豫西北小寨组的变形作用

本文应用有限应变测量方法,结合不同变形特征分析认为,小寨组变形作用以挤压和简单剪切为主.根据磁性组构得出本区构造变形的最大压应力方向约为215°-226°,并且确认变形作用在一个大的构造旋回中至少经历两个阶段.     

江苏、南部下、中侏罗统的划分

江苏南部的下、中侏罗统,长期以来笼统称之为象山群。本文根据地层岩性特征和大量动植物化石的研究,结合与邻区地层之对比,将江苏南部下、中侏罗统进一步划分为下侏罗统南象山组及中侏罗统北象山组;前者为含煤地层,大致相当于原象山群下部(或下段为),后者为红色地层,大致相当于原象山群上部(或上段)。     

云南宣威群地层路堑边坡滑带土蠕变特性研究

为研究云南宣威群地层路堑边坡滑带土的蠕变特性,采用GDS非饱和反压直剪仪,对边坡滑带土进行直剪蠕变试验,研究该路堑边坡滑带土在不同法向应力下的蠕变特性和长期强度.试验结果表明:该路堑边坡滑带土的绝对蠕变量随水平剪切应力的增加而增加,当水平剪切应力一定时,滑带土的绝对蠕变量与法向应力呈负相关性,而滑带土的瞬时蠕变量随水平...     

Formation mechanism and control strategy for particulate nitrate in China

Over the past decade, fine particulate matter (PM) pollution in China has been abated significantly, benefiting from strict emission control measures, but particulate nitrate continues to rise. Here, we review the progress in particulate nitrate (pNO₃⁻) pollution characterization, nitrate formation mechanisms, and the proposed control strategies in China. The spatial and temporal distributions of pNO₃⁻ are summarized. The current status of knowledge on the chemical mechanism is updated, and the significance of its formation pathways is assessed by various approaches such as field observation and modelling of nitrate production rate, as well as isotopic analysis. The factors impacting pNO₃⁻ formation and the corresponding pollution regulation strategies are discussed, in which the importance of atmospheric oxidation capacity and ammonia are addressed. Finally, the challenges and open questions in pNO₃⁻ pollution control in China are outlined.     

Review of the influencing factors of secondary organic aerosol formation and aging mechanism based on photochemical smog chamber simulation methods

The formation and aging mechanism of secondary organic aerosol (SOA) and its influencing factors have attracted increasing attention in recent years because of their effects on climate change, atmospheric quality and human health. However, there are still large errors between air quality model simulation results and field observations. The currently undetected components during the formation and aging of SOA due to the limitation of current monitoring techniques and the interactions among multiple SOA formation influencing factors might be the main reasons for the differences. In this paper, we present a detailed review of the complex dynamic physical and chemical processes and the corresponding influencing factors involved in SOA formation and aging. And all these results were mainly based the studies of photochemical smog chamber simulation. Although the properties of precursor volatile organic compounds (VOCs), oxidants (such as OH radicals), and atmospheric environmental factors (such as NO_x, SO₂, NH₃, light intensity, temperature, humidity and seed aerosols) jointly influence the products and yield of SOA, the nucleation and vapor pressure of these products were found to be the most fundamental aspects when interpreting the dynamics of the SOA formation and aging process. The development of techniques for measuring intermediate species in SOA generation processes and the study of SOA generation and aging mechanism in complex systems should be important topics of future SOA research.     

Brominated dioxins and furans in a cement kiln co-processing municipal solid waste

A field study and theoretical calculations were performed to clarify the levels, profiles, and distributions of polybrominated dibenzo-p-dioxins and dibenzofurans(PBDD/Fs) in a cement kiln co-processing solid waste, with a focus on the PBDF formation mechanism.The raw materials contributed greatly to input of PBDD/Fs into the cement kiln. The PBDD/F concentrations in the raw materials were much higher than those in particle samples from different process stages in the cement kiln. The PBDD/F concentrations in the clinkers were1.40% of the concentrations in the raw materials, which indicated that the high destruction efficiencies for PBDD/Fs by cement kiln. PBDD/F distribution patterns in particle samples collected from different process stages indicated the cement kiln backend was a major site for PBDD/F formation. PBDFs with high levels of halogenation, such as heptabrominated furans(Hp BDF), were the dominant contributors to the total PBDD/F concentrations and accounted for 42%–73% of the total PBDD/F concentrations in the particle samples. Our results showed that co-processing of municipal solid waste in a cement kiln may influence the congener profile of PBDD/Fs, especially for the higher halogenated PBDD fraction. In addition, there were significant correlations between the decabromodiphenyl ether and heptabrominated furan concentrations, which is an indicator of transformation from polybrominated diphenyl ethers to PBDD/Fs. Theoretical calculations were performed and demonstrated that elimination of HBr and Br_2 from polybrominated diphenyl ethers were the dominant formation pathways for PBDD/Fs. These pathways differed from that for polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs).     

胶东地块在古生代的浮沉

胶东—京畿地块在古生代并非“铁板一块”。中泥盆一早石炭世,裂解再生临津江—烟南冒地槽带;中、晚石炭世,郯庐海湾仲入成“诸城海湾”,并可能有二叠纪沼泽盆地。中生代运动使胶东地块复杂化。     

Protoplast preparation and regeneration conditions of Bacillus subtilis ZGL14 producing alkaline pectinase北大核心CSCD

The protoplast fusion technique is one of the important microbial breeding methods. The main factors that affect protoplast preparation and regeneration were investigated using Bacillus subtilis ZGL14 as the starter strain. The optimal conditions for protoplast preparation and regeneration were determined in this study by optimizing the cell age, lysozyme concentration, enzymolysis time, enzymolysis temperature, pH values of the osmotic pressure stabilizer, regeneration medium types, and culture type. The results indicated that the optimal condition for protoplast preparation of B. subtilis ZGL14 was as follows: 9 h of cell age, 0.2 mg/mL of lysozyme concentration, 10 min of enzymolysis time, 32 °C of enzymolysis temperature, and 7.0 of osmotic pressure stabilizer pH value. Under this condition, the protoplast formation and regeneration rates were > 98% and > 30%, respectively. A good protoplast regeneration effect can be achieved using the regeneration medium with sodium succinate as osmotic pressure stabilizer in combination with Ca2+. The single-layer culture was better than double-layer for regeneration. The optimal condition for protoplast preparation and regeneration of B. subtilis ZGL14 was determined in this study, which provides technical support for protoplast fusion breeding of B. subtilis. © 2018 Science Press. All rights reserved.     

广东的滨海沙土资源

滨海沙土是广东沿海重要而急待改造利用的一种国土资源。分布广、面积大,风沙为害较甚。它集中分布在琼东北和西南部、陆丰至海丰、阳江至广州湾沿岸一带。主要因河流和地表径流携带的泥沙受潮浪、风力作用逐渐发育而成。按形成时间和特性,可分流动、半固定、固定和耕型沙土等亚类。并具有沙瘦的共同特性。改造利用主要措施是营林绿化。其次,是因地制宜地积极发展果蔬、热作等经济作物,改造沙荒草地,发展畜牧业,施肥改土,兴修水利和开发其旅游资源。     

朝鲜晚奥陶世——志留纪和泥盆纪地层发现的启示

本文在比较系统介绍朝鲜于60-70年代发现泥盆纪临律群和晚奥陶世—志留纪地层的基础上,论证前者西延登上山东半岛,后者指向辽东、冀东的可能性。