技术进步路径选择与中国制造业出口隐含碳排放强度

本文采用考虑反馈性出口隐含碳的MRIO模型,测算了2000—2011年中国14个制造业行业出口隐含碳排放强度;在此基础上,基于全球价值链(GVC)分工地位的视角,理论分析并实证检验了不同技术进步路径对中国制造业出口隐含碳排放强度的影响。研究发现:中间品进口、自主研发、模仿创新显著降低了中国制造业出口隐含碳排放强度,而国外技术引进和外商直接投资(FDI)对中国制造业出口隐含碳排放强度的影响不显著;提升中国制造业在GVC中的国际分工地位能够显著降低其出口隐含碳排放强度。进一步研究发现,不同技术进步路径对中国制造业出口隐含碳排放强度的作用效果受到制造业在GVC中的国际分工地位的影响,并表现出明显的门槛特征,即只有中国制造业在GVC中的分工地位越过门槛值后,技术进步路径才能显著降低中国制造业出口隐含碳排放强度。此外,将制造业分为知识密集型、资本密集型和劳动密集型三类,发现不同技术进步路径对中国制造业出口隐含碳排放强度还存在着显著的行业差异。因此,中国制造业应充分发挥中间品进口、自主研发、模仿创新在降低中国制造业出口隐含碳排放强度中的作用,在引进FDI和国外技术的过程中,优先考虑引进发达国家的先进低碳制造技术和清洁生产技术。同时,中国制造业还应积极培育自身竞争优势,构建自我主导的国内价值链和区域价值链体系,主动嵌入全球创新链,提升中国制造业在GVC中的国际分工地位。此外,政府应根据技术创新和引进政策在不同制造业行业中的执行效果,有所侧重地制定和实施相关政策。     

沉积物原位物理洗脱技术对苦草萌发生长的影响

原位物理洗脱技术是一种应用于修复受污染的沉积物的新兴技术,但沉积物洗脱处理后对沉水植物萌发生长的影响尚不明确。通过模拟原位空气洗脱与原位水力洗脱2种典型原位物理洗脱技术,处理富含有机质的沉积物,研究洗脱对苦草萌发和生长指标的影响,以及洗脱后沉积物的理化性质的变化。结果表明:2种方式洗脱后沉积物中苦草种子的萌发率、萌发速度以及幼苗的株高、鲜质量、根数、叶数等指标均优于未洗组,其中水力洗脱后沉积物中苦草的萌发生长状况最好,萌发率是未洗组的2.9倍,株高和根数分别是未洗组的2.29和4.76倍;物理洗脱后,沉积物中氨氮($NH_{4}^{-}$-N)与酸可挥发性硫化物(AVS)等还原性物质浓度分别下降34.15%~35.19%和7.67%~44.89%,有机质浓度下降70.04%~77.90%,表层(0~5 cm)沉积物由强还原状态(ORP<-350 mV)改善至弱还原状态(ORP为-200~-100 mV);此外,沉积物中大粒径(50~2 000 μm)颗粒占比增至89.02%~92.84%,有利于上覆水中的O₂向沉积物中扩散,促进苦草的萌发生长。原位物理洗脱尤其是水力洗脱后,沉积物的理化条件更有利于苦草的萌发生长。     

3种高级氧化体系处理氯苯及其稳定中间体

在运用芬顿(Fe2+/H2O2)、亚铁离子活化过硫酸钠(Fe2+/PS)和碱活化过硫酸钠(NaOH/PS)3种氧化体系处理典型污染物氯苯(CB)时,发现了3种氧化体系在氧化CB过程中对氯苯酚中间体(4-CP)产生量存在较大差异.探究了氧化剂用量对3种氧化体系降解CB及中间体4-CP的影响,通过总有机碳和游离氯离子浓度变...     

过硫酸盐在岩溶管道地下水中的稳定性及其对苯系物的去除效果

原位化学氧化(in situ chemical oxidation,ISCO)是一种高效便捷的去除地下水有机污染物的技术,相比于多孔介质,岩溶地下河中ISCO技术应用还未见报道.为了更好地认识ISCO技术在岩溶地下河石油污染修复中应用的可行性,使用过硫酸盐(persulfate,PS)作为化学氧化剂,在实验室利用碳酸盐...     

一种新型隔热材料在原位土壤热修复工程中的表面阻隔效应

对原位热修复场地表层土壤采用有效的隔热措施,有助于实现节能降耗.纳米中空陶瓷微珠水性隔热涂料是一种新型隔热材料,导热系数低,可作为原位热修复修复场地的表面阻隔材料.通过现场实验,探究了该涂料的隔热性能及其受施工方法、实验区域尺寸等因素的影响.结果 表明,在加热井热影响区域内,新型隔热材料的温度梯度最高可达13600℃·...     

基于电絮凝法处理矿区高浓度含氟地下水动力学分析

采用铝电极电絮凝体系对矿区高含氟地下水进行处理,研究了高氟浓度下电絮凝除氟过程,分别考察了电流密度、极板间距、进水氟质量浓度及pH对除氟效果和动力学常数的影响,并建立了电絮凝除氟动力学方程模型。结果表明：最佳除氟参数为电流密度为450 A·m⁻³,极间距为5 mm,pH为6.0~7.0;当进水氟质量浓度为12.1 mg·L⁻¹时,经60 min电絮凝除氟后可使进水氟质量浓度由12.1 mg·L⁻¹降为0.6 mg·L⁻¹以下,整个除氟过程遵循一级反应动力学模型且除氟动力学常数取决于电流密度、极板间距和进水氟质量浓度。絮体结构与成分分析表明,在pH=6.0~7.0条件下,电絮凝体系中主要形成的无定型羟基铝化合物使除氟效果达到最好,较高的进水氟质量浓度有助于提高铝离子利用效率。     

垃圾填埋场污泥坑原位修复工程实践

垃圾填埋场内污泥坑的存在严重影响填埋场竖向扩建和填埋堆高。对某垃圾填埋场内污泥坑进行现场勘察取样、原位测试与室内实验,获得污泥的分层及沿深度变化的物理、力学特性,并针对不同分层的污泥,提出表层垃圾清除、污水抽排、泥水混合污泥土工管袋脱水、流塑、软塑污泥原位固化综合处理方法。对污泥坑抽排污水过程中垃圾堆体边坡进行渗流稳定分析,发现渗滤液水位快速下降将导致污泥坑垃圾边坡滑移失稳,在污泥坑治理过程中应采取相应措施。根据污泥坑上覆80~120 m垃圾堆体沿原位固化污泥滑移稳定分析,获得污泥坑原位固化处理强度指标,不排水抗剪强度Cu为40 kPa。     

The in vitro effect of selected essential oils on the growth and mycotoxin production of Aspergillus species

The aim of the present study was to assess the antifungal and anti-toxinogenic activity of 15 essential oils (EOs) against three fungi of the genus Aspergillus (A. parasiticus KMi-227-LR, A. parasiticus KMi-220-LR and A. flavus KMi-202-LR). The minimum inhibitory doses (MIDs) of the tested essential oils and their antifungal activity were determined using the micro-atmosphere method. The original commercial essential oil samples of Jasminum officinale L., Thymus vulgaris L., Syzygium aromaticum (L.) Merrill &; Perry, Rosmarinus officinalis L., Ocimum basilicum L., Eucalyptus globulus Labill., Salvia officinalis L., Citrus limon (L.) Burm, Origanum vulgare L., Lavandula angustifolia Mill., Carum carvi L., Citrus sinensis (L.) Osbeck., Zingiber officinalis Rosc., Mentha piperita L. and Cinnamomum zeylanicum Nees. (C. verum J.S.Presl.) were produced in Slovakia (Calendula a.s., Nová ?ubovňa, Slovakia). All essential oils exhibited activity against all tested strains of fungi. After 14 days of incubation, A. flavus (KMi-202-LR) showed the highest susceptibility with a growth inhibition percentage (GIP) of 18.70% to C. limon and 5.92% to C. sinensis, while A. parasiticus (KMi-220-LR) exhibited a GIP of 20.56% to J. officinale. The minimum inhibitory doses (MIDs) of EOs with the most significant activity were recorded. The best antifungal activity, using the micro-atmosphere method was found in S. aromaticum with an MID of 62.5 μL L^?1 air, T. vulgaris (MID of 62.5 μL L^?1 air) and O. vulgare (MID of 31.5 μL L^?1 air) against all tested strains. Mycotoxin production of the tested strains was evaluated by the thin layer chromatography (TLC) method. Mycotoxin production of AFB₁ and AFG₁ was inhibited following all treatments with C. carvi, R. officinale and S. officinale, Eucalyptus globulus L. and O. basilicum L. Essential oils exhibited a potential inhibition activity against toxic fungi, although, these affected only the production of AFB₁.     

Influence of concentration distribution of hydrogen in air on measured flammability limits

There is a clear difference between exiting data on the measured flammability limits of hydrogen-air mixture. The non-uniformity of concentration distribution of hydrogen in air is a contributor to deviations of the upper flammability limit (UFL) and the lower flammability limit (LFL) measured in different experiments. This paper presents a numerical model to simulate the gas mixing process from start to stability, to predict the concentration distribution, and to research the influence of concentration distribution of hydrogen in air on measured UFLs and LFLs. The commercial software package Fluent was used to carry out the numerical simulation for the concentration distribution of hydrogen in air in the vessels with length-to-diameter ratios (L: D) of 1:1, 3:1, 5:1 and 7:1 respectively. Based on the numerical simulation and analysis, the influence of concentration distribution on measured flammability limits was demonstrated for hydrogen in air in the vessel. It is found that the deviations of measured flammability limits of hydrogen in air are the minimum in the vessel with length-to-diameter ratio of 1:1, and augment with the augmentation of vessel length-to-diameter ratio. Moreover, it is presented that the deviations of measured flammability limits of hydrogen in the center of the vessel are lower than that in the top and the bottom.     

Gas flame acceleration in long ducts

In many practical situations, a flame may propagate along a pipe, accelerate and perhaps transform into a devastating detonation. This phenomenology has been known, more or less qualitatively, for a long time and mitigation techniques were proposed to try and avoid this occurrence (flame arresters, vents,...). A number of parameters need to be known and in particular the “distance to detonation” and more generally the flame acceleration characteristic scales. Very often, the ratio between the detonation run-up distance and the pipe diameter is used without any strong justification other that using a non-dimensional parameter (L/D). In this paper, novel experimental evidence is presented on the basis of relatively large scale experiments using 10 cm and 25 cm inner diameter duct with a length between 7 and 40 m. Homogeneous C₂H₄-air, CH₄-air, C₃H₈-air and H₂-air mixtures were used and different ignition sources. The interpretation suggests that the self-acceleration mechanism of the flame may be much better represented by flame instabilities than by turbulence build-up. One consequence would be that the maximum flame velocity and, following, the maximum explosion overpressure, would be rather linked with the run-up distance than with the L/D ratio.