基于线性预测残差倒谱的基音检测

传统的基音检测算法对含噪语音的检测结果较差,本文在线性预测倒谱方法的基础上采用基于线性预测残差倒谱的方法对含噪语音进行基音检测。实验结果表明,该方法使基音峰点更加清晰,提高了基音检测的精度。     

Chemical and thermal resistance of basalt fiber in inclement environments

To study the applicability of the basalt fiber through various experimental works in thermal and chemical environments, glass fiber and carbon fiber were compared and discussed. The tensile strength testing was used to investigate the corrosive resistance of basalt fiber, meanwhile, surface study by scanning electron microscopy and microanalysis with complementary X-ray diffraction analysis (SEM/EDS) was also used to ascertain the durability of basalt fiber. The basalt fiber showed better strength retention than the glass fiber at relatively high temperature. Its tensile strength increased when exposed at 300 °C for several hours, and still maintain about 70% of the initial strength at 400 °C, whereas that of the glass fiber decreased dramatically. The better stability of the basalt fiber was observed in hydrothermal and chemical environment. The tensile strength of the basalt fiber increased by 20% after the immersion in boiling water and remained well in acid solution, when it comes to glass fiber, the tensile strength decreased to some extent. Although the alkali resistance of basalt fiber was poor at the initial stage, it shows better resistance than the glass fiber after long time treatment.     

侧面碰撞车门解锁问题结构优化

为解决某车型侧面移动式可变形壁障(MDB)碰撞过程中后侧门门锁解锁问题,通过在与试验对标良好的侧面碰撞仿真模型中加入后侧门门锁机构模型,仿真分析得出碰撞时门把手区域发生过大的翻转变形,是导致车门解锁开启的原因。提出了车门外板上部增加一根加强板的优化方案,改善外板门把手区域局部变形。试验结果表明:该优化方案能够有效降低门把手区域的翻转变形,车门保持锁止状态,提高了车身侧面碰撞安全性能;在侧面碰撞仿真模型中增加精细的门锁机构模型,不仅能更准确地模拟车门整体变形,而且能很好地发现和解决门锁解锁问题。     

Enzymatic biosensor for nitrite detection based on direct electron transfer by CPO-ILEMB/Au@MoS2/GC

Journal of Applied Electrochemistry - A novel nitrite electrochemical biosensor is constructed by glassy carbon electrodes (GC) coated by chloroperoxidase (CPO) -Au nanoparticles-MoS2 nanoflowers...     

超超临界汽轮机调试出现的问题及解决方法

某新建百万机组电厂在调试过程中,循环水系统、闭式水系统、给水系统、凝结水系统、EH油系统、润滑油系统、真空系统、辅助蒸汽系统以及振动出现一些问题,对问题逐一解决,保证机组顺利投产,对解决同一类型机组调试中遇到的问题,以及运行中遇到的问题有一定的借鉴。     

CsCl-PEG400-H2O三元体系在15,25和35℃时的等温溶解度、密度及折光率研究

采用半微量相平衡测定装置和高精度密度-折光率测定仪,精确测定了CsCl-PEG 400-H2O三元体系在15,25和35℃3个温度下不同组分百分比溶液的折光率和密度数据,通过关联密度和折光率数据获得了CsCl在上述温度下的等温溶解度.对饱和体系的溶解度研究表明:在同一温度下CsCl的溶解度随聚乙二醇质量分数的增加而减小;在不同温度下CsCl的溶解度随温度的升高而增大.采用经验方程lnS=A1+A2ω2+A3ω2(2)+A4ω2(3)对饱和体系的溶解度进行了关联,效果较好.对不饱和体系的研究表明:当盐含量一定时,随着醇水比例的增加,体系的密度不断增大,折光率也随盐含量增加而增大;当醇水质量比一定时,体系的密度和折光率随盐含量的增加而增大,对不饱和体系的密度和折光率用经验方程Y=(A0+A1ω2+A2ω1+A3ω1ω2+A4ω2ω1(2))×exp[A5(ω1/ω3)+A6(ω1/ω3)2]进行拟合,拟合效果较好,同时给出了体系的盐析率曲线.本研究不仅为溶液化学提供了基础数据,也为混合溶液中盐和醇的分离纯化提供一种新的方法和思路,对CsCl进一步的应用、开发和研究具有一定的参考价值.     

应用三罗拉长短胶圈改造A456M型粗纱机

介绍了采用三罗拉长短胶圈牵伸改造A456M型粗纱机的工艺效果,三罗拉长短胶圈牵伸装置,其纤维变速点的平均位置离前罗拉钳口较近,离散度最小,其半制品和成纱质量较高.     

直接空冷机组冬季防冻试验研究

以某典型300 MW直接空冷机组的三角单元散热器为试验对象,测试了直接空冷机组在自然抽吸、风机停运、关闭蒸汽分配管蝶阀以及风机入口加装堵风装置后的散热器风温、风速变化规律,为确定合理的防冻运行方式提供依据。     

漂浮式风机运动抑制方法综述

通过可靠可控的技术手段,实现浮式风机系统支撑平台的运动抑制,对保障浮式风机的安全性与可靠性具有重要意义。综述各类主要浮式风机运动抑制方法与技术,介绍各种方法的基本原理、技术特点、研究现状和应用情况,以期为相关领域研究人员提供技术参考和研究思路。     

Roundoff noise in multirate digital filters

The roundoff noise problem for multirate digital filters is difficult because rate changing inside the filter makes both scaling and roundoff noise calculation complicated. With a new multirate filter analysis technique, the transfer function between any two points inside a multirate filter can be easily found, thus, simplifies the scaling and noise calculation. This paper finds theL _P scaling and derives the roundoff noise expressions for fixed point implementations of the multistage decimator, interpolator, and multirate narrow-band low-pass filter. It is shown that the noise source at a low sampling rate stage is more important than that at a higher sampling rate stage. Methods to reduce output roundoff noise are discussed.This research was supported by NSF grant ECS 81-00453.