基于需求与供给理论的甘肃省人口土地承载力研究

从供给和需求平衡的经济学视角,运用生态能值分析的研究方法,对2006年-2012年甘肃省农业土地人口承载力进行了实证研究.发现中国取消农业税政策提高了农民生产积极性,同时发现近年来甘肃省农业土地能值供给无法满足人口能值需求,但供需差距在缩小,预计未来十数年内随着农业产业化生产及农业科技的提高,甘肃省将实现农业土地产出和人口能值需求的自给自足.     

A Geographic Information System (GIS)-based approach to adaptation to regional climate change: a case study of Okutama-machi,Tokyo, Japan

Recently, local governments have an increasing need to take extensive and effective local measures to adapt to regional climate change, but have difficulty knowing how and when to adapt to such change. This study aims: 1) to characterize an efficient and cost-effective database management tool (DMT) for developing a Geographic Information System (GIS) based approach to using observed and projected data, for decision-making by non-expert government authorities, and 2) to document how DMT can be used to provide specialized yet understandable climate change information to assist local decision-makers in clarifying regional priorities within a wide array of adaptation options. The DMT combines climate change mapping, statistical GIS, and a vulnerability assessment. Okutama-machi, a 225.63 km² sparsely populated mountainous region (2012 population 5,856) northwest of Tokyo, Japan, was chosen for this pilot study. In this paper, the most recent regional climate projections (5 km resolution) are transcribed into an understandable form for use by non-expert citizens who use the GIS-based DMT. Results illustrate qualitative agreement in projection of summer daily mean temperatures; the mean temperature increase at Okutama-machi is the greatest of any area in Tokyo. In comparing near future and future conditions, August monthly mean temperature will increase more than 0.7–0.9 °C and 2.8–2.9 °C, and monthly precipitation by 50 % and 25–41 %, respectively. However, the root mean square (RMS) errors and bias of percentage change for monthly precipitation in summertime are 26.8 % and 4.3 %, respectively. These data provide an early warning and have implications for local climate policy response.     

城市生活垃圾处理中的碳排放及其评价模型研究

城市生活垃圾是温室气体的重要排放源,研究其碳排放评价模型意义重大.本文介绍了温室气体减排的履约机制和垃圾处理碳排放的常用评价模型,并重点强调了CO2ZW模型的适用性和优点,为垃圾处理碳排放的评价引入了新工具.选择适合中国国情和各地特点的碳排放评价模型,有助于推动固废处理行业的低碳生产和保持国民经济的可持续发展.     

A Simulation Study on the Efficacy of Advanced Belt Restraints to Mitigate the Effects of Obesity for Rear-Seat Occupant Protection in Frontal Crashes

Objective: Recent field data analyses have shown that the safety advantages of rear seats relative to the front seats have decreased in newer vehicles. Separately, the risks of certain injuries have been found to be higher for obese occupants. The objective of this study is to investigate the effects of advanced belt features on the protection of rear-seat occupants with a range of body mass index (BMI) in frontal crashes.

Methods: Whole-body finite element human models with 4 BMI levels (25, 30, 35, and 40 kg/m²) developed previously were used in this study. A total of 52 frontal crash simulations were conducted, including 4 simulations with a standard rear-seat, 3-point belt and 48 simulations with advanced belt features. The parameters varied in the simulations included BMI, load limit, anchor pretensioner, and lap belt routing relative to the pelvis. The injury measurements analyzed in this study included head and hip excursions, normalized chest deflection, and torso angle (defined as the angle between the hip–shoulder line and the vertical direction). Analyses of covariance were used to test the significance (P <.05) of the results.

Results: Higher BMI was associated with greater head and hip excursions and larger normalized chest deflection. Higher belt routing increased the hip excursion and torso angle, which indicates a higher submarining risk, whereas the anchor pretensioner reduced hip excursion and torso angle. Lower load limits decreased the normalized chest deflection but increased the head excursion. Normalized chest deflection had a positive correlation with maximum torso angle. Occupants with higher BMI have to use higher load limits to reach head excursions similar to those in lower BMI occupants.

Discussion and Conclusion: The simulation results suggest that optimizing load limiter and adding pretensioner(s) can reduce injury risks associated with obesity, but conflicting effects on head and chest injuries were observed. This study demonstrated the feasibility and importance of using human models to investigate protection for occupants with various BMI levels. A seat belt system capable of adapting to occupant size and body shape will improve protection for obese occupants in rear seats.     

磁性吸附材料的制备及其在污水处理中的应用

磁性吸附材料是利用多种物理化学作用来处理水体中的无机污染物和有机污染物,其具有的磁性便于与污水分离,有利于集中处理污染物,具有快速、高效、可重复利用等优点。从Fe3O4磁性颗粒和纳米磁性粒子出发,对磁性吸附材料的制备以及其在污水处理中的应用研究进展进行综述,并对磁性吸附材料今后的研究方向进行展望。     

2013年成都地区一次秸秆焚烧特征及成因分析

2013年9月14~17日成都及周边地区出现了一次秸秆焚烧空气污染过程,成都、德阳受污染影响较严重,乐山、眉山影响相对较轻。基于空气污染指数API,结合雷达消光系数反演图、在线气团后向轨迹及探空斜温图分析本次空气污染过程,主要是由成都城区以南地区秸秆焚烧及区域边界层辐射逆温等不利扩散气象条件共同造成的。     

Application of different foliar iron fertilizers for enhancing the growth and antioxidant capacity of rice and minimizing cadmium accumulation

Environmental Science and Pollution Research - Iron (Fe) fertilizer can reduce cadmium (Cd) uptake and toxicity in rice, but the underlying mechanisms of Cd mitigation by different fertilizers are...     

Dynamics of phosphorus fractions and potential bioavailability along soil profiles from seasonal-flooding wetlands in a Chinese estuary

Environmental Science and Pollution Research - Soil phosphorus fractions in wetland ecosystems have received increasing attention due to its high eutrophication risks. Soil samples were collected...     

临水河表层沉积物中的重金属污染评价

选取临水河底部表层沉积物为研究对象,采用地质累积指数、潜在生态危害指数对其重金属污染进行评价。结果表明:沉积物Cr、Cd、Cu、Pb的含量介于203.971~412.363 mg/kg,浓度由高到低依次为Cr>Cu>Pb>Cd;Cd、Cu、Pb的空间变异系数较大,依次为82.8%、65.1%和43.1%,表明这3种重金属可能存在点源污染;Cr的空间变异系数较小,为28.2%,说明该重金属可能存在面源污染。地质累积指数表明:Cd和Cr的污染等级分别为3~5级和1~2级,为中度污染到极强度污染,Cu和Pb无污染。潜在生态危害指数RI值为280.54~879.27,污染程度为中等污染至很强污染。Cd为河流表层沉积物重金属污染的最大贡献者。     

气相色谱法测定饮用水中三氯乙烯含量的不确定度评定研究

分析和评定气相色谱法测定饮用水中三氯乙烯含量过程中引入的不确定度,分析了标准物质、分析操作、重复性测定等方面对不确定度的影响,实验表明在置信水平95%,包含因子k=2时,水中三氯乙烯测量结果的相对扩展不确定度为8.31%,三氯乙烯含量为3.17μg/L,扩展不确定度为0.263μg/L,测试过程的随机效应引入的不确定度对合成不确定度的贡献最大.