Measuring the costs of improving the quality of the environment in the United States

The analysis in this paper is directed at comparing the relative effectiveness of meeting the objectives outlined in the recently passed Clean Air Act Amendments of 1990 through taxation and through regulation. The analytical vehicle used in the analysis consists of a computable general equilibrium model composed of 12 producing sectors, 13 consuming sectors, 6 household categories classified by income, a foreign sector and a government. We find first that, irrespective of what type of strategy is followed, both output and consumption decline. Hence, there is an identifiable and quantifiable tradeoff between economic activity (economic growth) and the quality of the environment. Beyond this, the aggregate loss in production and economic welfare (measured by consumption expenditures and utility) is less under a policy which stresses reliance on alternative fuels than through one that requires the installation of pollution abatement devices.     

优化书库环境加强图书保护

通过分析损害图书的各种自然因素,阐明优化书库环境、加强图书保护的重要性。     

Assessment of the effect of the climatic parameters on the distribution of the Al-Fe-humus horizons in the soils of the Russian planes

A comparative-ecological approach for studying the general regularities of soil ecology on the basis of geoinformation systems is suggested. It has been applied to analyze the distribution of Al-Fe-humus horizons. The quantitative climatic parameters of soils with Al-Fe-humus horizons have been estimated, and the relationships between them have been established. The applicability of this approach for assessing the general regularities of soil ecology is shown.     

跟踪学科前沿，引导学科发展——《农业工程学报》的发展探索

论述了《农业工程学报》跟踪农业工程学科发展的成功经验，详细分析了未来《农业工程学报》跟踪学科各个专业的报道方向。指出随着学科的发展及时调整学术期刊的报道方向是科技学术期刊的任务和职责，是使期刊保证及时反映相关学科的发展，保持在学科发展中应有的促进作用，在众多期刊的竞争中立于不败之地的保证。在充分分析中国学术期刊面临的形势和问题、机遇与挑战的基础上，提出了学术期刊如何规避不利因素等应对策略，为中国科技学术期刊的发展提供参考。     

硅基材料包膜肥对红壤区双季稻生长和土壤肥力的影响

选择了高肥力田、低肥力田,通过早、晚双季稻连续2年4季的大田试验,研究了施用硅基材料包膜肥对双季稻动态生长、产量、土壤肥力、微生物量、酶活性的影响。结果表明:不论是高肥力田还是低肥力田,与传统施肥相比,一次性基施硅基材料包膜肥能提高双季稻的最大分蘖数3~6枝·兜~(-1),提高成熟期叶片的叶绿素含量,提高成熟期双季稻的生物产量7.8%~22.4%,提高年均产量3.0%~14.7%,并且在低肥力田上效果显著。与传统施肥处理相比较,施硅基材料包膜肥可以显著提高双季稻成熟期土壤中的矿质态氮含量,提高幅度为28.3%~37.7%。包膜肥对土壤中微生物群落没有影响,在低肥力田施用80%的包膜肥其土壤酶活性综合指数最高。由此可见,施用硅基材料包膜肥在南方水稻上完全可以替代分次施用常规肥料,并且在高肥力田减少20%肥料用量的情况下仍然等效,达到了减肥增效和节本省工的目的。     

下一代Internet发展综述——下一代Internet的产生和发展

本文论述了IPV6产生的社会原因,阐述了国外发达国家下一代Internet的发展状况和中国下一代Internet的发展状况及最新进展。     

植物根际促生菌(PGPR)的研究与应用前景

植物根际微生物主要以细菌为主,多样性高且活跃,分为有益菌（2 % ~ 5 %）、有害菌（8 % ~ 15 %）以及中性菌（80 % ~ 90 %）。从有益菌中筛选出的植物根际促生菌（Plant Growth Promoting Rhizobacteria,简称PGPR）具有促进植物生长、防治病害等功能,成为土壤科学领域的研究热点。本文目的是了解PGPR在国内外的研究现状,寻求高效、长效且安全的开发与利用方式对PGPR促生及生物防控功能具有重要意义。基于Web of Science核心合集数据库,采用CiteSpace、VOSviewer、HistCite等工具对PGPR研究领域的发文数量与学科分布、发文国家及机构间的合作关系、发文期刊、主要研究热点以及发展趋势等进行了计量分析。结果表明：① 印度、中国、美国、巴基斯坦、德国等国在该领域发文的引用频次较高,研究较为深入。②全球对PGPR研究的重视程度越来越高,主要集中于植物科学学科与微生物学学科。③ 发文主要期刊有Frontiers in Microbiology、Frontiers in Plant Science及Plant and Soil,关键文献中PGPR的促生、抗胁迫、污染修复等内容占据较高比例。④ 关键词聚类主要分为生物修复功能与措施、PGPR的促生及胁迫耐受性等、根际功能菌群的种类及系统抗性、根际菌群促生及生物防控功能等4类。生物防控是PGPR领域的一个研究热点,该领域未来研究趋势主要集中于PGPR及其它土著菌群与植物之间的互作关系以及PGPR高效应用的方式等。     

水氮耦合对苹果光合特性和果实品质的影响

通过不同灌水量和施氮处理,研究水氮耦合对红富士苹果光合特性及品质的影响。结果表明:红富士苹果的光合特性在不同水肥组合下的变化不同,其光合作用存在明显的“午休”现象。中水高肥和高水高肥的肥水组合对光合速率的保持有一定的作用。低水中肥的肥水组合的蒸腾速率最低,保水效果最好。中度水分供应条件下,施用较多的氮肥可以提高气孔导度利于光合的进行。肥水管理以灌溉量5250m³/hm²、氮肥施用量600kg/hm²方案能获得较高的品质效益。     

Simulating the carbon flux between the terrestrial environment and the atmosphere

A Terrestrial C Cycle model that is incorporated in the Integrated Model to Assess the Greenhouse Effect (IMAGE 2.0) is described. The model is a geographically explicit implementation of a model that simulates the major C fluxes in different compartments of the terrestrial biosphere and between the biosphere and the atmosphere. Climatic parameters, land cover and atmospheric C concentrations determine the result of the dynamic C simulations. The impact of changing land cover patterns, caused by anthropogenic activities (shifting agriculture, de- and afforestation) and climatic change are modeled implicitly. Feedback processes such as CO₂ fertilization and temperature effects on photosynthesis, respiration and decomposition are modeled explicitly. The major innovation of this approach is that the consequences of climate change are taken into account instantly and that their results can be quantified on a global medium-resolution grid. The objectives of this paper are to describe the C cycle model in detail, present the linkages with other parts of the IMAGE 2.0 framework, and give an array of different simulations to validate and test the robustness of this modeling approach. The computed global net primary production (NPP) for the terrestrial biosphere in 1990 was 60.6 Gt C a^?1, with a global net ecosystem production (NEP) of 2.4 Gt C a^?1. The simulated C flux as result from land cover changes was 1.1 Gt C a^?1, so that the terrestrial biosphere in 1990 acted as a C sink of 1.3 Gt C a^?1. Global phytomass amounted 567.5 Gt C and the dead biomass pool was 1517.7 Gt C. IMAGE 2.0 simulated for the period 1970–2050 a global average temperature increase of 1.6 °C and a global average precipitation increase of 0.1 mm/day. The CO₂ concentration in 2050 was 522.2 ppm. The computed NPP for the year 2050 is 82.5 Gt C a^?1, with a NEP of 8.1 Gt C a^?1. Projected land cover changes result in a C flux of 0.9 Gt C a^?1, so that the terrestrial biosphere will be a strong sink of 7.2 Gt C a^?1. The amount of phytomass hardly changed (600.7 Gt C) but the distribution over the different regions had. Dead biomass increased significantly to 1667.2 Gt C.     

岩质边坡确定性块体稳定性的研究

在岩质边坡中,岩体的失稳与破坏主要受岩体内结构面的控制,它们相互之间的空间分布位置、组合关系(包括自然边坡或边坡开挖面的产状)和结构面的物理力学性质等,对边坡的稳定都起着至关重要的作用.将野外测量的结构面资料,用一定的几何图形植入三维地形模型中,可以直观显示各软弱结构面的空间展布规律和交切关系,再根据赤平投影原理进行分析统计,确定优势产状,进而对边坡在潜在不稳定块体宽度、高度、体积、失稳模式和滑动方向做出定量的判断,从而指导现场工作人员采取处理措施.     

贵阳市蔬菜上市量与气象灾害关系的研究

统计,分析了贵阳市蔬菜气象灾害的成因,种类,特征及其对蔬菜生产影响的程度,结合蔬菜受害机制,再生力,影响程度,对蔬菜气象灾害进行分类,分级。初步认为暴雨,冰雹,连阴雨,,连续高温高湿,春旱,倒春寒６种气象灾害是贵阳市蔬菜生产的主要气象灾害,其中后４种气象灾害应作为防灾减灾的重点,提出蔬菜均衡上市的防灾减灾对策措施。     

互联网冲击下的图书馆差异化功能定位

互联网对图书馆的持续发展既是机遇也是挑战。图书馆利用互联网扩大了服务范围,图书馆以往简单阅读、快速阅读的作用在减弱。因此,图书馆需要针对读者群的特点进行差异化定位,聚焦读者严肃阅读的需求,成为更专业、可靠和高效的信息源。     

气候变化对黄河中上游地区潜在蒸散影响的估算

采用Penman—Monteith公式计算潜在蒸散,分析1961-2010年黄河中上游地区气候因子的变化趋势,并用偏微分方法定量分析各气候因子变化对潜在蒸散的影响。结果显示：1）近50年来黄河中上游地区气温显著升高（α〈0．01）,风速和日照时间显著减少（α〈0．01）。半干旱区面积不断扩大,气候总体呈暖干变化趋势。2）潜在蒸散对实际水汽压变化最敏感,其次为最高气温、风速和日照时间,对最低气温变化最不敏感。夏季潜在蒸散对日最高气温最敏感,其他季节对实际水汽压最敏感。3）风速对年潜在蒸散变化贡献最大,其次为气温和日照时间,实际水汽压贡献最小。春夏秋冬对潜在蒸散变化贡献最大的气候因子依次为风速、日照时间、气温。温度升高、湿度减少埘潜在蒸散的正影响已被风速、辐射下降的负影响所抵消。综合考虑各气候因子对潜在蒸散的作用有助于加深对气候变化影响机制的认识,并为气候变化适应对策研究提供科学依据。     

Effect of errors in positioning the sampling points on the assessment of the relationships between the remote sensing data and the soil properties

The stochastic modeling of the shift in coordinates of the sampling points was performed for a typical land plot in Bryansk opolie with the purpose to assess the influence of the accuracy of the sampling point positioning on the predicted properties of the plow horizon. It was proved that, for agro-gray soils, an occasional shift of the sampling points by 2–6 m regarding the coordinates on satellite photographs of superhigh resolution may significantly change the correlation between the soil properties and the brightness in the infrared channel. Based on the modeling data, the 95% confidence interval was estimated for the possible correlation coefficients of such properties of the arable agro-gray soil as the density, moisture, specific surface, carbon, and mobile nitrogen content. The use of the brightness in the infrared channel as a covariate for building charts may noticeably improve the map’s quality; however, it may unjustifiably complicate the mapping units delineation.     

Excel应用于显著性检验的实训过程探究

在Excel环境中采取编算式并调用粘贴函数,逐步实现了单个或两个样本的显著性检验过程。其中的数据分析软件运行T检验、F检验过程的结果进行比较,发现其中的不同之处有时会造成误判。明确这些差别有助于澄清显著性检验的每一个步骤和细节,正确运用Excel界面编程或通过运行数据分析软件提高效率。Excel界面用作生物统计课程实训操作平台,具有毋庸置疑的价值和优势,对于初学者,使用Excel电子表格逐步实现各种统计检验过程取得的教学效果,其他任何专业统计软件都无法替代。     

影响板栗产量的气象条件分析及产量评估方法

统计近24年兴隆县板栗的产量资料与生育期的气象资料,分析了板栗产量与气温、降水、日照等气象条件的相关关系,选取与板栗产量相关好的气象要素为预报因子,用多元回归的方法建立了板栗气象产量评估方程,并进行了回代和检验。     

饮用水氯消毒及余氯控制技术展望

液氯作为一种消毒剂已有上百年历史,随着社会的发展,人们对健康意识的加强,氯消毒所引发的副作用越来越引起人们的重视。通过介绍液氯消毒原理,阐述余氯的几种基本测定方法及余氯在工艺上的控制和脱氯技术现状及发展方向。     

内蒙古农村地区网络普及对生活方式影响的研究

通过对内蒙古东部农村地区网络普及现状的调查,发现内蒙古农村地区使用家庭电脑的居民逐渐增多,但是多数以娱乐为主,没有运用到农业生产流通等领域。通过对内蒙古农村居民购买电脑和网络意识的分析,进一步探讨了内蒙古农村地区网络普及对于生活方式所带来的影响。     

泵站侧向进水前池几何参数优化

为了减少泵站侧向进水结构内的不良流态,提高泵组运行效率,基于计算流体力学（Computational Fluid Dynamics,CFD）和响应面法（Response Surface Method,RSM）对泵站侧向进水前池进行几何参数优化。采用参数化设计对泵站侧向进水前池进行建模,通过与Workbench关联以对侧向进水前池的扩散角α、坡度β以及转向角γ实现指定值,采用典型Box-Behnke设计（Box-Behnke Design,BBD）方法得到17组三因素三水平试验方案,利用响应面法建立喇叭管出口断面流速分布均匀度与侧向进水前池扩散角α、坡度β以及转向角γ的回归方程,以最大出口断面流速分布均匀度为响应目标,确定最优参数组合,并将最优侧向进水结构的内部流动特性同原模型进行对比分析。研究结果表明,扩散角α、坡度β以及转向角γ对喇叭管出口断面流速分布均匀度具有显著影响（P<0.05）,扩散角α与转向角γ的交互项对出口断面流速分布均匀度耦合作用显著,扩散角10°~13°、坡度8°~9°、转向角74°~75°时喇叭管出口断面流速分布均匀度达到最优。同原模型相比,优化后的侧向进水结构在设计水位下,断面流速分布均匀度至少提高23.41个百分点,流速加权平均偏流角提高13.95°,在低水位下断面流速分布均匀度至少提高18.30个百分点,流速加权平均偏流角提高14.79°,流道内没有偏斜流和大面积回流产生。该研究对于促进泵站侧向进水结构的优化设计具有一定的参考意义。     

Effect of the Substrates upon the Regeneration of the Engrafted Cuttings and the Yield of Engrafted Rooted Vines

Engrafted cuttings of the variety Rkaciteli on stocks B?×?R Cober 5BB and R?×?R 101-14, having endured open and covered stratification on different substrates, were planted in a polyethylene glasshouse on four artificial substrates after the postplanting preparation. The complex effect of the stock variety was examined, as well as the effects of the stratification methods and the substrates on the yield of engrafted vines. The characteristics of the regeneration of the engrafted cuttings during the stratification were established. The optimal substrates for stratification of the transplants and the growing of engrafted vines in glasshouses were defined.