镧掺杂的二氧化钛纳米颗粒的合成、结构表征及光催化性能

以无水乙醇为溶剂、1-丁基-3-甲基咪唑四氟硼酸盐([Bmim]BF4)离子液体为表面活性剂,以钛酸四丁酯、六水合硝酸镧为原料,采用共沉淀法制备了不同掺镧量的La-TiO2光催化材料。采用X-射线衍射仪(XRD)、傅里叶变换红外光谱仪(FTIR)、场发射扫描电镜(FESEM)、差热-热重分析仪(TG-DSC)、紫外-可见吸收光谱仪(UV-vis)、比表面及孔隙度分析仪(BET)对其结构、形貌、热稳定性、光学性能及比表面积进行表征。所制备产品的光催化性能在紫外光下进行了光催化降解甲基橙实验,实验结果表明在离子液体的量为0.5mL,掺杂镧量为5%的TiO2纳米材料对甲基橙的降解效果相对较好,降解率最高达到98.73%。     

1991-2010年中国大陆化石能源消费的CO2排放研究（英文）

本文采用IPCC推荐的表观消费量法计算了中国大陆30省区1991到2010年化石能源消费产生的CO2排放,发现:(1)排放总量由 2293.01Mt 增长到 7467.77Mt;(2)煤炭消费的排放比重最高达到79.98%;(3)人均排放量由 1.98t 增长至 5.57t;(4)CO2排放强度显著降低,由6.66 kg USD-1降至1.07kg USD-1,近年来趋于稳定;(5)区域发展不平衡始终存在,根据省际数据,在一些落后地区经济增长过度依赖于化石能源消费。关于CO2高排放,中国已经做出承诺并采取了行动。基于对可持续发展和全球气候变化不确定性的综合考虑,健康的产业结构、化石能源集约利用,以及区域发展平衡应更加受到重视。     

Growing up and cleaning up: The environmental Kuznets curve redux

Borrowing from the Kuznets curve literature, researchers have coined the term “environmental Kuznets curve” or EKC to characterize the relationship between pollution levels and income: pollution levels will increase with income but some threshold of income will eventually be reached, beyond which pollution levels will decrease. The link between the original Kuznets curve, which posited a similar relationship between income and inequality, and its pollution-concerned offspring lies primarily with the shape of both curves (an upside-down U) and the central role played by income change. Although the EKC literature has burgeoned over the past several years, few concrete conclusions have been drawn, the main themes of the literature have remained constant, and no consensus has been reached regarding the existence of an environmental Kuznets curve. EKC research has used a variety of types of data and a range of geographical units to examine the effects of income levels on pollution. Changes in pollution levels might also be at least partly explained by countries’ position in the demographic transition and their general population structure, however little research has included this important aspect in the analysis. In addition, few analyses confine themselves to an evaluation for one country of the long-term relationship between income and pollution. Using United States CO₂ emissions as well as demographic, employment, trade and energy price data, this paper seeks to highlight the potential impact of population and economic structure in explaining the relationship between income and pollution levels.     

Prospects of multifunctional agriculture as a facilitator of sustainable rural development: Swedish experience of Pillar 2 of the Common Agricultural Policy (CAP)

Agriculture remains one of the dominant activities in rural areas across the European Union (EU), not least in respect of land use and its impact on landscapes. The Agenda 2000 reform of the EU's Common Agricultural Policy (CAP) introduced rural development as an integrated part of agricultural policy. The present study focuses on the second pillar of CAP. Multifunctional farming, more than any other rural activity, has a role to play in integrating the natural environment with the cultural landscape and socio-economic development. The question of how multifunctional agriculture can facilitate sustainable rural development is addressed in terms of mechanisms and inherent possibilities. Results from a case study in Östergötland in Sweden are discussed in relation to five other European case studies. Some main findings are that Pillar 2 has made it possible for rural inhabitants to continue living in rural areas and that the policies are effective in identifying and supporting new opportunities for farm diversification. The traditional agricultural landscape can be seen as a key component in various diversification activities in rural areas, contributing to economic as well as social and environmental sustainability.     

Moisture transport over the Arabian Sea associated with summer rainfall over Pakistan in 1994 and 2002

In this study,we aimed to elucidate the critical role of moisture transport affecting monsoon activity in two contrasting summers over the Arabian Sea during the years 1994,a relatively wet year,and 2002,a relatively dry year.A comprehensive diagnostic evaluation and comparisons of the moisture fields were conducted;we focused on the precipitation and evaporation as well as the moisture transport and its divergence or convergence in the atmosphere.Monthly mean reanalysis data were obtained from the National Centers for Environmental Prediction(NCEP-I and-II).A detailed evaluation of the moisture budgets over Pakistan during these two years was made by calculating the latent energy flux at the surface(E P) from the divergence of the total moisture transport.Our results confirm the moisture supply over the Arabian Sea to be the major source of rainfall in Pakistan and neighboring regions.In 1994,Pakistan received more rainfall compared to 2002 during the summer monsoon.Moisture flow deepens and strengthens over Arabian Sea during the peak summer monsoon months of July and August.Our analysis shows that vertically integrated moisture transport flux have a significant role in supplying moisture to the convective centers over Pakistan and neighboring regions from the divergent regions of the Arabian Sea and the Bay of Bengal.Moreover,in 1994,a deeper vertically integrated moisture convergence progression occurred over Pakistan compared to that in 2002.Perhaps that deeper convergence resulted in a more intense moisture depression over Pakistan and also caused more rainfall in 1994 during the summer monsoon.Finally,from the water budget analysis,it has been surmised that the water budget was larger in 1994 than in 2002 during the summer monsoon.     

The sensitivity of ground surface temperature prediction to soil thermal properties Using the Simple Biosphere Model (SiB2)

Using the Simple Biosphere Model (SiB2), soil thermal properties (STP) were examined in a Tibetan prairie during the monsoon period to investigate ground surface temperature prediction. We improved the SiB2 model by incorporating a revised force-restore method (FRM) to take the vertical heterogeneity of soil thermal diffusivity (k) into account. The results indicate that (1) the revised FRM alleviates daytime overestimation and nighttime underestimation in modeled ground surface temperature (T_g), and (2) its role in little rainfall events is significant because the vertical gradient of k increases with increasing surface evaporation. Since the original formula of thermal conductivity (λ) in the SiB2 greatly underestimates soil thermal conductivity, we compared five algorithms of λ involving soil moisture to investigate the cause of overestimation during the day and underestimation at night on the basis of the revised FRM. The results show that (1) the five algorithms significantly improve T_g prediction, especially in daytime, and (2) taking one of these five algorithms as an example, the simulated T_g values in the daytime are closer to the field measurements than those in the nighttime. The differences between modeled T_g and field measurements are mostly within the margin of error of ±2 K during 3 August to 4 September 1998.     

黄河流域冬、夏季水汽输送及收支特征

利用NCEP/NCAR再分析资料和我国实测雨量资料,对黄河流域1月和7月多年平均及旱、涝年整层积分的水汽通量、辐合(辐散)及各分区水汽收支进行了研究。结果表明,1月黄河流域无明显的水汽输送,而7月水汽沿西南、东南及西北3条路径输送,前两支气流在多年平均时主要影响黄河下游区。涝年时影响到黄河中、下游区,而上游区水汽流入较小;旱年,黄河中、上游区均无明显的水汽输送,只有下游的小范围地区受西南气流影响。各区净水汽通量分别与其地面降水的时空演变相对应,而经向净水汽通量是影响水汽收支变化及供给流域降水的主要水汽来源;涝年的水汽净收支与各边界水汽流入明显大于旱年。1月,西边界和北边界微弱的水汽输入远小于东边界和南边界的输出,各区均为水汽净辐散,不利于降水;7月,大量的水汽主要来自西边界和南边界,涝年各区均为水汽盈余,多年平均也以净辐合为主,而旱年则以水汽亏损为主。     

中国西天山季节性积雪热力特征分析

利用中国天山积雪雪崩站干、湿雪雪层内每隔5min一次的10层雪温数据,探讨了一次降雪过程后干、湿雪的雪层温度特征,对比分析了干、湿雪的雪面能量平衡方程中各分量的差异。结果表明:(1)整个冬半年积雪各层温度基本<0℃,雪温日变化振幅由雪面向下逐渐减小,积雪深层温度的波峰(谷)值稍滞后于积雪浅层温度极值1～2天。(2)湿雪冷中心的出现时间早于干雪,暖中心的出现时间晚于干雪,太阳辐射对湿雪的穿透深度大于干雪。(3)雪层温度振幅变化与能量吸收随雪深都呈指数衰减分布。积雪密度越大,吸收系数越小,穿透深度越大。(4)干雪雪面的感热通量和潜热通量几乎都为负值,积雪积累。湿雪雪面的潜热通量与感热通量方向相反,互相抵消,所以净辐射是导致湿雪消融的主要因素。     

不同平均时间对LOPEX10资料涡动相关湍流通量计算结果影响的探讨

通过处理涡动相关系统观测的近地层湍流脉动量可以获取地—气间感热和潜热通量,然而选择不同平均时间对通量计算的结果有较大影响。采用黄土高原陆面过程野外观测试验(LOPEX10)期间获得的涡动相关系统观测资料,分析了不同平均时间对湍流通量计算的影响,并采用雷诺平均和分解方法推导了平均时间引起的通量差值的数学表达式(Flux Compensation,FC)。结果表明:(1)FC公式可以说明采用不同平均时间数据之间的关系,也可以直接计算低频涡旋对湍流通量的贡献。FC公式计算的结果与直接计算的不同平均时间通量计算之差的相关系数在0.95以上,并可以确定计算湍流通量的最佳平均时间。(2)通过采用Ogive函数确定了计算LOPEX10期间通量的最佳平均时间长度为30min,印证了利用雷诺平均和分解方法计算湍流通量补偿的准确性。(3)通过进一步的数学变换,证明了平均时间对湍流通量计算的影响直接与湍流低频变化相关,FC公式可以用来确定涡动相关观测数据的最佳平均时间,并且在获得较高时间分辨率的湍流通量数据的同时,补偿因平均时间过短而遗漏的低频信息。     

中国西北干旱区戈壁下垫面夏季的热力输送

以敦煌戈壁站2004年6月和2008年8月的常规观测和超声观测为例,分析了西北干旱区戈壁下垫面夏季热力输送的一般过程及特征。首先评价了湍流通量的观测质量以及仪器观测的地表能量通量闭合问题,结果表明敦煌戈壁站的观测在白天总体较好。夏季地表能量通量的平均日变化显示,潜热通量整天都很小,可以忽略,白天到达地表的短波辐射以及地表向上的长波辐射非常强,地表净辐射主要转化为感热输送（敦煌戈壁站在中午时平均分别达380W·m-2以上和250W·m-2以上）;夜间土壤释放热量以平衡地表的辐射冷却,感热通量略低于0。白天时地表大气经常触发自由对流活动,影响动量通量的观测质量,并有效输送地表热力至上层大气中,有助于形成超厚大气边界层。分析了戈壁下垫面的动量粗糙度特征和热力粗糙度特征（敦煌戈壁站动量粗糙度约为0．6mm）,热力粗糙度基本小于动量粗糙度一个量级,这符合目前对干旱区戈壁下垫面热力输送特征的初步认识。