论水稻土肥力进化与土壤质量——以太湖地区为例

太湖地区是我国古老农业区之一。在六七千年之前先民已开始种植水稻 ,随着耕作培肥措施不断加强 ,与土壤肥力进化同步伴随着耕作轮作制的不断演进 ,由轮荒———沤田———水旱轮作———三熟制的变化 ,土壤基础肥力稳步提高 ,稻麦单位面积产量逐年上升。该区水稻土历经数千年的耕肥与平田整地等人为活动 ,在起源土壤背景上发育成五类水稻土 ,这五类水稻土经过培肥改良均达到水旱轮作高产稳产阶段 ,尽管地力上还存在不同程度的差异 ,这不能不说是人为定向培育的成果。在一般情况下 ,土壤质量是由土壤肥力决定的 ,基础肥力高低是农业生产优质高产低耗的关键 ,在评价土壤质量时必需首先予以关注。当然 ,随着工业的发展 ,土壤污染所波及的农产品超标问题 ,也应在评价土壤质量时予以关注 ,并作为评价因素在综合评价体系中占有应有的份量     

施肥对稻田甲烷排放的影响

采用自动连续测量系统，对不同施肥情况下稻田甲烷排放通量进行了监测。结果表明：施肥是影响稻田甲烷排放的重要因素。增施有机肥会导致甲烷排放量增加．应用化肥可降低甲烷排放，有机肥加倍处理，３２ｄ甲烷总排放量１６．４０ｇＣＨ＿４／ｍ￣２，是化肥加倍处理的１．５６倍；常规施肥处理介于两者之间。略高于常规加倍处理。肥料种类对甲烷排放量也有影响。全施有机肥高于有机肥加化肥（１：１）组，施沼渣肥组次之，全化肥组排放量最低，不到全有机肥处理排放量的１／５．有机肥又以施人畜粪的甲烷排放率最高，绿肥次之，沼渣肥和稻草的甲烷排放率最低。有机肥的多级利用是减少稻田甲烷排放的一条重要途径。     

Sustaining Economic Welfare: Estimating Changes in Total and Per Capita Wealth

Genuine saving measures the real change in0 total wealth, factoring in the depreciation of produced assets, depletion of natural resources, pollution damages, and expenditures on education. This paper presents a theoretical framework for measuring changes in wealth in total and per capita terms, establishes the link between savings measures and prospects for social welfare, and provides summary empirical estimates of the savings measures. China excepted, the majority of countries below median income are distinguished by apparent declines in total wealth per capita.     

成都市可持续发展水平空间分布特征

本文通过对成都市 8县 4市 3区的可持续发展静态指数计算 ,定量地表达了成都市各区县目前可持续发展状况的对比关系 ,分析造成这种格局的原因并提出相应对策     

Changes in earth’s dipole

The dipole moment of Earth’s magnetic field has decreased by nearly over the past 150 years and by about 30% over the past 2,000 years according to archeomagnetic measurements. Here, we explore the causes and the implications of this rapid change. Maps of the geomagnetic field on the core–mantle boundary derived from ground-based and satellite measurements reveal that most of the present episode of dipole moment decrease originates in the southern hemisphere. Weakening and equatorward advection of normal polarity magnetic field by the core flow, combined with proliferation and growth of regions where the magnetic polarity is reversed, are reducing the dipole moment on the core–mantle boundary. Growth of these reversed flux regions has occurred over the past century or longer and is associated with the expansion of the South Atlantic Anomaly, a low-intensity region in the geomagnetic field that presents a radiation hazard at satellite altitudes. We address the speculation that the present episode of dipole moment decrease is a precursor to the next geomagnetic polarity reversal. The paleomagnetic record contains a broad spectrum of dipole moment fluctuations with polarity reversals typically occurring during dipole moment lows. However, the dipole moment is stronger today than its long time average, indicating that polarity reversal is not likely unless the current episode of moment decrease continues for a thousand years or more.     

重型柴油车车载排放实测与加载影响研究

采用车载排放测试仪,对2辆重型柴油卡车在空载和加载条件下进行实际道路车载排放测试.通过分析获得了油耗与排放速率的速度-加速度及其工况点的分布,发现高油耗与高排放工况点主要集中在高速加速区域,加载时油耗与排放高值随工况点分布更广;车辆在(30±2.5)km·h^-1等速及加速行驶时受加载影响最大,此时加载油耗与排放约是空载的1.6～3.2倍左右;由实测结果发现,卡车Ⅰ和卡车Ⅱ加载时油耗及CO、HC、NO_x排放因子分别是空载的1.6倍、3.5倍、1.1倍、1.5倍以及1.2倍、1.0倍、0.9倍和1.5倍,加载对油耗与NO_x排放影响最为明显,对HC影响最小,CO影响取决于车辆保养水平;卡车Ⅱ较卡车Ⅰ车型更大,发动机功率更高,相同荷载时受加载影响较小,说明重型车在发动机负荷可承受的范围内合理装载,有助于避免油耗与排放恶化,提高燃油经济性和排放水平.     

高强与高性能混凝土温湿度场应力分析

针对高强与高性能混凝土易于开裂的特点,对高强高性能混凝土早期温湿度场随龄期发展的分布情况以及混凝土的收缩变形进行理论分析,建立相应的计算模型,编制三维有限元程序,分析在外界温湿度变化以及不同养护条件下由混凝土内部温差和湿度变化产生的温度应力和干燥收缩应力,从施工养护方法上探讨了高强与高性能混凝土抗裂性能的改善措施.     

The characteristic of in situ stress in outburst area of China

In order to obtain the characteristics of in situ stress field in outburst mining area, using the hollow inclusion (HI) technique to measure the in situ stress of coal and gas outburst mining area. The measurement sites located in northeast, middle and east of china, which include eight mining areas such as Fuxin, Pingdingshan, Hebi and Huainan. Base on the analysis of measurement data from outburst mining area, conclusions could be obtained as follow: (a) major principal stress and minor principal stress is horizontal stress and interim principal stress is vertical stress, and the type of outburst area’s stress field is dynamic stress field; (b) the major principal stress and minor principal stress are higher than other regions and the tectonic stress is outstanding; and (c) the ratio of major principal and vertical stress is decrease with the increase of depth and the type of stress field is likely transfer dynamic to static. Thus, in situ stress plays a key role during the occurring and development of coal and gas outburst, which is an important reason of severe outburst in China.     

基于未确知测度模型的非煤矿山安全标准化运行状况评价

为了实现对非煤矿山安全标准化运行状况的全员参与的评价,基于未确知理论,从监管、保障、能力、绩效等4个方面选取评价指标,建立安全标准化运行未确知测度模型。运用层次分析法(AHP)确定指标权重,以1级、2级、3级、4级作为评价等级。以某矿山企业为例进行评价。基于100位员工的评分结果,计算单指标未确知测度。结合权重、根据置信度识别准则,进行等级判定。最终得出该矿山企业安全标准化运行等级,并与专家考评结果进行对比分析。研究结果表明,该企业安全标准化运行等级为2级,与专家评价结果相吻合。     

高温热表面油液蒸发的时变性热质传递模型与实验研究

针对高温热表面油液蒸发热质传递过程的时变性,考虑这一过程中的对流传质传热,建立了热环境作用下油液蒸发的热质传递模型方程,通过无量纲变换,求得空间浓度分布和温度场随时间的变化规律。以庚烷为试验对象,对高温热表面油液蒸发过程进行了实验研究。理论分析与实验表明:庚烷蒸发过程中,刘易斯数大于1,传热速率大于传质速率;蒸发导致的质量损失与时间平方根的成正比,与液面的面积成正比,且与质量扩散系数的平方根成正比,饱和蒸气浓度越大,蒸发速率也越大。油液蒸发计算结果与试验结果基本一致,表明了模型的有效性。