穿孔

The construction and properties of the absorption curve of microperforated panel absorber are discussed.

引言微穿孔板吸声器是1966年发展，为吸收高温、高湿度下的强噪声而设计的。

Absorption curve of four micro-perforated panel is the best in three different structure. But its performance is close to three layer micro-perforated panel.

优化后的四层微穿孔板结构在整个频率内的吸声系数曲线最为饱满，但是与三层结构相比，吸声性能提高不多。

Theoretical analysis and calculation on the acoustic properties of perforated panel absorber were described herein.

文章对穿孔板背面紧贴吸声薄层时的声学特性进行了理论分析与计算，并与实验结果作出比较。

Based on the theoretical and experimental studies in electrical and mechanical parameters, micro-perforated absorption material in the box, and positions optimization of the actuators and attached masses on the panel, several optimization methods for the acoustic performance of panel speaker are proposed.

基于对平板扬声器电－力参数测量、箱体内衬微穿孔吸声材料、驱动器以及附加质量位置优化的理论研究和实验测试，提出了若干种提高平板扬声器声性能的方法。

Using transfer matrix method to analyze microperforated panel absorber s acoustic characteristic;2. 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。

And the wall of test workshop is completely paved with 25mm thickness stainless steel perforated acoustic panel, 50mm cavity; using the sound lock double sound insulation door, the sizes are 2.4×1.64 m、2.149×1.04 m respectively; Double layer 3×8 mm thickness bulletproof glass sound insulation window, 50mm cavity; air inlet uses dissipative muffler, the size is 5×3×2 m, sound splitter is 150 mm thickness stainless steel protective facing.

试车间墙面满铺25 mm厚不锈钢穿孔吸声板，50 mm安装后空腔；采用声闸双重隔声门，尺寸分别为2.4×1.64 m、2.149×1.04 m；双层3×8 mm厚防弹玻璃隔声窗，50 mm空腔；进风口选用阻性消声器，尺寸为5×3×2 m，消声片为150 mm厚不锈钢护面。

White and yellow perch, and striped bass were enroute for the fresh water farther north. When thepeople alongshore made the discovery, they turned

当沿岸的人们发现这一现象时，他们出动了，就像在乡区当鸽子来临时他们所采取的做法一样，用在冰上的穿孔中放下的一些小刺网来捕鱼，所捕获的数量之大令人难以置信。

Aperture card.

穿孔卡片

Different DNA constructs were introduced into the decapsulated cysts of Artemia by electroporation under 2KV, 20 μsec pulse length, 20 number of pulses and a DNA concentration of 20μg/μl in a volume of 100μl.

不同的构筑质体经由电穿孔法，被导入经去壳处理后的丰年虾休眠卵中，在2千伏特、20微秒的脉冲波长度、20次的脉冲数和在100微升的体积中DNA浓度为每微升20微克的设定条件下。

There are decreased synthesis of GAGs in the sample of severe arthritic changes.

在关节盘穿孔的标本糖胺多糖持续减少。

Chrysanthemum of 10 thousand birthday is lax to edaphic requirement, with the arenaceous qualitative loam with fecund, good drainage had better.

万寿菊对土壤要求不严，以肥沃。排水良好的砂质壤土为好。

He unstepped the mast and furled the sail and tied it.

他拔下桅杆，把帆卷起，系住。