考虑材料应变率效应的冲击响应模型相似律研究

目的 研究考虑材料应变率效应的冲击响应模型相似律,获得一个能够综合材料弹塑性和应变率效应的精确相似解,支撑工程领域的模型试验。方法 根据BuckinghamΠ定理,综合考虑材料的弹性、应变硬化和应变率效应,进一步推导了工程结构在冲击响应的模型相似律表达式。在此基础上,提出改变结构质量和冲击器速度来满足模型相似律的方法。结果 相比最近冲击模型相似律的研究中存在近似相似、迭代求解的缺陷,该方法是一个显式、完全精确的相似解,并且能够同时考虑材料的弹性、应变硬化和应变率效应。采用圆板撞击的有限元数值模型进行了验证。结论 推导出的模型相似律能够准确地预测原型的动态冲击的响应。相比而言,使用以往的相似方法具有明显的误差。     

污染源自动监测异常数据识别规则及处理方法探索

基于大量污染源自动监测数据的特征分析与异常原因解析,探索建立针对自动监测异常数据的识别规则与标志处理方法,并通过模型训练实现了异常数据的自动标志.经实例验证,该方法可识别异常偏高、异常偏低、异常为0、迟滞不变、逻辑错误等5种类型的异常数据,按照数据有效性及异常原因进行标志处理,可以为后续数据分析及各类模型训练提供数据基...     

空气质量与气象因子间关联规则的挖掘方法研究

传统数据相关性分析仅能揭示空气质量与气象因子之间的相关系数,关联规则挖掘方法使用支持度、置信度、作用度、兴趣度等指标能够发掘隐藏在大量监测数据内部的关联规则。文章使用SQL语言实现了Apriori算法,挖掘出研究区内空气主要污染物浓度与气象因子之间的关联规则,定量表示气象因子变化对主要污染物浓度的影响。     

滇池湖滨带人工湿地削减规律研究探讨

文章分析了滇池湖滨带人工湿地各级结构单元的水质指标数据,从pH、SS、BOD5、COD、TP、TN的污染消减规律入手,深入探讨了人工湿地对污染河水的净化效果。结果表明:人工湿地系统对TP、TN的消减效果最好;COD消减效果最差;湿地构造及植物群落影响人工湿地对污水的净化能力。     

Conservation of biodiversity through taxonomy,data publication,and collaborative infrastructures

Taxonomy is the foundation of biodiversity science because it furthers discovery of new species. Globally, there have never been so many people involved in naming species new to science. The number of new marine species described per decade has never been greater. Nevertheless, it is estimated that tens of thousands of marine species, and hundreds of thousands of terrestrial species, are yet to be discovered; many of which may already be in specimen collections. However, naming species is only a first step in documenting knowledge about their biology, biogeography, and ecology. Considering the threats to biodiversity, new knowledge of existing species and discovery of undescribed species and their subsequent study are urgently required. To accelerate this research, we recommend, and cite examples of, more and better communication: use of collaborative online databases; easier access to knowledge and specimens; production of taxonomic revisions and species identification guides; engagement of nonspecialists; and international collaboration. “Data‐sharing” should be abandoned in favor of mandated data publication by the conservation science community. Such a step requires support from peer reviewers, editors, journals, and conservation organizations. Online data publication infrastructures (e.g., Global Biodiversity Information Facility, Ocean Biogeographic Information System) illustrate gaps in biodiversity sampling and may provide common ground for long‐term international collaboration between scientists and conservation organizations.     

高地应力作用下乌鞘岭深埋长隧道软弱围岩流变规律研究

在高地应力环境下的软弱围岩中修建深埋长隧道,软弱围岩流变一是个突出的工程地质问题。位于兰新铁路上的鸟鞘岭隧道工程在穿越宽迭785m的活动断裂带F7时,软弱围岩发生了显著流变,围岩最大收敛变形超过1m,对支护结构造成了严重破坏。本文在对鸟鞘岭隧道进行长期围岩收敛变形的基础之上,分析了乌鞘岭左右两主洞的收敛变形规律。此外,作者提出了对软岩围岩流变进行工程治理的原则。     

Assessment of risks, implications, and opportunities of waterborne neurotoxic pesticides

Pesticides are a well-known family of chemicals that have contaminated water systems globally. Four common subfamilies of pesticides include organochlorines, organophosphates, pyrethroids, and carbamate insecticides which have been shown to adversely affect the human nervous system. Studies have shown a link between pesticide exposure and decreased viability, proliferation, migration, and differentiation of murine neural stem cells. Besides human exposure directly through water systems, additional factors such as pesticide bioaccumulation, biomagnification and potential synergism due to co-exposure to other environmental contaminants must be considered. A possible avenue to investigate the molecular mechanisms and biomolecules impacted by the various classes of pesticides includes the field of -omics. Discovery of the precise molecular mechanisms behind pesticide-mediated neurodegenerative disorders may facilitate development of targeted therapeutics. Likewise, discovery of pesticide biodegradation pathways may enable novel approaches for water system bioremediation using genetically engineered microorganisms. In this mini-review, we discuss recently established harmful impacts of various categories of pesticides on the nervous system and the application of -omics field for discovery, validation, and mitigation of pesticide neurotoxicity.     

有效提高英语水平的一种途径——识记

本文针对大学生在英语学习过程中出现的识记能力差，贬低记忆作用的偏见，提出教学中应帮助学生了解和掌握记忆规律，提倡识记词汇、句法、段落或课文，有助于提高学生听、阅读和写作能力。     

环境水样中痕量Fe3+的测定方法研究

在酸性介质中(pH 5.0),Fe3+能与硫氰酸盐生成稳定的配离子[Fe(SCN)6]3-,该配阴离子能与碱性717型阴离子交换树脂定量交换缔合,形成阴离子交换树脂(R+)--金属离子(Mn+)--硫氰酸盐(SCN-)三元配合缔合体系,其最大吸收波长分别为490 μm,与二元水相最大吸收波长相同,通过制作薄层测定了水中Fe3+含量.本法具有较高的灵敏度ε630Fe3+=2.4×105 L·mol-1·cm-1,测定0.6 μgFe3+6次,RSD=2.7%,实测了水样中,Fe3+含量并与AAS法测定结果比较,Fe3+测定的线性范围0～10 μg/25mL,体系检出限为0.12 μmol/L.     

排污权交易与我国环境法治进程

排污许可证制度、排污收费制度和排污权交易制度对于环境污染的治理能够发挥出无可替代的作用.作为三种不同性质的治污手段,其运行机制有本质上的区别,也使得其实施的过程以及效用存在质的差别.本文通过对此三种治污手段的比较,意在揭示政府管制与市场调节两种不同的治理机制对我国环境法治进程的影响,并初步探讨了我国环境法治进程的路径选择.