本文简单的介绍了噪声污染现状、固定结构传播噪声的危害及监测方法和限值要求。详细列举了固定结构传播噪声噪音控制的三个主要途径,生活中声环境是复杂多变的,在测量噪声实际情况过程中,确保检测数据的准确性和可靠性是第一要素,现场...本文简单的介绍了噪声污染现状、固定结构传播噪声的危害及监测方法和限值要求。详细列举了固定结构传播噪声噪音控制的三个主要途径,生活中声环境是复杂多变的,在测量噪声实际情况过程中,确保检测数据的准确性和可靠性是第一要素,现场可疑噪声源的确认、监测点位的布设、测量时长的选择、背景噪声的测量与修正等技术环节的把握,直接影响监测数据及监测结论,以北京市朝阳区西大望路某小区供暖水泵房的结构传声影响为例,分别对不同房间的等效 A 声级、各倍频带声压级昼夜进行监测,通过前、后两次的数据比对,判断其处理方式对结构传声的治理是否有效。针对噪声源供暖水泵房的这种后期的降噪改造, 因为改动较大,所以投入的成本还是很大的,在北京城区,以往碰到的案例,有一些小区类似于这种水泵房、电梯机房在一开始的设计上就存在严重缺陷,如果能在刚开始设计和建造施工阶段就多引起重视,就能大大提高居住生活质量也更加符合经济发展需求。展开更多
目的探讨采用计算机辅助设计和有限元声固耦合计算方法分析耳模中导声管声学特性的可能性。方法通过螺旋断层数字扫描仪(computed tomography,CT)扫描并获取志愿者耳部数据,建立外耳模型,再布尔计算出耳模及导声管模型。应用Ansys软件和...目的探讨采用计算机辅助设计和有限元声固耦合计算方法分析耳模中导声管声学特性的可能性。方法通过螺旋断层数字扫描仪(computed tomography,CT)扫描并获取志愿者耳部数据,建立外耳模型,再布尔计算出耳模及导声管模型。应用Ansys软件和Aurical真耳分析仪分别计算和实测,输入90 d B声压,记录频率500~8000 Hz耳模导声管出口处压力值。结果有限元计算与实际测试耳模声学特性结果趋势相同;在导声管影响下耳模的共振频率在4000 Hz左右,最大增益约为24 d B,模拟计算结果较实际测试结果高6.8 d B。结论有限元分析方法可有效应用于耳模声学特性的研究。展开更多
With the help of scattering-matrix method, the acoustic phonon ballistic transmission and the thermal conductivity are studied detailedly in a four-terminal structure. We find that the transmission coefficients and th...With the help of scattering-matrix method, the acoustic phonon ballistic transmission and the thermal conductivity are studied detailedly in a four-terminal structure. We find that the transmission coefficients and the reduced thermal conductance for each region sensitively depend on geometric parameters, and are of quantum character, but the reduced total thermal conductance for all regions seems independent of structure parameters when the temperature is not very low. Our results show that one can control the thermal conductivity for each region to match practical requirements in devices by adjusting the geometric parameters.展开更多
A novel mobile self-reconfigurable robot is presented. This robot consists of several independent units. Each unit is composed of modular components including ultrasonic sensor, camera, communication, computation, and...A novel mobile self-reconfigurable robot is presented. This robot consists of several independent units. Each unit is composed of modular components including ultrasonic sensor, camera, communication, computation, and mobility parts, and is capable of simple self-reconfiguring to enhance its mobility by expanding itself. Several units can not only link into a train or other shapes autonomously via camera and sensors to be a united whole robot for obstacle clearing, but also disjoin to be separate units under control after missions. To achieve small overall size, compact mechanical structures are adopted in modular components design, and a miniature advanced RISC machines （ARM） based embedded controller is developed for minimal power consumption and efficient global control. The docking experiment between two units has also been implemented.展开更多
文摘本文简单的介绍了噪声污染现状、固定结构传播噪声的危害及监测方法和限值要求。详细列举了固定结构传播噪声噪音控制的三个主要途径,生活中声环境是复杂多变的,在测量噪声实际情况过程中,确保检测数据的准确性和可靠性是第一要素,现场可疑噪声源的确认、监测点位的布设、测量时长的选择、背景噪声的测量与修正等技术环节的把握,直接影响监测数据及监测结论,以北京市朝阳区西大望路某小区供暖水泵房的结构传声影响为例,分别对不同房间的等效 A 声级、各倍频带声压级昼夜进行监测,通过前、后两次的数据比对,判断其处理方式对结构传声的治理是否有效。针对噪声源供暖水泵房的这种后期的降噪改造, 因为改动较大,所以投入的成本还是很大的,在北京城区,以往碰到的案例,有一些小区类似于这种水泵房、电梯机房在一开始的设计上就存在严重缺陷,如果能在刚开始设计和建造施工阶段就多引起重视,就能大大提高居住生活质量也更加符合经济发展需求。
文摘目的探讨采用计算机辅助设计和有限元声固耦合计算方法分析耳模中导声管声学特性的可能性。方法通过螺旋断层数字扫描仪(computed tomography,CT)扫描并获取志愿者耳部数据,建立外耳模型,再布尔计算出耳模及导声管模型。应用Ansys软件和Aurical真耳分析仪分别计算和实测,输入90 d B声压,记录频率500~8000 Hz耳模导声管出口处压力值。结果有限元计算与实际测试耳模声学特性结果趋势相同;在导声管影响下耳模的共振频率在4000 Hz左右,最大增益约为24 d B,模拟计算结果较实际测试结果高6.8 d B。结论有限元分析方法可有效应用于耳模声学特性的研究。
基金The project supported by the Natural Science Foundation of Hubei Province of China under Grant No. 2003ABA004
文摘With the help of scattering-matrix method, the acoustic phonon ballistic transmission and the thermal conductivity are studied detailedly in a four-terminal structure. We find that the transmission coefficients and the reduced thermal conductance for each region sensitively depend on geometric parameters, and are of quantum character, but the reduced total thermal conductance for all regions seems independent of structure parameters when the temperature is not very low. Our results show that one can control the thermal conductivity for each region to match practical requirements in devices by adjusting the geometric parameters.
基金Supported by the National High Technology Research and Development Programme of China ( No. 2004AA420110)Heilongjiang Province Technology Foundation (No. GB04A502)
文摘A novel mobile self-reconfigurable robot is presented. This robot consists of several independent units. Each unit is composed of modular components including ultrasonic sensor, camera, communication, computation, and mobility parts, and is capable of simple self-reconfiguring to enhance its mobility by expanding itself. Several units can not only link into a train or other shapes autonomously via camera and sensors to be a united whole robot for obstacle clearing, but also disjoin to be separate units under control after missions. To achieve small overall size, compact mechanical structures are adopted in modular components design, and a miniature advanced RISC machines （ARM） based embedded controller is developed for minimal power consumption and efficient global control. The docking experiment between two units has also been implemented.
