基于三维福利的城市生态福利强度及驱动模式——以长三角地区为例

基于2000—2017年长三角城市生态消耗和福利水平,分析生态福利强度时空演化过程及驱动模式。研究发现：长三角地区城市生态福利强度不断降低,多以低强度类型为主,城市生态系统服务的生态效率得以提高;空间演化上表现为外围地市的生态福利强度低于核心地市,较低和低强度类型范围呈现由四周向中心地区蔓延态势,中高强度类型主要分布在资源型、工业密集型地市;驱动因素中资源消耗效应、技术效应及福利效应对城市生态福利强度表现为显著的正向驱动效应,效率效应和经济效应的增强导致城市生态福利强度的降低,环境消耗效应和规模效应驱动作用不显著。据此,城市福利生态强度的驱动模式可划分为单因素支配型、双因素主导型、三因素协同型及四因素均衡型。     

Trends in Rainfall Exceedances in the Observed Record in Selected Areas of the United States1

Bonnin, Geoffrey M., Kazungu Maitaria, and Michael Yekta, 2011. Trends in Rainfall Exceedances in the Observed Record in Selected Areas of the United States. Journal of the American Water Resources Association (JAWRA) 47(6): 1173–1182. DOI: 10.1111/j.1752‐1688.2011.00603.x Abstract: Semantic differences have led to a gap in the understanding of the impacts of climate change on precipitation frequency estimates. There is popular perception that heavy rainfalls have become more frequent, and that this trend will increase with global warming. Most of the literature examines this question from the point of view of climatology using definitions of “heavy,”“very heavy,” or “extreme” rainfall, which are different from those commonly used by civil engineers. This article identifies the differences in meaning used by the climate and civil engineering communities and examines trends in the observed record in the frequency of exceedances (not trends in magnitudes). Using concepts recognized as the basis for design of the Nation’s civil infrastructure, we look at trends in the number of exceedances of thresholds for a variety of precipitation frequencies and event durations used by civil engineers. We found that the estimated trends in exceedances at one‐day and multiday durations were statistically significant and increasing for the Ohio River Basin and surrounding states but the reverse was true for the Semiarid Southwest (i.e., not significant and decreasing trends). In addition, we found the magnitude of the trends was small for all but the more frequent events and also small with respect to the uncertainty associated with the precipitation frequency estimates themselves.     

压力容器表面裂纹断裂参数的有限元计算与分析

借助ANSYS软件建立了适合压力容器表面裂纹断裂分析的有限元模型,能方便地计算出应力强度因子和J积分,与理论近似表达式的计算值对比,该方法具有较高的精度,能满足工程应用的要求.在验证模型合理的基础上,构造表征表面裂纹形状和尺寸的无量纲因子,通过分析其对J积分弹塑性分量的影响,指出断裂分析中除应力水平外,还应当将裂纹形状...     

Significant emission reductions of carbonaceous aerosols from residential coal burning by a novel stove

Carbonaceous aerosols (CA) are crucial components in the atmospheric PM_2.5 and derived from diverse sources. One of the major sources for CA is from the incomplete combustion of bituminous coal that has been prevailingly used by household stoves in rural areas for heating during winter. To efficiently eliminate the CA emission, a new household stove (NHS) was developed based on a novel combustion technology and CA emissions from the NHS and a traditional household stove (THS) were comparably investigated under the actual stove operation conditions in a farmer's house. Compared with the THS, the emission factors of organic carbon (OC), elemental carbon (EC), and water-soluble organic carbon (WSOC) from the NHS were reduced by 96%±1%, 98%±1%, and 91%±1% under the flaming process and 95%±1%, 96%±2%, and 83%±4% under the smoldering process, respectively. Additionally, the mass absorption efficiency of WSOC from the NHS reduced by 3 folds and the radiative forcing by WSOC relative to EC shrank remarkably by a factor of 3-8. Based on the reduction of emissions and light absorption of WSOC, the promotion of the NHS offers a possible solution to achieve the clean combustion of residential solid fuel.     

辽河下游CDOM吸收与荧光特性的季节变化研究

有色溶解有机物(CDOM)是一类广泛分布于水体中的溶解有机物(DOM),是水环境中最大的溶解有机碳贮库.辽河是中国七大河流之一,年径流量为14.8亿m3,因此对于辽河CDOM的研究对辽河有机碳通量的估算具有重要意义.基于吸收光谱和荧光光谱分析了不同季节辽河下游河流中CDOM的光学特性.通过分析CDOM的吸收光谱及斜率(S)得到春季水样CDOM在355 nm的吸收系数[aCDOM(355)]低于秋季和冬季;秋季CDOM的分子量要小于冬季和春季,而春季CDOM的分子量大于秋、冬季.通过对比分析3期荧光强度及各荧光峰(类腐殖酸荧光峰,峰A、峰C;类蛋白质荧光峰,峰B、峰T),发现辽河下游水体CDOM的荧光特性表现明显的季节性,而且都表现出较强的类蛋白质荧光峰(峰B和峰T).春季的两个类腐殖质荧光之间以及秋、冬季两个类蛋白质荧光之间均存在很强的相关性(R2>0.9),说明来源或性质相同.春季CDOM的两个类蛋白质荧光峰的相关性较差(R2=0.21),反映了其组分的复杂性和来源的多样性;春季水体显现出较强的类腐殖酸荧光峰,说明外源输入是春季水体CDOM中类腐殖酸成分的主要来源.另外,本研究将aCDOM(355)和Fn(355)进行分析发现冬季两者相关性最好(R2=0.75),秋季次之(R2=0.48),冬季结果较不理想(R2=0.01).通过荧光峰值与CDOM浓度之间的相关分析可以得到荧光峰B是秋、冬季CDOM荧光的主要控制发光基团(R=0.66;R=0.89),而春季CDOM的类腐殖酸荧光(峰A和峰C)表现比较突出(R=0.74;R=0.82).     

放牧阉牦牛提前出栏甲烷排放强度减排潜力探讨

以阉牦牛提前出栏项目活动为例,按照2006年IPCC国家温室气体清单优良做法指南的计量方法,在同等牧草利用量的前提下,分别对4岁和7岁阉牦牛一生CH4排放总量和单位体重CH4排放量(即排放强度)进行了初步比较分析.发现在同等牧草利用量的基础上,由于饲养一头7岁阉牦牛一生所消耗的牧草量相当于可饲养2.1头4岁的阉牦牛所消耗的牧草量,所以从CH4排放总量而言,前者一生排放CH4总量比后者少86.3 kg.然而,由于后者总体重比前者重192 kg,所以,后者的单位体重CH4排放强度(以CH4/体重计)只有0.973 kg·kg-1,而前者为1.374 kg·kg-1.根据排放强度的概念,在同等牧草消耗量的基础上,如果将一头7岁阉牦牛替代成饲养2.1头4岁的阉牦牛,可以多生产192 kg的活体重,在同样生产192 kg活重的基础上,利用替代法估算后者饲养方式比前者饲养方式可以实现77 kg CH4减排量,即相当于总减排1.6 t CO2当量.因此,基于排放强度减排而不是总量减排的概念,提前出栏有较大的CH4减排潜力.     

基于改进型萤火虫群优化算法泄漏源源强及位置反算研究*

针对标准萤火虫群优化算法（GSO）在危化品泄漏源源强及位置反算中存在精度不高,容易陷入局部最优等局限,提出混合萤火虫-Nelder Mead单纯形算法（GSO-NM）,并与基于步长的改进萤火虫群优化算法（MGSO）以及单纯形搜索混合协同进化萤火虫群优化算法（HCGSOSSM）进行比较分析,将3种改进型萤火虫群优化算法应用于泄漏源源强及位置反算中进行比较分析。研究结果表明:GSO-NM算法可以有效提高定位精度和稳定性,能较为精确地反算出泄漏源源强及位置,为泄漏源源强及位置反算研究提供1种新思路。     

棉花阴燃和明火燃烧特性的对比研究

利用锥形量热仪,选取不同辐射强度,分别在使用和不使用点火器条件下,对棉花进行了热辐射引燃实验,发现在热辐射强度大于6kW/m2的情况下,使用点火器时棉花发生明火燃烧,不使用点火器时棉花发生阴燃燃烧。实验分别测得了在两种燃烧形式下的引燃时间、热释放速率、质量损失速率一氧化碳生成率,结果表明:无论是发生阴燃还是明火燃烧,引燃时间均随着辐射强度的增加而减小,且引燃时间平方根的倒数与辐射强度成线性关系;热释放速率、质量损失速率的峰值和平均值均随辐射强度的增加而增加,但在同一辐射强度下,明火燃烧的峰值和均值均比阴燃燃烧时的大;明火燃烧的一氧化碳平均生成率随着辐射强度的增加而减小,阴燃燃烧的一氧化碳平均生成率随着辐射强度的增加而增加。     

Job Redesign Needs for Aged Workers

The aim of this paper is to explore and present a proposal for redesigning elements of the workplace for agech workers. The method of research was to observe, record, and measure the actions of sitting workers performing assembly operations on electrical products in the Kani Plant Nagoya Works of Mitsubishi Electric Co. (Japan). The evaluation index used in the experiment was obtained by measuring time motion elements, cycle time per product, and motion velocity waves of elderly workers. Those motion characteristics were then compared to the motion characteristics of young workers. The results led to job redesign elements being identified to reduce handling factors of high difficulty for aged workers and to the necessity to consider a coefficient of correction in Method Time Measurement (MTM) according to differences in the manufactured object’s weight.     

中国大陆水资源强度的收敛特征检验:基于省际面板数据的实证

文章从水资源与居民生活、生产及生态环境等要素构成的复合系统视角,借鉴能源强度概念内涵界定了水资源强度、水资源相对强度概念及其内涵,并提出相应表征方法,在此基础上依据有关用水部门的面板数据对2003—2013年中国大陆地区的省际水资源强度收敛特征进行了实证检验。结果表明:1)省际居民生活用水及农业用水强度差异变化相对平稳,σ-收敛趋势不明显;工业用水强度经历了"发散—平稳—收敛"的演变趋势;生态用水强度的σ-收敛趋势波动较大,且整体收敛速度较快,省际差异迅速缩小;2)大陆80%以上的省区4个用水部门的水资源相对强度受到的正面影响是持续的,整体未受短期冲击效应影响,故不具备全局性的随机收敛特征;3)4用水部门水资源强度具备绝对β-收敛特征,收敛速度分别为3.17%(居民生活用水)、4.21%(农业用水)、1.82%(工业用水)和12.41%(生态用水);4)东部省区生态用水强度呈俱乐部收敛趋势,西部省区居民生活用水和生态用水具备俱乐部收敛特征,中部省区的4用水部门均呈俱乐部收敛趋势;5)4用水部门均存在条件β-收敛特征,其中:显著驱动居民生活用水、工业用水及生态用水强度收敛的因素分别是第三产业比重、工业废水达标率和年降水量,而显著制约三者收敛的因素则分别为进出口总额、人均国民生产总值及工业废水达标率。