异质性环境规制与高新技术企业共聚交互因果关系研究——基于多空间收敛交叉映射技术

异质性环境规制与高新技术企业共聚之间存在复杂而紧密的交互因果关系,如何加快两者融合发展,构建区域经济环境协调优势值得进一步研究。本文利用大数据分析方法,基于国内2011—2019年异质性环境规制与高新技术企业共聚的省域面板数据,采用多空间收敛交叉映射模型,在区域间高新技术企业共聚水平测度基础上,从“被共聚”和“向共聚”两个维度实证检验了高新技术企业共聚与不同类型环境规制间的交互因果关系。研究结果表明,不同类型环境规制与高新技术企业共聚之间存在的耦合关系各不相同,其中,命令控制型环境规制一方面受高新技术企业“向共聚”带来的促进作用,另一方面又将促进高新技术企业“被共聚”水平提升,且后者的影响程度略高于前者,存在显著双向因果关系;而市场激励型环境规制仅受高新技术企业“向共聚”的正向促进作用,存在显著单向因果关系;但公众参与型环境规制与高新技术企业共聚两者间不存在相互影响,无显著因果关系。本文聚焦异质性环境规制与高新技术企业共聚间的良性互动,为客观评价高新技术企业共聚微观绩效提供经验证据,为进一步在开放中实现经济与环境协同发展提供有益的政策启示。     

不同流速下零价铁调控污水管道节点硫转化的影响

研究了不同污水流速下,各粒径零价铁(ZVI)对实际污水中硫化物(S~(2-))和硫化氢(H_2S)浓度以及pH值的影响,并考察了不同污水流速下各粒径ZVI的损失量和消耗量.结果表明,当污水流速为0.2 m·s~(-1)和0.6 m·s~(-1)时,ZVI粒径越小,S~(2-)和H_2S的去除效果越好,其中R3-ZVI对S~(2-)和H_2S的控制效果最好,但其损失量和消耗量最高且pH偏高(分别为8.5和8.3),而R2-ZVI对S~(2-)和H_2S的控制效果与R3-ZVI接近且pH适中(分别为8.1和8.0),当污水流速提高至1.2 m·s~(-1)时,R2-ZVI对S~(2-)和H_2S的控制效果最好且pH值适中(7.9),而R3-ZVI的损失量和消耗量因受水流速度影响而显著增加,从而导致其对S~(2-)和H_2S的控制效果降低,综合考虑,采用R2-ZVI控制污水中的S~(2-)和H_2S产生更经济有效.     

白洋淀典型抗生素与底栖藻类群落指标相关性研究

底栖藻类作为湖泊中主要的生产者,其对抗生素较为敏感,目前有关喹诺酮类抗生素(quinolones, QNs)与底栖藻类群落的相关性研究较为缺乏,因此本研究选取白洋淀为研究区,利用超高效液相色谱串联质谱法(HPLC-MS/MS)检测水体QNs浓度,并分析底栖藻类群落结构和功能指标,利用商值法(RQ)计算QNs的生态风险值,建立QNs生态风险与底栖藻类群落指标的相关性。研究结果如下。(1)白洋淀QNs浓度存在明显时空差异。就空间分布而言,QNs的最高浓度出现在生境1(1 309.80ng·L~(-1));就时间变化而言,4月QNs浓度最高;就QNs种类而言,氟甲喹(flumequine, FLU)浓度最高(1 054.38 ng·L~(-1));(2)就藻类群落指标的空间分布而言,除藻密度(AD)、叶绿素a(Chl a)、叶绿素b(Chl b)、叶绿素b/a(Chl b/a)、绿藻比例(CHL)、蓝藻比例(CYA)、碱性磷酸酶(APA)、β-葡萄糖苷酶(GLU)、亮氨酸氨基肽酶(LEU)和无灰干重(AFDW)等指标最大值出现在生境2外,其他指标最大值出现在生境3;就时间分布而言,大部分底栖藻类群落指标11月值高于4月和8月;(3)除FLU的生态风险处于中等水平外,其余QNs生态风险较低;其中,8月生境2的生态风险值最高(RQ最大值为0.9446);(4) AD、Chl a、Chl b、叶绿素c(Chl c)、Chl b/a与RQ_(CIP)和RQ_(FLU)呈显著相关,其中Chl a与RQ_(FLU)的相关性显著(r=0.827,P<0.01)。结果表明,底栖藻类结构指标与QNs风险值相关性较为显著,因此,可考虑筛选较为敏感的底栖藻类群落结构指标,为富营养化湖泊生态监测方法研究提供理论基础及相关数据支撑。     

Characterization of extractable and non-extractable polycyclic aromatic hydrocarbons in soils and sediments from the Pearl River Delta, China

Formation of bound residues of pollutants in soils and sediments is an important process to control the fate of pollutants in the environment. The most of bound residue is not solvent extractable. In this paper, we measured both extractable and non-extractable polycyclic aromatic hydrocarbons (PAHs) in different organic matter fractions of samples from the Pearl River Delta, China. Non-extractable PAHs concentration was 234.45-1424.57 μg/kg and accounted for 33.78-57.44% of total PAHs. 2-3 Ring PAHs were the dominant species and differed in concentration substantially between the samples. The atomic ratio of PAHs over organic-C in the fractions ordered as solvent soluble organic matter > humin > humic acids, matching the content of aliphatic moieties in the fractions of organic matter. The ratio of extractable and non-extractable PAHs may relate to the aging process of PAHs in soil and sediment.     

Accuracy of ultrasound diagnoses in pregnancies complicated by suspected fetal anomalies

Referral of pregnancies complicated by suspected fetal anomalies to level III perinatal centres for further evaluation and management is increasing as use of real-time ultrasound spreads, but the sensitivity and specificity of the prenatal diagnoses made in this population are unknown. We undertook a prospective study that followed pregnancies referred to a designated programme dealing with suspected fetal abnormalities. Follow-up of 257 pregnancies revealed that 282 separate anomalies were accurately diagnosed in 212 cases. Normal anatomy was correctly predicted in 42 cases, 16 per cent of the referred population. False-positive and false-negative rates were 1·5 per cent (4/257) and 2 per cent (1/46), respectively. However, 37 per cent of those infants born with anomalies had additional problems not prenatally detected by ultrasound. These results indicate that prenatal ultrasound diagnoses are remarkably accurate overall but that they may be insensitive to associated anomalies in individual cases.     

Bioaccumulation and changes of trace metals over the last two decades in marine organisms from Guangdong coastal regions, South China

Trace metal (Cr, Ni, Cu, Zn, Cd and Pb) exposures, distribution and bioaccumulation were investigated in marine organisms from Guangdong coastal regions, South China. The results showed that all of the selected metals were observed in marine organisms with a predomination of Cu and Zn. The metal exposure levels exhibited obvious variations between species with the decreasing order of crab>shellfish>shrimp>fish. The higher metals enrichment seen in shellfish and crab species primarily attributed to their living habits and the higher sediment background values of trace metals. Endpoint bioaccumulation factor (BAF_fd) was used to characterize the bioaccumulation potentials of marine organisms to trace metals, of which Cu and Zn were the most accumulated elements. The exposure of trace metals in the cultured organisms was far lower than those in wild marine organisms, which is probably due to the effect of growth dilution. Comparisons with previous studies demonstrated that the concentration profiles of most trace metals declined over the last one to two decades, except Cu, that increased indistinctively.     

浅谈当前我国环境执法的障碍与对策

环境执法是我国环境法制建设的一个重要组成部分。本文从当前环境立法权威、环境立法之间的关系、环境立法内容、环境职能部门的权力配置、执法人员素质、地方领导、环境管理体制、环境执法的群众参与以及公民的环境法律意识等方面问题和障碍的分析，提出了应对策略和建议。     

基于人体动力学模型钢楼梯振动舒适度及其控制研究

基于人体动力学模型研究钢楼梯人致振动舒适度问题,并利用TMD对其振动进行控制。采用移动质量-弹簧-阻尼的单自由度体系模拟人体动力学模型,将模型施加在钢楼梯有限元模型上,运用完全时程方法得到钢楼梯在人-结构动力相互作用下的动力响应,并对比分析不考虑人-结构动力相互作用时的动力响应,以峰值加速度为指标评估该楼梯的振动舒适度;对振动过大的钢楼梯,采用3种不同优化模型的TMD进行振动控制。结果表明:行人步频的倍频与结构自振频率相近时,考虑人-结构动力相互作用时结构加速度峰值多则会减小20%以上;3种不同优化模型的TMD都能够有效减小楼梯的振动响应,建议优先选用Warburton参数优化模型。