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1.
茉莉花茶产业概况与创新发展   总被引:1,自引:0,他引:1  
茉莉花茶是中国具有悠久产销历史的再加工茶类。文章剖析了中国茉莉花茶产销概况,指出了茉莉花茶产业发展的瓶颈,提出了茉莉花茶加工技术创新与产品创新路径,展望了茉莉花茶产业发展前景,阐述了茉莉花茶的健康属性与消费空间。笔者认为,依托创新驱动,茉莉花茶产业将具有较大的发展潜力和市场消费空间。  相似文献   
2.
With changes in food preferences and life styles,more and more attentions have been focused on healthier food.Nowadays,resistant starch(RS)which can resist digestion in the human intestine has been recognized and accepted.High RS diet shows great benefit for the human health,and breeding high RS rice variety is a great target for realizing dietary intervention.To provide guidance for RS improvement in rice,this review summarized the unique physiochemical properties of RS and the possible approaches,i.e.genetic regulation,for enhancing RS content in rice,and proposed the potential ways to obtain rice variety with high RS content.  相似文献   
3.
研究火力楠心材与边材的颜色和物理力学性质,为该树种木材的合理开发和利用提供参考。采用CIE Lab颜色系统表征木材的颜色参数(明度指数L*、红绿轴色品指数a*、黄蓝轴色品指数b*);按照国家标准测量木材的物理性质(密度、干缩性、湿胀性)和力学性质(顺纹抗压强度、横纹抗压强度、抗弯强度、抗弯弹性模量、顺纹抗剪强度、硬度、冲击韧性、顺纹抗拉强度、抗劈力、握钉力)。结果表明,火力楠心材的L*a*b*均小于边材,表明心材的颜色偏向黑色的程度更大,而偏向红色和黄色的程度更小,整体颜色更加暗深;火力楠心材与边材的总色差属人视觉感觉差异“可察觉”。火力楠心材的密度小于边材,二者密度均属中等;心材的差异干缩大于边材,二者气干干缩的不均匀性均属小;心材的体积干缩系数小于边材,二者干缩性均属很小。火力楠边材的吸水增重率大于心材,表明边材的渗透性优于心材。火力楠边材的硬度、冲击韧性、抗劈力和握钉力大于心材,而其余力学指标小于心材。火力楠心材和边材的顺纹抗压强度、抗弯强度、顺纹抗剪强度、端面硬度和冲击韧性,均属木材各项力学指标品质分级的中等及以上水平。火力楠心材的综合强度和综合品质系数均大于边材,二者均分别属高强度和强重比很高。  相似文献   
4.
以不同林型(草类、杜香、杜鹃)兴安落叶松林0~60 cm土壤为研究对象,探讨兴安落叶松林土壤理化性质及其相关性。结果表明:1)0~60 cm土层,兴安落叶松林土壤含水量为17.93%,容重为1.07 g/cm3,随土层深度增加,土壤含水量呈下降趋势,容重呈递增趋势;2)兴安落叶松林土壤为弱酸性(pH=5.59),随土层深度增加,pH呈递增趋势;3)兴安落叶松林土壤铵态氮含量为17.94 mg/kg,速效K含量为89.05 mg/kg,有效P含量为17.85 mg/kg,有机P含量为0.43 g/kg,随土层深度增加,各养分指标含量均呈下降趋势;4)兴安落叶松林土壤各金属氧化物的含量大小依次为Al2O3(13.77%)>Fe2O3(5.44%)> K2O(2.33%)>Na2O(1.80%)>MgO(1.30%)>CaO(1.25%),随土层深度增加,除CaO外,各指标含量整体呈增加趋势,且表层含量与其他土层间差异显著;5)林型对土壤含水量、pH、铵态氮、有效P、MgO、Al2O3、CaO、Fe2O3的影响显著,而对容重、速效K、有机P、Na2O和K2O的影响不明显。表明兴安落叶松3种林型的土壤理化性质存在一定差异,草类-兴安落叶松林的土壤理化特征显著区别于杜香-兴安落叶松林和杜鹃-兴安落叶松林,可为兴安落叶松林的可持续经营提供依据。  相似文献   
5.
GC-MS结合保留指数分析白柠檬油挥发性成分   总被引:1,自引:0,他引:1  
本文综述了果蔬多酚的分类、成分、含量、抗氧化作用和机理,展望了其发展空间和市场前景,以期为果蔬多酚的应用和开发提供参考。  相似文献   
6.
Soil particle size distribution (PSD) is a fundamental physical property affecting other soil properties. Characterizing spatial variability of soil texture is very important in environmental research. The objectives of this work were: 1) to partition PSD of 75 soil samples, collected from a flat field in the University of Guilan, Iran, into two scaling domains using a piecewise fractal model to evaluate the relationships between fractal dimensions of scaling domains and soil clay, silt, and sand fractions and 2) to assess the potential of fractal parameters as an index used in a geostatistical approach reflecting the spatial variability of soil texture. Features of PSD of soil samples were studied using fractal geometry, and geostatistical techniques were used to characterize the spatial variability of fractal and soil textural parameters. There were two scaling domains for the PSD of soil samples. The fractal dimensions of these two scaling domains (D1 and D2) were then used to characterize different ranges of soil particle sizes and their relationships to the soil textural parameters. There was a positive correlation between D1 and clay content (R2 = 0.924), a negative correlation between D1 and silt content (R2 = 0.801), and a negative correlation between D2 and sand content (R2 = 0.913). The geometric mean diameter of soil particles had a negative correlation with D1 (R2 = 0.569) and D2 (R2 = 0.682). Semivariograms of fractal dimensions and soil textural parameters were calculated and the maps of spatial variation of D1 and D2 and soil PSD parameters were provided using ordinary kriging. The results showed that there were also spatial correlations between D1 and D2 and particle size fractions. According to the semivariogram models and validation parameters, the fractal parameters had powerful spatial structure and could better describe the spatial variability of soil texture.  相似文献   
7.
对北京市大兴区北程庄村的土地征占、整建制转居和集体经济产权制度改革进行调研发现,乡村在快速城市化进程中的核心问题是维护和发展农民的财产权利。建议从根本上改变现行的征地思维和征地制度,保障两种土地公有制的平等地位;落实户籍制度改革,全面取消农转居政策;实行集体土地与国有土地同样可以开发建设城市的政策制度;及时撤销“三无村”或“空壳村”的村委会建制,完善撤制乡村集体资产处置办法。  相似文献   
8.
黄土塬边坡植被类型对土壤孔隙的影响   总被引:2,自引:0,他引:2  
黄土塬边坡植被建设以固坡为目的,不同植被的土壤孔隙结构有利于增加降水入渗,从而减少坡面产流的水蚀危害。本研究以长武塬黄土塬边坡的侧柏(Platycladus orientalis)林地、沙棘(Hippophae rhamnoides)灌丛、草地和农地4种植被为研究对象,采集0–30 cm的原状土柱,利用CT扫描和图像处理技术,对其土壤孔隙度、孔隙数目、孔隙成圆率和孔隙分形维数进行定量分析,结合土层样品的理化性质,研究影响土壤孔隙结构的主要因素。结果表明,农地、侧柏孔隙的孔径大小分异不大,而草地、沙棘自身根系互动穿插生成的根孔扩展了孔径分布范围,不仅增加了孔隙度和大孔隙数目,也降低了孔隙成圆率。草地、沙棘有利于降水入渗,是固坡的优先选择。土壤有机质、粘粒含量等性质与孔隙参数之间具有极显著(P<0.001)或显著(P<0.05)相关关系,它们的改变对土壤孔隙特征变化和提高蓄水保土能力具有重要影响。  相似文献   
9.
Changes in atmospheric aerosols have profound effects on ecosystem productivity, vegetation growth and activity by directly and indirectly influencing climate and environment conditions. However, few studies have focused on the effects of atmospheric aerosols on vegetation growth and activity in the vulnerable arid and semi-arid regions, which are also the source areas of aerosols. Using the datasets of aerosol optical depth(AOD), normalized difference vegetation index(NDVI) and multiple climatic variables including photosynthetically active radiation(PAR), surface solar radiation(SSR), surface air temperature(TEM) and total precipitation(PRE), we analyzed the potential responses of vegetation activity to atmospheric aerosols and their associated climatic factors in arid and semi-arid regions of Asia from 2005 to 2015. Our results suggested that areas with decreasing growing-season NDVI were mainly observed in regions with relatively sparse vegetation coverage, while AOD tended to increase as NDVI decreased in these regions. Upon further analysis, we found that aerosols might exert a negative influence on vegetation activity by reducing SSR, PAR and TEM, as well as suppressing PRE in most arid and semi-arid regions of Asia. Moreover, the responses of atmospheric aerosols on vegetation activity varied among different growing stages. At the early growing stage, higher concentration of aerosol was accompanied with suppressed vegetation growth by enhancing cooling effects and reducing SSR and PAR. At the middle growing stage, aerosols tended to alter microphysical properties of clouds with suppressed PRE, thereby restricting vegetation growth. At the late growing stage, aerosols exerted significantly positive influences on vegetation activity by increasing SSR, PAR and TEM in regions with high anthropogenic aerosols. Overall, at different growing stages, aerosols could influence vegetation activity by changing different climatic factors including SSR, PAR, TEM and PRE in arid and semi-arid regions of Asia. This study not only clarifies the impacts of aerosols on vegetation activity in source areas, but also explains the roles of aerosols in climate.  相似文献   
10.
将‘72杨’、杉木和毛竹的木质部进行对比试验,观察并测试‘72杨’韧皮部的解剖构造以及理化特性,为其高值化利用提供基础数据。使用场发射环境扫描电镜、X射线衍射仪、傅里叶变换红外光谱仪等设备和NREL标准对‘72杨’韧皮部的微观结构、结晶度、化学成分等物化性质进行测定与分析。研究结果表明,‘72杨’韧皮部中韧皮薄壁细胞和筛管分子占细胞总面积的(81.9±1.8)%,结构相对简单。‘72杨’韧皮部气干密度为0.358 g/cm3,绝干密度为0.321 g/cm3;而木质部的相应密度较高,分别为0.497和0.482 g/cm3;‘72杨’韧皮部结晶度仅为19.4%,比木质部低8.7%。‘72杨’韧皮部纤维素、半纤维素、木质素的含量分别为28.7%,11.1%,24.1%,均低于木质部中相应成分的含量,且木质化程度低,半纤维素以木糖为主。此外,由红外谱图发现‘72杨’韧皮部含有单宁、酚类、胼胝质等物质。‘72杨’韧皮部具有低密多孔、结构疏松、结晶度低、木质素含量低、抽提物含量高等特点。因此,‘72杨’韧皮部特别有利于机械(能耗低)或化学(抗降解屏障低)降解以及物化改性(多孔、可及性强),可提取酚类、单宁、胼胝质等物质用于工业应用,研究结果可为‘72杨’韧皮部的高值化利用提供重要的理论依据。  相似文献   
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