摘要：
For getting a better understanding of molecular association between water and wood, molecular structure of desorbed water in a typical wood (i.e. heat-treated wood) during moisture desorption process was investigated using micro-FTIR spectroscopy. Spectra were collected in the relative humidity (RH) region from high level to low level. A qualitative analysis of these spectra and corresponding difference spectra confirmed moisture sorption sites and determined main spectral region affected by moisture sorption. In addition, from component peak analysis of the identified spectral region of difference spectra, three component peaks were attributed to three types of bound water. Based on change of bound water against RH, the entire moisture desorption process of heat-treated wood could be separated to three parts. Moreover, molecular structure of desorbed water in these three parts was demonstrated, separately.
通讯机构：
[Wen, Ruizhi] C;Cent South Univ Forestry & Technol, Coll Sci, Changsha 410004, Hunan, Peoples R China.
关键词：
Teak wood (Tectona grandis Linn. fil.);discoloration;FTIR;GC-MS
摘要：
To investigate the discoloration behaviour of teak (Tectona grandis Linn. fil.) during irradiation, teak veneer specimens were exposed to xenon lamp light simulating sunlight for 80 h and subsequently analysed with a colorimeter. The colour changes were explained by recording Fourier transform infrared (FTIR) and gas chromatography-mass spectrometry (GC-MS) spectra at different exposure times. Forty hours of simulated irradiation marked a key point in the colorimetric analysis. During irradiation of 40 h, the increase in the CIELAB parameters Delta a* and Delta b* originated from the generation of carbonyl derivatives that were determined by FTIR analysis. Besides that, by combining GC-MS and microscopic analyses, the decrease in Delta L* in the first 20 h resulted from extractives migrating from the interior to the surface, and that the subsequent increase in Delta L* mainly arose from volatilization of the extractives. Additionally, the decrease in Delta b* after another 40 h of irradiation was mainly due to decreasing volatile extractive contents. Our conclusion reveals the causes of photo-induced discoloration in teak.
摘要：
As many properties of lignin are relied on moisture content, water adsorption is very important for its product performance. To better understand water adsorption mechanism of lignin, the molecular interactions between adsorbed water and lignin was studied using micro-FTIR spectroscopy. Spectra of lignin were collected at various relative humidity (RH) levels from low to high. From qualitative analysis of these spectra and corresponding difference spectra, water adsorption sites of lignin was recognized, and the spectral ranges closely related to water adsorption were identified. Further, from component peak analysis of the identified spectral region, three component peaks were attributed to three types of bound water separately. Based on the change of bound water vs. RH, the moisture adsorption process of lignin could be separated to three parts. Moreover, molecular association of adsorbed water with lignin was all demonstrated in these three parts. (C) 2019 Elsevier B.V. All tights reserved.
期刊：
International Journal of Biological Macromolecules,2019年132:1106-1111 ISSN：0141-8130
通讯作者：
Guo, Xin
作者机构：
[Ma, Qiang; Xiao, Teng; Guo, Xin; Yuan, Hanmeng] Cent South Univ Forestry & Technol, Coll Sci, Changsha 410004, Hunan, Peoples R China.;[Wu, Yiqiang; Xiao, Teng] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Guo, Xin] C;Cent South Univ Forestry & Technol, Coll Sci, Changsha 410004, Hunan, Peoples R China.
关键词：
Lignin;Micro-FTIR spectroscopy;Qualitative and quantitative analysis
摘要：
Moisture sorption has a great impact on the mechanical properties of lignin. To better characterize the moisture sorption of lignin, an approach for in situ qualitative and quantitative analysis of moisture adsorption in nanogram-scaled lignin by using micro-FTIR spectroscopy and partial least squares regression is introduced in this study. Spectra of nanogram-scaled lignin were collected within the relative humidity (RH) of 0%-92%. A qualitative analysis of these measured spectra confirmed the effective water sorption sites and determined spectral ranges related to moisture adsorption. Using these identified spectral ranges, a quantitative forecasting model for the moisture content (MC) of lignin was built and developed according to partial least square regression (R-2, 0.9996; RMSECV, 0.408; RMSEP, 0.118). Furthermore, the water sorption isotherm of lignin was acquired using the established forecasting model in which a very positive correlation between the estimated and measured MCs was demonstrated using a dynamic vapor sorption (DVS) setup. The results confirmed the practicability and effectiveness of this in situ qualitative and quantitative analysis approach. (C) 2019 Elsevier B.V. All rights reserved.
摘要：
For cellulose nanocrystal film, water adsorption is extremely important for its product performance. For gaining a deeper understanding of hygroscopic behavior, two cellulose nanocrystal films, such as TEMPO oxidized cellulose nanocrystal film (TOCNF) and sulfuric acid treated cellulose nanocrystal film (SACNF) were investigated using dynamic water vapor sorption apparatus. During the water vapor sorption process, the running time, real-time sample mass, target relative humidity (RH), actual RH and real-time temperature were all collected. Through the comparison of these collected data, significant differences in the equilibrium moisture content, sorption hysteresis and sorption kinetics were confirmed. It was important to note that TOCNF and SACNF had equilibrium moisture contents of 28.2% and 22.8, respectively, at a RH of 95%. Then, using parallel exponential kinetics (PEK) model, sorption kinetics data were accurately fitted. Furthermore, two Kelvin-Voigt elements were introduced to interpret the fitting results and calculate the modulus of TOCNF and SACNF.
作者机构：
[郭鑫; 吴义强; 李贤军] College of Material Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, China;[郭鑫] College of Sciences, Central South University of Forestry and Technology, Changsha, 410004, China
通讯机构：
College of Material Science and Engineering, Central South University of Forestry and Technology, Changsha, China
关键词：
Adsorption;Cells;Chemical bonds;Computerized tomography;Cytology;Hydrogen bonds;Image resolution;Infrared devices;Magnetic resonance imaging;Molecules;Nuclear magnetic resonance;Nuclear magnetic resonance spectroscopy;Spectroscopy;Vibrational spectroscopy;Water supply systems;Wood;Chemical functional groups;Existing states;Hydrogen-bonded water molecules;Magnetic Resonance Imaging (MRI);Nuclear Magnetic Resonance (NMR);Spectroscopic imaging techniques;Water distributions;Wood water relationships;Fourier transform infrared spectroscopy
作者机构：
[李立君; 赵兵; 文韬; 张仟仟; 刘付] School of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha, China;[郭鑫] School of Science, Central South University of Forestry and Technology, Changsha, China;[洪添胜] Division of Citrus Machinery, China Agriculture Research System, Guangzhou, China;[洪添胜; 文韬] Key Laboratory of Key Technology for South Agricultural Machinery and Equipment, Ministry of Education, Engineering College of South China agricultural University, Guangzhou, China
通讯机构：
Key Laboratory of Key Technology for South Agricultural Machinery and Equipment, Ministry of Education, Engineering College of South China agricultural University, Guangzhou, China
关键词：
模型;光谱检测;农业;霉变稻谷;脂肪酸;可见/近红外光谱;特征波段;样本集划分
摘要：
为了实现霉变稻谷脂肪酸含量无损、快速检测,该文研究应用可见/近红外光谱技术检测霉变稻谷的脂肪酸含量。考虑到直接选用霉变稻谷可见/近红外光谱数据构建脂肪酸含量预测模型存在建模费时、预测失准等问题,研究提出了霉变稻谷脂肪酸含量的可见/近红外优化校正模型。研究中通过光谱-理化值共生距离(sample set partitioning based on joint x-y distance, SPXY)算法结合偏最小二乘法初步分析了不同校正集样本预测霉变稻谷脂肪酸含量的差异;利用连续投影算法(SPA)提取了反映霉变稻谷脂肪酸含量变化的特征波段;采用偏最小二乘法(partial least square, PLS)和多元线性回归法(multivariable linear regression, MLR)分别建立了基于特征波段光谱反射值的霉变稻谷脂肪酸含量预测模型,并对比分析了采用SPXY样本集划分的模型预测效果。结果表明:采用SPXY法筛选出的65个校正集样本分布与初始校正集相近,脂肪酸含量变化范围为18.55~127.26 mg,其标准差为32.39;SPA算法最终从256个全光谱波段中优选出9个特征波段,实现了光谱数据的压缩;分别建立的SPXY-SPA-PLSR模型和SPXY-SPA-MLR模型预测霉变稻谷脂肪酸含量相关系数RP为0.922 1和0.915 9,预测均方根误差RMSEP为13.889 3和14.261 0;SPXY筛选校正集所构建模型预测精度与初始校正集所建模型相当,但校正集样本数量减少为初始校正集的41%,运算时长缩短为初始样本集的32%,提高了模型的校正速度。
作者机构：
[李立君; 赵兵; 文韬; 张仟仟; 刘付] School of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha, China;[郭鑫] School of Science, Central South University of Forestry and Technology, Changsha, China;[洪添胜] Division of Citrus Machinery, China Agriculture Research System, Guangzhou, China;[洪添胜; 文韬] Key Laboratory of Key Technology for South Agricultural Machinery and Equipment, Ministry of Education, Engineering College of South China Agricultural University, Guangzhou, China
通讯机构：
Key Laboratory of Key Technology for South Agricultural Machinery and Equipment, Ministry of Education, Engineering College of South China Agricultural University, Guangzhou, China
作者机构：
[文韬; 李立君] College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha, China;[郭鑫] College of Science, Central South University of Forestry and Technology, Changsha, China;[张南峰] Guangzhou Entry-exit Inspection and Quarantine, Guangzhou, China;[洪添胜; 李震] Division of Citrus Machinery, China Agriculture Research System, Guangzhou, China;[李震; 洪添胜; 文韬] Key Laboratory of Key Technology for South Agricultural Machinery and Equipment, College of engineering, South China agricultural University, Guangzhou, China
通讯机构：
Key Laboratory of Key Technology for South Agricultural Machinery and Equipment, College of engineering, South China agricultural University, Guangzhou, China
