民族地区旅游资源开发的人类学透析——以西北省区甘肃省为例

在旅游业飞速发展的时代背景下,对民族地区旅游资源开发进行更为理性的人类学思考是本文的初衷.在对西北省区甘肃省民族旅游考察的基础上,发现民族旅游存在民族文化特异性缺失、真实性缺失和旅游产品形式单一等问题,并以此提出对民族旅游资源合理开发、原生态开发、深度挖掘文化内涵等意见和建议.     

澎溪河流域水中碳素分布特征的研究

面对三峡库区日益突出的环境问题,研究人员做出众多研究,但对库区河流碳的赋存形态及其影响研究报道较少.在2019年春夏两季通过现场采样室内分析的方式测定了各形态碳含量,重点分析了澎溪河流域水中碳素的分布特征.结果 表明:澎溪河流域碳含量总体呈现上游低下游高,春季低夏季高的分布特点,两季TOC均值均超过水体富营养化标准达1...     

Are denser cities greener? Evidence from China, 2000–2010

Whether a city develops into a more compact one with a higher density or a more sprawling one may affect multiple aspects of the urban environment, including ecosystem health, greenhouse gas emissions, and quality of life. Using panel data gathered from China's cities from 2000 to 2010, we take advantage of the significant variation in the temporal change of density across cities to estimate the relationship between gross urban population density and multiple indicators of urban greenness. Fixed‐effects estimates support the widely held belief that density improves air quality and reduces the per capita carbon footprint. Results also suggest that higher density reduces the growth of road infrastructure and vehicle ownership and promotes walking. While density often translates into proximity and accessibility, higher density does reduce a city's per capita urban park and green space. This study strengthens the urban policy and planning literature with much needed longitudinal evidence. Our overall findings support higher density as opposed to lower density urban development in China.     

Characterization and source identification of submicron aerosol during serious haze pollution periods in Beijing

Submicron aerosol is of extensive concern not only due to its significant impact on air quality but also because it is detrimental to human health. In this study, we investigated the characteristics, sources and chemical processes of submicron aerosol based on realtime online measurements of submicron aerosols（NR-PM 1） during December 2015 at an urban site in Beijing. The average mass concentration of NR-PM 1 was 92.5 ±84.9 μg/m³, the hourly maximum was 459.1 μg/m³ during t...     

黄石市磁湖水质时空分布及污染源解析

为解析黄石磁湖污染来源和水质时空分布,以磁湖2015—2019年水质监测数据为基础进行污染因子主成分分析（PCA）,通过绝对主成分-多元线性回归（APCS-MLR）受体模型计算污染源贡献率,采用反距离权重插值法（IDW）分析水质时空分布规律。结果表明：影响磁湖水质的第1、第2、第3主成分分别是城市面源、城镇生活污染源及气象因子;第1主成分对BOD₅、COD_Cr、COD_Mn、NH₃-N、TN、TP的贡献率最大,分别为88%、76%、67%、55%、46%、67%,第2主成分对BOD₅、NH₃-N的贡献率较大,分别为39%、32%。磁湖主要污染来源为城市面源及城镇生活污染源,受历史上工矿企业生产造成的底泥淤积和上游区域城镇生活污水排放的影响,磁湖下陆港入湖口（1#点位）处的污染最严重。     

动力送风过滤式呼吸器的标准化

本文结合动力送风呼吸器国家标准的制订工作,概述了该国家标准的编制背景、原则,对该类呼吸防护装备的分类、主要技术内容及其编制依据,如送风量、泄漏率、防护时间、有效气流量等进行了介绍。该国家标准的制定对于规范和指导我国动力送风过滤式呼吸器的发展以及推动其应用具有重要的意义。     

防毒面具新型多功能检漏测试评价系统

一种新型轻便的多功能防毒面具泄漏测试评价系统已研制成功并装备部队.该系统易于在野外或实际作业场所进行相应的测试评价,同时还能够测定防毒面具的可靠性、适合性,对于防毒面具的缺陷部件如饮水管、呼气阀等部件具有较好的测试与评价能力.通过该仪器对防毒面具进行的可靠性和适合性测试,可以帮助使用者显著增加其对所佩戴防毒面具的信心,保证了作业人员的人身安全,提高了作业效率,对于防毒面具等呼吸器的性能检测与监控具有重要的现实意义.     

环己烷泄漏事故模拟与风险控制措施研究

环己烷具有闪点低、爆炸极限宽等特点,一旦发生泄漏,着火爆炸的危险性随时存在。利用计算流体动力学模拟的方法对工程项目中环己烷的泄漏事故进行模拟及风险分析,建立环己酮生产装置的全尺寸三维模型并进行仿真计算,模拟了不同泄漏场景所形成的环己烷可燃气体云团瞬态发展过程及影响范围,并对建构筑物的布局对可燃气体云团的扩散行为的影响进行研究。研究结果表明,通过优化建构筑物布局,可有效降低该装置环己烷的燃爆风险,为企业相关装置的总图布置及环己烷泄漏的安全监控和应急响应提供有价值的参考数据。     

桥式起重机安全评估指标体系研究和系统设计

在对桥式起重机的设计、结构组成和常见事故故障资料进行调查研究的基础上,分析了桥式起重机在工程应用中遇到的不安全因素,建立了较完善的安全评估指标体系。设计了一种基于模糊神经网络的桥式起重机安全评估系统并对系统的软件功能设计进行了初步探讨。建立了模糊神经网络评估数学模型,利用MATLAB工具对模型进行了仿真验证,结果表明此模型是可行的。通过研究,为进一步针对桥式起重机展开定性、定量评估及安全管理与决策提供了有益参考     

Experimental study on gas explosion and venting process in interconnected vessels

A pilot scale interconnected vessels experiment system was established, and the closed and vented gas explosion characteristics in the system were studied, using 10% methane–air mixture. Regularity of pressure variation in vessels and flame propagation in linked pipes was analyzed. Furthermore, the effects of transmission style, ignition position, pipe length, and initial pressure on explosion severity were discussed. For the closed explosion: explosion in interconnected vessels presents strongly destructive power to secondary vessel, especially transmission from the big vessel to the small one; the worst ignition position is shifting from ignition in the interconnected pipe to the walls of the two vessels; as far as ignition in big vessel is concerned, the peak pressure in secondary vessel increases with the pipe length much faster than that for ignition in small vessel; the peak pressures in two vessels are approximate linear functions of initial pressure. For the vented explosion: the transmission style and interconnected pipe length have significant impacts on the effect of venting on the protection; in order to obtain the better venting effect, the use of a divergent interconnected pipe from the big vessel to the small one in industry is advised and it is necessary to reduce the interconnected pipe length as far as possible or install flame arrester in the interconnected pipe.