Predicting survival of planted Douglas-fir and ponderosa pine seedlings on dry,low-elevation sites in southwestern Oregon

Four equations were developed for predicting the probability of Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] and ponderosa pine (Pinus ponderosa Dougl. ex Laws.) survival for the first (0–1) and first to third (1–3) growing seasons after applying mulching, scalping, or artificial shading (shade cards) treatments in plantations in southwestern Oregon, U.S.A. Variables describing conifer size, levels of competing vegetation, presence of silvicultural treatments, site factors, and climate factors were collected from 13 sites ranging from 0 to 6 years after planting and examined as potential predictors of survival. Age, stem diameter, a competition index for shrubs, severity of growing season at time of treatment, average annual precipitation, aspect, and slope angle were predictors of Douglas-fir survival during 0–1 and 1–3 growing seasons after treatment; the presence of silvicultural treatments was also a predictor only during the first growing season after treatment. Age, aspect, and slope angle were predictors of ponderosa pine survival over both 0–1 and 1–3 growing seasons after treatment; height-diameter ratio, competition indices for herbs, shrubs, and hardwoods, silvicultural treatment, severity of growing season at time of treatment, and average annual precipitation were also predictors only during the first growing season after treatment; crown width was a predictor of survival only during 1–3 growing seasons after treatment. When significant in the models, predicted probability of survival increases with treatments, less severe weather conditions, diameter, crown width, age, and precipitation; probability decreases with increasing height-diameter ratio and competition indices for herbs, shrubs, and hardwoods.     

阳离子分散松香施胶剂施胶性能的研究

阳离子分散松香施胶剂（ＣＤＲＳ）作为松香系列施剂的新型换代产品之一,其施胶性能是评价其应用价值的重要依据。本研究对自制的ＣＤＲＳ在不同条件下的施胶效果进行了试验并与现有的商品松香施胶剂进行了对比。中碱性条件一的施胶试验结果表明,ＣＤＲＳ相对阴离子分散松香胶而言,消耗助留剂硫酸铝的量约低５０％,而且在ＰＨ６．５－７．５条件下具有较好的施胶效果。     

The Calculation on the Size of Foundation Basein Reinforced Concrete Single-Foundation under Column

This paper discusses the size of foundation base in reinforced concrete single-foundation under column.The two kinds of direct-calculating formulas have been derived. They are simple and helpful.They can be easily used in foundation design.     

井灌工程优化规划方法的研究

以平原灌区旱、涝、碱综合治理为前提,以控制地下水位等为约束条件,进行灌溉水资源供需平衡计算;用供需平衡计算确定的最大开采量作为各种布井方案的标准,计算各种布井方案的投资、运行管理费用和能耗;进行各种井灌工程方案的优选。     

区域土地利用结构的碳效应评估及低碳优化

区域土地利用是引起碳排放的重要因素,土地利用结构优化能在一定程度改变土地利用的碳源/汇格局,并引导区域经济社会的低碳发展。基于线性规划方法,该文建立了区域土地利用碳效应综合评估及优化调控的方法,并以南京市为例,提出了3种土地利用低碳优化方案,并对其碳减排潜力进行了对比分析及蒙特卡洛模拟,最后提出了低碳土地利用优化的政策建议。结果发现,2020年南京市土地利用总体规划方案使区域的总碳蓄积量有所提升,但预期碳排放远远大于碳蓄积的增加值,同时也将会导致生态系统碳汇能力的降低;在3种优化方案中,基于碳排放最小化的土地利用结构优化方案比2020年规划方案的碳排放减少了73.75万 t,碳减排潜力为8.50%,表明该方案起到了较好的预期减排效果;因此,该文建议将基于碳排放最小化的土地利用结构优化方案作为南京市未来土地结构调整和产业规划的参考,该方案不仅有助于实现碳减排的目标,而且对于控制建设用地的过快增长、增加生产性土地面积、引导农地整理和居民点用地整理等土地利用规划和开发活动都具有重要的现实意义。     

基于GF-3全极化SAR影像多特征优选的水产养殖塘提取

高分三号作为中国首颗民用高分辨率多极化合成孔径雷达卫星,为水产养殖用地监测提供了重要的数据源.为了充分利用GF-3全极化SAR影像,该研究提出了一种基于特征优选的全极化SAR影像养殖塘提取方法.首先通过极化分解和灰度共生矩阵方法共获取了55维特征;然后对影像进行多尺度分割,并利用随机森林-递归特征消除(Random F...     

Polychlorinated biphenyls (PCBs) in bulk soil and particle size separates of soils in a rural community

In a rural community (Stephanskirchen, Southern Germany) situated near a waste incineration plant six A horizons were sampled to determine 14 polychlorinated biphenyls (PCBs) in bulk soil and particle size separates (clay, silt, fine and coarse sand) and to test the suitability of alkaline saponification for PCB extraction. The PCB concentrations were higher in alkaline saponification extracts than in Soxhlet extracts. However, the extraction efficiency of up to fourfold chlorinated PCBs was lower and more than sevenfold chlorinated PCBs were destroyed. Nevertheless, alkaline saponification was suitable to determine the indicator congeners 28, 52, 101, 138, 152, and 180. The sum of the PCB concentrations ranged from 8.4 to 59.5 μg kg^?1 which was as high as in soils of big cities. However, the concentrations did not reach the threshold value for agricultural purposes of 200 μg kg^?1 as proposed in literature for the sum of the six indicator congeners. The hexachlorinated PCBs 138 and 153 were the most abundant (together > 50% in all samples) whereas PCB 1 could not be detected in any sample. On the average, PCB concentrations increased as particle size decreased. When normalized to C_org, however, the fine sand fraction had the highest PCB concentrations. A slight decrease of lower chlorinated PCBs as particle size decreased indicated an increasing state of degradation. The PCB compositions in the emissions of a comparable waste incineration plant (Bamberg, Bavaria) and in Stephanskirchen soils differed markedly. Therefore, we did not get any indications that waste incineration was a main source of PCBs in the examined soils. Instead, higher chlorinated technical PCB mixtures such as Clophen A 60 or Aroclor 1260 may be the most important sources.     

Tandem size exclusion chromatography-Polyacrylamide gel electrophoresis of humic acids

Humic acids (HAs) from four soils were fractionated by size exclusion chromatography (SEC) on Sephadex G-75. Three fractions were obtained in all humic acids, collected and assayed by Polyacrylamide gel electrophoresis (PAGE). The unfractionated HA from each soil was used as reference. Each chromatographic fraction formed one electrophoretic zone corresponding closely to one band of the reference sample with some admixture of the fractions preceding or following. The results indicate that fractionation of HAs by tandem SEC-PAGE can be successfully used for obtaining fractions of reduced polydispersity and different electrophoretic mobilities. Pyrolysis/methylation-gas chromatography-mass spectrometry of the full size preparations of HA and fractions with exactly defined molecular size and electrophoretic mobility showed a different distribution in humic components, mainly lipids, lignin derivatives and N-containing compounds.     

秦京输油管道优化运行研究

在对秦京输油管道系统分析的基础上,建立了秦京输油管道优化运行的动态规划数学模型,将这个数学模型看作二维资源分配问题,即把全线总压头和全线总热负荷在各站间进行最优分配。提出了一种二维动态规划求解方法,在求解时用逐次法降维。这种方法既充分考虑了秦京输油管道的特点,又兼顾了数学上的严密性,在所建立的数学模型及提出的优化计算方法的基础上,用Ｗｉｎｄｏｗｓ环境下Ｖｉｓｕａｌ Ｂａｓｉｃ语言开发了秦京输油管道     

硒都黑猪体重与体尺指标的通径分析及最优回归模型的建立

为了探讨硒都黑猪体重与体尺指标的相关性,研究体尺指标对体重的直接和间接作用,构建体重与体尺的最优回归模型,试验选取190日龄硒都黑猪167头,测量体重(Y)与体高(X1)、体长(X2)、胸围(X3)、腹围(X4)、臀长(X5)、臀宽(X6)、臀围(X7)等各项体尺指标,并进行相关性分析、通径分析、逐步线性回归分析.结果...