Prediction Intervals for Estimates of Site Index Based on Ecosystem Type

/ British Columbia has an ecosystem classification system that classifies sites into site series. Foresters commonly measure the productivity of these sites by their site index. In British Columbia, site index is defined as the height of a stand at breast height age 50 and is usually estimated from height-age models. Biogeoclimatic site series/site index relationships are an increasingly popular method of estimating site index in British Columbia for stands where site index cannot be reliably estimated with height-age models. The precision of the predicted site index from these relationships can be evaluated with prediction intervals. This is done for the predicted site index of a single site, a group of sites, or the areally weighted site index of a group of sites. The methodology is also useful in determining the number of sites required to meet a specified precision. These prediction intervals will assist foresters in making sound forest management decisions.KEY WORDS: Biogeoclimatic Ecosystem Classification; Precision; Prediction interval; Site index; Site series     

双组分VOCs在吸附树脂上的吸附穿透特性

选取超高交联吸附树脂（H-resin）和大孔吸附树脂（M-resin）作为吸附剂，采用固定床吸附法研究了单、双组分的正戊烷和环己烷在2种不同孔结构吸附树脂上的吸附穿透特性.结果表明：2种吸附树脂对正戊烷和环己烷的吸附主要依靠色散力作用，吸附树脂对摩尔极化率大的环己烷有更优秀的吸附能力.双组分吸附实验中，由于富含微孔的H-resin对不同组分VOCs的吸附作用力差别大，发生环己烷取代正戊烷的现象，并且取代随环己烷浓度升高而更加显著，但吸附温度由30升至50℃过程中，取代现象减弱.M-resin的孔主要分布在中、大孔区，对环己烷和正戊烷的吸附作用力相近，因而正戊烷和环己烷在M-resin上始终为共同吸附.     

括苍山地区火山构造

括苍山火山岩区是由不同阶段、不同火山机构组成的火山构造组合体。总体的构造格局是隆起和断块。不同旋回具有不同的火山构造组合,同一旋回的火山构造类型也不甚相同。第一旋回是火山喷发一侵入穹窿;第二旋回发育三类破火山口;第三旋回由上叠式火山沉积洼地和破火山口组成;第四旋回主要为较完整的锥火山和小别破火山口。这四个旋问的火山机构呈叠瓦式和复合继承式组合,尤以叠瓦式组合为主。     

催化铁内电解法处理难降解有机废水

催化铁内电解法是一种新型的有效处理废水的方法。在传统的铁碳内电解中加入无机催化剂铜，扩大原电池的两极电位差，使更多的有机物得到还原。结果表明，催化铁内电解法可改善难降解有机废水的可生化性，使活性艳红染料废水的B/C比从0升高到0.15。运行成本低廉、预处理能耗低，催化剂铜经连续运行数月后未发生纯化现象，只需一次性投资。     

Chemical speciation and anthropogenic sources of ambient volatile organic compounds(VOCs)during summer in Beijing,2004

Volatile organic compounds (VOCs) were measured at six sites in Beijing in August, 2004. Up to 148 VOC species, including C₃ to C₁₂ alkanes, C₃ to C₁₁ alkenes, C₆ to C₁₂ aromatics, and halogenated hydrocarbons, were quantified. Although the concentrations differed at the sites, the chemical compositions were similar, except for the Tongzhou site where aromatics were significantly high in the air. Based on the source profiles measured from previous studies, the source apportionment of ambient VOCs was preformed by deploying the chemical mass balance (CMB) model. The results show that urban VOCs are predominant from mobile source emissions, which contribute more than 50% of the VOCs (in mass concentrations) to ambient air at most sites. Other important sources are gasoline evaporation, painting, and solvents. The exception is at the Tongzhou site where vehicle exhaust, painting, and solvents have about equal contribution, around 35% of the ambient VOC concentration. As the receptor model is not valid for deriving the sources of reactive species, such as isoprene and 1,3-butadiene, other methodologies need to be further explored.     

室内空气中苯和甲苯浓度分布特征调查

室内挥发性有机物(VOCs)中的苯和甲苯是造成室内空气污染的主要原因之一。对某系列办公室和民用住宅进行空气采样，运用气相色谱法进行分析。结果表明，对于内部装修后超过1年的办公室、室内苯、甲苯浓度均不超过标准限值：苯浓度占TVOC的1．3％—13％，其中大部分房间为7％左右：甲苯浓度占TVOC的0％—8．5％，其中大部分房间为5％以下：室内苯浓度一般高于甲苯浓度。对于内部装修后1—2月内的民用住宅，室内苯、甲苯污染相当严重，部分住宅远远超出标准限值：苯浓度一般低于或接近甲苯浓度。因此，可以认为室内甲苯的释放速度比苯快。     

中国近代大震系列与预测

本文研究了中国近代的三列大震系列.在它们发生之前都出现过强震系列.在地震预报中,使用强震系列与大震系列及其公式:Ni'=Ni-k'/(1-b)k可以预报强震与大震.利用强震系列的相关性,预测大震系列也是有益的.     

Description of adsorption of hydrophobic organic compounds on sediment using multi-component adsorption model

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不同硒化合物在WISTAR大鼠主要组织器官中的分布

对Wistar大鼠一次性灌服亚硒酸钠、硒代硫酸软骨素、硒代蛋氨酸和硒酵母后,硒在小肠、肝脏、肾脏和心脏中的含量均有提高,不同硒化合物在不同脏器中的时效规律不完全相同,但主要脏器的硒排出过程均符合指数扩散规律.硒代蛋氨酸在脑中积累,在其他脏器中表现明显滞留效应.脏器硒含量顺序为硒代蛋氨酸>亚硒酸钠≈硒代硫酸软骨素>硒酵母.     

超声辐射Fenton试剂耦合法降解直链十二烷基苯磺酸钠的研究

对超声辐射Fenton试剂耦合法降解水中直链十二烷基苯磺酸钠进行了研究。采用单因子法考察了硫酸亚铁用量，氧化剂H2O2用量，超声辐射反应温度和初始溶液pH值等因素对降解率的影响；采用正交试验法优化降解条件，得出了各因素影响的显著性次序。在环境压力下，超声辐射频率40kHz，超声辐射功率500W，反应时间15min，反应温度95℃，溶液起始pH值3，降解物起始质量浓度200mg／L，硫酸亚铁与双氧水质量浓度分别为O．65g／L和1．2g／L的最佳降解条件下，十二烷基苯磺酸钠的降解率可达99．31％。研究结果表明：超声波辐射Fenton试剂耦合法是一种有效的降解十二烷基苯磺酸钠的方法。与Fenton试剂氧化催化法相比，能够显著地缩短反应时间，提高降解率。