响应面分析法优化山楂叶中黄酮的提取工艺

响应面分析法优化山楂叶中黄酮的提取工艺,以黄酮粗提取率为指标,采用乙醇回流法提取。通过单因素试验及响应面分析,研究了提取温度、液固比、乙醇体积分数和提取时间4个主要因素对山楂叶中黄酮粗提取率的影响。采用Box-Behnken中心组合设计和响应面分析法,建立了回归方程的预测模型,确定最佳提取条件为液固比29 mL/g ,乙醇体积分数68％,提取温度64℃,提取时间34 min ,在此条件下黄酮粗提取率为3．07％。试验结果与模型预测值基本相符,因此,该工艺可应用于山楂叶中黄酮的提取。     

一类总量依赖型竹林发展系统的古典解

针对竹林发展系统边界不满足通常的三类条件的问题,采用在"竹龄-直径"存在区域内引进一类特殊的曲线族的方法,以避开边界条件问题;通过对竹子直径尺度量纲的适当选择,提出了一类总量依赖型二维竹林发展系统模型,并综合作特征线、先验估计、构造初始状态积分方程、迭代等手段证明了该系统整体古典解的存在唯一性。     

TiO2-SnO2 coated bamboo biochar for electrochemical treatment of coking wastewater

A new type of bamboo biochar (BC) loaded TiO₂-SnO₂ particle electrode was prepared and characterized by SEM, FT-IR, BET and XRD for efficient treatment of the coking wastewater in a three-dimensional electrochemical reaction system(3DERs). The results showed that bamboo biochar had a dense microporous space structure, and a significant amount of Ti-Sn oxides existed on the surface and in the interior of the BC. The removal rates of COD and DOC in coking wastewater reached to 73.96% and 66.72% respectively, and UV₂₅₄ reduced from 6.65 cm^-1 to 3.00 cm^-1 by the electrolysis treatment of 150 min at the current density of 30 mA/cm². The three-dimensional fluorescence spectra indicated that the most of the soluble organic compounds and soluble microbial by-products were degraded and transformed. The addition of Ti and Sn enhanced the efficacy of the electrooxidation, electro-adsorption and electrocatalytic behavior of the BC particle electrodes, which improved the treatment effect on coking wastewater in the 3DERs. In addition, this study provides the possibility of basic research for the engineering practice of electrochemical oxidation treatment of coking wastewater.     

Responses of the reflectance indices PRI and NDVI to experimental warming and drought in European shrublands along a north-south climatic gradient

The aim of this study was to evaluate the use of ground-based canopy reflectance measurements to detect changes in physiology and structure of vegetation in response to experimental warming and drought treatment at six European shrublands located along a North-South climatic gradient. We measured canopy reflectance, effective green leaf area index (green LAIe) and chlorophyll fluorescence of dominant species. The treatment effects on green LAIe varied among sites. We calculated three reflectance indices: photochemical reflectance index PRI [531 nm; 570 nm], normalized difference vegetation index NDVI₆₈₀ [780 nm; 680 nm] using red spectral region, and NDVI₅₇₀ [780 nm; 570 nm] using the same green spectral region as PRI. All three reflectance indices were significantly related to green LAIe and were able to detect changes in shrubland vegetation among treatments. In general warming treatment increased PRI and drought treatment reduced NDVI values. The significant treatment effect on photochemical efficiency of plants detected with PRI could not be detected by fluorescence measurements. However, we found canopy level measured PRI to be very sensitive to soil reflectance properties especially in vegetation areas with low green LAIe. As both soil reflectance and LAI varied between northern and southern sites it is problematic to draw universal conclusions of climate-derived changes in all vegetation types based merely on PRI measurements. We propose that canopy level PRI measurements can be more useful in areas of dense vegetation and dark soils.     

小兴安岭7种松叶挥发油GC-MS数据的分析

用化学计量学方法分析小兴安岭7种松科植物松叶挥发油气相色谱-质谱(GC-MS)数据,为松叶挥发油的药理活性与其它的应用研究提供依据。(1)用直观推导式演进特征投影(heuristic evolving latent projections,HELP)法分辨重叠色谱峰,得各组分的纯色谱峰和质谱;(2)用正交投影法比较不同挥发油的GC-MS数据;(3)用峰面积归一化法确定各化合物的相对含量;(4)用主要化学成分进行聚类分析。7种松叶挥发油的化学成分为单萜、倍半萜及其衍生物和酯类化合物,按化学成分7种松叶挥发油可分为3类。     

初探民间竹制品之设计意匠——以浙江省缙云地区竹制品的研究为例

英国学者李约瑟在深入研究中国科技史后认为,东亚文明乃是"竹子文明,中国人民的血液里流着竹子的文化"。我国不仅竹资源丰富,更是在竹资源的开发与利用上历史最为悠久的国家。我国南方有着大面积的竹产地,竹子及竹制品对当地的社会经济、民俗文化都有很大的影响。如何对"竹"这一传统材料进行创新性的开发和利用,最大限度的实现竹自身的价值,使制竹产业焕发出新的活力,成为当前研究的主要问题。     

竹质建筑装饰构件应用研究

随着中式风格的风靡,中式的建筑装饰构件在市场上的需求越来越大,例如中国古代的窗格在装饰中起着画龙点睛的艺术效果。本次的研究将本着利于装配,降低物流成本的原则,利用窗格设计作为载体,推广竹质建筑装饰构件的应用。同时,竹集成材具有各种优势,并符合可持续发展的国情,做到环保、生态的要求,竹质建筑装饰构件将具有无穷的市场潜力。     

正交设计法优选木瓜叶总黄酮超声提取工艺

为了充分利用木瓜叶资源,优化木瓜叶总黄酮提取工艺,采用超声波辅助提取法,通过单因素和正交试验设计法考察了乙醇浓度、固液比、提取温度和提取时间对木瓜叶总黄酮提取率的影响．优化得到的提取工艺为：当乙醇质量分数70％,固液比1：40（g／mL）,提取温度70℃,提取时间70min时,提取的总黄酮提取率达2．50％,此法提取率高,可为木瓜叶资源综合利用提供参考．     

Experimental and theoretical study on thermal and moisture characteristics of new-type bamboo structure wall

Thermal and moisture characteristics of the bamboo structure wall were tested in natural climate and three representative variation processes of heat and moisture: heating from solar radiation in summer at normal temperature and humidity, heating from solar radiation in summer at normal temperature and high humidity after rain, humidifying from brash in summer at high temperature and normal humidity. The results show that, in summer, the largest temperature difference between external and internal surface of the 28 mm-thick bamboo plywood wall is 11.73 °C (at 15:40) and the largest strain difference is 136 μm/m (at 18:50), both in ambient and indoor conditioned environment. In heating process, lengthways of the wall surface are in contracting strain while transverse ways are in expanding strain at initial stage and in contracting strain during later period. When the high temperature wall is humidified by rain, the surface temperature drops, moisture content increases and the expanding strain is presented on the surface during the whole process. Temperature and moisture content are two important factors which affect thermal and moisture stress (TMS) of the bamboo structure wall. The TMS is not only related to temperature and moisture content, but also greatly affected by temperature gradient, moisture content gradient and rates of changing.