Study on the vessel elements and perforation plate of secondary xylem in Litchi chinensis;
荔枝次生木质部导管分子及穿孔板观察研究
The variation of perforation plates of vessels in the secondary xylem of Euptelea pleiosperma (Eupteleaceae);
领春木茎次生木质部中导管穿孔板的变异
Perforation plates could be divided into two types:1.
结果发现,人心果次生木质部导管分子中存在着许多不同的样式,多数导管分子具尾;导管分子穿孔板存在着两种类型:1。
Acoustic properties of perforated panels closely pasted with an absorptive thin layer;
穿孔板背面紧贴吸声薄层时的声学特性
Experimental study on improving absorbing property of perforated panel;
提高穿孔板吸声性能的实验研究
Theoretical analysis and calculation on the acoustic properties of perforated panel absorber were described herein.
对穿孔板吸声结构的声学特性进行了理论分析与计算。
Our work is focused on the control method to suppress the instability by perforated plate surrounded with an annular cavity.
本文通过一个电加热镍铬丝作为热源的Rijke管实验装置,观察了电热丝在管中相对位置变化引起的不稳定发声声压级变化情况,并且研究了穿孔板加环形背腔这种结构对Rijke管不稳定发声的控制效果。
In this paper, a new compound flexural transducer with perforated plate is introduced, and the impedance transforming mechanism of the perforated plate is explained theoretically.
本文介绍了一种用于多波节复合弯曲振动换能器的穿孔板，并对穿孔板的阻抗变换机理进行了理论分析。
The lateral walls contain perforation plates (multi-perforation plates).
结果显示,这些管状分子端壁和侧壁的形态及结构分别相同且侧壁具有穿孔板(多穿孔板)。
Scalariform perforation plates .
利用扫描电子显微镜对毛茛科类叶升麻(Actaea asiatica Hara)根和根状茎次生木质部中的管状分子进行观察，发现其管状分子类型丰富，主要有：管胞、管胞状导管、纤维导管和典型的导管分子，其中管胞、管胞状导管和纤维导管为在该类群中首次报道；在导管分子中，存在着梯状穿孔板、网状穿孔板、混合型穿孔板和单穿孔板，其中网状穿孔板和混合型穿孔板为在该类群中的首次报道；对其导管分子上的侧壁穿孔板、多穿孔板和纹孔膜残余也进行了描述。
The lateral walls have perforation plates.
利用扫描电镜观察了国产球盖蕨科10种植物,鳞毛蕨科6种植物的管状分子,结果显示:它们的管状分子端壁和侧壁的形态及结构分别相同,且侧壁具有穿孔板。
Using transfer matrix method to analyze microperforated panel absorber s acoustic characteristic;
用传递矩阵法分析微穿孔板的声学特性
The possibility and the significance of replacing fibred absorption materials by fibreless materials,especially by microperforated panels,are discussed.
简要地介绍了吸声材料的基本特点，阐述了无纤维性吸声材料（特别是微穿孔板吸声结构）取代传统的纤维性吸声材料的可能性及其重要意义，较详细地介绍了近年来德国以及我国科研人员在无纤维吸声材料研究上所取得的进展。
A calculating program of microperforated panel construction is worked out in this paper.
文中编制了微穿孔板结构的数值分析程序，通过计算实例，对微穿孔板结构的声学特性进行了探讨。
Based on theory about micro perforated panel,a micro perforated panel muffler was developed to meet the requirement of the pneumatic motor in roofbolter.
在微穿孔板消声理论的基础上 ,根据气动马达消声器的实际需要设计了一种微穿孔板消声器 ,并通过实验对这种消声器的消声特性和流阻进行了研究。
In this paper, based on Maa's theory, the theory of micro perforated panel(MPP) absorber is summarized, a comparison between the calculated result and the testing result for intermediate and lower frequency standing wave tubes is made.
微穿孔板吸声结构具有吸声系数高、吸收频带宽等优点 ,广泛应用于噪声控制的各个领域 根据马大猷的微穿孔吸声理论 ,总结了微穿孔板吸声结构的吸声原理 ,并用基于此理论的计算结果与在低频、中频驻波管中实验的结果进行对比 ,得到了比较满意的结果 采用微穿孔板吸声结构 ,进行汽车发动机隔声降噪模拟实验 ,结果表明 ,微穿孔板吸声结构具有良好的降噪功能 微穿孔板吸声结构的吸声性能的初步研究 ,为微穿孔板吸声结构在工程中的应用提供了依
The Influence of Pore's Media on Sound Absorption Characteristics of Thick Microperforated Panel
孔中介质对厚微穿孔板吸声性能的影响
Design and Research on the Transparent Absorbing Structure of Microperfrated Panel;
通透微穿孔板吸声结构的设计及研究
The Mode Analysis and Position Selection of Perforated Panel Absorber
穿孔板吸声结构模态分析及位置选择
" Test sieves--Metal wire cloth, perforated metal plate and electroformed sheet--Nominal sizes of opening"
GB/T6005-1997试验筛金属丝编织网、穿孔板和电成型薄板筛孔的基本尺寸
The study of the stem's secondary xylem of Rhus chinensis Mill reveals that perforation plate is simple perforation plate.
对盐肤木茎进行木材解剖学研究,发现其导管分子穿孔板为单穿孔板。
Rudimentary Researches on the Acoustic Characteristics of Microperforated Panel Absorbers with Alterable Air-Cavity;
不等腔微穿孔板组合吸声结构的吸声特性初探
The Type and Evolution of Vessel Element Perforation Plate of Vaccinium uliginosum;
笃斯越桔根导管分子穿孔板的类型及演化
The Computer Simulation Analysis of Micro Perforated Panel Spacial Absorbers (Rectangular Pyramid)
微穿孔板空间吸声体（四棱锥）的计算机仿真分析
The research of perforated plate sound absorption in the flow
气流条件下微穿孔板结构吸声特性研究
Acoustics Software Development of Micro-perforated Panel Absorber Based on AML
基于AML的微穿孔板吸声体的声学软件开发
Improvement of the transfer matrix calculation method for micro-perforated plate absorption structure and experiments
微穿孔板传递矩阵计算方法的改进及实验
Study on Acoustic Characteristic of Double Layer Micro-perforated Panel Absorber at High Temperature
高温下双层串联微穿孔板结构声学特性研究
The Computer Simulation Analysis of Micro Perforated Panel Absorbers and Parallel Structures;
微穿孔板吸声结构及其并联结构的计算机模拟分析
The Application of Perforation Plate in Reducing Oil Sump Noise of Some 6-cylinder Diesel Engine
穿孔板在降低某6缸柴油机油底壳噪声中的应用
This board bores easily.
这块木板易於穿孔。
INFLUENCE OF HOLE POSITION ON BENDING RIGIDITY OF UD-LAMINATE
穿孔位置对单向层板弯曲刚度的影响
Stamp-tax, press the flower, engraving and bore hole the series ceiling.
印花、压花、浮雕、穿孔系列天花板。
not punched card of paper or paperboard[fur punch card machines, whether or not in strips]
未穿孔卡纸或纸板卡片[用于穿孔卡片机,无庥是否条形]