Simulation investigations on the marble deterioration by sulphur dioxide

This paper deals with investigations on corrosion of marble SO2. We have simulated oxidation of SO2 by photochemical process in the atmosphere. The experiments indicate that formation of SO3 aerosols is related to the concentration of SO2, the UV light intensity, the time of irradiation and the humidity of the air. The corrosion feature of surfaces of the marble and the depth profiles of sulphur were obtained by SEM (Scanning electron microscope), EDXA (Energy-dispersive X-ray analyzer) and SIMS (Secondary ion mass spectrometer). The results of experiments show the corrosive extent of marble depends on its compositions and microareas of marble, which contain lower silicon content can be easily corroded by SO2.     

Conservation for the landscape ecological diversity in Wulingyuan scenic area of China

Wulingyuan is located at the mountainous area of the middle reach of the Yangtze River,it is one of the three nature heritages in China which ranks in the “List of Worls‘s Heritage”by UNESCO.It is characterized by quartz sandstone peaks landform with several landform components(pattern,corridor)and rich in landscape ecological diversity and biodiversity.The main patterns(ecosystem)include mid-height mountain peaks,rift-avlley and streams among peaks,peaks and gullies on slopes,square mountain-platforms and peaks among blind valleys and so on.The corridor system consists of natural corridors and artificial corridors among which the stream corridors account for a major part.The fracturing of habitat is unfavorable for the biodiversity conservation,but meanwhile the habitat diversity leads to an increase in biodiversity.Therefore,it is still rich in landscape ecological diversity in Wulingyuan.The biodiversity at the level of landscape component(ecosystem) and the function of the Wulingyuan complex ecosystem,and the measures for the biodiversity conservation in Wulingyuan ecotourism area are discussed in this paper.     

粉煤灰混凝剂的性能研究

粉煤灰混凝剂的性能研究于衍真李国忠傅兴华戴宝刚（山东建筑材料工业学院，济南２５００２２）关键词混凝；粉煤灰；工业废水．当前水污染问题已遍及世界各地，特别是城市和工业区附近的水体污染尤为严重．造成这种现象的原因除城市人口密度大、生活废水多以外，主要是来...     

印染废水治理研究现状

本文综述了印染废水水质及特点 ,染料的分类和发色机理。评述了目前印染废水治理研究中的各种物理、化学和生物方法应用现状、优点和存在的问题 ,及其对脱色效果的影响机理。     

积极推行清洁生产技术

叙述了清洁生产技术的产生、发展及推广应用的必然趋势、侧重末端治理是不能从根本上解决工业污染问题．积极推行清洁生产技术、控制污染物的产生与排放已成为当今世界环保的潮流．     

气相色谱法快速测定蔬菜中灭杀毙

用蒸馏水一次提取新鲜蔬菜样品，以SE－30和QF－1为固定液，Chromosorb W AW DMCS为固定相，2m填充柱分离，氢火焰检测器检测，进样10uL测定灭杀毙含量，以保留时间定性，外标法定量，分析时间小于150s，方法回收率95．4％，相对标准差3．6％，可用作上市蔬菜灭杀毙农药残留量的快速测定。     

氟氯烃检测中的富集采样研究

本文用自制的吸附采样管和解吸装置完成了大气中痕量氟氯烃的采样测定，其吸附效率达８５％以上，解吸效率达８７％，富集倍数达１１４４倍。研究了温度对吸附和解吸效率的影响。     

布托别山金成矿带构造特征

布托别山金矿带为新疆多拉纳萨依金矿田的西矿带.其构造作用主要经历三期:早期,区域右旋剪切形成一类规模较大的同斜、紧闭、倾竖型褶皱;中期,左旋剪切形成一套由“B”型转换成“A·B”过渡型系列柔性褶皱;晚期,在左旋剪切条件下,产生滑劈理群和微观变形,并叠加于前两期构造之上.构成一条特别醒目的NNW向脆-韧性剪切带。金矿化体严格受这一剪切带控制.     

Changes in visibility with PM2.5 composition and relative humidity at a background site in the Pearl River Delta region

In fall–winter, 2007–2013, visibility and light scattering coefficients(b sp) were measured along with PM_(2.5)mass concentrations and chemical compositions at a background site in the Pearl River Delta(PRD) region. The daily average visibility increased significantly(p 0.01) at a rate of 1.1 km/year, yet its median stabilized at ~13 km. No haze days occurred when the 24-hr mean PM_(2.5)mass concentration was below 75 μg/m~3. By multiple linear regression on the chemical budget of particle scattering coefficient(b sp), we obtained site-specific mass scattering efficiency(MSE) values of 6.5 ± 0.2, 2.6 ± 0.3, 2.4 ± 0.7 and 7.3 ± 1.2 m2/g,respectively, for organic matter(OM), ammonium sulfate(AS), ammonium nitrate(AN) and sea salt(SS). The reconstructed light extinction coefficient(b ext) based on the Interagency Monitoring of Protected Visual Environments(IMPROVE) algorithm with our site-specific MSE revealed that OM, AS, AN, SS and light-absorbing carbon(LAC) on average contributed 45.9% ± 1.6%,25.6% ± 1.2%, 12.0% ± 0.7%, 11.2% ± 0.9% and 5.4% ± 0.3% to light extinction, respectively.Averaged b ext displayed a significant reduction rate of 14.1/Mm·year(p 0.05); this rate would be 82% higher if it were not counteracted by increasing relative humidity(RH) and hygroscopic growth factor(f(RH)) at rates of 2.5% and 0.16/year-1(p 0.01), respectively, during the fall–winter, 2007–2013. This growth of RH and f(RH) partly offsets the positive effects of lowered AS in improving visibility, and aggravated the negative effects of increasing AN to impair visibility.     

Effects of digital countdown timer on intersection safety and efficiency: A systematic review

Objective: To investigate the available evidence referring to the effectiveness of digital countdown timers (DCTs) in improving the safety and operational efficiency of signalized intersection.

Methods: A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement guidelines. Relevant literature was searched from electronic databases using key terms. Based on study selection and methodological quality assessment, 14 studies were included in the review. Findings of the studies were synthesized in a narrative analysis.

Results: Three types of DCT had different effects on intersection safety and operational efficiency. Green signal countdown timers (GSCTs) reduced red light violations, type I dilemma zone distributions, and rear-end collision likelihood but increased crossing after yellow onset and had mixed impacts on type II dilemma zone distributions and intersection capacity. In contrast, red signal countdown timers (RSCTs) increased intersection capacity, although their effectiveness in reducing red light violations dissipated over time. Likewise, continuous countdown timers (CCTs) significantly enhanced intersection capacity but had mixed influences on red light violations and crossing after yellow onset.

Conclusions: Due to the limited and inconsistent evidence regarding DCTs' effects on intersection safety and efficiency, it is not sufficient to recommend any type of DCT to be installed at signalized intersections to improve safety and operational efficiency. Nevertheless, it is apparent that both RSCTs and CCTs enhance intersection capacity, though their impacts on intersection safety are unclear. Future studies need to further verify those anticipated safe and operational benefits of DCTs with enriched field observation data.