In situ preparation of g-C3N4/Bi4O5I2 complex and its elevated photoactivity in Methyl Orange degradation under visible light

A graphite carbon nitride(g-C₃N₄) modified Bi₄O₅I₂ composite was successfully prepared insitu via the thermal treatment of a g-C₃N₄/Bi OI precursor at 400°C for 3 hr.The as-prepared g-C₃N₄/Bi₄O₅I₂ showed high photocatalytic performance in Methyl Orange(MO) degradation under visible light.The best sample presented a degradation rate of 0.164 min^-1,which is...     

用光伏污泥焚烧灰渣制备轻集料

针对工业污泥焚烧灰渣处置难的现状,以光伏污泥焚烧灰渣为主要原料制备轻集料。确定轻集料烧制的最佳条件为,黏土投加量为70%,MgO投加量为5%,污泥焚烧灰渣投加量为25%,预热温度为450 ℃,预热时间为15 min,焙烧温度为1 050 ℃,焙烧时间分别为10 min,所制备出的轻集料的抗压强度为9.52 MPa,堆积密度为867 kg·m-3,烧失量为0.12%,1 h吸水率为1.94%。所制得的轻集料强度高,吸水率小,符合《轻集料及其实验方法.第二部分：轻集料实验方法》（GB/T 17431.2-2010）的要求,可为光伏污泥焚烧灰渣资源化提供理论指导。     

Ti(IV)与铜离子共掺杂的羟基磷灰石薄膜弱紫外光杀菌研究

采用共沉淀水热合成和离子交换的方法,制备了钛与铜离子共掺杂的羟基磷灰石(Ca10(PO4)6(OH)2:HAP)(HAPTiCu),以大肠杆菌为目标物,研究了不同材料负载的多孔镍网薄膜在弱紫外光下的杀菌活性.结果表明,HAPTiCu在弱紫外光下具有高效杀菌效率,并远远高于HAPTi和P25 TiO2薄膜.这主要是铜离子的抗菌与光催化分解细菌的协同作用的结果.电子自旋共振(ESR)研究表明杀菌反应的主要活性物种是O2-.HAPTiCu薄膜释放的铜离子在光催化杀菌反应过程中,被光催化还原沉积在表面,导致了较低的铜离子溶出,从而保证了材料的稳定性.     

基于细胞尺度的光照对四尾栅藻生长的影响

以四尾栅藻（Scenedesmus quadricauda）为研究对象,采用平行平板流动腔装置,基于计算机视觉的藻细胞动态生长观察方法,从单细胞尺度研究不同光照强度对四尾栅藻藻细胞生长的影响.成功建立了四尾栅藻个体生长曲线模型,模型拟合效果良好.结果表明：在8000lux光照强度下,藻细胞的体积最大比生长速率最大,即四尾栅藻生长的最适光照强度为8000lux;适宜的光照条件可以增加藻细胞分裂时的大小,小于8000lux时,藻细胞分裂体积随着光照强度的增加而增加,大于8000lux时,藻细胞分裂时体积反而越来越小;较高的光照强度还有利于藻细胞适应新的环境,减少藻细胞复苏时间.     

Do Nutrients Limit Algal Periphyton in Small Blackwater Coastal Plain Streams?1

Abstract: We examine the potential for nutrient limitation of algal periphyton biomass in blackwater streams draining the Georgia coastal plain. Previous studies have investigated nutrient limitation of planktonic algae in large blackwater rivers, but virtually no scientific information exists regarding how algal periphyton respond to nutrients under different light conditions in smaller, low‐flow streams. We used a modification of the Matlock periphytometer (nutrient‐diffusing substrata) to determine if algal growth was nutrient limited and/or light limited at nine sites spanning a range of human impacts from relatively undisturbed forested basins to highly disturbed agricultural sites. We employed four treatments in both shaded and sunny conditions at each site: (1) control, (2) N (NO₃‐N), (3) P (PO₄‐P), and (4) N + P (NO₃‐N + PO₄‐P). Chlorophyll a response was measured on 10 replicate substrates per treatment, after 15 days of in situ exposure. Chlorophyll a values did not approach what have been defined as nuisance levels (i.e., 100‐200 mg/m²), even in response to nutrient enrichment in sunny conditions. For Georgia coastal plain streams, algal periphyton growth appears to be primarily light limited and can be secondarily nutrient limited (most commonly by P or N + P combined) in light gaps and/or open areas receiving sunlight.     

滇池水体除藻材料的除藻作用试验研究

利用昆明地区的粘土矿制作新型轻质除藻材料,试验研究该材料对滇池湖水中藻类的除藻及净化作用.实验室小试(20 L)结果表明,该除藻材料放入滇池水样实验70 d后,水质明显好转,藻类去除率可达95.8%,CODMn、TN及TP的去除率分别为34.4%、81.5%、28.2%.在滇池湖边300 m2水面围栏扩大试验结果显示,除藻材料放入试验区水体10 d后,水体中藻类含量明显减少,水体透光率从55%增加到80%,水质状况也有很大改善.研究结果表明,该材料具有良好的湖泊水体除藻及净化作用,有必要对其开展进一步的深入研究.     

Quantifying the erosion of natural darkness in the global protected area system

The nighttime light environment of much of the earth has been transformed by the introduction of electric lighting. This impact continues to spread with growth in the human population and extent of urbanization. This has profound consequences for organismal physiology and behavior and affects abundances and distributions of species, community structure, and likely ecosystem functions and processes. Protected areas play key roles in buffering biodiversity from a wide range of anthropogenic pressures. We used a calibration of a global satellite data set of nighttime lights to determine how well they are fulfilling this role with regard to artificial nighttime lighting. Globally, areas that are protected tend to be darker at night than those that are not, and, with the exception of Europe, recent regional declines in the proportion of the area that is protected and remains dark have been small. However, much of these effects result from the major contribution to overall protected area coverage by the small proportion of individual protected areas that are very large. Thus, in Europe and North America high proportions of individual protected areas (>17%) have exhibited high levels of nighttime lighting in all recent years, and in several regions (Europe, Asia, South and Central America) high proportions of protected areas (32–42%) have had recent significant increases in nighttime lighting. Limiting and reversing the erosion of nighttime darkness in protected areas will require routine consideration of nighttime conditions when designating and establishing new protected areas; establishment of appropriate buffer zones around protected areas where lighting is prohibited; and landscape level reductions in artificial nighttime lighting, which is being called for in general to reduce energy use and economic costs.     

稻田CO2通量对光强和温度变化的响应特征

采用涡度相关法对我国亚热带稻田生态系统CO2通量进行了连续监测,并对CO2通量随光强和温度变化的响应特征进行了分析.结果表明,白天稻田生态系统CO2通量对光强的响应过程可以用直角双曲线方程进行描述.随光强的增加,CO2通量(绝对值)呈增加趋势,当光强大于1 000μmol/(m2·s)时,CO2通量变化比较稳定.早、晚稻间以及不同生育期水稻的光量子利用效率和最大光合速率存在一定的差异.晚稻的光量子利用效率(0.046 5～0.099 9 μmol/μmol)高于早稻(0.0176～0.0541μmol/μmol),并以水稻生长旺盛期的光量子利用效率和最大光合速率最高.夜间稻田生态系统呼吸速率随土壤温度的升高呈指数增加,5 cm土层温度可以作为反映稻田呼吸速率变化的温度指标.早稻生长季生态系统呼吸对温度的变化明显较晚稻生长季更为敏感.     

Corporate occupational exposure limits: An example of a strategy

Occupational exposure limits (OELs) developed by authorities play a key role in the implementation of programs to protect workers against hazardous chemicals. Unfortunately, many hazardous substances do not have OELs or the OEL could be outdated. To assure the health of the workers, it is therefore useful for companies to develop corporate OELs. An inhouse strategy will be presented hereafter. Expertise in toxicology, industrial hygiene, and occupational health should be available within the company and clear selection criteria for substances are needed. A corporate OEL is only developed for hazardous substances (e.g., carcinogenic or reprotoxic) with a high potential for worker exposure when an appropriate national OEL or threshold limit value is not available. The methodology to calculate corporate OELs is based on the existing methods for national or community OELs and also on the guidance from the European Union's (EU) regulation on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH). For carcinogenic substances with a nonthreshold mode of action, there is always a residual chance that a cancer develops even when the exposure of workers is low. To establish an OEL for these substances, the “German traffic light model” is recommended. It is pragmatic, defines an unacceptable, tolerable, and acceptable risk level when workers are exposed to these substances, and determines risk management for exposure reduction. Overall, the professional practice to develop OELs is a good example of corporate leadership to proactively protect the health of workers.