防毒面具新型多功能检漏测试评价系统

一种新型轻便的多功能防毒面具泄漏测试评价系统已研制成功并装备部队.该系统易于在野外或实际作业场所进行相应的测试评价,同时还能够测定防毒面具的可靠性、适合性,对于防毒面具的缺陷部件如饮水管、呼气阀等部件具有较好的测试与评价能力.通过该仪器对防毒面具进行的可靠性和适合性测试,可以帮助使用者显著增加其对所佩戴防毒面具的信心,保证了作业人员的人身安全,提高了作业效率,对于防毒面具等呼吸器的性能检测与监控具有重要的现实意义.     

城市地表灰尘颗粒体积分形特征及其吸附性

以地表灰尘颗粒分析数据为基础,运用分形模型,分析了芜湖市高新技术开发区地表灰尘颗粒的分维数.结果表明:19个地表灰尘样品的粒径较粗,粒径的平均值多出现在140～230 gm之间,峰值多出现在200～400 μm之间;分维数为2.5392～2.7408.平均值为2.665 7,pH值为7.97～12.36,平均值为10.22,呈较强的碱性.分维数与pH值之间的相关系数r=-0.221 0,相关性不明显;地表灰尘分维数对吸附性的影响效果不明显.     

Heavy metal concentrations in edible bivalves and gastropods available in major markets of the Pearl River Delta

ＩｎｔｒｏｄｕｃｔｉｏｎＩｔｉｓｉｎｃｒｅａｓｉｎｇｌｙｄｉｆｆｉｃｕｌｔｔｏｃｏｎｓｉｄｅｒｍａｒｉｎｅｐｏｌｌｕｔｉｏｎｉｎＨｏｎｇＫｏｎｇｗｉｔｈｏｕｔｒｅｆｅｒｅｎｃｅｔｏＧｕａｎｇｄｏｎｇＰｒｏｖｉｎｃｅｏｒｔｈｅｅｎｔｉｒｅＰｅａｒｌＲｉｖｅｒＤｅｌｔａ.ＴｈｅＰｅａｒｌＲｉｖｅｒＤｅｌｔａｉｓｎｏｔｏｎｌｙａｇｅｏｍｏｒｐｈｉｃａｌｕｎｉｔｂｕｔａｌｓｏａｇｅｏｇｒａｐｈｉｃａｌｕｎｉｔａｎｄｔｈｅｓｃｏｐｅｏｆｔｈｅＰｅａｒｌＲｉｖｅｒＤｅｌｔａｓｈｏｕｌｄｉｎｃｌｕｄｅｍａｊｏ…     

长春秋季细颗粒物中有机气溶胶组成特征及来源

利用大流量采样器采集了长春城郊2016年10月至2016年11月大气细颗粒物(PM_(2.5))样品共40套,分析了颗粒物中的有机碳(OC)、元素碳(EC)以及非极性有机化合物(主要包括正构烷烃、多环芳烃以及藿烷类化合物)和生物质燃烧标志物左旋葡聚糖的质量浓度,并用分子标记物、特征比值及主成分分析-多元线性回归(PCA-MLR)模型等方法探讨了有机气溶胶的主要来源.结果表明,观测期间PM_(2.5)的平均质量浓度为(79. 0±55. 7)μg·m~(-3),OC和EC的平均质量浓度分别为(20. 7±15. 6)μg·m~(-3)和(2. 2±1. 1)μg·m~(-3),分别占PM_(2.5)的26. 2%和2. 8%.所测非极性有机化合物的总平均浓度为(186. 3±104. 5) ng·m~(-3),浓度高低顺序为正构烷烃[(101. 3±67. 0) ng·m~(-3)]多环芳烃[(81. 4±46. 0) ng·m~(-3)]藿烷类化合物[(3. 8±1. 9) ng·m~(-3),其主要来源包括煤燃烧源、生物质燃烧源以及交通源.主成分分析-多元线性回归模型得出该地区有机气溶胶主要排放源的相对贡献依次是煤燃烧源(47. 0%)、生物质燃烧源(42. 6%)和交通源(10. 4%).本研究结果可为我国东北地区有机气溶胶污染防控提供科学依据.     

Diverse molecular compositions of dissolved organic matter derived from different composts using ESI FT-ICR MS

Dissolved organic matter (DOM) derived from various composts can promote significant changes of soil properties. However, little is known about the DOM compositions and their similarities and differences at the molecular level. In this study, the molecular compositions of DOM derived from kitchen waste compost (KWC), green waste compost (GWC), manure waste compost (MWC), and sewage sludge compost (SSC) were characterized by electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). The molecular formulas were classified into four subcategories: CHO, CHON, CHOS, and CHONS. The KWC, MWC, and SSC DOM represented the highest fraction (35.8%-47.4%) of CHON subcategory, while the GWC DOM represented the highest fraction (68.4%) of CHO subcategory. The GWC DOM was recognized as the nitrogen- and sulfur-deficient compounds that were less saturated, more aromatic, and more oxidized compared with other samples. Further analysis of the oxygen, nitrogen-containing (N-containing), and sulfur-containing (S-containing) functional groups in the four subcategories revealed higher organic molecular complexity. Comparison of the similarities and differences of the four samples revealed 22.8% ubiquitous formulas and 17.4%, 11.1%, 10.7%, and 6.3% unique formulas of GWC, KWC, SSC, and MWC DOM, respectively, suggesting a large proportion of ubiquitous DOM as well as unique, source-specific molecular signatures. The findings presented herein provide new insight into the molecular characterization of DOM derived from various composts and demonstrated the potential role of these different compounds for agricultural utilization.     

羟基磷灰石对成都平原水稻土中重金属的钝化效果研究

本研究选取成都平原典型农田系统受Cd和Zn复合污染土壤为研究对象,采用淋溶试验和老化试验,探索添加羟基磷灰石对土壤中重金属生物有效性以及形态分布的影响,羟基磷灰石添加比例（w/w）设置为0%（CK）、1%（P1）、3%（P3）和5%（P5）。结果表明：①添加羟基磷灰石能够明显降低土壤中Cd和Zn淋失量,P1、P3和P5与CK的Cd累积淋失量（110 μg）相比,降低比例分别为82.7%、92.7%、90.7%,P1、P3和P5与CK的Zn累积淋失量（9.30 mg）相比,降低比例分别为94.8%、97.1%、94.6%;②添加羟基磷灰石能够显著提高土壤pH,P1、P3和P5的pH分别比CK升高了0.30、0.53、0.95个pH单位;③添加羟基磷灰石能够显著降低土壤有效态Cd和Zn（0.025 mol HCl）,相较于CK,P1、P3和P5的有效态Cd含量分别降低了59.0%、94.7%、98.7%,有效态Zn含量分别降低了18.6%、49.6%、87.6%;④添加羟基磷灰石能够显著降低土壤可交换态和碳酸盐结合态Cd和Zn含量,增加土壤中残渣态Cd和Zn含量,从而促进Cd和Zn向非活性态转化。本研究结果表明羟基磷灰石在成都平原区典型农田系统耕地Cd和Zn污染的修复中有较大的应用潜力。     

水解-好氧生物法处理城市污水试验研究

采用水解 好氧工艺的原理 ,设计了将污水与污泥处理合二为一的高效组合水解池 三相生物流化床流程 ,在广州经济技术开发区进行了处理量为 1 0 0L/h的城市污水处理试验。试验结果表明 :在平均进水CODCr为 4 92 3mg/L ,BOD5为 2 4 0 9mg/L ,SS为 5 5 2 3mg/L ,NH4 N为 1 8 8mg/L ,TP为 2 0mg/L条件下 ,平均出水CODCr为 4 7 3mg/L ,BOD5为 2 2 lmg/L ,SS为 1 3 9mg/L ,NH4 N为 5 2mg/L ,TP为 1 4mg/L ,并进行了该工艺中污泥循环的初步分析 ,为该工艺处理城市污水工业化提供了技术参考。     

Distinct community assembly processes underlie significant spatiotemporal dynamics of abundant and rare bacterioplankton in the Yangtze River

• Season and landform influenced spatiotemporal patterns of abundant and rare taxa. • Different stochastic processes dominated abundant and rare subcommunity assembly. • River flow and suspended solids regulated assembly processes of rare taxa. The rare microbial biosphere provides broad ecological services and resilience to various ecosystems. Nevertheless, the biogeographical patterns and assembly processes of rare bacterioplankton communities in large rivers remain uncertain. In this study, we investigated the biogeography and community assembly processes of abundant and rare bacterioplankton taxa in the Yangtze River (China) covering a distance of 4300 km. The results revealed similar spatiotemporal patterns of abundant taxa (AT) and rare taxa (RT) at both taxonomic and phylogenetic levels, and analysis of similarities revealed that RT was significantly influenced by season and landform than AT. Furthermore, RT correlated with more environmental factors than AT, whereas environmental and spatial factors explained a lower proportion of community shifts in RT than in AT. The steeper distance–decay slopes in AT indicated higher spatial turnover rates of abundant subcommunities than rare subcommunities. The null model revealed that both AT and RT were mainly governed by stochastic processes. However, dispersal limitation primarily governed the AT, whereas the undominated process accounted for a higher fraction of stochastic processes in RT. River flow and suspended solids mediated the balance between the stochastic and deterministic processes in RT. The spatiotemporal dynamics and assembly processes of total taxa were more similar as AT than RT. This study provides new insights into both significant spatiotemporal dynamics and inconsistent assembly processes of AT and RT in large rivers.     

Photochemical degradation of six polybrominated diphenyl ether congeners under ultraviolet irradiation in hexane

The photodegradation of six individual PBDE congeners (BDE-28, 47, 99, 100, 153, 183) in hexane was investigated under UV light in the sunlight region, employing a mercury lamp filtered with Pyrex glass. All photodegradation reactions followed the pseudo-first-order kinetics, with the half-lives ranging from 0.26h for BDE-183 to 6.46h for BDE-100. The photochemical reaction rates of PBDEs decreased with decreasing number of bromine substituents in the molecule, also in some cases were influenced by the PBDE substitution pattern. Principal photoproducts detected were less brominated PBDEs, and no PBDE-solvent adducts were found. Consecutive reductive debromination was confirmed as the main mechanism for the photodegradation of PBDEs in hexane. In general, debromination firstly occurred on the more substituted rings, when the numbers of bromine atoms on the two phenyl rings were unequal. For less brominated PBDEs, the photoreactivity of bromines at various positions of phenyl rings decreased in the order: ortho>para; while for higher brominated PBDEs, the difference became not significant.     

可见光响应的碘掺杂TiO2光催化剂的制备及其作用机理

以钛酸四丁酯为前驱物制备了碘掺杂TiO2催化剂(I-TiO2),考察了碘掺杂量、水解水量、水解温度和煅烧温度对催化剂物理化学性质与光催化活性的影响。X射线衍射(XRD)结果显示,I-TiO2由锐钛矿相和金红石相组成。在可见光照射下,通过降解水溶液中的苯酚评价了I-TiO2催化剂的光催化性能。结果表明,在水解温度为20℃,水解水量为300 mL,煅烧温度为400℃,碘钛比(摩尔比)为20%的制备条件下,催化剂显示了最优的光催化活性。通过向反应体系中引入自由基捕获剂及降低溶解氧,证实光催化降解苯酚主要由光生空穴或吸附的羟基自由基引发。