，字的应用有着非常重要的作用。设计宜从字本身的个性流露、点线面空间层次的形成、视觉流动的引导以及字编排的情感表达等四个方面深刻把握，才能使平面设计中的字和字群更好地为整体效果服务。     

Low-Temperature Selective Catalytic Reduction of NO with NH<Subscript>3</Subscript> over Fe–Ce–O<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> Catalysts

In this study, we used a simple impregnation method to prepare Fe–Ce–O _x catalysts and tested them regarding their low-temperature (200–300 °C) selective catalytic reduction (SCR) of NO using NH₃. We investigated the effects of Fe/Ce molar ratio, the gas hourly space velocity (GHSV), the stability and SO₂/H₂O resistance of the catalysts. The results showed that the FeCe(1:6)O _x (Ce/Fe molar ratio is 1:6) catalyst, which has some ordered parallel channels, exhibited good SCR performance. The FeCe(1:6)O _x catalyst had the highest NO conversion with an activity of 94–99% at temperatures between 200 and 300 °C at a space velocity of 28,800 h^?1. The NO conversion for the FeCe(1:6)O _x catalyst also reached 80–98% between 200 and 300 °C at a space velocity of 204,000 h^?1. In addition, the FeCe(1:6)O _x catalyst demonstrated good stability in a 10-h SCR reaction at 200–300 °C. Even in the presence of SO₂ and H₂O, the FeCe(1:6)O _x catalyst exhibited good SCR performance.     

高职院校聘任制改革与教师职业生涯规划

教师是高职院校办学的主体,他们渴求良好的职业预期并有强烈的成功愿望,期望通过积极的职业生涯规划走向成功。遵循“以人为本”的管理理论,聘任制改革应在立足于激发教师活力、增强其规划职业生涯的动力和自主性、推动其事业走向成功的基点上进行,通过充分发挥聘任制在教师职业生涯规划中的作用,最终在学校事业发展和教师个人发展的和谐统一中实现聘任制改革的终极目标。     

中国上市银行竞争力评价体系构建及其实证分析

上市银行的竞争力直接关系到我国银行业整体的竞争力水平。然而,目前我国尚未形成统一完善的上市银行竞争力评价体系。一个健全的评价体系应遵循全面性、可操作性、科学性以及结构层次性原则,涵盖规模性、盈利能力、流动性风险、资产质量以及成长能力等评价指标。根据上述原则和评价指标来构建我国上市银行竞争力评价体系,并选取了6家具有代表性的上市银行来对其竞争力进行分析,指出其在竞争力方面的优势及缺陷,以期能够促进我国上市银行竞争力的全面提升。     

PPP模式下战略性新兴产业评价维度的构建

为应对高不确定性而产生的战略性新兴产业协同创新中PPP模式的事后无效性,本文认为应在事前对PPP项目的事后无效性进行评价,从而确定可接受的事前谈判成本范围。我们从PPP合约双方对合同外收益的控制权要求入手,对相关可能影响双方剩余控制权索取要求的因素进行分析,通过建立剩余可控制权模型确定事前评价的维度。