Contribution of In‐Channel Processes to Sediment Yield of an Urbanizing Watershed1

Abstract: A study was conducted between September 2003 and September 2006 to obtain baseline sediment inventories and monitor sediment transport and storage along a 3.7 km length of the channel of Valley Creek within Valley Forge National Historical Park, Pennsylvania. Valley Creek is a tributary of the Schuylkill River and drains an urbanizing 60.6 km² watershed that currently has 18% impervious land cover. Numerous field methods were employed to measure the suspended sediment yield, longitudinal profile, cross‐sections, banklines, and particle size distribution of the streambed. Suspended sediment yield for the watershed was measured at a USGS gage located just upstream of the park boundary between July 2004 and July 2005, the period corresponding to field surveys of bank erosion and channel change. The estimated suspended sediment yield of 95.7 t/km²/year is representative of a year with unusually high discharge, including a storm event that produced a peak of 78 m³/s, the second highest discharge on record for the USGS gage. Based on the median annual streamflow for the 24 years of record at the USGS gage from 1983 to 2006, the median annual sediment yield is estimated to be closer to 34 t/km²/year, considerably lower than median and mean values for other sites within the region. The mass of silt, clay, and fine sand derived from bank erosion along the 3.7 km study reach during the field survey period accounts for an estimated 2,340 t, equivalent to about 43% of the suspended sediment load. The mass of fine sediment stored in the bed along the study reach was estimated at 1,500 t, with about 330 t of net erosion during the study period. Although bank erosion appears to be a potentially dominant source of sediment by comparison with annual suspended sediment load, bed sediment storage and potential for remobilization is of the same order of magnitude as the mass of sediment derived from bank erosion.     

线路交换开关级联失效的评估

本文主要针对信号线路交换网络设计中的失效问题展开讨论，对输出信号在传输网络中失效性进行了评估，根据失效评估在设备可靠性设计方面做了相应的考虑。     

初中教育师资力量与教育成效耦合协调研究--以大连市为例

基于2015年大连市初中学校教育统计数据,利用熵值法、耦合协调度模型和空间插值分析法,从市域内校际间对大连市初中师资力量与教育成效耦合协调的空间特征进行了研究。结果表明:①师资力量高低分离、抱团分布,教育成效呈现核心高、边缘低的格局。②师资力量与教育成效的耦合度总体水平较高,以高水平耦合为主,空间上基本覆盖整个大连市。③协调度上,勉强协调与初级协调为主,空间呈现明显的中心—外围分布趋势,其中勉强协调占大部分。④学校类型具体划分为6种协调类型,呈核心—外围的圈层分布模式,其中核心城区为师资高成效高的中级协调。     

Welfare effects of rural-urban land conversion on different aged land-lost farmers: exemplified in Wuhan city

Rural-urban land conversion is a universal phenomenon in the rapid process of economic development and urban growth. The welfare of farmers who lost their farmland attracted a widespread concern within the society and academia. However, further research about differentiated policies according to the characteristics of different farmer groups is still need to be conducted. This article divides the land-lost farmers into three age groups: younger than 45, 45–65, and more than 65. It proposes a welfare index system including eight functional areas based on different age groups of affected farmers, taking four districts of Wuhan City as case study area. Fuzzy mathematics method is used to derive the aggregated welfare effect index. Our analysis show that the overall welfare levels of land-lost farmers of all age groups declined, but with a varying degree, with the level of welfare in those farmers who are 45–65 years old, younger than 45 years old, and older than 65 years old decreased by 18.7%, 16.6%, and 12.7%, respectively. The direction and degree of effects on the functional activity index varies among different groups. Economic conditions, living environment, health, and social participation of all age groups decrease while social security and housing conditions increase. On the other hand, development opportunities, social communication, and leisure have different changing directions in different age stages. These results call for differentiated and tailor-made compensation policies for land-lost farmers, towards improving the welfare levels of all farmers and reduce the disparity among them.     

基于平均负荷的降雨径流污染负荷模型研究

在九寨沟旅游景区,对公路和栈道进行人工降雨径流污染负荷的过程研究。浓度过程曲线表明,初始高浓度与平台期浓度之间相差3~5倍,而负荷过程曲线表明,各时段负荷曲线无明显峰值存在。这意味着污染物平均浓度的获取,需要降雨径流的水量水质同步监测数据的较大样本,才能消除随机性影响。而各时段负荷数据向平均负荷期望收敛的速度,将比平均浓度期望更快。利用这一规律,以平均负荷值代替降雨事件的污染物平均浓度(EMC),构建了基于平均负荷值的年地表径流负荷模型。本模型只需要有限场水量水质同步监测数据,就可获得特定地区面源污染物的平均负荷值。在消除随机不确定性同时,提高了可操作性。采用研制的模型,计算出九寨沟各子区公路面源的TP排放负荷,在0.87~2.07 kg/a之间,栈道面源TP排放负荷,在0.27~1.22 kg/a之间。     

水罗兰对不同密度铜绿微囊藻抑制作用的研究

通过水罗兰与铜绿微囊藻共培养12 d,研究了水罗兰对低密度、高密度的铜绿微囊藻的抑制作用.结果表明,铜绿微囊藻初始光密度(OD680)分别为0.026、0.257时,水罗兰可显著抑制铜绿微囊藻的生长,使其OD680降低.水质检测结果显示,培养过程中共培养液营养盐浓度一直处于较高水平,铜绿微囊藻OD680降低及生长停滞并非因营养不足所引起.通过实验证实了水罗兰可作为铜绿微囊藻水华控制的生态修复物种.     

Variability in Three Finnish Integrated Acidification Models

Integrated assessment models have been used to support ofnegotiations for further emission reductions of acidifyingcompounds in Europe. More attention is being paid to theuncertainties in integrated models. Data from three Finnishintegrated acidification models were compiled to estimate thevariation and relative importance of different modules. Themodels included site-specific and regional dynamic simulationsand steady-state critical load calculations for forest soilsand lakes. The main emphasis was on the variability ofemissions and the uncertainties in ecosystem effects. Althoughmaximum technically feasible emission reduction measures cantheoretically result in very low deposition, the variabilitybetween realistic scenarios is rather restricted. Thevariability of deposition loading is largely determined byreductions in nearby emission sources. The dynamicsimulations, which are often based on detailed input data,seem to retain larger variability than steady-state criticalload approaches. This study suggests that the uncertainties ineffects seem to be larger generally than other modules ofintegrated acidification models. The results indicate the needfor further work on uncertainty analysis for integrated modelsand the availability of useful model systems for furtherconfirmation of ecosystem effects.     

Air ventilation impacts of the “wall effect” resulting from the alignment of high-rise buildings

The objective of this study is to investigate the air ventilation impacts of the so called “wall effect” caused by the alignment of high-rise buildings in complex building clusters. The research method employs the numerical algorithm of computational fluid dynamics (CFD – FLUENT) to simulate the steady-state wind field in a typical Hong Kong urban setting and investigate pollutant dispersion inside the street canyon utilizing a pollutant transport model. The model settings of validation study were accomplished by comparing the simulation wind field around a single building block to wind tunnel data. The results revealed that our model simulation is fairly close to the wind tunnel measurements. In this paper, a typical dense building distribution in Hong Kong with 2 incident wind directions (0° and 22.5°) is studied. Two performance indicators are used to quantify the air ventilation impacts, namely the velocity ratio (VR) and the retention time (T_r) of pollutants at the street level. The results indicated that the velocity ratio at 2 m above ground was reduced 40% and retention time of pollutants increased 80% inside the street canyon when high-rise buildings with 4 times height of the street canyon were aligned as a “wall” upstream. While this reduction of air ventilation was anticipated, the magnitude is significant and this result clearly has important implications for building and urban planning.     

紫外光促进盐酸聚苯胺催化H_2O_2氧化处理罗丹明B废水

以苯胺和过硫酸铵为主要原料合成了盐酸聚苯胺（HClPANI）催化剂,并通过FTIR、XRD、SEM和EDS对催化剂进行了表征。研究了在紫外光照下、HClPANI催化H2O2氧化处理罗丹明B染料废水工艺参数,探讨了各种因素对废水脱色效果的影响,并对催化氧化机理进行了初步探讨。结果表明,催化剂HClPANI对催化H2O2氧化处理罗丹明B具有较好的催化活性、稳定性和重复使用性能。UV-H2O2-HClPANI体系产生了明显的协同效应,在pH=3、200 mg/L的罗丹明B废水中,30%H2O2用量为1.2 mL/L、HClPANI用量1 g/L、反应温度25℃、紫外灯功率500 W、光照70 min,罗丹明B脱色率达到了98.2%。     

瓦斯爆炸中的火球伤害效应

针对瓦斯爆炸事故3种危害中的高温热辐射伤害进行研究,结合火灾爆炸事故中的火球热辐射的传播公式,得出适合井下瓦斯爆炸事故的火球传播规律公式.依据该公式划分了瓦斯爆炸事故中火球热辐射的死亡、重伤、轻伤的半径公式,为瓦斯爆炸事故安全评价提供了理论基础.