冶金工厂呼吸性粉尘危害及评价方法探讨

随着冶金企业规模的扩大和接尘人员的增加，粉尘危害，尤其是呼吸性粉尘对作业人员的危害日益突出。治理呼吸性粉尘必须对呼吸性粉尘进行科学、合理的评价。针对冶金工厂实际情况，经过现场实验调查、数据统计分析，探讨了冶金工厂作业场所呼吸性粉尘的危害程度。建立了冶金工厂采用划分粉尘单元确定粉尘中游离二氧化硅含量的方法和采用餐尘危害程度分级评价呼吸性粉尘危害程度的方法。同时对国家呼吸性矽尘卫生标准在冶金工厂的实旋提出了扩档建乩     

A study on marine industry and environment of China: regarding Japan’s experience

China is facing the challenge of many marine environment problems with rapid economic growth. Japan had experienced similar marine environmental pressure during its industrialization and had been facing the problem through successful environment policy step by step. The paper reviews the lessons and experiences of Japan’s marine environment protection and analyzes the marine environment pollution in China and its causes, taking Shandong province as a case, such as GDP-oriented economic growth, heavy coal assumption, etc. The paper also analyzes the marine industry with focuses on coastal tourism and its relationship with marine environment. Suggestions on polices are provided based on the analysis on China’ marine environment and Japan’s experience.     

深圳市浅层地下水环境状况调查及保护对策

依托深圳市浅层地下水质量监测调查成果,开展全市浅层地下水质量评估工作。结果显示:多数监测点位水质属《地下水质量标准》(GB/T 14848—1993)的Ⅳ类和Ⅴ类标准,综合质量评价水质为较差级别。深圳市浅层地下水环境质量不容乐观,需要加强地下水环境的保护。在此基础上分析深圳市浅层地下水环境质量较差的原因,并提出地下水环境保护对策及建议。     

Rheology,Morphology, Crystallization Behaviors,Mechanical and Thermal Properties of Poly(lactic acid)/Polypropylene/Maleic Anhydride-Grafted Polypropylene Blends

The rheologies, morphologies, crystallization behaviors, mechanical and thermal properties of poly(lactic acid) (PLA)/polypropylene (PP) blends and PLA/PP/maleic anhydride-grafted PP (MAPP) blends were investigated. The results showed that the complex viscosities of PLA/PP blends were between those of neat PLA and neat PP, and MAPP had a thinning effect on those of the blends. PLA/PP blends exhibited the distinct phase separation morphologies due to the limited partial miscibility of the blend components. MAPP slightly improved the miscibility between PLA and PP. Both the cold crystallization of PLA component and melt crystallization of PP component were enhanced, probably because PLA and PP were reciprocal nucleating agents. The tensile strength and flexural modulus decreased, while the tensile strain at break and heat deflection temperature (HDT) increased with the increasing PP content. MAPP had the positive effects on the notched impact strength and HDT of PLA-rich blends and also increased the flexural modulus of the binary blends. The thermal stability of the blend was improved by PP, and the incorporation of MAPP further enhanced the thermal stability.     

集抄系统电表变更识别和故障诊断研究综述

针对由于用户电表及设备档案变更、损坏、通信故障等因素导致集抄系统数据采集成功率和质量出现的问题,对集抄系统路由方法和集抄系统故障诊断方法的新进展进行综述。研究结果表明:(1)利用电力线载波路由算法并构建新的网络结构模型,将复杂的电力线通信网络拓扑转化成简单清晰的网络拓扑,解决集抄系统电表更换识别问题;(2)将数据挖掘技术和专家系统相结合,开发基于数据挖掘的故障诊断专家系统,使集抄系统故障诊断智能化,提高数据采集的质量;是未来需要进一步研究的课题。     

The impacts of Robinia pseudoacacia litter cover and roots on soil erosion in the Loess Plateau,China

The impacts of vegetation on soil erosion are closely associated with the combined effects of above- and below-ground components. In this study, we explore the effects and contributions of Robinia pseudoacacia litter cover and roots on soil erosion. Experiment sites under natural conditions with vegetation cover, plant roots and bare ground plots were investigated for overland flow discharges of 0.5, 1.0 and 2.0?L?s^?1 and slope gradients of 8.7%, 17.6%, 26.8%, 36.4% and 46.6%. Results indicate that litter cover and roots have a significant impact on sediment reduction; soil loss was reduced by about 57% and plant roots had a greater impact on the reduction of soil erosion than litter cover. The combination of litter cover and plant roots had a significant effect on decreasing K_r, increasing τ_c and consequently strengthening soil resistance capacity to erosion. When plants and roots existed on the slopes, K_r decreased by 81% and 66%, and τ_c increased by 319% and 246%, respectively, in comparison with bare slopes. These results illustrate the importance of high-forest in controlling soil erosion by quantifying the specific contributions of litter cover and plant roots in erosion reduction in the Loess Plateau.     

Enhancing the Ability of a Soil Moisture‐based Index for Agricultural Drought Monitoring by Incorporating Root Distribution

Agricultural drought differs from meteorological, hydrological, and socioeconomic drought, being closely related to soil water availability in the root zone, specifically for crop and crop growth stage. In previous studies, several soil moisture indices (e.g., the soil moisture index, soil water deficit index) based on soil water availability have been developed for agricultural drought monitoring. However, when developing these indices, it was generally assumed that soil water availability to crops was equal throughout the root zone, and the effects of root distribution and crop growth stage on soil water uptake were ignored. This article aims to incorporate root distribution into a soil moisture‐based index and to evaluate the performance of the improved soil moisture index for agricultural drought monitoring. The Huang‐Huai‐Hai Plain of China was used as the study area. Overall, soil moisture indices were significantly correlated with the crop moisture index (CMI), and the improved root‐weighted soil moisture index (RSMI) was more closely related to the CMI than averaged soil moisture indices. The RSMI correctly identified most of the observed drought events and performed well in the detection of drought levels. Furthermore, the RSMI had a better performance than averaged soil moisture indices when compared to crop yield. In conclusion, soil moisture indices could improve agricultural drought monitoring by incorporating root distribution.     

四川甘洛自勒沟泥石流运动特征及预测防治效果研究∗

甘洛县位于四川省西南部,所处区域高山峡谷地貌特征显著,地质构造运动强烈且为强震影响区,泥石流灾害频发。甘洛县自勒沟分别于 1987 年和 2019 年发生两次特大泥石流,大量泥石流堆积物顺沟而下,堵塞 245 国道和尼日河,并对沟口凉红水电站及尼日河河岸成昆铁路造成严重威胁。对此,基于现场调查资料和无人机航拍数据,利用 Massflow 数值模拟方法,对该沟泥石流运动特征进行分析以及治理措施防治效果进行预测。结果表明：若沟内现有物源再次爆发泥石流,最大泥深将达到 11.9 m,流速达到 11.7 m/s,流动强度达到 123.37 m² /s,堆积物一次冲出量为 11.18×10⁴ m³ ,堆积扇面积为 6.925×10⁴ m² 。根据预测结果,采用合理的工程措施进行治理后,最大泥深下降为 8.5 m,流速下降为 9.1 m/s,而流动强度可下降 52.7%,为 58.32 m² /s,堆积扇面积和一次冲出量分别为 1.406×10⁴ m² 和 2.75×10⁴ m³ ,分别下降 80% 和 75%。这表明,采用固源为主,拦挡、排导为辅的措施对自勒沟泥石流灾害进行治理,可取得较好治理效果,对保护沟口建筑及成昆铁路安全运营有重要意义。     

炭管膜曝气生物膜反应器SNAD脱氮研究

以包裹无纺布的微孔炭管作为膜曝气生物膜反应器（MABR）的膜组件,进行了短程硝化,厌氧氨氧化和反硝化耦合脱氮(SNAD)研究。实验中,控制温度34±1℃,pH 7.5～8.5, HRT 8 h,通过逐步降低膜内压力使反应器中的溶解氧由8 mg/L逐步降低到0.5 mg/L以下。实验采用亚硝酸细菌挂膜,然后接种厌氧氨氧化细菌,实现在单一反应器中同时发生短程硝化、厌氧氨氧化和反硝化耦合脱氮功能。结果表明,经过180 d的连续稳定运行,氨氮去除率达到了93.4%,总氮去除率达到了92.5%,COD去除率达到97.2%, 氨氮去除负荷0.6 kg N/（m³ ·d）。适合SNAD工艺的最佳C/N比为0.2～0.6,当COD浓度过高时,会抑制厌氧氨氧化细菌,使SNAD工艺的处理效果明显下降。     

Distribution and migration of 95Zr in a tea plant/soil system

(95)Zr is a primary radionuclide in the radioactive liquid efflux from a pressurized water reactor and one of the main radionuclides released after nuclear accidents. The fission yield of (95)Zr is as high as 6.2%, however, its environmental behavior has not been well documented. An experiment was conducted to evaluate the accumulation and distribution of (95)Zr in a tea plant/soil system. (95)Zr was accumulated primarily in the trunk of tea plants after being taken up from the soil. The radioactivity concentration of (95)Zr in the trunk increased slowly with time, then it reached a dynamic equilibrium 14 days after application. The radioactivity concentration of (95)Zr in the other parts of the tea plant was very low; only slighter greater than the detection limit. The results indicated that (95)Zr was not readily translocated in the tea plant. About 98.9% of applied (95)Zr was found to concentrate in the upper 5 cm layer after being sprayed onto the soil surface. The results indicated that (95)Zr could not readily move downwards with percolating water due to strong adsorption to surface soil.