秸秆还田模式对农田土壤碳库特性及产量的影响

为探明南方稻麦两熟制农田秸秆还田模式对土壤总有机碳、活性有机碳、碳库管理指数和稻麦产量的影响,论文通过8 a的水稻-小麦轮作田间定位试验,设置了4个秸秆还田模式处理：秸秆不还田（CK）、秸秆稻麦季均还田（RW）、仅麦秸稻季还田（W）、仅稻秸麦季还田（R）。结果表明,与CK处理相比,秸秆还田显著提高了0~20 cm土壤的总有机碳、活性有机碳、稳定态有机碳（P<0.05）;不同秸秆还田模式处理之间的土壤总有机碳、稳定态有机碳差异均不显著（P>0.05）,RW处理的活性有机碳、碳库活度指数、碳库管理指数与R处理无显著差异性（P>0.05）,显著大于W处理（P<0.05）;RW与R处理的水稻产量均值无显著差异性（P>0.05）,显著大于W处理;活性有机碳、碳库管理指数与水稻产量均值呈极显著相关（P<0.01）,与小麦产量均值关系不密切（P>0.05）;上述结果表明,与稻麦两季还田模式相比,南方稻麦两熟制农田实施仅稻秆麦季还田模式,并不影响作物稳产性与土壤地力的提升。     

盐池北部风沙区土地利用格局变化对沙漠化的影响

以盐池北部风沙区为研究区域,利用1989、1995、2000、2007年土地利用现状图,借助地理信息系统软件提取有关格局分析的基础数据,基于景观生态学原理,构造主要土地利用类型和沙地景观格局指数,探讨不同时段内盐池北部风沙区土地利用格局变化对沙化景观的影响。结果表明：（1）沙地景观在1995年之前不断扩张,1995年以后开始减少,集中连片沙地被零星分布的小沙化斑块取代;（2）林地和草地经历了先减少后增大的过程,土地利用格局变化中,中、低覆盖度草地和灌木林地变动性大;中、低覆盖度草地、耕地、灌木林地不稳定性程度较高;（3）受农作活动影响,尤其在灌溉条件较好区域,草地沙化明显,而灌木林能起到很好的防沙作用;（4）盐池北部风沙区土地利用格局特征指标与沙地面积呈负相关,随着特征指标增大沙化面积减小。土地利用格局变化能够综合反映相应时段内的人类活动结果,以此为切入点研究其对沙漠化的影响,有利于揭示沙漠化的驱动机制。     

崇明岛典型土地利用方式对土壤有机碳和酶活性的影响

为了研究上海崇明岛不同土地利用方式对土壤有机碳以及酶活性的影响,对冬小麦地、蔬菜地、柑桔地和冬绿肥地4种土地利用方式的土壤进行了调查、样品测定和分析。结果表明,土地利用方式对有机碳和4种酶活性的影响极显著。冬小麦地总有机碳和活性有机碳质量分数均最高,分别为19.23g·kg^-1和2.26mg·g^-1,柑桔地土壤脲酶、碱性磷酸酶、纤维素酶和蛋白酶等4种酶活性均高于其他3种土地利用方式,表明采用秸秆还田式的冬小麦地,可以增加土壤总有机碳和活性有机碳质量分数;常年处于免耕状态的柑桔地可以使土壤酶活性增强。     

Driving under the influence of alcohol and drugs in the eastern part of Denmark in 2015 and 2016: Abuse patterns and trends

Objectives: The objective of this study was to examine the frequency of psychoactive drugs and alcohol in drivers under suspicion of driving under the influence of drugs and alcohol in 2015 and 2016 in the eastern part of Denmark. The trends in the number of traffic cases sent for drug analysis since 2000 and alcohol analysis since 2011 are also discussed.

Methods: Blood samples from drivers suspected of being under the influence of alcohol and/or medication and/or illicit drugs in 2015 and 2016 were investigated as requested by the police. The blood samples were screened for alcohol and/or tetrahydrocannabinol (THC) alone, for other drugs (covering all drugs, except THC, listed in the Danish list of narcotic drugs), or for THC and other drugs. Age and gender were also recorded. The number of drug traffic cases since 2000 and the number of alcohol cases since 2011 were extracted from our Laboratory Information Management System (LIMS).

Results: In total, 11,493 traffic cases were investigated. Alcohol and/or drugs exceeded the legal limit in 9,657 (84%) cases. Men constituted 95% of the drivers investigated for drugs and 88% of the alcohol cases. The drivers investigated for drugs consisted primarily of young men, whereas drivers investigated for alcohol were older.

The frequency was higher for positive alcohol cases above the legal limit (87%) than for drug cases (76%) above the fixed concentration limit. THC (67–69%) was the most frequently detected drug above the legal limit, followed by cocaine (27–28.5%), amphetamine (17%), and clonazepam (6–7%) in both years. Morphine (5.4%), included among the 5 most frequent drugs in 2015, was replaced by methadone (4.6%) in 2016. Few new psychoactive drugs (NPS) were detected.

The number of traffic cases sent for drug analysis has increased more than 30-fold since 2000–2006, and the number of traffic cases submitted in 2016 for drug analysis was higher than the number for alcohol analysis; the latter has decreased since 2011.

Conclusion: Overall, alcohol was the most frequent compound detected above the legal limit in both years, followed by the well-known illicit drugs THC, cocaine, and amphetamine. NPS were seldom seen. One consequence of the increased focus on drugs in traffic has been an immense increase in drug traffic cases sent for analysis since 2006 in the eastern part of Denmark. Although this survey revealed only minimal changes compared to earlier investigations, surveys like this are invaluable for monitoring abuse patterns and trends in drugged and drunken driving.     

中部3省城市建设用地功能时空演化特征

定量识别区域城市建设用地功能演化特征与模式,是推进可持续城市建设用地开发利用与管理、助力新型城镇化等国家战略的重要基础。从人口承载、生产与消费、公共服务3个方面构建了城市建设用地功能评价指标体系与模型,以地级市为研究单元探究了2000~2014年期间我国中部3省多尺度城市建设用地功能演化特征与模式。研究结果表明:(1)中部3省城市建设用地人口承载、生产与消费、公共服务和综合功能总体呈改善趋势,但演化过程复杂;(2)不同尺度尤其是城市群地区城市建设用地功能演化特征差异明显。沿长江和城市群地区城市建设用地功能演化强度高,但城市群地区空间异质性较强;(3)城市建设用地功能演化以复合型演化模式为主,演化格局复杂。其中,城市建设用地人口承载功能演化模式类型最多,且局部地区呈衰退型演化格局;城市建设用地生产与消费、公共服务功能和综合功能演化模式类型相对较少,且大多集中连片分布,武汉城市建设用地综合功能加速改善型演化特征显著。如何深入探究城市建设用地功能演化模式形成机理,并系统制定多级城市建设用地可持续利用管理策略,是实现我国新型城镇化和"美丽中国梦"等战略的重要任务。     

焦化厂土壤中多环芳烃分布特征及淋洗粒级分割点确定

土壤粒径分布和污染物在不同粒级土壤中的分布特征是污染土壤淋洗可处理性的重要依据,淋洗粒级分割点则是淋洗工艺的重要参数.根据土壤异位淋洗的技术要求,在焦化厂污染场地进行了采样,测定了土样的粒径分布曲线及不同粒级土壤中美国EPA优控的16种多环芳烃(PAHs)的初始浓度,并采用Tween 80和Triton X-100溶液对不同粒级污染土样进行了振荡清洗实验.结果表明,16种PAHs在6个粒级中的总浓度在6.27～40.18 mg/kg范围,呈双峰分布模式,单个PAH污染物的最高浓度大多出现在250～500 μm的颗粒中, 50～75 μm的颗粒中污染物浓度最低;PAHs去除率与其初始浓度及土壤特性有关,初始浓度越低,去除率越高,粗颗粒中由于有机碳含量较高,PAHs去除效率反而低于细颗粒.根据清洗效果并从废物减量化角度出发,确定以50 μm作为土壤淋洗的粒级分割点,这样减容率可以达到82.95％.     

Linear and branched perfluorooctane sulfonate (PFOS) isomer patterns differ among several tissues and blood of polar bears

Perfluorooctane sulfonate (PFOS) is a globally distributed persistent organic pollutant that has been found to bioaccumulate and biomagnify in aquatic food webs. Although principally in its linear isomeric configuration, 21–35% of the PFOS manufactured via electrochemical fluorination is produced as a branched structural isomer. PFOS isomer patterns were investigated in multiple tissues of polar bears (Ursus maritimus) from East Greenland. The liver (n = 9), blood (n = 19), brain (n = 16), muscle (n = 5), and adipose (n = 5) were analyzed for linear PFOS (n-PFOS), as well as multiple mono- and di-trifluoromethyl-substituted branched isomers. n-PFOS accounted for 93.0 ± 0.5% of Σ-PFOS isomer concentrations in the liver, whereas the proportion was significantly lower (p < 0.05) in the blood (85.4 ± 0.5%). Branched isomers were quantifiable in the liver and blood, but not in the brain, muscle, or adipose. In both the liver and blood, 6-perfluoromethylheptane sulfonate (P6MHpS) was the dominant branched isomer (2.61 ± 0.10%, and 3.26 ± 0.13% of Σ-PFOS concentrations, respectively). No di-trifluoromethyl-substituted isomers were detectable in any of the tissues analyzed. These tissue-specific isomer patterns suggest isomer-specific pharmacokinetics, perhaps due to differences in protein affinities, and thus differences in protein interactions, as well transport, absorption, and/or metabolism in the body.     

中国低碳城市发展模式与行动策略

建设低碳城市是促进节能减排和经济社会持续发展的重要战略举措,成为未来城市发展的重要导向和路径选择.从低碳城市发展重要性和紧迫性入手,在立足基本国情的基础上设计了低碳城市发展愿景.结合城市化快速推进预期和经济社会发展需求,分阶段提出了低碳城市发展目标.从总体模式、指导理念、基本思路、主要领域等对我国低碳城市发展模式进行了构想.在此基础上,提出我国低碳城市发展的实施步骤和行动策略.研究认为,我国低碳城市发展模式应选择“C”模式,以低碳发展为主导方向,以节能减排为发展方式,以低碳生产和低碳生活为主要方法.按照控源、减碳、增汇的基本思路,依靠理念创新、技术创新和制度创新,在低碳产业、低碳能源、低碳技术以及低碳生活等领域,通过构建低碳城市规划理论框架、建立低碳城市评价标准和体系、加快相关政策规章与制度建设、开展城市碳交易试点以及加强监督指导等措施,立足国情、统筹兼顾,分步骤、分阶段有序推进低碳城市发展.     

开发区城市化效应的作用机制与空间模式——以大连市为例

结合大连的开发区时间,从集聚和引力扩散、制度创新、跨国公司主导下的产业链式成长、对母城的有机疏散、产业空间优化与重组、行政区划调整等6个方面探讨了开发区城市化效应的作用机制.在此基础上,总结了开发区城市化的3种空间模式,即大型综合经济功能区的飞地型模式、大型高新技术园区的郊区化模式、中小园区组群发展的嵌入与填充模式,提出了优化开发区城市化效应的对策建议.     

酸碱调控及底物浓度对木糖发酵产酸特性的影响

以木糖为碳源采用间歇培养方式,对木糖厌氧发酵产酸进行研究。考察木糖浓度和初始pH值对木糖厌氧产酸的影响。结果表明,随着木糖浓度的增加,总产酸量得到提高,但木糖利用率却呈现下降的趋势。当木糖浓度为5 g/L时,其利用率为100%,15 g/L时利用率为73.9%,此时挥发性脂肪酸(VFAs)为9.22 g/L。木糖的分批投加可有效促进产酸,尤其是促进乙酸浓度的提高。pH为5.0和6.0左右时,VFAs主要成分为乙酸和丁酸;而pH为7.0～9.0时,乙酸含量明显增高,在pH值为8.0的条件下乙酸含量占总VFAs的80.1%。在pH=8.0时经过8 d左右的发酵,VFAs浓度可达9.34 g/L。