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41.
Tributyltin compounds have been successfully used for many years as wood preservatives, although their chemical nature in timber has not been fully elucidated. This study by 119Sn and 13C NMR spectroscopy has shown that, on impregnation into Pinus sylvestris sapwood, bis(tributyltin) oxide [(Bu3Sn)2O] is rapidly converted to tributyltin carboxylates (Bu3SnOCO·R) via reaction with components of the wood resin. It is further suggested that the formation of these species is a prerequisite for the known disproportionation reaction which occurs in (Bu3Sn)2O-treated timber.  相似文献   
42.
不同辐照源对黑松花粉粒的生物学效应   总被引:1,自引:1,他引:0  
研究了N+离子束、 紫外线和γ射线辐照对黑松花粉粒的影响, 对3种辐射源在诱发花粉粒细胞出现损伤效应上的差异性进行了比较分析。 研究结果表明, 3种辐照源对黑松花粉粒萌发和花粉管生长所表现出的效应存在明显的差异。 γ射线的剂量效应曲线表现为近S型; 紫外线辐照的剂量效应曲线呈现出近L型; 离子束的生物学效应主要在两个方面表现出特异性, 即离子束所导致的剂量 效应曲线呈“马鞍型”趋势和N+离子束注入后会诱发花粉管顶端产生出明显的肿胀现象。The effects of pollens and pollen tubes of Pinus thunbergii induced respectively by N+ beam, γ ray and ultraviolet ray were measured , and the differences of the effects caused by the different radiant factors were distinguished. The results showed that there was obvious difference in the damages of the pollen germination and the pollen tube growth led by the radiant factors. The curve of dose effects from γ ray irradiation was similarly S type, and that from ultraviolet ray treatment approximately L type . The effects from ion implantation expressed the two characteristics, the curve of the saddle type and the top inflation of pollen tube.  相似文献   
43.
ICP-OES测定两种松树中的矿质元素   总被引:3,自引:0,他引:3  
采用HNO3-HF-HClO4湿法消解木材样品,电感耦合等离子体发射光谱法(ICP-OES)测定思茅松、云南松茎干中的Ca、Fe、K、Mg、P、Mn、Zn等矿质元素。结果表明,思茅松、云南松中的矿质元素表现为不同的含量顺序,思茅松中矿质元素含量为Ca〉K〉Zn〉Mg〉P〉Fe〉Mn,而云南松中矿质元素含量为Ca〉Fe〉K〉Mg〉P〉Mn〉Zn。该方法具有良好的准确度及精密度,加标回收率在95.63%—108%范围内,相对标准偏差(RSD)在0.3%—2.4%范围内,结果可靠,操作方便,可用于其他树木样品中相同矿质元素的测定。  相似文献   
44.
Formic acid pretreatment onPinus radiata D. Don was studied in order to improve the cellulose hydrolysis by commercial cellulase. The formic acid treatment effectively removed the lignin. A low substitution (formylation) and a crystallinity decrease of the cellulose in the pulp were observed. As consequence of these parameter changes, owing to the formic acid pretreatment on sawdust, a higher saccharification value was observed. The degree of saccharification increased when the degree of substitution (measured by titration) decreased and the portion of amorphous cellulose (measured via an X-ray technique) increased.Trichoderma reesei cellulase hydrolyzed the untreated and pretreated Pinus sawdust with formic acid in 25% and 56% of saccharification, respectively.  相似文献   
45.
气相色谱-质谱技术分析红松松塔挥发性成分   总被引:8,自引:0,他引:8  
采用水蒸气蒸馏法,对红松松塔挥发性成分进行提取和研究,最佳蒸馏时间5.5h,挥发油提取率1.28%。利用气相色谱-质谱联用技术对提取的挥发油成分进行分析,共鉴定出32种化学成分,主要为单萜和倍半萜类化合物,其中相对含量较高的有α-蒎烯(44.258%)、D-柠檬烯(23.426%)、β-蒎烯(8.674%)、有石竹烯(3.462%)、β-月桂烯(3.018%)等。研究结果表明红松松塔挥发油中富含α-蒎烯、D-柠檬烯、石竹烯等多种具有药理活性的成分。因此,红松松塔是一种具有较好前景的天然药用资源。  相似文献   
46.
The chemical composition of Pinus silvestris essential oil from contaminated areas was studied. An apparent effect of radionuclides and toxic elements on the biosynthesis of terpenoids in common pine essential oil was found. Increasing contamination apparently increased the content of sesquiterpenes and O-containing substances and decreased the content of monoterpenes in the essential oil. The contents of α-pinene, camphene, and limonene increased and those of 3-carene, terpinolene, and β-pinene decreased in the monoterpene fraction. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 47–49, January–February, 2007.  相似文献   
47.
Differential scanning calorimetry (DSC) was used to compare the thermal curing of two adhesives suitable for using in the manufacture of exterior-grade plywood boards: a commercial phenol-formaldehyde (PF) resin, and a tannin-phenol-formaldehyde (TPF) resin developed in our laboratory. The experimental curves were well simulated by means of the Model Free Kinetics isoconversional method incorporated in the Mettler-Toledo STARe software package. The corresponding kinetic calculations predict that the TPF resin cures faster than the PF resin. This finding implies the possibility that the TPF resin may allow the achievement of higher productivity by permitting the use of shorter press times than with conventional PF resins. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
48.
Increasing heavy metal pollution in the environment and the fact that pine needles are good bio-monitors for air pollutants was the reason to investigate their accumulation in pine needles in Vienna (Austria). Pinus nigra is widespread over the city, thus allowing the study of different parameters influencing metal accumulation. The sampling sites were chosen based on traffic volume (low, medium, high). Fresh shoots were collected alongside one-year-old needles once per week from May to August 2015. The needle samples were washed and dried prior to acidic microwave-assisted digestion followed by quantitative determination using spectrometric methods. The investigation was focused on the following elements: Ag, Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Se, Sr, U, V, and Zn. The one-year-old needles mainly contained higher contents of elements than fresh shoots; in many cases, the values differed statistically significantly. By correlating needle elemental contents with the sampling site, statistically significant differences were registered for the majority of the investigated elements. These differences originate from the local traffic situation, soil elemental levels, translocation processes, and not traffic-related sources. No general trend of metal accumulation from spring to summer was registered.  相似文献   
49.
Pinus koraiensis nut-coated film is a kind of by-product of nut processing, which has been shown to contain flavonoids, polyphenols, and other substances that can be used to produce natural antioxidant extracts. In this study, response surface methodology (RSM) was used to optimize the extraction process of flavonoids of P. koraiensis nut-coated film (PNF), and macroporous resin HPD600 was used to purify PNF (P-PNF). Its antioxidant activity was examined by DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging capacity, oxygen free radical absorption capacity (ORAC), total oxygen radical capture (TRAP), and iron ion reduction capacity. Under the ideal extraction conditions comprising a cellulase dosage of 90 U/g, a material/liquid ratio of 1:20 (g/mL), and an extraction time of 2 h, the PNF yield was 3.37%. Purification conditions were sample concentration of 2.0 mg/mL, pH of 5, water washing volume of 3 bed volume (BV), eluent ethanol concentration of 50%, and volume of 2 BV. The P-PNF recovery was 84.32%, and purity increased from 33.80% to 61.70%. Additionally, P-PNF showed increased antioxidant activity compared to PNF. Cumulatively, this study obtained the optimal values for the process parameters in order to achieve the maximum rates of extraction of PNF for economically optimal production at an industrial scale.  相似文献   
50.
马尾松和湿地松松针挥发性成分的提取及GC-MS比较分析   总被引:2,自引:1,他引:1  
采用水蒸气蒸馏法提取马尾松和湿地松松针叶挥发油的油相部分,用乙醚萃取法提取蒸馏残液中的水溶性挥发性组分,利用气相色谱-质谱联用分析比较它们的化学成分。由于增加了水溶性部分的提取,马尾松和湿地松挥发油总的得油率提高到0.4709%和0.3452%,提高率分别达19.17%和24.62%。马尾松挥发油的油相成分和水溶性成分组成部分相同,但含量相差较大;而湿地松针叶精油的油相和水相部分成分组成差别较大;马尾松和湿地松相比较,针叶精油(油相部分)的主要化学成分大致相同,都是以单萜和倍半萜为主,但在含量上有较大差别。  相似文献   
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