Galleria mellonella Linnaeus (Lepidoptera: Pyralidae) is a pest that feeds on the spleen of honey bee nests worldwide. In this study, the toxicity of chlorantraniliprole (CAP) to G. mellonella was determined by ingestion toxicity and contact toxicity methods. We compared the effects of sublethal doses of CAP on the activity of major detoxification and protective enzymes as well as gene expression of related enzymes under the 2 treatment methods. The median lethal concentrations of CAP administered using ingestion toxicity and contact toxicity methods were 217.666 and 50.453 mg L-1, respectively. Compared with the control group, both methods increased the activities of carboxylesterase (CarE) and cytochrome P450 (CYP450), decreased the activities of glutathione S-transferase (GST) and peroxidase (POD), and had no effect on catalase activity. Superoxide dismutase activity decreased under ingestion toxicity but remained unchanged under contact toxicity. Significant changes were observed in the gene expression levels of detoxification and protective enzymes under both treatment methods; the expression levels of GmCarE4a, GmCarE2a, GmCarE1f, and GmPOD1a were significantly upregulated, whereas those of GmGST2a and GmGST2b were significantly downregulated. CAP exhibited both ingestion toxicity and contact toxicity against G. mellonella, with better contact toxicity effects. Galleria mellonella responded to CAP stress by adjusting enzyme activities (increasing CarE and CYP450 activities and decreasing GST and POD activities) and related gene expression levels (upregulating the relative expression levels of GmCarE4a, GmCarE2a, GmCarE1f, and GmPOD1a and downregulating those of GmGST2a and GmGST2b). The findings from the 2 distinct poisoning methods offer a scientific foundation for optimizing the application of CAP in the effective control of G. mellonella, while also providing valuable insights into the development of CAP resistance.

Urea-formaldehyde (UF) resin has a high annual output, but the used and waste UF resin poses a challenge for recycling due to the difficulty in effectively decomposition them. In this study, A novel one-step degradation method was proposed, i.e., using eco-friendly malic acid and hydrogen peroxide to degrade cured UF resin residues using carboxylic acid through the hydrothermal oxidation method (HPMA), which was proved to have high cured UF resin degradation efficiency. This method will offer a new path for effectively recycling the UF resin out of service.

以含有竹青的巨龙竹(Dendrocalamus sinicus)和尾巨桉(E.urophylla×E.grandis)为原料,使用酚醛-异氰酸酯树脂制备正交胶合竹木(Cross laminated bamboo timber,CLBT),分析竹青对竹木间胶合能力、抗弯强度以及尺寸稳定性的影响.结果表明:使用酚醛树脂制备的含竹青CLBT,其抗弯性能弱于去竹青CLBT.当酚醛-异氰酸酯树脂作为胶黏剂时,含竹青CLBT具有较高的抗弯强度和尺寸稳定性.竹青会降低竹木间胶合能力,但会提高CLBT的抗弯性能.研究结果为实现竹青的合理利用提供了依据.

针对黄桦(Betula arneghaniensis britton)木片刨花生产过程中的关键影响因素进行研究,旨在通过优化刨花机参数和切削工艺实现节能降耗、提高木材资源利用率和刨花质量的目的.研究考察了CAE式圆盘刨片机的飞刀前角、后角、刀伸量、底刀刃角及木材温度、切削方向、刨花切削高度对黄桦刨花生产过程的影响.以黄桦刨花的长度分布和抗拉强度作为刨花质量的评价指标,并以卷曲指数和能源消耗为依据优化黄桦刨花的生产控制.结果表明:采用纵向切削获得的刨花质量更好.增加木材温度和底刀刃角也可以有效提升刨花质量,但增加底刀刃角会增加能耗.研究结果对于指导定向刨花板(OSB)的生产、提高木材资源利用效率,及提高经济效益具有重要意义.

Based on the difference in the reaction rate of different groups of urea-formaldehyde resins and isocyanate resins, this study designed two different urea-formaldehyde resins: a normal urea-formaldehyde resin (UF) and one with high mono-hydroxymethylurea content (UF*) to react with polymeric methylene diphenyl diisocyanate (pMDI) resin. The difference in mono- and di-hydroxymethyl urea content between UF and UF* resins was analyzed by nuclear magnetic resonance (NMR) spectroscopy, and results showed that the mono-hydroxymethyl urea content of the UF* resin was much higher than that of the conventional UF resin. The fourier transform infrared spectrometer (FTIR) analysis of differences between UF* and UF resin showed that the UF* process did not change the main structure of the conventional urea formaldehyde resin. Differential scanning calorimeter (DSC) analysis showed that the curing temperature of the hybrid UF*-pMDI resin was reduced 27.3 degrees C compared to that of the UF-pMDI resin. When these hybrid resins were used to bond plywood respectively, test results showed that the UF*-pMDI resin improved the dry and wet bonding strength by 2.6% and 3.9%, respectively, compared with the UF-pMDI resin under the condition of hot pressing time (3 min) and temperature (140 degrees C), meeting the requirement of Chinese standard of GB/T 9846-2015 for Class III board. This study provides a new path for further improving the performance and design of hybrid resins based on isocyanate and urea-formaldehyde resin.

The effects of extraction temperature, equilibration time, extraction time and resolution time for headspace solid-phase microextraction(HS−SPME) on the extraction of volatile organic compounds(VOCs) of Eucalyptus particleboard were investigated by single factor experiment combined with gas chromatography-mass spectrometry(GC−MS) analyses, and the extraction condition were optimized by using response surface methodology. The results showed that the extraction time and temperature showed remarkable effect on VOCs extraction, and the optimal extraction parameters were 91℃ of extraction temperature, 34 min of equilibration time, 24 min of extraction time and 2.5 min of resolution time. Under this optimal condition, the relative error between the validation test results and the predicted value was 0.62%, and a total of 54 VOCs including 23 olefins, 11 alcohols, 8 alkanes, 5 aromatic hydrocarbons, 5 aldehydes, 1 ester and 1 acid were detected from Eucalyptus particleboard. The results will provide a basis for the further detection and analysis of the VOCs in Eucalyptus particleboard.

正交胶合木(CLT)是一种新型的工程木,主要应用于木结构建筑方面,可作为楼板、墙体、地板等建筑构件.全球范围内,CLT是发展速度最快的林产品.本文简述了CLT在国外的发展历程,介绍了CLT的生产工艺;阐明CLT在国内的进一步发展需要社会各方面系统的支持;并且根据CLT在建筑中的发展,指出国内CLT的未来研究方向应该注重于降低成本、提高质量、CLT原料多元化和有自主知识产权的标准的建立.

为解决变温变湿状态下木材拉伸和压缩蠕变试验过程中普遍存在的试验环境难以控制、蠕变变形量难以测量、数据采集烦琐、设备长期运行稳定性较差等问题,依据木材拉伸及压缩力学性能的测试基本原理和相关国内外标准研制了 一套木材拉伸及压缩一体化蠕变自动监测系统.系统主要由软件系统和硬件系统两个部分组成,软件系统基于VB语言和查表算法进行开发,硬件系统包括蠕变测试环境系统、框架和受力导向系统、加载系统、拉伸和压缩蠕变测试的转换系统、试件夹装系统及数据采集系统、检测装置与环境系统的连接机架、信号接收和转换系统.该套系统的试验环境参数可调控范围为温度-10～70℃,相对湿度10％～98％,风速为0.3～5.6 m/s,蠕变变形量测试精度为0.001 mm,数据采集间隔1 s～24 h多梯度可调.经过前期14.6 d的木材拉伸蠕变测试和30 d的木材压缩蠕变试验检验,证明该系统可对木材的拉伸或压缩蠕变变形量进行长时间、稳定可靠和高精度的实时动态监测、记录和显示.同时,本次研究的拉压转化装置和加载装置大大降低了同类系统的总质量及试验操作的复杂性,为木材拉伸及压缩蠕变测试和研究提供了一个新的平台.

木结构建筑以其优良的性能得到了产业界和国家的重视而发展迅猛,但由于缺乏必要的历史延续性以及与现代学科相融相伴发展的学科积淀,国内木结构建筑专业特别是构建于林科基础上的木结构建筑专业的建设和发展目前还较为滞后.通过调研国内外大学和科研院所木结构建筑专业或研究方向的设置情况,发现该专业目前主要构建于土木工程、建筑学或木材科学与技术学科基础之上,由于专业建设方向和课程体系间的巨大差异致使不同学科体系之间的“强行嫁接”很容易造成学科间无法有效融合的“两张皮”现象.因此,林科背景下木结构建筑专业建设需要以木结构建筑及木质材料为研究对象,考虑不同学科体系知识点间的逻辑次序和内在关联性,并根据学科支撑条件和重点培养方向重新组织学科知识点和学科知识体系,合理安排基础课程、外延性课程.基于以上特点,从林科背景下木结构建筑专业课程体系的构建、专业基础教材的选用和编写、专业实践课程的设置以及专业课程体系的实施策略方面进行了探讨和思考,同时给出了今后林科背景下木结构建筑专业发展的趋势.

综述了大豆蛋白、异氰酸酯、水性高分子-异氰酸酯(EPI)、聚乙烯胶膜、聚醋酸乙烯酯等无醛胶粘剂在常见复合地板中的应用现状,探讨了目前存在的问题,展望了今后主要的研究发展方向.

The objective of this study was to investigate the feasibility of using polyurethane (PU) foam wastes obtained from automobile shredder residue (ASR) in wood composite panel (fiberboard) production. PU foam wastes from ASR were picked by hand, cleaned by water and acetone, grounded into powders of two sizes (60 mesh and 120 mesh), and dried to remove moisture. The PU powders were characterized by stereomicroscope and then partially replaced pMDI resin at percentages of 10%, 20%, 30%, 40%, and 50% (based on the weight of pMDI resin). The PU powders were mixed with wood fibers to make fiberboards. The results showed that the addition of PU powders increased both the physical and mechanical properties of fiberboards. At replacing percentages from 5% to 30%, the properties of fiberboards increased. However, further increase of replacing percentages (from 30% to 50%) resulted in lower properties of fiberboard. When observed at a magnification of 125 times by a stereomicroscope, PU powders of 60 mesh had more foam features while PU powders of 120 mesh had more particle features. The fiberboards bonded by pMDI resin and PU powders of 120 mesh had better water resistance and mechanical properties than those bonded by pMDI and PU powders of 60 mesh. The use of PU powders in fiberboard production provided a new possible way of recycling PU foam wastes. The fiberboard has advantages of formaldehyde-free, better water resistance, higher mechanical properties, and lower material cost.

Liquefaction of southern pine wood in phenol in 30-40 : 70-60 weight ratios resulted in homogeneous liquefied materials, which were directly used to synthesize phenol-formaldehyde (PF)-type resins. The synthesized resins showed good physical and handling properties: low viscosity, stability for storage and transportation, and resin applicable by a common sprayer. Particleboard panels bonded with the synthesized resins showed promising physical properties and significantly lower formaldehyde emission values than those bonded with the urea-formaldehyde resin control. One deficiency observed for the synthesized resins was lower internal bond values, which might be overcome the use of a hot-stacking procedure. Overall, the process of wood liquefaction with limited amounts of phenol as a solvent was shown to have the potential of providing practical, low-cost PF-type resins with very low formaldehyde emission potentials. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 1436-1443, 2009

The characteristics of urea-formaldehyde (UF) resin curing in the presence of wood extracts and a catalyst [ammonium chloride (NH4Cl)] were investigated by differential scanning calorimetry (DSC). The effects of extracts from 16 wood species on resin curing behaviors were evaluated. A model developed in this study, T-p = 53.296 exp(-9.72C) + 93.104, could be used to predict the resin curing rate in terms of the DSC peak temperature (Tp) as influenced by the NH4Cl content (C). The results indicated that the curing rate of UF resin increased as the catalyst content increased and reached a maximum when the catalyst content ranged from 0.5 to 1.0% (solid basis over liquid UF resin weight). Further increases in the catalyst content had no effect on the resin curing rate. The curing rates of UF resin in the presence of wood extracts increased with decreased pH values or increased base buffer capacities. It was also discovered that the activation energy could not fully explain the resin curing behavior when some species of wood extracts were present, and therefore, the pre-exponential factor had to be taken into account. The concept of the equivalent catalyst content (ECC) of wood extracts to the NH4Cl content was introduced in this study; ECCs ranged from 0.0022 to 0.0331% among the 16 wood species. (c) 2007 Wiley Periodicals, Inc.

Southern pine wood specimens were impregnated with butanetetracarboxylic (BTCA) acid at 1.0-5.0% levels using vacuum/pressure method and hot-pressing at 150 degrees-210 degrees C in the radial direction. The acid treatments gave anti-swelling efficiency (ASE) Values LIP to 57% in all exhaustive first water-soak cycle. The ASE values were higher ill the radial than tangential direction, and higher for irreversible than reversible components. Laboratory strandboards made with wood strands impregnated with 0.5 degrees-1.0% BTCA levels under vacuum showed ASE values of up to 53%. but internal bond and modulus of elasticity and rupture values decreased somewhat excessively. The strength values of boards were modest, higher than the minimum industry requirements for commodity-type oriented strandboard. The various effects of BTCA oil wood and board properties were discussed. Use of BTCA at less than 0.5% level and optimization of hot-pressing and resin binder and wax levels may result in a method of manufacturing oriented strandboard with significantly improved dimensional stability.

The improvement of Brinell hardness of sugar maple (Acer saccharum Marsh.) samples through impregnation and in-situ polymerization of methyl methacrylate, 2-hydroxylethyl methacrylate, and ethylene glycol dimethacrylate monomers was investigated. The formulation combinations were determined by a mixture design. Sugar maple samples were impregnated with these mixtures by a vacuum and pressure process and polymerized in situ by a catalyst-thermal procedure. The effects of the monomers and their combinations on Brinell hardness and hardness modulus were analyzed. Chemical impregnation enhanced both Brinell hardness and hardness modulus. A significant relationship between hardness modulus and Brinell hardness was found. Modulus of elasticity of sugar maple was also improved through impregnation with methacrylates. (c) 2005 Wiley Periodicals, Inc.

in this study, aspen, yellow birch, and sugar maple samples were treated with four different fungi for 2, 4, and 8 weeks, for biological incising to improve wood permeability. The four fungal species were Ophiostoma piceae (wood staining fungus), Gliocladium roseum (mold fungus), Trametes versicolor, and Irpex lacteus (white-rot fungi). The fungal bio-incised wood samples and control samples not exposed to fungi were then impregnated with a low molecular weight phenol-formaldehyde (PF) resin and cured in an oven to improve wood hardness. The treated wood samples were tested for hardness according to European Standard EN 1534. Generally, bio-incising improved the PF resin uptake in wood, which improved wood hardness. The impact of bio-incising oil the hardness of PF resin-treated wood samples was also related to wood species, bio-incising time, and fungi species. Microscopic examination of aspen samples treated with T. versicolor showed that fungal hyphae had moved from cell to cell through the pits. Such bio-incising behavior seems to improve wood permeability by leading PF resin to pass through the pit pairs between neighboring cells. Since the hardness of bio-incised wood samples was not always improved, the application of a bio-incising treatment to improve the hardness of resin-impregnated wood should be based oil the wood species and fungal type. The bio-incising time period is also very crucial.

Wood plastic composites were prepared through impregnation of solid wood with polyethylene. The effects of impregnation parameters on polymer retention and hardness were investigated. A screening strategy of 16-run resolution IV design for seven factors at two levels was adopted. The seven factors were: ratio of maleated polyethylene in formulations, ratio of polyethylenes with different molecular weights, four process factors (vacuum, pressure, time, and temperature), and wood species (red maple and aspen). Polymer retention (PR) and Brinell hardness (H-B) were investigated and discussed on the basis of the impregnation parameters. The present work showed that process parameters (pressure and temperature), polymer impregnants (different molecular weight polyethylenes), and wood species contributed significantly to PR and H-B. Increasing pressure and temperature resulted in a higher PR and H-B, whereas increasing the molecular weight of polyethylene and switching wood species from aspen to red maple gave a lower PR and H-B. This study was aimed at understanding how impregnation parameters affect the final properties of wood plastic composites and developing an optimal fabrication process for wood plastic composites. (c) 2006 Wiley Periodicals, Inc.

Low molecular weight phenol-formaldehyde (PF) resins were impregnated into southern pine wood using a vacuum/pressure method and the specimens were hot-pressed in the radial direction. Anti-swelling efficiency (ASE) values of treated specimens were up to 26% and 45%, respectively, for 1.0% and 5.0% resin solids loading levels in the first water-soak/dry cycle. The high ASE values were due to reduction in the irreversible swelling in radial and tangential directions of wood in spite of some negative effects that occurred in the reversible swelling. In the second and third water-soak/dry cycles, the ASE values were reduced mostly due to increased swelling of irreversible components in the radial direction with the tangential direction components little affected. Vacuum impregnation of southern pine/hardwood strands with 1.0% or 2.0% PF resin solids levels and hot-pressing gave strandboards with ASE values up to 45% in 24-h water-soak tests. ASE and board strength values of boards were higher for 2.0% resin solids loading level, higher hot-pressing temperatures, and longer press times. The high ASE values of boards arose from both irreversible and reversible swelling components and also increased adhesive bonds due to impregnating PF resins. The results would be useful for manufacturing oriented strandboard with reduced swelling if a low-cost resin impregnation process can be found.