期刊文献+
共找到13篇文章
< 1 >
每页显示 20 50 100
直干型大叶相思在南宁的引种与生长研究 被引量:5
1
作者 侯远瑞 龚建英 +2 位作者 陈金艳 马志悦 陈海军 《广西林业科学》 2007年第4期209-211,共3页
8年的引种试验表明,直干型大叶相思主干较通直,适应性强,生长迅速,年平均高生长达2.9 m,胸径达2.4 cm,蓄积量年生长量可达16.77m3/hm2;可推广建立速生丰产工业用材林和贫瘠立地绿化造林。
关键词 大叶相思 直干型 引种
下载PDF
直干型大叶相思种子品质和幼苗质量的研究 被引量:2
2
作者 黄永芳 谭绍满 《广东林业科技》 1997年第3期25-28,共4页
对直干型和普通型大叶相思的种子品质和苗期质量的对比试验结果表明:直干型的种子品质优于普通型的;幼苗高、径生长量两者差异不显著;直干型苗期的死亡率较高,说明其抗逆能力较差。
关键词 直干型 大叶相思 种子品质 苗期质量
下载PDF
直干型大叶相思选择的探讨 被引量:5
3
作者 郑政明 杨民权 +1 位作者 陈传启 李伟雄 《广东林业科技》 1994年第3期27-29,34,共4页
在广州龙洞、增城梳脑、新会罗坑、珠海南溪及海南白石岭、尖峰等地对大叶相思进行直干型选择与测定。现已选出干型较直的类型,经后代测定与一般商品种相比,其材积增益达160%─180%,并能保存原来特性。
关键词 大叶相思 直干型 选择 引种
下载PDF
直干型大叶相思胸径性状的生长规律研究
4
作者 黄斌龙 《乡村科技》 2022年第21期117-119,共3页
为探究直干型大叶相思早期的生长规律,以福建省漳浦中西国有林场14年生直干型大叶相思为研究对象,利用树干解析方法,计算并绘制出胸径与树龄之间的生长关系曲线,并采用7种常见的林木生长经验模型对胸径生长量进行回归分析,选取其中最适... 为探究直干型大叶相思早期的生长规律,以福建省漳浦中西国有林场14年生直干型大叶相思为研究对象,利用树干解析方法,计算并绘制出胸径与树龄之间的生长关系曲线,并采用7种常见的林木生长经验模型对胸径生长量进行回归分析,选取其中最适合直干型大叶相思树种的生长模型。研究表明,直干型大叶相思胸径在第1~3年、7~8年处在生长高峰期,与同年其他相思类树种相比,直干型大叶相思的生长速率更高,是相思类树种中长势较好的树种。生长模型的拟合结果表明,最适合此次研究的直干型大叶相思树种的生长模型为立方模型。 展开更多
关键词 直干型大叶相思 解析 生长规律 生长模拟合
下载PDF
综合评分与PCA在直干大叶相思选优中的应用 被引量:5
5
作者 孙冰 杨民权 何耀洪 《林业科学研究》 CSCD 北大核心 1995年第6期641-646,共6页
应用5株优势木法在海南岛尖峰岭和琼海的20hm2大叶相思人工林中初选出优树10株,入选率为1%,对候选优树的树高、胸径、干形、冠形和健康状况等10个因子进行测定并数量化,所得数据运用STAT程序进行方差分析和主成分分... 应用5株优势木法在海南岛尖峰岭和琼海的20hm2大叶相思人工林中初选出优树10株,入选率为1%,对候选优树的树高、胸径、干形、冠形和健康状况等10个因子进行测定并数量化,所得数据运用STAT程序进行方差分析和主成分分析。结果表明:优树、优势木和林分间高径生长的差异极显著,影响优树质量性状的主要因子为高径生长、干形(通直度和圆满度)及自然整枝情况。综合评分显示:优树质量性状的得分大于52,优树的高径生长应大于优势木10%和15%以上,大于林分平均生长量的15%和30%以上。 展开更多
关键词 直干型 大叶相思 相思树属 选择 综合评分
下载PDF
刺槐(Robinia pseudoacacia)新品种介绍 被引量:5
6
作者 田砚亭 李云 《中国水土保持科学》 CSCD 2003年第1期7-7,共1页
“多倍体刺槐新品种及繁殖技术引进”为国家林业局“九四八”项目之一,项目承担单位北京林业大学自1997年至2002年在全国15个省(市、区)进行了区域性引种试验,于2002年11月通过国家林业局组织的项目验收,并选出大叶饲料型四倍体刺槐和... “多倍体刺槐新品种及繁殖技术引进”为国家林业局“九四八”项目之一,项目承担单位北京林业大学自1997年至2002年在全国15个省(市、区)进行了区域性引种试验,于2002年11月通过国家林业局组织的项目验收,并选出大叶饲料型四倍体刺槐和直干速生型刺槐新品种。自2003年开始。 展开更多
关键词 刺槐 Robinia-pseudoacacia 新品种 营养价值 大叶饲料刺槐 速生刺槐 蜜源刺槐
下载PDF
An observational study on vertical raindrop size distributions during stratiform rain in a semiarid plateau climate zone 被引量:2
7
作者 CHEN Yong AN Jun-Ling +1 位作者 LIU Hui-Zhi DUAN Jing 《Atmospheric and Oceanic Science Letters》 CSCD 2016年第3期178-184,共7页
Vertical raindrop size distributions of two stratiform rain events were measured with a Micro Rain Radar during summer 2009 at a semiarid continental site located in Xilinhot, China (43°38′N, 116°42′E). ... Vertical raindrop size distributions of two stratiform rain events were measured with a Micro Rain Radar during summer 2009 at a semiarid continental site located in Xilinhot, China (43°38′N, 116°42′E). The sequential intensity filtering technique (SIFT) was used to minimize the effect of the spurious variability on disdrometric data to obtain the reflectivity-rain rate (Z-R) relationship (Z = αRb). Compared with the least squares regression (LSR) method, SIFT led to a -5% to 4% change in the coefficient (a) and an 8%-1 5% increase in the exponent (b) of the Z-R relationship at 300 m. Rainfall estimation using the Z-R relationship with SIFT had lower standard deviation than that with LSR. The vertical variability of the mean rain rate, total raindrop numbers, and parameters (a and b) of the Z-R relationship was small below a melting layer, suggesting that using the radar reflectivity of weather radar to estimate stratiform rainfall is relatively accurate, at least in the Xilinhot area. 展开更多
关键词 Stratiform rain vertical dropsize distributions semiaridclimate Micro Rain Radar
下载PDF
图解树木盆景制作(十一)
8
作者 黄翔 《花木盆景(下半月)》 2003年第11期36-37,共2页
直斜干型有矮壮双千直斜式、高飘双千直斜式和健壮双千直斜式之分.
关键词 树木盆景 制作技术
下载PDF
Improved direct power injection model of 16-bit microcontroller for electromagnetic immunity prediction 被引量:3
9
作者 高雪莲 田聪颖 +2 位作者 落丽媛 陈银红 陈彦宇 《Journal of Central South University》 SCIE EI CAS 2011年第6期2031-2035,共5页
To promote the modeling standardization process of the integrated circuits, an improved electrical simulation model for a direct power injection (DPI) setup which was used to measure the conducted immunity of a 16-b... To promote the modeling standardization process of the integrated circuits, an improved electrical simulation model for a direct power injection (DPI) setup which was used to measure the conducted immunity of a 16-bit microcontroller to radio frequency aggression was investigated. Based on the existing model of the same microcontroller, the PDN module was modified by adding the core, PLL and MD network models, which could reflect the actual electric distribution situation within the microcontroller more accurately. By comparing the simulation results with the measurement results, the effectiveness of the modified model can be improved to 500 MHz, and its uncertainty is within +1.8 dB (+2 dB is acceptable). Then, to improve the simulation accuracy of the complete model in the high frequency range, the I/O model which contained the dynamic and nonlinear characteristics reflecting the variation of the internal impedance of the microcontroller with increasing the frequency of the external noise was introduced. By comparing the simulation results with the measurement results, the effectiveness of the second modified model can be improved up to 1.4 GHz with the uncertainty of ~1.8 dB. Thus, a conclusion can be reached that the proposed model can be applied to a much wider frequency range with a smaller uncertainty than the latest model of the similar type. Furthermore, associated with the electromagnetic emission testing platform model, the PDN module can also be used to predict the electromagnetic conducted and radiated emission characteristics. This modeling method can also be applied to other integrated circuits, which is very helpful to the standardization of the IC electromagnetic compatibility (EMC) modeling process. 展开更多
关键词 electromagnetic immunity MICROCONTROLLER direct power injection passive distribution network
下载PDF
Vegetative Habitus and Fruit Production of Self-rooted Cherry Cultivar 'Hedelfingen' Wild Type and Somaclonal Grafted on 'Gisela 6' and 'Colt' Rootstock
10
作者 Piagnani Maria Claudia Chiozzotto Remo 《Journal of Environmental Science and Engineering(A)》 2017年第7期363-369,共7页
The study considers the morphological and physiological behaviour of self-rooted sweet cherry CV (Cultivar) 'Hedelfinger' wild type (H) and somaclonal (HS) grafted on 'Gisela 6' and 'Colt' rootstock. The s... The study considers the morphological and physiological behaviour of self-rooted sweet cherry CV (Cultivar) 'Hedelfinger' wild type (H) and somaclonal (HS) grafted on 'Gisela 6' and 'Colt' rootstock. The somaclonal showed reduced vegetative vigour without any variation of the natural tree's architecture. The rootstock 'Gisela 6' caused change in genotype habitus inducing a spreading shape, while 'Colt' increased trunk diameter and height. Fruit quality and size were not affected by genotype nor rootstock. 'Gisela 6', from these preliminary data, had proved the most suitable rootstock for both genotypes since it reduced the tree size and vigor and induced early bearing and the production of a greater number of fruiting spurs. 展开更多
关键词 Cherry CV 'Hedelfingen' growth habit self-rooted somaclonal 'Gisela 6' 'Colt' rootstock.
下载PDF
TIME-VARYING AR MODELING AND ADAPTIVE IIR NOTCH FILTER FOR ANTI-JAMMING DSSS RECEIVER
11
作者 Feng Jining Yang Xiaobo +1 位作者 Diao Zhejun W.u. Siliang 《Journal of Electronics(China)》 2010年第4期465-473,共9页
Using Time-Varying AR (TVAR) model and adaptive notch filter is a new method for the non-stationary jammer suppression in Direct Sequence Spread Spectrum (DSSS). The performance of TVAR model for Instantaneous Frequen... Using Time-Varying AR (TVAR) model and adaptive notch filter is a new method for the non-stationary jammer suppression in Direct Sequence Spread Spectrum (DSSS). The performance of TVAR model for Instantaneous Frequency (IF) estimation will be affected by some factors such as basis functions. Focusing on this problem, the optimal basis function of TVAR model for the IF estimation of the LFM signal is obtained in this paper. Besides the depth and width of notching, the phase properties of notch filter affect the Signal-to-Interference plus-Noise Ratio (SINR) of correlation output to the narrowband jammer suppression in DSSS, in response to the problem the closed solution of correlation output SINR improvement has been derived when a single frequency jammer passes through direct IIR notch filter, and its performance has been compared with those of five coefficient FIR filters. Later, a novel method for LFM jammer suppression based on Fourier basis TVAR model and direct IIR notch filter is proposed. The simulation results show the effectiveness of the proposed method. 展开更多
关键词 Direct Sequence Spread Spectrum (DSSS) receiver Time-Varying AR (TVAR) model IIR adaptive notch filter ANTI-JAMMING
下载PDF
马占相思种源选择研究 被引量:1
12
作者 陈瑞炳 《林业科技通讯》 2000年第6期12-15,共4页
对从澳大利亚昆士兰引进的马占相思 8个种源 ,在阳江市林业科学研究所 4个试点进行对比试验 ,结果表明 :生长快、产量高的132 4 2 (A5)和 132 2 9(A6 ) 2个种源 ,其树高、胸径生长量均比其余种源高 ,且显著或极显著地大于A3、A1、A8种源 。
关键词 马占相思 种源选择 直干型 生长量 生长分析
原文传递
飘枝在柏树盆景创作中的应用
13
作者 吴乃臻 《花木盆景(下半月)》 2015年第1期58-59,共2页
在树木盆景创作过程中,枝法的应用对作品的成功与否有着至关重要的作用。上乘的素材是不可多得的,欲使一般化的素材成为佳品,就需要合理运用枝法(如飘枝、拖枝、探枝、跌枝等),以弥补其不足,使作品产生灵动之感,产生质的飞跃。飘枝,... 在树木盆景创作过程中,枝法的应用对作品的成功与否有着至关重要的作用。上乘的素材是不可多得的,欲使一般化的素材成为佳品,就需要合理运用枝法(如飘枝、拖枝、探枝、跌枝等),以弥补其不足,使作品产生灵动之感,产生质的飞跃。飘枝,是盆景创作中较为常用的一种枝型,常用于斜干型或直干型,干基有与飘枝相反方向的拖根,出枝点在干的下部,其长度在全树各枝中最长,显得飘逸、灵动,具有雄霸一方之势。一枝成功的飘枝,最能体现"盆景四美",即力度美、节奏美、韵律美和空间变化美。 展开更多
关键词 盆景创作 应用 柏树 创作过程 树木盆景 空间变化 直干型 一般化
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部