52 research outputs found

    晋升激励、地域偏爱与企业环境表现:来自A股上市公司的经验证据

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    晋升激励和地域偏爱是影响地方政府官员决策行为的关键因素。本文以2009-2015年沪深A股上市企业为样本,探讨官员更替对企业环境表现的影响,并分别从晋升激励和地域偏爱两个角度切入分析这种影响背后的机制。研究发现,地方政府换届后,若继任官员来自本地调任,则当地企业的环境表现将得到改善;而若继任官员来自异地调任,则当地企业的环境表现将发生恶化。这一研究结论在解决可能的内生性问题、改变度量指标、考虑滞后反应、进行安慰剂测试、调整样本及控制其他可能的遗漏变量等一系列稳健性测试后仍然成立。进一步研究发现,异地调任的继任官员出于晋升激励的动机而倾向于降低地方环境治理水平;而本地调任官员出于对曾经任职地区的地域偏爱而更重视当地环境治理。本文创新性地从地方官员的晋升激励和地域偏爱视角探讨企业的环境社会责任,为理解地方官员的决策模式和企业环境责任行为提供了新思路。国家自然科学基金资助项目(71572158,71772155);;\n厦门国家会计学院云顶课题资助项目(YD20180206

    EMBA背景的董事长更擅长投资吗?——基于中国上市公司投资效率视角的检验

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    本文以2007—2015年沪深A股非金融类上市公司为研究对象,实证检验董事长的EMBA背景和所属企业投资效率间的关系。研究发现:(1)相较于其他企业,拥有EMBA背景的董事长所属企业的投资不足现象明显更少,而投资过度水平却更高,该结论在采用工具变量法、Heckman两阶段模型、倾向得分匹配法和安慰剂检验等控制可能的内生性问题后依然成立。(2)分样本检验发现,董事长EMBA背景对企业投资效率的影响仅存在于缺乏商科知识储备、社会关系网络较弱的董事长所属企业,说明EMBA背景通过改善董事长的知识结构、拓宽社会关系网络作用于企业的投资效率。(3)进一步研究发现,拥有"名校"EMBA背景的董事长更擅长投资决策,其所属企业的投资不足和投资过度现象相对不明显。本文丰富了高层梯队理论的研究内涵,为教育部门制定相关政策及市场对EMBA项目价值的正确认识提供了实证支持。国家自然科学基金面上项目(71572158;71372071

    Simulation Study of the Emission of Polycyclic Aromatic Hydrocarbons and Sugar Alcohols from Biomass Burning

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    选择水稻、小麦、玉米及棉花秸秆与马尾松枝,采集模拟燃烧时排放的PM2.5,分析PM2.5中多环芳烃(PAHS)和糖醇类化合物的含量,获得PM2.5及负载的两类化合物的排放因子;采用500 W汞灯直接照射收集了PM2.5的尘膜,获得了中、高环PAHS及左旋葡聚糖的光解动力学.结果表明,PM2.5的排放因子介于(2.26±0.60)g·kg-1(马尾松枝)~(14.33±5.26)g·kg-1(玉米秸秆)之间;19种PAHS的排放因子介于(0.82±0.21)Mg·kg-1(马尾松枝)~(11.14±5.69)Mg·kg-1(棉花秸秆)之间,且以4环类PAHS所占比例最高,介于51%~71%之间(其中马尾松枝燃烧时惹烯的排放因子最大);9种糖醇类化合物的排放因子范围为(52.34±50.16)Mg·kg-1(水稻秸秆)~(238.81±33.62)Mg·kg-1(小麦秸秆),且都以左旋葡聚糖占绝对优势(72%~96%).光照模拟显示,目标化合物的光照损失都遵循拟一级动力学,其中≥4环的PAHS的光解速率常数随着尘膜中PAHS的负载量增大而减小,来源特征比值fluA/(fluA+Py)和IP/(IP+bg P)相对稳定,而左旋葡聚糖的光解速率常数为0.004 5 MIn-1,与苯并[A]蒽的光解速率常数(0.004 1~0.005 0 MIn-1)接近.To measure the emission factors of PM2.5and its associated PAHs and sugar alcohols,Chinese red pine stick and four crop straw including rice,wheat,corn and cotton were burned in a chamber.In addition,the kinetics of certain compounds were obtained through the irradiation of the glass filters with PM2.5loading by 500 W mercury lamp.The emission factors of PM2.5were ranged from( 2.26 ± 0.60) g·kg- 1( Chinese red pine stick) to( 14.33 ± 5.26) g·kg- 1( corn straw).Although the emission factors of the total19 PAHs differed from( 0.82 ± 0.21) mg·kg- 1( Chinese red pine stick) to( 11.14 ± 5.69) mg·kg- 1( cotton straw),4 ring PAHs showed predominance over other PAHs accounting for 51%-71% except Chinese red pine in which retene was the predominant compound.The emission factors of 9 sugar alcohols were ranged from( 52.34 ± 50.16) mg·kg- 1( rice straw) to( 238.81 ± 33.62)mg·kg- 1( wheat straw) with levoglucosan accounting for 72%-96% of the total sugar alcohols.Both the selected PAHs and levoglucosan associated with PM2.5followed the first order kinetics.The photolysis kinetic coefficient of PAHs( ring number≥4) was decreased with the increase of PAHs loading in filters.Two PAHs source characteristic ratios such as Flua /( Flua + Py) and IP /( IP +Bg P) were relative stable during the irradiation.The photolysis kinetic coefficient of levoglucosan( 0.004 5 min- 1) was comparable to benzo[a]anthracene( 0.004 1-0.005 0 min- 1).国家自然科学基金项目(41171365); 环境保护公益性行业科研专项(201009004); 厦门大学山海基金项目(2013SH011

    Road Dust Loading and Chemical Composition at Major Cities in Fujian Province

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    采集并分析了福建省重点城市厦门、漳州、泉州和莆田城区具有代表性的57个地面扬尘和16个土壤样品的26种无机元素、8种水溶性离子和碳成分等组成.不同城市粒径≤100μM的路面尘负荷平均值在6.99 g.M-2与10.11 g.M-2之间,而粒径≤2.5μM的路面尘(PM2.5)负荷平均值在4.0 Mg.M-2和12.5 Mg.M-2之间.不同城市土壤尘和路面尘PM2.5中浓度最高的元素都是SI、CA、Al、fE和k,路面尘中CA元素明显富集,而主要人为来源的重金属元素如Cu、Pb、zn、Cr在路面尘PM2.5中的浓度显著高于土壤尘.漳州城区路面尘PM2.5中二次离子nH4+、nO3-和SO24-的含量明显高于其它地区,厦门、漳州和泉州城区路面尘PM2.5中Mg2+和CA2+之间都存在显著的正相关关系.四城市路面尘中有机碳(OC)的含量均高于济南、石家庄以及北京地面扬尘OC的含量,元素碳(EC)的含量均低于北京地区路面扬尘EC的含量.泉州和莆田两地OC和EC的相关性较好,说明路面尘中OC和EC有相同或相似的来源.质量平衡结果显示泉州和莆田路面尘PM2.5中含量最高的是土壤尘,其次为有机物.按化学组成特征对路面尘PM2.5进行聚类解析,得到受大气沉降影响、受土壤尘影响、受大气沉降和土壤尘共同作用以及受土壤尘和建筑尘共同作用4类样品.A total of 57 road dust and 16 urban soil samples were collected from four cities,Xiamen,Zhangzhou,Quanzhou and Putian in Fujian Province,China.Twenty-six elements,eight water soluble ions,organic carbon and elemental carbon in the fraction of particulate diameter less than 2.5 μm(PM2.5) derived through a suspension chamber were analyzed.The average loading of road dust with diameter less than 100 μm in the four cities ranged from 6.99 g·m-2 to 10.11 g·m-2,while the loading of PM2.5 ranged from 4.0 mg·m-2 to 12.5 mg·m-2.Both the soil and road dust samples were characterized with much higher concentrations of Si,Ca,Al,Fe and K.But for the anthropogenic elements such as Cu,Pb,Zn,Cr and Ti,much lower levels were found in the soil PM2.5 than those in the road dust PM2.5.Significantly higher levels of NH+4,NO-3 and SO2-4 were found in the road dust PM2.5 from Zhangzhou in comparison with those from other cities in this study.The calcium ion(Ca2+) content was significantly positively correlated with the Mg2+ content in the road dust PM2.5 from Xiamen,Zhangzhou and Quanzhou.The levels of organic carbon(OC) in the road dust PM2.5 in these four cities were higher than those reported in Ji'nan,Shijiazhuang and Beijing while the levels of elemental carbon(EC) were all lower than those in the urban road dust from Beijing,Significant positive correlation between EC and OC was found in samples from Quanzhou and Putian,suggesting the same and/or similar sources.The result of mass balance indicated that higher percentage compositions were soil and OM in both Quanzhou and Putian.Based on the cluster analysis,the 57 road dust samples were divided into four types: influenced by atmospheric deposition,influenced by soil dust,influenced by atmospheric deposition and soil dust,and influenced by soil and construction dust.国家自然科学基金项目(40971257;41171365); 环境保护公益性行业科研专项(201009004); 福建省自然科学基金计划项目(2009J05106

    Establishment of air pollutant emission inventory in the West Coast of Taiwan Strait

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    以2009年为基准年,结合污染源普查数据、统计年鉴及工业活动、居民生活等多个方面对海峡西岸经济区包括SO2、nOX、PM2.5、VOCS和nH3在内的大气污染物的排放量进行了估算,建立了海西区大气污染物排放清单.结果发现,上述5类污染物基准年的排放量分别为40.67x104、55.84x104、50.57x104、152.26x104和26.18x104T.其中,SO2、nOX及PM2.5的排放主要来自电厂,占排放总量的比例分别为25.58%、34.89%和38.75%;VOCS和nH3的主要排放源分别来自植被排放和养殖业,其贡献量分别为49.12%和47.07%.采用gIS对排放清单进行网格化处理,得出SO2、nOX及PM2.5的高排放强度区域与固定源的空间分布较为一致.此外,结合国家和地方“十二五“发展规划,采用情景分析方法估算了2015年海西区大气污染物的排放清单.与基准年相比,SO2、nOX和nH3的排放量呈下降趋势,PM2.5和VOCS的排放量呈大幅度增加.基准年排放清单的不确定性分析显示,VOCS排放估算的不确定度最大,为225%.The emission inventories of SO2,NOx,PM2.5,VOCsand NH3 in the Western Taiwan Straits Economic Zone in the base year of 2009 were established based on the pollution source census,statistical yearbooks,industrial activities and residential activities.The total emissions of SO2,NOx,PM2.5,VOCs and NH3 were estimated to be 40.67×104,55.84×104,50.57×104,152.26×104and 26.18×104t,respectively.The power plants were the most important source and contributed to 25.58%,34.89% and 38.75% of the total emissions of SO2,NOxand PM2.5,respectively.However,the major source of VOCs and NH3 was vegetation and livestock breeding,which contributed to 49.12% and 47.07% of the total,respectively.The relative high emission areas of SO2,NOxand PM2.5were consistent with the locations of stationary sources based on GIS gridding techniques.In addition,the emission inventories in the year of 2015 were calculated using scenario analysis method based on the national and regional 12thFive-Year Plans.The emissions of SO2,NOx,and NH3 showed a slight decrease while the emissions of PM2.5and VOCs increase significantly(around 24.18% and 74.42%,respectively) in 2015,as compared to those in 2009.The estimate of VOCs had the highest uncertainty of around 225%.环境保护公益性行业科研专项(No.201009004); 厦门大学山海基金(No.2013SH011)~

    2017年厦门金砖会晤期间气象因素与管控措施对空气质量的影响

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    2017年厦门金砖会晤期间采取了大气污染临时管控措施,使AQI小时值和日均值均达到了双优的预期目标.本文根据管控措施实施的前、中、后阶段,厦门及周边城市大气污染物浓度的变化,对气象因素和人为因素的影响分别进行分析.结果发现,气态污染物对临时管控措施的敏感性最强,SO2和NO2的降幅(39.9%和25.6%)明显高于PM2.5和PM10的降幅(5.5%和4.8%),台风外围带来的大风和降水可显著改变大气污染物的周期性变化规律.大气PM2.5组成及SO2/NO2、SO【math395z】/NO【math396z】、OC/EC和WSOC/OC等比值变化显示机动车(尤其是柴油货车)是本地区大气污染物的重要来源.控制变量分析显示,厦门金砖会晤期间气象因素对颗粒物和NO2削减的贡献更大(20.3%),而临时管控措施对SO2的削减效果更明显(23.2%),且有一半以上(51%~64%)的大气污染物来自外来源输送.国家重点研发计划(No.2016YFC0502901);;国家自然科学基金(No.41471390);;厦门大学校长基金本科生项目(No.20720162006)~

    Glacial meltwater and sea ice meltwater in the Prydz Bay, Antarctica

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    Measurements of d D and salinity were carried out in the Prydz Bay during two Antarctic cruises, the 13th and the 14th Chinese National Antarctic Research expeditions (CHINARE). Mass balance calculations based on d D and salinity showed that during the 13th CHINARE cruise, per- centages of glacial meltwater and sea ice meltwater in the study region ranged from 0% to 3.82% and from 3.19% to 4.78%, respectively. Meanwhile, the percentages were 1.53%—3.98% and 3.80%—4.52% during the 14th CHINARE cruise. We dep..

    Size Distribution of Particle and Polycyclic Aromatic Hydrocarbons in Particle Emissions from Simulated Emission Sources

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    采用再悬浮箱模拟得到不同粒径的烹调油烟、生物质和塑料燃烧烟尘、汽车尾气和发电机烟气等颗粒,并用gC/MS对不同粒径颗粒中18种多环芳烃(PAHS)进行了分析.结果表明,烹调油烟中颗粒物存在0.44~1.0μM和2.5~10μM两个峰值,稻草和木材燃烧排放烟尘只有0.44~1.0μM一个峰值,塑料燃烧排放烟尘的峰值不明显,汽车尾气尘因含有大量的水汽导致其粒径峰值出现在2.5~10μM,而发电机排放的烟尘约93%集中在≤2.5μM的粒径范围.烹调油烟和汽车尾气尘中低环数PAHS在2.5~10μM范围内的峰值明显;随环数增加,0.44~1.0μM范围内的峰值变得明显;不同排放源亚微米颗粒中单一PAH占全部颗粒态中该PAH的比例都呈现随分子量的增大而增大的趋势.烹调油烟和燃烧排放颗粒中PAHS的组成以菲占主导,但汽车尾气和发电机烟尘中含量最高的PAHS分别是萘和苯并[g,H,I]苝.来源特征比值的比较显示,烹调油烟与生物质燃烧颗粒中PAHS的源特征较为接近,但两者都不同于汽车尾气和发电机烟尘.Particles from cooking lampblack,biomass and plastics burning smoke,gasoline vehicular exhausts and gasoline generator exhausts were prepared in a resuspension test chamber and collected using a cascade MOUDI impactor.A total of 18 polycyclic aromatic hydrocarbons( PAHs) associated with particles were analyzed by GC-MS.The results showed that there were two peaks in the range of 0.44-1.0 μm and 2.5-10 μm for cooking lampblack,and only one peak in the range of 0.44-1.0 μm for straw and wood burning smoke.But there were no clear peak for plastics burning smoke.The peak for gasoline vehicular exhausts was found in the range of 2.5-10 μm due to the influence of water vapor associated with particles,while the particles from gasoline generator exhausts were mainly in the range of ≤2.5 μm( accounting for 93% of the total mass).The peak in 2.5-10 μm was clear for cooking lampblack and gasoline vehicular exhausts.The peak in the range of 0.44-1.0 μm became more and more apparent with the increase of PAHs molecular weight.The fraction of PAH on particles less than 1.0 μm to that on the total particles increased along with PAH's molecular weight.Phenanthrene was the dominant compound for cooking lampblack and combustion smoke,while gasoline vehicular exhausts and generator exhausts were characterized with significantly high levels of naphthalene and benzo[g,h,i]perylene, respectively.The distribution of source characteristic ratios indicated that PAHs from cooking lampblack and biomass burning were close and they were different from those of vehicular exhausts and generator exhausts.国家自然科学基金项目(40971257;41171365); 环境保护公益性行业科研专项(201009004

    厦门海域水体无机氮和活性磷酸盐含量的变化趋势

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    根据2003~2008年每年丰水期、枯水期和平水期于厦门海域开展的海洋环境调查的资料,研究了该海域水体无机氮和活性磷酸盐含量区域分布和时间变化趋势.结果表明,调查期间该海域水体无机氮和活性磷酸盐平均含量都较高,分别为0.50、0.031 mg/dm3.其营养盐含量的区域分布相差较大,其中九龙江口水体无机氮含量最高,年均含量为0.52~1.37 mg/dm3;厦门西港水体活性磷酸盐含量最高,年均含量为0.039~0.061 mg/dm3;而大嶝海域水体无机氮和活性磷酸盐含量最低,年均含量分别为0.06~0.22、0.007~0.016 mg/dm3.调查期间全海域水体无机氮含量呈逐年增加趋势,活性磷酸盐含量在2003~2005年间呈上升趋势,而2005~2008年则有小幅度的下降.厦门海域水体N/P原子比较高,调查期间全海域年均值为27.4~47.5,且呈逐年增加趋势.无机氮含量的明显增加趋势及越来越严重的N/P比失衡,势必对该海域海洋生态系统尤其是浮游植物群落演替产生不良影响.此外,研究还发现厦门海域水体无机氮含量与盐度呈高度负相关(r=-0.96,n=30).这有力地证明了九龙江径流输入是厦门海域无机氮的最主要来源

    Species composition and ecological distribution of planktonic diatoms in the Changjiang River estuary during Spring

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    20 0 2年春季 ,在长江口附近海域典型赤潮高发区 2 8个大面站位采集了 5 3个样品 ,从中共鉴定出隶属于 31个硅藻属的 80个种和变种 ;其中种类多样性较高的属为圆筛藻属 (Coscinodiscus) ,有 17个种 ,斜纹藻属 (Pleurosigma) ,有 8个种和变种 ;数量上较优势的种为柔弱拟菱形藻 (Pseudo nitzschiadeli catissma) ,为 3.4 8× 10 3 cells·L-1,占 2 8.5 4 % ;具槽直链藻 (Melosirasulcata) ,为 1.4 3× 10 3 cells·L-1,占16 .98% ;尖刺拟菱形藻 (Pseudo nitzschiapungens) ,为 0 .71× 10 3 cells·L-1,占 9.85 % .它们在大部分站位中都有出现 ;柔弱拟菱形藻和尖刺拟菱形藻的高细胞密度区主要出现在 12 30E断面的站位 ,而具槽直链藻则主要出现在长江口的 31~ 32°N断面的站位 .浮游硅藻总细胞丰度变化于 0 .4 3× 10 3 ~ 2 3.3× 10 3 cells·L-1,平均 4 .6 1× 10 3 c... 【英文摘要】 water samples were collected from 28 stations in typical regions where redtide frequently occurred in the Changjiang River estuary during Spring, 2002. In total, 80 diatom species and varieties belonging to 31 genera were identified, among which, genera with high species biodiversity included Coscinodiscus which contained 17 species and Pleurosigma which contained 8 species and varieties. Quantitative analysis of diatom cell density showed that Pseudo-nitzschia delicatissma (3.48×10 3cells·L -1, 28.54%...国家重点基础研究发展规划资助项目 ( 2 0 0 1CB40 970 1)
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