无机物填充改性复合木材的制备及性能研究

为改善速生杉木木材的性质,试验中先后用硫酸铝和水玻璃等溶液对其进行处理,浸入木材的铝离子与硅酸根离子结合,在木材微纤丝间隙和管胞(或纤维)的胞腔中生成硫酸铝沉淀,从而使木材中填充了大量的无机物,得到杉木无机复合木材.无机复合木材的尺寸稳定性显著提高,在最优化工艺下,复合木材的抗收缩系数可达34.21,稳定系数在80%以上.同时,复合木材除抗冲击韧性略有下降外,其余如抗弯强度、抗弯弹性模量、顺纹抗压强度及硬度等主要力学性能指标均有明显提高.     

杉木改性复合木材的制备及性能研究

为改善速生材杉木木材的性质，实验中先后用硫酸铝和水玻璃溶液处理速生材杉木木材。浸入木材的铝离子与硅酸根离子结合，在木材微纤丝间隙和管胞（或纤维）的胞腔中生成硫酸铝沉淀，从而使木材中填充大量的无机物，得到杉木无机复合木材。无机复合木材的尺寸稳定性显著提高，抗收缩系数可达34．21，稳定系数达80％以上。同时，复合木材除抗冲击韧性略有下降外，其余如抗弯强度、抗弯弹性模量、顺纹抗压强度及硬度等主要力学性能指标均明显提高。     

碧护对“红富士”苹果品质的影响

通过对"红富士"苹果树喷施不同浓度的碧护溶液来研究碧护试剂对"红富士"苹果品质的影响。试验共分4次进行,分别为:展叶露红期,溶液浓度为0.02%,0.016 7%,0.014 3%;花期,溶液浓度为0.013 4%,0.011 8%,0.010 5%;花后和果实膨大期均喷施浓度为0.006 7%的溶液,且每次试验均与水作对照试验。果实采摘后,对果实单果质量、果形指数、可溶性固形物、硬度进行测定。结果表明:与对照组相比,在不同时期,喷施不同浓度的碧护溶液均可提高果实品质,使果实大小均匀,果泽鲜亮,含糖量增加。其中A2B2处理最为显著,浓度最为适宜。     

平压浸注填充PF树脂工艺对杨木增重率的影响研究

为探讨浸注工艺对木材增重率的影响,以PF树脂为浸注材料,以树脂浓度、压缩次数、保压时间、浸渍时间和压缩率为试验因素,采用单因素试验方法在平压浸注装置上对杨木试件进行了浸注填充。结果显示:2次压缩较1次压缩,杨木木材增重率增加了20. 2%;保压时间从0 min延长至10 min,杨木木材增重率增加了11. 5%;浸渍时间从1 h延长至2 h,杨木木材增重率提高了8. 8%;再增加压缩次数、延长保压时间和浸渍时间,杨木木材增重率均变化不大;而杨木木材增重率随PF树脂浓度和杨木木材压缩率增加呈线性增加,PF树脂浓度与压缩率对杨木木材增重率具有显著影响。因此选择压缩次数为2次,保压时间为10 min,浸渍时间为1 h,PF树脂浓度与杨木木材压缩率由改性木材的用途决定。     

PEG400复配ε-己内酯在樟子松饱水木材脱水定型中的应用研究

以人工速生材樟子松为原料,通过热水蒸煮法模拟饱水木材试件,选择50%PEG400水溶液和50%PEG400/50%ε-己内酯(ε-CL)复配溶液用于樟子松饱水木材试件的脱水定型研究。通过催化剂预浸渍、常温置换脱水和50℃热干燥聚合工艺,对比研究了PEG400和PEG400复配ε-CL对樟子松饱水试件的脱水定型效果,分析了各个阶段的质量和尺寸变化,探讨了脱水定型工艺对木材的尺寸稳定性、质量增加率、可逆性的影响;并对脱水定型后的木材试件进行红外光谱(FT-IR)、热重-差热联用(TGA-DTA)、扫描电子显微镜(SEM)分析表征。结果表明:PEG400及PEG400复配ε-CL溶液对樟子松饱水木材试件脱水定型效果良好,均表现出良好的可逆性,PEG400复配ε-CL脱水定型处理的木材试件质量增加明显,脱水定型试件干质量增加率为124.1%,干燥定型过程弦向、径向和体积收缩率分别为0.01%、0和0.01%,表现出良好的尺寸稳定性;FT-IR、TGA-DTA和SEM分析表明,ε-CL单体在木材内部发生开环聚合反应形成聚己内酯(PCL),PCL与PEG400包覆木材细胞壁,填充于木材内部结构中,加固木材细胞壁结构;PCL与PEG400的填充作用导致木材热稳定性降低,PCL于150℃最先发生降解,保护木材细胞壁成分。     

二氧化氯对藤稔葡萄保鲜及贮藏品质的影响

以藤稔葡萄为试验材料,研究二氧化氯对其保鲜及贮藏品质的影响。将藤稔葡萄分别浸入浓度为25、50、100 mg／L的ClO2溶液中,每种浓度均作浸泡10、20、30 min 3种处理。室温(20℃)贮存25 d后,测定其腐烂率、硬度、呼吸强度、总酸含量、总糖含量、Vc含量、SOD酶活性、POD酶活性。结果表明,ClO2有利于保持果粒的颜色、形态、硬度,保持果实中的总酸和Vc含量,抑制果实衰老。25 mg／L ClO2溶液中浸泡10 min的处理对藤稔葡萄保鲜贮藏效果较为理想。     

白松系列木材胶合板生产工艺探讨

以白松系列木材为原料制作胶合板,采用正交试验,对胶合板生产工艺进行探讨,结果表明:白松系列木材的性质(pH值)与椴木、水曲柳等同属酸性,适合作为胶合板生产原料;60℃水温下通过加入软化剂,可以降低木材节子的硬度;最佳生产工艺参数为:涂胶量240~280 g/m2(双面),填充剂加量10%~15%,单板含水率7%~10%,热压温度105℃,热压压力1.0 MPa,热压时间50 s/mm,陈化时间1 h。     

采后不同浓度钙处理对贮藏期间李果实硬度及果胶含量的影响

以‘龙园桃李’为研究对象,运用咔唑比色法,通过不同浓度的CaCl2溶液对贮藏期间李果实的处理,研究果实硬度及果胶含量的变化。得出结论:贮藏期间,随着李果实硬度的下降,共价结合果胶含量逐渐降低,水溶性果胶和离子态果胶含量升高;经CaCl2溶液处理后,各时期李果实硬度和果胶含量明显高于对照,硬度和果胶含量的变化比对照慢;1%CaCl2溶液浓度处理下,对李果实贮藏效果最好。     

热处理复合硅石溶液改性杨木的性能及机理研究北大核心

将硅石溶液经有机硅烷杂化后浸渍人工林杨木,再对其进行热处理,测试分析改性材的物理力学性能、化学结构及形貌特征,探讨木材联合改性机理。结果表明:1)复合硅石溶液改性使杨木的密度、强度和阻燃性均显著提高,但尺寸稳定性欠佳,热处理可明显增强其尺寸稳定性和阻燃性;2)改性剂填充固化于木材细胞腔,甚至渗入细胞壁中,可起到有效的增强作用;3)热处理可促进改性剂与木材组分发生稳固的Si—O—Si化学结合;4)联合改性材中Si原子配位数增多,缩聚固化程度更高,稳定性增强。复合硅石溶液/热处理联合改性是一种应用前景广阔的绿色木材改性技术。     

杨、柳软质木材改性工艺研究及其物理性能比较

杨树、柳树是中原地区主要的速生树种,为充分利用速生林软质木材,研究其改性工艺,提高木材品质。作者通过对杨、柳木干燥改性实验,对软质木材进行改性。改性后木材尺寸稳定性增强、硬度大幅增大,杨树、柳树硬度分别提高49.2%、40.1%;木材的抗弯强度分别提高49.0%、51.5%。     

杉木枯落物燃烧释放污染物特征及PM2.5成分分析

【目的】探究杉木人工林枯落物在不同燃烧状态时的气态及颗粒态污染物排放特征,并提取、测定细颗粒物(PM 2.5 )污染物的化学成分,揭示林火及林地清理等对杉木枯落物分解、养分循环和大气环境的影响。【方法】分别以杉木人工林枯落物中的叶、枝、皮、干4种主要组分为研究对象,运用自主设计的生物质模拟燃烧系统,采用室内模拟燃烧试验,分析阴燃和明燃2种不同燃烧状态不同枯落物组分释放的气态污染物和PM 2.5 特征及差异。采用德国Elementar元素分析仪,测定PM 2.5 中的碳质成分;采用超声提取-离子色谱和ICP/MS技术,测定PM 2.5 中的水溶性离子和水溶性无机元素。【结果】基于杉木枯落物燃烧时的实时测定,CO 2、CO、NO x 、C x H y 、PM 2.5 的排放因子(EF,单位质量燃料在燃烧后产生的污染物质量)变化范围在阴燃条件下分别是1 001.4~1 364.5、202.3~358.8、0.53~3.09、23.17~53.07、5.11~38.37 g ·kg -1 ,而明燃时分别为1 092.4~1 520.7、115.1~242.6、0.16~1.96、1.21~41.50、2.58~21.07 g ·kg -1 。此外,提取测定PM 2.5 成分的结果表明,颗粒物主要由碳质组分、水溶性离子及少量水溶性无机元素等组成。其中碳质组分含量最大,占50%以上,有机碳(OC)和元素碳(EC)平均质量分数分别为43.29%和12.91%;PM 2.5 中测定出6种阳离子(Li +、Na +、NH + 4、K +、Mg 2+、Ca 2+)和5种阴离子(F -、Cl -、NO 2 -、SO 4 2-、NO - 3),总水溶性离子占10%~33%,阴燃以Cl -、K +、Ca 2+、SO 4 2-为主要组分,明燃以K +、Cl -、SO 4 2-、Na +为主;PM 2.5 中提取测定出16种无机元素,分别为K、Ca、Na、Mg、P、Zn、Al、Cu、As、Ba、Cr、Fe、Mn、Cd、Li、Pb,含量极少,仅占PM 2.5 的0.04%~0.58%,其中K、Ca、Na、Mg、P、Zn为主要元素成分,占总无机元素的96.8%~98.8%。【结论】在不同燃烧状态下,杉木枯落物释放各污染物的排放因子存在显著差异,除CO 2外的其他污染物排放因子在阴燃时显著高于明燃;在同一燃烧状态时,杉木枯落物不同组分的CO、CO 2、NO x 、C x H y 和PM 2.5 等污染物的排放因子也存在显著差异。杉木枯落物燃烧排放的PM 2.5 主要由碳质组分、水溶性离子及少量无机元素等成分组成,阴燃时的各成分排放因子整体表现为高于明燃时。     

氢氧化钠预处理对木材漂白促进作用的研究

用ＮａＯＨ的稀溶液处理泡桐木材,观察桐木渗透性、木材颜色的变化不碱液对泡桐木材漂泊白效果的促进作用进行了研究。结果表明ＮａＯＨ稀溶液对木材颜色没有明显损害作用,能显著提高桐木的渗透性,促进木材漂白效果。泡桐木材经过２ｄ的０．３％ＮａＯＨ稀溶液预处理,再经２％的硫代硫酸钠漂白处理３ｄ,半年老化后测色,桐木表面和内部的白有度比未处理材显著提高,色差显著降低。     

不同钠盐对班克松种子萌发的影响

采用不同浓度的NaCl、Na2SO4和Na2CO3溶液处理班克松种子,测定发芽率、发芽势和发芽指数,研究钠盐胁迫对班克松种子发芽的影响。结果表明:低浓度(10、20 mmol·L-1)的NaCl、Na2SO4可以促进种子萌发,随着浓度增加,抑制作用加强,250 mmol·L-1的各项指标降到最低。Na2CO3溶液对种子萌发有较强的抑制作用,浓度相同时,Na2CO3胁迫下的各指标值均小于NaCl、Na2SO4。250 mmol·L-1时各项指标为0。由此可以得出,班克松种子具有耐盐性,但对不同钠盐的敏感性不同,对NaCl、Na2SO4的耐受性要高于Na2CO3。     

超临界CO_2流体携带戊唑醇对木质材料的防腐处理工艺

以杉木、马尾松木材和中密度纤维板、刨花板为试材,利用超临界CO2携带戊唑醇对试材进行防腐处理,研究超临界CO2流体辅助防腐处理工艺对戊唑醇的留着率以及分布状况的影响。结果表明,随着处理压力的增大,试材中戊唑醇的平均留着率和分布梯度都增大;温度对戊唑醇剂的留着率影响较复杂,处理温度45℃,留着率最高,同时温度与戊唑醇分布梯度没有明显的相关性;处理时间以30 min为宜。     

应用Na_2CO_3液防治杨树溃疡病初报

通过应用Na2CO3液防治杨树溃疡病的试验,结果表明:应用Na2CO3液防治杨树溃疡病,有效率平均达94.4%,此方法简便易行、无毒害、无污染,而且节省防治资金,平均每株费用0.1元。     

Scots pine responses to elevated temperature and carbon dioxide concentration: growth and wood properties

Growth and wood properties of 20-year-old Scots pine (Pinus sylvestris L.) trees were studied for 6 years in 16 closed chambers providing a factorial combination of two temperature regimes (ambient and elevated) and two carbon dioxide concentrations ([CO2]) (ambient and twice ambient). The elevation of temperature corresponded to the predicted effect at the site of a doubling in atmospheric [CO2]. Annual height and radial growth and wood properties were analyzed during 1997-2002. Physical wood properties analyzed included early- and latewood widths and their proportions, intra-ring wood densities, early- and latewood density and mean fiber length. Chemical wood properties analyzed included concentrations of acetone-soluble extractives, lignin, cellulose and hemicellulose. There were no significant treatment effects on height growth during the 6-year study. Elevated [CO2] increased ring width by 66 and 47% at ambient and elevated temperatures, respectively. At ambient [CO2], elevated temperature increased ring width by 19%. Increased ring width in response to elevated [CO2] resulted from increases in both early- and latewood width; however, there was no effect of the treatments on early- and latewood proportions. Mean wood density, earlywood density and fiber length increased in response to elevated temperature. The chemical composition of wood was affected by elevated [CO2], which reduced the cellulose concentration, and by elevated temperature, which reduced the concentration of acetone-soluble extractives. Thus, over the 6-year period, radial growth was significantly increased by elevated [CO2], and some wood properties were significantly affected by elevated temperature or elevated [CO2], or both, indicating that climate change may affect the material properties of wood.     

水培胡杨抗盐特性的研究*

1987和1989年,利用1、2年生胡杨苗,在水培条件下,通过电导率仪控制培养液浓度,对受盐害苗木进行了分析。研究结果表明,几种盐对苗木危害的排序是:Na_2CO_3>NaHCO_3>NaCl>CaSO_4>MgSO_4>以NaCl为主的盐渍皮。CaSO_4对苗木没有毒害作用。1年生苗比2年生苗受盐害后症状明显,但总的趋势是一致的。蒸馏水催根苗木,在蒸馏水中加盐后死亡浓度是:Na_2CO_3 0.05％、NaHCO_3 0.07％、NaCl 0.17％、CaSO_4 0.7％、MgSO_4 1.9％、以NaCl为主的盐渍皮3.5％。0.1％相应盐水催根苗在盐水培养液中加盐后,抗盐极限提高到:NaCl1.1％、MgSO_4 3.5％、NaCl为主的盐渍皮3.7％。说明胡杨幼苗经过抗盐处理后,可以显著地提高抗盐害能力。     

Free-air CO2 enrichment (FACE) enhances biomass production in a short-rotation poplar plantation

This paper investigates the possible contribution of Short Rotation Cultures (SRC) to carbon sequestration in both current and elevated atmospheric CO2 concentrations ([CO2]). A dense poplar plantation (1 x 1 m) was exposed to a [CO2] of 550 ppm in Central Italy using the free-air CO2 enrichment (FACE) technique. Three species of Populus were examined, namely P. alba L., P. nigra L. and P. x euramericana Dode (Guinier). Aboveground woody biomass of trees exposed to elevated [CO2] for three growing seasons increased by 15 to 27%, depending on species. As a result, light-use efficiency increased. Aboveground biomass allocation was unaffected, and belowground biomass also increased under elevated [CO2] conditions, by 22 to 38%. Populus nigra, with total biomass equal to 62.02 and 72.03 Mg ha-1 in ambient and elevated [CO2], respectively, was the most productive species, although its productivity was stimulated least by atmospheric CO2 enrichment. There was greater depletion of inorganic nitrogen from the soil after three growing seasons in elevated [CO2], but no effect of [CO2] on stem wood density, which differed significantly only among species.     

CaCl2在毛白杨幼苗抗冻性低温诱导中的作用

不同浓度的CaCl2 处理对毛白杨幼苗抗冻性的提高效应是不同的 ,其中 10mmol·L-1CaCl2 处理更有利于幼苗抗冻性的提高 ,而且处理最适宜时间为 5天 .低温锻炼不仅提高了毛白杨幼苗叶片和枝条中钙调素含量 ,同时也提高了幼苗抗冻性 .CaCl2 处理对低温锻炼的作用有加强效果 ,而钙离子螯合剂EGTA、钙离子通道阻断剂LaCl3 或钙调素拮抗剂CPZ处理则减弱低温锻炼效应 ,表现出CaM含量和幼苗抗冻性明显降低 .这表明Ca2 + CaM可能参与了幼苗抗冻性的诱导     

Wood properties of Scots pines (Pinus sylvestris) grown at elevated temperature and carbon dioxide concentration

Impacts of elevated temperature and carbon dioxide concentration ([CO2]) on wood properties of 15-year-old Scots pines (Pinus sylvestris L.) grown under conditions of low nitrogen supply were investigated in open-top chambers. The treatments consisted of (i) ambient temperature and ambient [CO2] (AT+AC), (ii) ambient temperature and elevated [CO2] (AT+EC), (iii) elevated temperature and ambient [CO2] (ET+AC) and (iv) elevated temperature and elevated [CO2] (ET+EC). Wood properties analyzed for the years 1992-1994 included ring width, early- and latewood width and their proportions, intra-ring wood density (minimum, maximum and mean, as well as early- and latewood densities), mean fiber length and chemical composition of the wood (cellulose, hemicellulose, lignin and acetone extractive concentration). Absolute radial growth over the 3-year period was 54% greater in AT+EC trees and 30 and 25% greater in ET+AC and ET+EC trees, respectively, than in AT+AC trees. Neither elevated temperature nor elevated [CO2] had a statistically significant effect on ring width, early- and latewood widths or their proportions. Both latewood density and maximum intra-ring density were increased by elevated [CO2], whereas fiber length was increased by elevated temperature. Hemicellulose concentration decreased and lignin concentration increased significantly in response to elevated temperature. There were no statistically significant interaction effects of elevated temperature and elevated [CO2] on the wood properties, except on earlywood density.