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Hygroscopicity of ambient submicron particles in urban Hangzhou, China

Jiachen ZHANG, Lin WANG, Jianmin CHEN, Shengmao FENG, Jiandong SHEN, Li JIAO

《环境科学与工程前沿（英文）》 2011年第5卷第3期页码 342-347 doi: 10.1007/s11783-011-0358-7

摘要： In this study, hygroscopicity of size-segregated ambient submicron particles in urban Hangzhou was studied from 28th December 2009 to 18th January 2010, using a hygroscopicity-tandem differential mobility analyzer (H-TDMA). The submicron particles in Hangzhou showed a minor hygroscopic growth at 73% relative humidity (RH), and then grew significantly between 77% and 82% RH. Monomodal distribution accounted for 90% for 30 nm particles, 17% for 50 nm particles, and less than 7% for particles larger than 50 nm at 82% RH. Deconvolution of the bimodal distribution indicated a less hygroscopic group and a more hygroscopic group, with the fraction of the more hygroscopic group increasing with the initial dry particle size and then remaining almost constant for accumulation mode particles. Our results imply that submicron particles in urban Hangzhou were almost entirely externally mixed, and the hygroscopic properties of ambient particles in urban Hangzhou were mainly a function of their size and chemical composition.

关键词： hygroscopicity hygroscopic tandem differential mobility analyzer (H-TDMA) submicron ambient particles Hangzhou

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Prevalence and drug resistance characteristics of carbapenem-resistant Enterobacteriaceae in Hangzhou

null

《医学前沿（英文）》 2018年第12卷第2期页码 182-188 doi: 10.1007/s11684-017-0529-4

摘要：

With the abuse of antimicrobial agents in developing countries, increasing number of carbapenem-resistant Enterobacteriaceae (CRE) attracted considerable public concern. A retrospective study was conducted based on 242 CRE strains from a tertiary hospital in Hangzhou, China to investigate prevalence and drug resistance characteristics of CRE in southeast China. Bacterial species were identified. Antimicrobial susceptibility was examined by broth microdilution method or epsilometer test. Resistant β-lactamase genes were identified by polymerase chain reaction and sequencing. Genotypes were investigated by phylogenetic analysis. and were the most prevalent types of species, with occurrence in 71.9% and 21.9% of the strains, respectively. All strains exhibited high resistance (>70%) against β-lactam antibiotics, ciprofloxacin, trimethoprim–sulfamethoxazole, and nitrofurantoin but exhibited low resistance against tigecycline (0.8%) and minocycline (8.3%). A total of 123 strains harbored more than two kinds of β-lactamase genes. , , , and were the predominant genotypes, with detection rates of 60.3%, 61.6%, 43.4%, and 16.5%, respectively, and were highly identical with reference sequences in different countries, indicating potential horizontal dissemination. IMP-4 was the most frequent class B metallo-lactamases in this study. In conclusion, continuous surveillance and effective prevention should be emphasized to reduce spread of CRE.

关键词： Enterobacteriaceae carbapenem β-lactamase genes phylogenetic analysis

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human-induced influence on microbial community: A comparative study in the effluent-receiving areas in Hangzhou

Yuhan Zheng, Zhiguo Su, Tianjiao Dai, Feifei Li, Bei Huang, Qinglin Mu, Chuanping Feng, Donghui Wen

《环境科学与工程前沿（英文）》 2019年第13卷第6期 doi: 10.1007/s11783-019-1174-8

摘要： Microbial compositions showed high differences in two study areas. COD was the key anthropogenic indicator in the coastal wastewater disposal area. Distinctive microbes capable of degrading toxic pollutants were screened. Microbial communities in effluent-receiving areas followed “niche theory”. Microbial community structure is affected by both natural processes and human activities. In coastal area, anthropegenetic activity can usually lead to the discharge of the effluent from wastewater treatment plant (WWTP) to sea, and thus the water quality chronically turns worse and marine ecosystem becomes unhealthy. Microorganisms play key roles in pollutants degradation and ecological restoration; however, there are few studies about how the WWTP effluent disposal influences coastal microbial communities. In this study, sediment samples were collected from two WWTP effluent-receiving areas (abbreviated as JX and SY) in Hangzhou Bay. First, based on the high-throughput sequencing of 16S rRNA gene, microbial community structure was analyzed. Secondly, several statistical analyses were conducted to reveal the microbial community characteristics in response to the effluent disposal. Using PCoA, the significant difference of in microbial community structure was determined between JX and SY; using RDA, water COD and temperature, and sediment available phosphate and ammonia nitrogen were identified as the key environmental factors for the community difference; using LDA effect size analysis, the most distinctive microbes were found and their correlations with environmental factors were investigated; and according to detrended beta-nearest-taxon-index, the sediment microbial communities were found to follow “niche theory”. An interesting and important finding was that in SY that received more and toxic COD, many distinctive microbes were related to the groups that were capable of degrading toxic organic pollutants. This study provides a clear illustration of eco-environmental deterioration under the long-term human pressure from the view of microbial ecology.

关键词： Microbial community structure Effluent-receiving area High-throughput sequencing Costal sediments Wastewater treatment plant (WWTP)

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新型高黏度改性沥青的研发和应用

杨林江

《中国工程科学》 2008年第10卷第12期页码 92-96

摘要：

针对杭州湾大桥桥面铺装对高黏度改性沥青的技术要求，研发了一种新型高黏度改性沥青［1］。通过分析基质沥青、SBS、化学助剂的红外光谱，在研究沥青改性过程中微观结构变化规律的基础上，提出了采用SBS加化学接枝反应剂（增黏剂）TW-1和增容剂TW-2的沥青改性配伍设计，使改性沥青在提高低温延度、弹性恢复能力的同时，大幅度提升了60 ℃动力黏度，而施工和易性不受影响，产品在杭州湾大桥工程中得到了成功的应用。

关键词：杭州湾大桥高黏度改性沥青配伍机理红外光谱分析路用性能施工性能