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1.
马岩 《生物数学学报》2003,18(4):473-476
为船舶、乐器等特殊行业需要的弦切板数控加工提供数学描述理论,提出的这些理论将为数控加工的数学模型建立提供基础理论,为板材纹理的视频再现提供数学方法.本文提出的理论还将为三角形下锯法提供理论依据,与制材工艺结合起来,将使传统加工工艺数学化,为科学管理和数字化控制提供了理论.本文是木材工业中用数学描述加工过程的开始,可以推进木材工业加工过程数学描述研究的开展.  相似文献   

2.
原木形状分段描述方法的数学描述理论研究   总被引:4,自引:0,他引:4  
马岩 《生物数学学报》2006,21(3):435-440
为制材、木材检尺等特殊行业需要的原木数控检测提供数学描述理论,提出的这些理论将为数控检测的数学模型建立提供具体的数学方法,为原木形状的视频再现提供编程的数学工具.本文提出的理论还将为数控下锯法提供理论依据,与制材工艺结合起来,将使传统原木检测数字化,为科学管理原木和数字化统计与检尺控制提供了理论,本文是木材工业中用数学描述检测过程的开始.通过本文的研究,可以推进木材工业检测过程数学描述研究的开展.  相似文献   

3.
本文为制材、剩余物利用等行业需要的板皮数控加工提供数学描述理论,提出的这些理论将为板皮裁边的数控加工数学模型建立提供编程的数学方程,为板材最优下锯的视频再现提供数学方法.本文提出的理论还将为锯切、板皮材积精确检测提供理论依据,与制材工艺结合起来,将使传统加工工艺数学化,为科学管理和数字化控制提供了理论.本文是木材工业中用板皮数学描述加工过程的开始.通过本文的研究,可以推进木材工业加工过程数学描述研究的开展.  相似文献   

4.
面对我国森林质量不高的现状,提高木材出材率已逐渐成为缓解木材供需矛盾的根本途径.本文提出弯曲原木的数学模型,全面地描述出弯曲原木的解析形状,并借助计算机辅助设计实现原木的三维再现,对于提高原木出材率和利用率、提高木材加工技术水平与现代化程度有着极为重要的影响和广泛的应用前景.  相似文献   

5.
一种为害建筑物的触角锯天牛   总被引:1,自引:0,他引:1  
无产阶级文化大革命以来,我们在群众性的消灭白蚁运动中,在杭州市及浦江县发现一种锯天牛对建筑物为害很大。经鉴定为触角锯天牛(Eurypoda ante-nnata W. Saunders)。据记载,此虫分布于我国浙江(兰溪、舟山)、上海、江西(婺源)、贵州(贵阳、湄潭)、台湾、以及香港等地,但未见有为害情况和防治方法的报道。 触角锯天牛为害干燥木材,如梁柱、楼板櫊栅、木器家具等。主要为害树种是枫木、樟木、桦木、麻栎等阔叶树,其次为松、杉木等针叶树。蛀孔呈椭圆形,直径多为19×9毫米、也有27×8或19×7毫米的。一根受害严重的梁柱,其孔洞最多可达数百个,内部蛀蚀的坑道纵横交错,层次很多,极不规则。受害地区每年因此而需要翻修的房屋很多,耗费了不少国家资财,有的甚至能造成房屋倒塌的事故。 我们在调查研究过程中,对它的年生活史和生活习性做了一些记载,同时做了一些药剂防治试验,收到一定的效果。现作一简要介绍,以供参考。  相似文献   

6.
最近,笔者在鉴定由中华人民共和国广州动植物检疫所雷淑媚同志送来的从马来西亚进口原木中输入的天牛,共有八种。其中三种〔黄八星白条天牛Batocera rubus Linnaeus 1785,地衣天牛Palimna annulata(0livier)1792及刺缝裂眼天牛Dialeges Pauper Pascoe 1856〕在国内有分布。这些新输入的天牛种类,有可能在与马来西亚气候相近的我国南部地区存活而成为新的木材害虫。为此,极需我国有关方面在各口岸立即加强对进口林木的检疫工作,并建议就地采用辐射杀虫或其它措施杀灭进口原木中的天牛等害虫,以免蔓延为害。  相似文献   

7.
林业剩余物资源量评估方法   总被引:1,自引:0,他引:1  
根据近十年来相关文献报道,分析了前人所建方法的合理性,结合中国林业生产实际,完善了林业剩余物资源潜力的计算方法。主要贡献包括:林业剩余物第二级分类的10个主要类型,即林木苗圃剩余物、林木修枝剩余物、木材采伐剩余物、木材造材剩余物、木材加工剩余物、竹材加工剩余物、薪材、废旧竹材、废旧木材、香蕉和菠萝残体;将经济林采伐和进口原木产生的剩余物计入相关木材剩余物计算范围;首次建立了包括木本水果在内的林木修枝剩余物的计算方法,以及多年生草本水果剩余物即香蕉和菠萝残体产量的计算方法;确定计算公式中参数所需要数据的来源;建议今后重点研究相关系数取值、林业剩余物资源量及其空间分布和相关行业标准等。  相似文献   

8.
于伸  毛子军 《植物研究》2001,21(2):290-292
介绍了我国高级家具用材树种的分布、生态学特性、木材宏观构造、木材加工工艺性质及树种资源保护和利用情况。研究表明,我国高级家具用材树种较少,还不到10种,其中大多数分布在我国热带、亚热带地区。我国高级家具用材树种利用过度,其中麻楝、降香黄檀已很少见,林分径级下降,资源面临濒危状态。因此,对这些种树的保护和人工造林越来越重要和迫切。  相似文献   

9.
木材横断面六棱规则细胞数学描述理论研究   总被引:32,自引:0,他引:32  
本文采用微观力学和细胞学理论,在横观各向同性的假设下,提出了一种木材规则细胞主方向截面形状描述的理论方法。应用本文提出的理论,可以根据纤维、木质素、细胞直径和排列的程度,绘出理想状态下木材的主方向规则细胞结构形状,为木材学运用数学手术深入到细胞结构研究的深度提供了一种新的数学方法,并且可以为定量解释木材规则细胞变异后材性与性能提高的原因提供定量解释的数学手段。  相似文献   

10.
为何人们把明清家具称为红木家具?古代史中没有红木的说法,红木一词不到百年。从民国到今天,人们把明清家具称为红木家具。红木一词最早出现在上海,当时全国有钱人大半在上海经营、生活,他们对用珍贵木材所制作的家具情有独钟。精明的商人发现,凡是紫檀、黑酸枝、白酸枝、乌木、鸡翅木、花梨木等这些硬木,有个明显的特征,即木质内均为红颜色,于是笼而统之称呼为"红木"。  相似文献   

11.
通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.  相似文献   

12.
The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.  相似文献   

13.
Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m−2 s−1. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to Pfr.  相似文献   

14.
龙胆科药用植物化学成分的研究现状   总被引:16,自引:0,他引:16  
龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。  相似文献   

15.
Summary Embryogenic tissues of sugi (Cryptomeria japonica) were induced on a modified Campbell and Durzan (CD) medium containing 1 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 600 mg l−1 glutamine, and subcultured in the medium of the same composition for over 1 yr. This resulted in a mixed culture of embryogenic and non-embryogenic cells. When embryogenic cells were isolated and cultured independently, their capacity to form embryogenic aggregates was lost. Thus, the non-embryogenic cells present within a mixed culture system were essential to the formation of embryogenic aggregates. When embryogenic tissues were isolated and cultured independently on a high glutamine-containing (2400 mg l−1) medium, dry weights and endogenous levels of glutamine increased, and the tissue could generate a large number of embryogenic aggregates. Amino acid analysis of embryogenic and non-embryogenic cells from the maintenance culture indicated a higher level of glutamine was present in the latter. The high endogenous level of glutamine in the non-embryogenic portion of mixed cell masses may be the supplier of glutamine for maintaining the embryogenic property of the tissues.  相似文献   

16.
The review deals with study of enzymologic properties of a novel highly specific acetylcholinesterase substrate, N-(β-acetoxyethyl) piperidinium iodomethylate (“piperidylcholine”), and its 30 derivatives that were tested as effectors of cholinesterases of mammals and various species of Pacific squids. It was proven for the first time that responsible for specificity of action was structure of cyclic ammonium grouping of the alcohol part of molecule of the ester substrate. Analysis of specificity is performed based on enzymatic hydrolysis parameters—activity of catalytic center of cholinesterases and bimolecular constant of the reaction rate that are determined at optimal and low substrate concentrations. Among the specially synthesized group of thioester compounds there is revealed one more highly specific acetylcholinesterase substrate—N-(β-acetoxyethyl) piperidinium.  相似文献   

17.
A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.  相似文献   

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20.
真菌类遗传学分析的知识结构教学   总被引:5,自引:2,他引:3  
罗桂花 《遗传》2002,24(3):349-350
本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.  相似文献   

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