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To better understand the attractiveness of host tree, Chinese white pines (Pinus armandi Fr.) to Chinese white pine beetle (Dendroctonus armandi Tsai and Li), the antennal responses of D. armandi to the host volatile, as well as the pure enantiomers and racemates of some monoterpenes, were examined using an electroantennogram
(EAG). EAG responses of male and female D. armandi to blended volatiles extracted from the host and some synthetic terpenes (α-phellandrene, (−)-β-pinene, (+)-α-pinene, (−)-α-pinene,
(−)-camphene, β-myrcene, (S)-(−)-limonene, (+)-camphene and (R)-(+)-limonene) showed significant variation due to different compound concentrations and sex of the beetles. EAG responses
to extracted blended volatiles were significantly greater in females than in males, but the EAG response was not always proportional
to the volatile concentration. At lower concentrations, females responded strongly to α-phellandrene and males to (−)-β-pinene,
while at higher concentrations, females responded most strongly to α-phellandrene and males to (+)-α-pinene. Females were
significantly responsive to (−)-α-pinene, α-phellandrene and (−)-camphene, while males were more responsive to (S)-(−)-limonene, (+)-α-pinene and (R)-(+)-limonene. The EAG responses of the female D. armandi to the volatile oil were significantly higher than that of the males, and the infested pine volatiles could evoke higher
EAG response. Most of the test compounds elicited similar responses, which suggested that several of the compounds may be
used in combination by D. armandi in habitat and/or host community location at the Qinling forest ecosystem. 相似文献
184.
近年来酸雨危害频繁发生,特别是长江三角洲地区,酸雨致使土壤中重金属锌的吸附和解吸发生了一定的变化。选取具有代表性的长江三角洲地区4种典型土壤,通过加入外源重金属锌培育污染土样,在不同pH的酸雨下对已污染土样进行解吸。通过实验探究土壤母质对于重金属锌的吸附及解吸的特点,为国家制定土壤标准提供可靠的数据支持。结果表明:土壤中锌的解吸量随着pH的降低而增加;比较不同母质发育而成的土壤,在pH=4.0、5.6模拟已污染土壤中锌的解吸量顺序为:沟沟堆积母质〉湖相沉积物母质〉河相沉积物母质〉海相沉积物母质。在pH=2.0、3.0时,河相沉积物母质、湖相沉积物母质解吸量迅速增加,超过海相沉积物母质锌的解吸量。 相似文献
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焊接细节断裂参数与其疲劳裂纹扩展和疲劳性能直接相关,为探讨几何参数和裂纹参数对应力强度因子的影响规律,选取十字形焊接细节为研究对象。借助ANSYS软件建立了含半椭圆形裂纹的三维断裂力学模型,基于位移法分析了应力强度因子,讨论了几何参数(焊缝尺寸、板厚、对接焊缝参数)和裂纹参数(裂纹尺寸和裂纹形状比)对其的影响规律,拟合了裂纹形状修正系数函数。研究结果表明:(1)应力强度因子随对接焊缝余高和腹板板厚的增大而逐渐减小,而基本不受焊脚尺寸、翼缘板板厚和对接焊缝宽度的影响;(2)应力强度因子随裂纹形状比的增大而先增大后逐渐减小,但是随裂纹尺寸的增长而逐渐增大;(3)裂纹形状比和裂纹尺寸对应力强度因子影响最为显著,其影响幅度达18.0%。 相似文献
188.
聚羟基烷酸(PHA)是微生物在不平衡营养条件下贮存的一种胞内聚合物,限磷和限氮两种方式均有助于活性污泥中的混合菌群合成PHA,研究考察了两种不同方式下活性污泥合成PHA的情况。实验结果表明,当C:N为125时,活性污泥中PHA的合成量达到细胞干重的59%;当c:P为750时,活性污泥积累的最大PHA含量占细胞干重的37%,说明限氮和限磷两种方式对活性污泥合成PHA均有很大影响,且限氮方式更有效。 相似文献
189.
Jingzhi Wang Xuwei Jia Shutao Gao Xiangying Zeng Huiru Li Zhen Zhou Guoying Sheng Zhiqiang Yu 《Environmental science and pollution research international》2016,23(11):10361-10370
The concentrations and distribution of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), and tetrabromobisphenol A (TBBPA) were investigated in 28 sediment samples collected from Taihu Lake, Eastern China. The results showed that all three classes of compounds were detected in 28 sediment samples but that PBDEs were the main contaminants in the study area. The total PBDE concentrations ranged from 3.77 to 347 ng/g dry weight (dw) with a mean value of 72.8 ng/g dw, whereas the concentrations ranged from 0.168 to 2.66 and from 0.012 to 1.30 ng/g dw for HBCD and TBBPA, respectively. In all of the sediment samples, BDE-209 was the predominant congener, accounting for 95.9 to 98.6 % of the total PBDEs, which indicated that commercial mixtures of deca-BDEs were the main sources of PBDE contamination. Higher concentrations of PBDEs were found in samples collected from Meiliang Bay and Gonghu Bay near the inflow river, which suggested that inflow runoff might play an important role in the PBDE levels in Taihu Lake sediments. 相似文献
190.
Shi X Liu X Liu G Sun Z Xu H 《Environmental science and pollution research international》2012,19(3):739-747