基于新ECO标准要求的吸尘器地刷设计及研究

现有市面上的地刷设计,可分为无滚刷、单滚刷、多滚刷。无滚刷主要用于附件,或卧式吸尘器。单滚刷由于其结构简单,成本低,在地板及地毯均能做到较好的清洁能力,是目前的主流设计。多滚刷中双滚刷居多,例如Shark的Duo-cleaning设计,Dyson的Double Fluffy^(TM )cleaner head设计。无论是单滚刷还是多滚刷,大部分只能满足向前推动时的大颗粒灰尘或堆叠灰尘吸入。后拉时大颗粒灰尘容易堆叠。为了提高地刷吸入口的真空度,地刷吸口后侧设有密封结构,密封结构一般是绒毛条或帆布条、橡胶条等柔性材料,这些材料与地面有1 mm左右的过盈以增加密封。但是这种设计存在弊端,在地刷回拉时,由于地刷吸口后侧密封结构的阻挡,大的颗粒灰尘或堆叠的灰尘无法进入吸口,产生垃圾堆叠。为了满足地刷在前推和后拉时具有同样的吸尘效果,我们对后置密封结构就行优化设计。该文对可实现上述功能的设计进行研究,并从成本,新的欧盟能耗法规要去,清洁能力,使用受命等多方面对比,剖析不同设计的优缺点。

地图四色印刷网点面积率的计算

本文用《实用标准色卡》光谱反射率测试数据，研究了四色版网点地图印刷Ｎｅｕｇｅｂａｕｒｅ方程的修正。用回归分析方法确定修正系数ｎ＿ｘ，ｎ＿ｙ，ｎ＿ｚ，根据黑油墨网点梯尺各级三刺激值与相应网点面积率函数关系，确定黑版量，以此计算四色版地图印刷网点面积率，计算值和实测值相符。

Quantitative Relationship Between Land Use and Phosphorus Discharge in Subtropical Hilly Regions of China

The increase of phosphorus concentration is a crucial factor causing the eutrophication of water body,while land use has an important impact on agricultural non-point sources (NPS) phosphorus discharge. Sevensites controlling the water in four sub-watersheds and the main exit of the Meicun Watershed of XuanchengCounty, Anhui Province, were investigated by dynamic monitoring of stream water and nutrient discharge,integrating interpretation of aerial image and GIS analysis to find out how the land use affects phosphorusloss with stream water in typical agriculture-forest watershed in subtropical China. These monitored sitesare different in structure of land use. Phosphorus concentration of the stream water was analyzed everyweek and at the next day of rainfall. The velocity of flow was measured by kinemometer to calculatethe runoff flux and phosphorus discharge. The results showed that the runoff flux and the discharges ofdissolved phosphorus (DP), particle-associated phosphorus (PAP) and total phosphorus (TP) had significantexponential relationships with the area percentages of forest, pond and paddy field. There existed a significantlinear relationship between the TP and PAP concentrations in stream water and the area percentages of forest,pond and paddy field, and the discharge of PAP was also significantly linearly correlated with the dischargeof suspended soil particles. There was a logarithmic linear relationship between DP and PAP discharges. Thestudy indicated that the adjustment of land use patterns and construction of ecologically sound landscapewould be an important measure to reduce the runoff discharge of phosphorus. The results would be veryuseful in building the best management practices (BMPs) of agricultural watershed in subtropics.

Urban Journalism： Street by Street

The website philadelphianeighborhoods.com provides news coverage about more than 30 underreported and underserved communities in Philadelphia. Affiliated with Temple University, the website and bimonthly printed editions focus on hyperlocal journalism, or journalism at the street-by-street level. The website has won numerous state, regional, and national awards for its coverage. The goals focus on many aspects of journalism, but this paper will address the successes and failures of this hyperlocal approach and the potential applicability for other organizations.

An Anti-aliasing Algorithm Suitable to Map Publishing Symbol

On the basis of analysis of various algorithms, an anti-aliasing algorithm called brush method was presented, which is suitable to map publishing symbol. After introducing the basic principle and implementation of brush method in detail, the result and efficiency were evaluated through experiments.

Nutrient Discharges from a Typical Watershed in the Hilly Area of Subtropical China

Agriculture is still the biggest contributor of non-point source (NPS) pollution to water bodies andrunoff discharges of nutrients and other chemicals are one of the most important pathways. This studywas conducted during 1998～1999 in a typical watershed with complex agriculture and forestry systems aswell as dotted farmer villages, in a transitional region between the mid- and northern subtropical zones ofChina. Continuous sampling of stream water was performed regularly at a weekly frequency, with additionalsampling after all major rainfall events. The discharges of N and P nutrients and suspended materials weremeasured and the total and area-averaged annual discharges of all components were calculated. The resultsshowed an uneven seasonal distribution of nutrient discharges with summer storms contributing most tothe total fluxes. This study demonstrated a high dependence of runoff volume on rainfall but the overallrunoff coefficients were dependent on land use type and watershed size. The area-averaged annual dischargesvaried greatly among the sub-watersheds with different sizes and land use structures. This is the first studyestimating the area-averaged annual discharges of N and P in the hilly areas of subtropical China, which were1.5 g m-2 a-1 and 0.1 g m-2 a-1, respectively, providing important reference values for the assessment ofregional agricultural non-point source pollution.

Scour effect on a sea-crossing bridge under combined action of service and extreme seismic loads

Foundation scour is an important cause for structural failure of sea-crossing bridges. Usually, the sea-crossing bridges operate under the harsh natural environment in which service wind, wave and vehicle loads are stronger and extreme loads such as earthquake, hurricane, and ship collision, are more frequent. As a result of the foundation scour,the dynamic behavior of bridge under different combined action of service and extreme loads may be further escalated.In particular, this work has investigated the scour effect on a sea-crossing bridge under service wind, wave and vehicle loads as well as extreme seismic loads. The dynamic coupled earthquake-wind-wave-vehicle-bridge(EWWVB) system is established by considering the interactions within the system, and the p-y curve method is used to calculate the loaddisplacement relation of the pile and soil under various levels of foundation scour. After that, a case study has been performed on a cable-stayed bridge with foundation scour. The results indicate that the dynamic characteristics of bridge structure will change after considering bridge scour, and the dynamic responses of bridge and vehicle will be affected to different degrees under service and seismic loads considering bridge scour.

没想到

以前,在我的印象里,妈妈是个胆子很大的人。我喜欢吃龙虾,但每次看到龙虾舞动双钳时,都躲得远远的。而她呢,却在那儿抓着龙虾,一个个仔细地刷,你说她胆子够大吧.可是,妈妈的胆子似乎也很小。假期里,我们去走玻璃栈道,妈妈一上去就两腿发软,紧紧抱住我,眼睛都不敢睁。我往下一看,哇,确实好深啊.下面的行人小得像蚂蚁一样。就这样,我走一步,妈妈就跟着挪一步,我俩像连体婴儿一样一点点地向前挪动。