芥子酸甲酯氧化偶合合成二聚体酯的研究     

陆志科  姚培园 《中南林业科技大学学报(自然科学版)》2007,27(2):57-60

在单锅中探讨了以芥子酸为底物,经酯化和氧化偶合两步反应合成芥子酸甲酯二聚体酯的方法.研究结果表明,此合成方法操作简便,反应条件温和(室温反应),无须分离中间体,且产率较高(收率高达66.58%).还探讨了时间、原料比、催化剂的用量等对一锅法产率的影响及氧化偶合机理.  相似文献   

正视杨树速生丰产林的现存问题   总被引：2，自引：0，他引：2  

梁德军  刘毅  姚飞 《辽宁林业科技》2005,(3):41-42,61

目前，不少人错误地把杨树造林都归为速生丰产林，认为只要种苗速生，就能够丰产，这是人们普遍存在的一个误区。近年来私营企业和个体生产者的加盟，一方面推动了杨树造林事业的发展，另一方面也忽视了杨树速生丰产林的质量，其经营措施各式各样，对定向培育、适地适树和栽培密度缺乏了解，因而造林质量不高。正视杨树速生丰产林的现存问题，把握适地适树原则，通过抚育间伐，调整定向不准，改善材种布局，这是当务之急。  相似文献   

线切割与镂铣图形的CNC自动编程及虚拟加工技术研究     

王述洋 《林业机械与木工设备》2001,29(12):11-15

以AutoCAD R14为开发平台，综合运用ObjectARX SDK、Visual C^ 6.0及CNC技术，在研究了AutoCAD R14的数据结构、平面图形CNC自动编程及加工过程仿真和虚拟现实算法基础上，开发出一种适用于CNC木工镂铣、CNC线切割和CNC激光平面轨迹加工的、集CAD／CNC APT／虚拟加工功能于一体的集成技术。该技术可直接将二维AutoCAD图形快速自动转换成二维CNC加工程序，并可对所编程序进行虚拟加工实验，以检验加工的正确性和可靠性；解决了实际二维平面图形加工CAD／CAM集成及其一体化的瓶颈问题。  相似文献   

Supercritical extracts of forest fuels in Great Xing’an Mountains     

Fengjun Zhao  Mingyu Wang  Lifu Shu  Xiaorui Tian  Kezhen Liu 《林业研究》2016,27(5):1143-1151

Extracts are important components of fuels.Fatty-extracts with high heating value(HV) are hypothesized by researchers as positively related to the HV of fuels.The Soxhlet extractor is typically used to extract fatty-extracts but it has shortcomings,including long processing time(8–10 h) and the requirement for large amounts of organic solvent.Supercritical extraction is an alternate and useful technique for extraction of natural products.However,published studies rarely discuss the relationship between extracts and HV.In this study,we assessed the supercritical extracts(Su E) of forest fuels in the Great Xing'an Mountains.Our results indicated that the optimum conditions for extraction of Su Es were40–60 mesh,40–50 MPa,45 °C,80 min and a CO_2 flow rate of 1.5–2.0 dm~3/min.The Soxhlet extracts contents and the Su E contents were all related to HV.However,R~2 of the coniferous samples(0.8499) and needle samples(0.9722) demonstrated that the correlation between HV and the Su E content was closer.We conclude that supercritical fatty-extracts provide a useful index of the HV of fuels,especially coniferous fuels.Su E data can be used in fire management,for example to estimate the rate of fire spread or fire intensity.  相似文献   

木质素合成酶基因F5H的RT-PCR引物筛选     

付月  薛永常  姚奇 《辽宁林业科技》2007,(4):9-11,59

据EMBL核酸序列库中发表的白杨杂种F5H的cDNA序列,利用Primer 5.0软件设计3组扩增引物。通过PCR及RT-PCR扩增反应,筛选出一组比较合适的引物,确定该引物对的最适反应体系和程序参数。利用该引物对,从正在分化的2年生欧美杨107茎的次生木质部提取的mRNA中RT-PCR扩增出一个867bp的木质素合成特异表达的f5h基因片段。将其克隆到pGM-T载体上,构建了f5h在大肠杆菌中的表达载体,并对引物筛选进行讨论。  相似文献   

植物热激蛋白的诱导合成     

李菁  姚延梼 《山西林业科技》2006,(1):16-18

热激蛋白是一类在有机体受到逆境(如高温等)刺激后大量表达的蛋白。主要参与生物体内新生肽的运输、折叠、组装、定位以及变性蛋白的复性和降解。该文综述了植物热激蛋白的种类、诱导合成方法、机理和基因表达及经典检测和分离手段。  相似文献   

Hymmen连续压机生产过程中次品产生的原因及降低措施     

田卫国  刘宇强  姚东 《林产工业》2007,34(6):36-38

Hymmen(惠门)连续压机是生产强化木地板的压贴设备,比低压短周期单层压机的生产效率高、质量更稳定。Hymmen(惠门)连续压机生产线生产使用的浸渍纸全部为成卷的复卷纸,而中密度纤维  相似文献   

珍稀树种小叶银缕梅和宝华玉兰自然现状及其就地保护研究   总被引：9，自引：4，他引：9  

徐惠强  郝日明  姚志刚  王中磊  刘兴剑  郭华祥 《江苏林业科技》2001,28(5):19-21

野外实地分别调查了江苏宜兴市和句容市分布的珍稀树种小叶银缕梅（Parrotia subaequalis）和宝华玉兰（Magnolia zenii Cheng），掌握了这2种珍稀树种在江苏的自然分布状况及其群落学特征，统计了它们的种群规模和种群结构。经综合分析，对其就地保护的现状及保护建议提出了看法。  相似文献   

"3S"技术在森林资源二类调查中的应用前景     

姚荣江  何丙辉 《林业调查规划》2004,29(3):22-26

通过“3S”技术和传统方法在森林资源二类调查中的应用的比较,“3S”技术在工作量、费用、精度等方面均优于传统技术,在实践中值得推广。  相似文献   

Temporal and spatial dynamics of an old-growth beech forest in western Japan     

Uyanga Ariya  Ken-Ya Hamano  Takushi Makimoto  Shu Kinoshita  Yasuaki Akaji  Yuko Miyazaki  Muneto Hirobe  Keiji Sakamoto 《Journal of Forest Research》2016,21(2):73-83

Dendrochronological approaches enable us to understand forest stand dynamics by estimation of disturbance history and age structure. The present study was conducted in an old-growth beech forest in a forest reserve in western Japan. Increment cores were taken for tree ring analysis from all canopy trees in a 50 m × 130 m study plot. Radial growth release criteria were developed to identify significant growth releases in each tree ring series and to characterize the disturbance history of the study site. The age structure of the forest was indicative of continuous establishment by Fagus crenata and simultaneous establishment by Magnolia obovata. A variety of low-intensity disturbances were identified in each decade, especially after the 1900s, but the occurrence of high-intensity catastrophic disturbance was rare, and likely played an important role in maintaining species diversity in the existing forest canopy. The results also suggest that F. crenata regenerates gradually before and after both large- and small-scale disturbances, whereas M. obovata and Betula grossa regenerate only after large-scale catastrophic disturbances.  相似文献