石家庄市春季PM_(10)和PM_(2.5)浓度及其水溶性离子组分特征分析

对2013年春季石家庄市PM10和PM2.5中水溶性离子进行分析,石家庄市春季PM10平均质量浓度为354.9μg/m3,总水溶性无机离子质量浓度为105.48μg/m3,其中SO2-4,NH+4,Ca2+,Cl-和NO-3是主要的水溶性无机离子,占总离子质量分数依次为40.89%,17.93%,13.49%,10.75%和9.09%,共计92.15%;PM2.5平均质量浓度为174.4μg/m3,总水溶性无机离子质量浓度为86.45μg/m3,与PM10中一样,SO2-4,NH+4,Cl-,NO-3和Ca2+是主要的水溶性无机离子,占总离子质量分数依次为41.06%,24.25%,12.11%,8.34%和5.32%,共计91.08%。石家庄市春季PM10及PM2.5中NO-3/SO2-4比值分别约为0.22和0.20,由此判断石家庄市春季主要污染以固定源为主,以燃煤及工业生产为主要来源。     

硫酸法钛白粉还原过程及机理研究

研究了硫酸法钛白粉的还原反应过程,并考察了还原剂添加量、反应温度、反应浓度以及反应体系pH值几种影响因素对硫酸法钛白粉制备还原反应的影响。结果表明,当还原剂添加量至0.20%时,还原反应最佳;反应物浓度对反应速度影响较小,在120g/L-160g/L达到还原反应较为彻底基本已趋于稳定;反应温度太低太高均不利于还原反应的进行,在55°C时反应最佳;强酸性条件有益于还原反应的进行,当pH值小于2时还原反应速率明显较快。基于硫酸法钛白粉还原过程中Fe3+还原成Fe2+,探讨了还原过程的反应机理。     

长治酸雨观测中pH值的研究分析

本文应用数理统计方法,对长治2007年—2014年逐次降水中的p H值进行分析研究,结果表明:2007年—2009年酸雨呈现逐年恶化趋势,2010年以后降水酸化逐渐改善,由于环境治理力度加大,长治由酸雨频发地区转变为酸雨多发地区,可见有针对性的保护和改善生态环境,对实现经济社会的可持续发展具有重要意义。     

基于Mann-Kendall和小波功率谱的丹东市近35年降水量变化特征解析

为探究丹东市降水时空变化规律，以1986—2020年站点观测资料和降水栅格数据为基础，运用Mann-Kendall检验、Morlet分析和统计方法，研究了该地降水倾向趋势、变化周期及空间分布。结果显示，丹东近35年来平均降水量以3.79mm/a的速率增加，但趋势不显著。降水变化具有多个短震荡周期，主周期为6a,在2000年发生弱突变。受季风与地形影响，降水量呈现中高周低分布，空间差异为823～1098mm。文章揭示了近35年丹东降水量变化特征，可为区域水资源管理提供参考依据。     

石家庄市PM_(10)和PM_(2.5)中多环芳烃的分布及来源分析

于2013年春、夏、秋、冬四季采集石家庄市6个采样点PM10和PM2.5样品,分析其中的多环芳烃,研究了石家庄市PM10和PM2.5中PAHs在不同季节的污染水平、组成特征和主要来源。结果表明,石家庄市PM10和PM2.5中有15种PAHs检出,全年PM10中PAHs的质量浓度为7.5~510.5ng/m3,PM2.5中PAHs的质量浓度为3.6~460.6ng/m3;PAHs浓度季节变化明显,冬季浓度明显高于其他季节。春、夏、秋、冬四季PM10和PM2.5中的PAHs主要分布在细粒子中。4环和5环化合物是PAHs的主要成分,占比为66%~79%。与其他季节相比,冬季4环PAHs的含量高,5环和6环PAHs的比例相对低。运用比值法综合分析,石家庄市PM10和PM2.5中PAHs在冬季主要受到燃煤污染源的贡献,在春、夏、秋季,受燃煤污染和机动车污染综合作用。     

VC磷酸酯的HPLC分析

建立了高效液相色谱法(HPLC)测定L-抗坏血酸-2-磷酸酯含量的分析方法。采用Agi-lent Eclipse XDB C18分析柱(250mm×4.0mm,5μm),以甲醇-0.1mol/L磷酸二氢钾(pH值为4.4)为流动相,二者体积比为35∶65,流速为1.0mL/min,检测波长为254nm。在此色谱条件下,L-抗坏血酸-2-磷酸酯在0.01～0.10mg/mL质量浓度范围内呈现良好的线性关系,相关系数为0.999 9,样品平均回收率为98.24%。     

特厚煤层分层放顶煤开采地表塌陷分析预测

华亭煤矿始建于1962年4月，核定生产能力为330万t/a。主采煤5层厚度16.5～47.2m,平均厚度37.5m,煤层倾角2～9°,煤层赋存标高+1405～+650m。矿井采煤方法为走向长壁倾斜分层综采低位放顶煤方法，顶板管理为全部垮落法。矿井目前开采水平标高为+840m,布置2501采区。该采区于2005年11月开始回采，上分层先期采用在首采工作面两边依次交错方式布置，自250106-1工作面后采取上、下分层工作面交错方式布置。目前已完成8个工作面的回采，采空区面积达290.9km²,地表塌陷情况愈发严重，通过分析预测特厚煤层分层放顶煤开采造成的地表塌陷情况，对矿井地质灾害防治、安全生产等具有重大意义。     

石家庄市区PM_(2.5)时空分布特征

石家庄市大气污染严重,尤其是PM_(2.5)浓度经常居高不下。为了更全面地掌握石家庄市PM_(2.5)浓度的变化规律,需要对其时间和空间变化规律进行长时间序列的分析。根据2013—2015年石家庄市区的监测数据,采用GIS空间分析方法,研究了PM_(2.5)的时空分布特征。结果表明,2013年PM_(2.5)平均质量浓度为154μg/m3,2014年为124μg/m3,2015年为89μg/m3;季节性分布规律明显,月均浓度均呈波浪形分布,日变化呈双峰形分布;还呈现出周末浓度高于工作日浓度的"周末效应"端倪;空间分布上呈现市区东南部污染较轻、北部污染较重的空间格局,并且污染较重的空间范围在逐渐缩小,污染较轻的空间范围逐渐扩大。研究结果有利于准确掌握石家庄市区PM_(2.5)污染的时空分布,从而有针对性地开展环境污染防控。     

运用市场经济手段 进行大气环境污染控制

<正> 酸雨是一种大气污染现象。形成酸雨的罪魁祸首主要是大气中由燃煤形成的超量的SO2。它与工业粉尘、烟尘并列为大气三大污染排放物。据统计,1995年我国的SO2的排放量高达2370万吨,居世界首位。这使得我国发生酸雨的地区发展迅速。据估计,平均降水PH<5.6的地区已占我国国土面积的40％左右,硫沉降量超临界负荷的面积为210万Km2,占国土面积的21.9％,每年酸雨污染仅给森林和农作物造成的直接经济损失就高达数百亿元,另外大气中的SO2是一种主要     

石家庄市冬季大气颗粒物中水溶性离子与重金属成分研究

为研究石家庄市冬季大气颗粒物中的组分特征,2015年1月采集了石家庄市大气中PM_(10)和PM_(2.5)样品,采用离子色谱和ICP-MS分别测定了颗粒物中的8种水溶性离子和6种重金属元素的含量。结果表明,石家庄市PM_(10)中Cr,Cu,Zn,Cd,Pb,Ni重金属质量浓度范围在0.02~1.72μg/m~3之间,水溶性离子平均质量浓度为125.5μg/m~3,其中Cl-,NO_3~-,SO_4~(2-),NH_4~+分别占总离子质量分数的11.6%,7.8%,43.4%,19.0%,共计81.8%。PM_(2.5)中6种重金属质量浓度范围在0.01~1.23μg/m~3之间,水溶性离子平均质量浓度为104.9μg/m~3,其中Cl-,NO_3~-,SO_4~(2-),NH_4~+分别占总离子质量分数的12.5%,7.2%,43.3%,18.7%,共计81.7%。PM_(10)和PM_(2.5)中NH_4~+与SO_4~(2-)的相关性较好,NH_4~+可能主要以硫酸盐形式存在。PM_(10)和PM_(2.5)样品中重金属的相关性基本一致,Cr和Ni的相关性较好,表明其可能来源于同一污染源,Cu,Zn和Ni之间的显著性相关说明这3个元素有可能同源。     

Comparing FTTH access networks based on P2P and PMP fibre topologies

There is an ongoing discussion in the market which Next Generation Access (NGA) architecture best suits future needs and which investment and cost differences exist. The discussion can be subsumed as P2P vs. GPON, which is somewhat misleading as this article reveals. The discussion is driven by the fact that the high capital cost and the long asset life time of fibre mean that the technology choices made today will dominate the opportunities for telecommunication business of all market players, incumbents, competitors, content providers and business and residential users for many years in the future.The paper analyzes the cost and other differences between Fibre-to-the-Home (FTTH) access network architectures and their related different wholesale approaches by using the well-known and understood steady state approach applied in other NGA analyses in the past. In addition to the steady state analysis a dynamic cost evaluation is included taking into account the different investment behaviour of the FTTH architectures over time. The results describe investment and cost differences between architectures, incumbents and wholesale based competitive operators. The analysis has been performed for different geotypes (clusters) of decreasing population density in a representative European settlement structure.     

Indigenous peoples’ nutrition transition in a right to food perspective

In indigenous communities the nutrition transition characterized by a rapid westernization of diet and lifestyle is associated with rising prevalence of chronic disease. Field work and literature reviews from two different policy environments, Argentina (Jujuy) and Canada (Nunavut), identified factors that add to indigenous peoples’ disease risk. The analytical framework was the emerging human right to adequate food approach to policies and programmes. Indigenous peoples’ chronic disease risk tends to increase as a result of government policies that infringe on indigenous peoples’ livelihoods and territories, undermining their economic system, values and solidarity networks. Policies intended to increase food security, including food aid, may also fuel the nutrition transition. There is a need to explore further the connection between well-intended policies towards indigenous peoples and the development of chronic diseases, and to broaden the understanding of the role that different forms of discrimination play in the westernization of their lifestyles, values and food habits. Food policies that take due account of indigenous peoples’ human rights, including their right to enjoy their culture, may counteract the growth of chronic disease in these communities.     

A strategic skill based model of supplier integration and its effect on supply management performance

Supplier integration is a tool to help organizations gain competitive advantage. Strategic supply management skills and the supply management function's perceived status are hypothesized as antecedents to supplier integration leading to supply management performance. The sample for this study includes 152 executive level supply management professionals. The empirical results suggest that strategic skills and perceived status are essential antecedents to supplier integration and subsequent performance. Further, the relationship between strategic skills and performance is mediated by supplier integration. Results of a dominance analysis also suggest which strategic skills are most likely to explain status integration, and performance. These findings have significant implications for supply management theory and practice.     

Cost allocation of WCDMA and wholesale pricing for mVoIP and data services

This study estimates cost-based prices for wholesale voice and data services provided to 3G (WCDMA) MVNOs according to their distinct types. For estimation, 3G MVNOs are classified into different types, and the overall cost of WCDMA facilities are separated into voice and data components based on their subscriber rates, actual traffic rates, as well as efficiency consideration of traffic rates. The study then calculates cost-based wholesale prices of voice and data services for each of the 3G MVNO types. The result of this study shows that a cost-plus pricing scheme can help achieve the policy goals of the regulator, namely, lowering telecommunications tariffs and facilitating the introduction of new convergent-type services, far more effectively than the current retail-minus pricing scheme. The findings of this study may assist firms in developing business models based on 3G networks and telecom regulators in designing policies related to interconnection, mVoIP, prepaid calls, wholesale services, and network neutrality.     

Collectivism,individualism, and outgroup cooperation in a segmented China

A consistent theme in cross-cultural management research is that collectivists are more cooperative than individualists. We use Hofstede's measure for individualism–collectivism and combine it with an experimental measure of cooperation to test this relationship in China. In contrast to the established paradigm, we find that groups with higher individualistic scores are more cooperative than those groups with higher collectivistic scores. We attribute these results to groups being composed of outgroup members. In addition, we find that subjects from the more developed coastal area are more individualistic and cooperative than are subjects from inland China.

电子产品的电磁兼容性设计

首先介绍电磁兼容性的基本概念与研究领域,然后重点阐述电子产品的电磁兼容性设计与测量。     

SPYRO在烯烃原料生产方案测算中的应用

文章对SPYRO裂解模拟软件在石化企业烯烃生产原料优化方案测算中的应用进行了比较深度的概括分析.结合该软件在上海石化的实际应用,认为在劣质化原油加工份额不断增加的趋势下,SPYRO裂解模拟软件有助于石化企业在烯烃生产原料优化选择、生产计划合理安排、原油加工生产效益比较等方面为企业相关决策者提供有效地帮助.     

施工企业工程项目部的建设浅论

工程项目的一次性决定了工程项目部的一次性，而工程项目成本中心与企业利润中心地位又辱致工程项目部的临时性，在工程项目实践过程中，项目经理部的一次性在实现其功能的过程中可能会产生很多局限和负面影响，故项目部应具有相对的稳定性，在此基础上，本对工程项目部建设实践进行了初步总结并提出了建议。     

European consumer preferences for beef with nutrition and health claims: A multi-country investigation using discrete choice experiments

The European Union (EU) nutrition labelling policy aims to facilitate consumers’ food choice, stimulate innovation and facilitate the circulation of foods bearing claims across countries. However, the beef industry has not fully taken advantage of utilizing nutrition and health claims based on the EU nutrition labelling policy to differentiate beef products in the market. This study investigates consumer preferences for nutrition and health claims on lean beef steak. Two choice experiments were conducted among 2400 beef consumers in four EU countries (Belgium, France, the Netherlands, United and United Kingdom). Multinomial logit and error component models were estimated. Our results generally suggest that consumer valuation of nutritional and health claims varies across countries. In Belgium, the Netherlands and France, nutrition and health claims on saturated fat yielded higher utilities than claims on protein and/or iron, while the opposite was found among consumers in the UK. The results imply that marketing opportunities related to nutrition and health claims on beef are promising, but that different nutritional marketing strategies are necessary within different countries.     

Social media as a useful tool in food risk and benefit communication? A strategic orientation approach

Although considerable progress has been made in understanding the determinants of risk perception and in identifying the necessary components of effective food risk and benefit communication, this has not been matched with the development of efficient and appropriate communication tools. Little work has been done examining the implications of the explosion of new media and web technologies, which may offer potential for improving food risk and benefit communication. First, this study examines the views of stakeholders (n = 38) and experts (n = 33) in the food domain on the potential use of these emerging media for food risk/benefit communication. Based on in-depth interviews in six European countries (Belgium, Ireland, Italy, Latvia, Spain and The Netherlands), strengths, weaknesses, opportunities and threats (SWOT) of social media in food risk and benefit communication were identified. Second, a Strategic Orientation Round (SOR) was used to evaluate the relative importance of the SWOT components according to stakeholders (n = 10) and experts (n = 13). Results show that both stakeholders and experts confirm a future role of social media in food risk and benefit communication. Strengths as speed, accessibility and interaction make social media an interesting tool in crisis communication or issue awareness raising. Weaknesses as the lack of a filter, low trust, the risk of information overload and a communication preference for traditional media are acknowledged.