Evaluation of ultrasonic bubble detectors in vitro using calibrated microbubbles at selected velocities.

Two standard Doppler ultrasonic devices, currently used for detecting bubbles in vivo, have been evaluated and compared in vitro using carefully calibrated uniform micro-bubbles rising at terminal velocity through a static aqueous medium. Two unexpected findings were observed: (a) the focal length of the transducer apparently decreases for smaller bubble sizes, and (b) a significant horizontal convection current was produced by one of the instruments. When the medium was in motion, it was found that the sensitivity varied markedly with bubble velocity, varying from a minimum detectable diameter of 40 mum at 55 cm/sec to 170 mum at 20 cm/sec. These findings are discussed with regard to the limitations of the Doppler technique for monitoring gas emboli in vivo and as an early warning for decompression sickness in divers.     

蛙人回波建模与实验研究

选用蛙人回波的简化模型,结合实验获得各主要因素对蛙人目标强度贡献的量值。分别选用简化的胸腔、躯干、大腿骨等人体器官和开式呼吸气泡群、干式潜水服、呼吸气瓶等的声散射模型。通过码头实验测量了蛙人的目标强度,频率为75kHz。在所有影响蛙人目标强度的因素中,开式呼吸气泡群对目标总强度贡献最大,其目标强度大于-16.9dB;其次是干式潜水服,约-17dB;再次是开式呼吸气瓶,约为-24dB;蛙人身体目标强度约-27.2dB;另外实验测量了肺部组织的目标强度,约-25.9dB,频率125kHz。理论模型和实验均表明,开式呼吸气泡群和潜水装备对蛙人回波的贡献远大于蛙人身体。     

Underwater speech communications with a modulated laser

A novel speech communications system using a modulated laser beam has been developed for short-range applications in which high directionality is an exploitable feature. Although it was designed for certain underwater applications, such as speech communications between divers or between a diver and the surface, it may equally be used for air applications. With some modification it could be used for secure diver-to-diver communications in the situation where untethered divers are swimming close together and do not want their conversations monitored by intruders. Unlike underwater acoustic communications, where the transmitted speech may be received at ranges of hundreds of metres omnidirectionally, a laser communication link is very difficult to intercept and also obviates the need for cables that become snagged or broken. Further applications include the transmission of speech and data, including the short message service (SMS), from a fixed installation such as a sea-bed habitat; and data transmission to and from an autonomous underwater vehicle (AUV), particularly during docking manoeuvres. The performance of the system has been assessed subjectively by listening tests, which revealed that the speech was intelligible, although of poor quality due to the speech algorithm used. PACS 42.55.Px; 42.60.By; 42.62.-b     

水下蛙人被动探测测向实验研究

为了对携带开式呼吸器的水下蛙人进行被动探测,本文采用四个水听器组成的十字阵在浅海水域对水下开式蛙人进行了被动探测、测向实验。结果表明:蛙人辐射噪声具有周期性特征,其周期与蛙人的呼吸频率有关;另外,蛙人呼吸辐射噪声具有显著频带,并且其频带与蛙人携带的呼吸器有关。根据蛙人辐射噪声的显著频带和周期性特征,设计信号处理算法实现了对蛙人的被动声学探测识别。使用互相关方法处理一对水听器的接收信号,可以确定蛙人的方位,但是根据理论分析会出现一个假方位。对比十字阵中两对水听器的测向结果可确定蛙人的准确方位。     

Hardware and software for ground tests of onboard charged particle spectrometers

The article presents a hardware and software complex for ground tests of onboard charged particle spectrometers that are designed at the National Research Nuclear University MEPhI for monitoring of nuclear-physical factors of space weather and can be installed in a wide class of satellites. The structural scheme and operating principles of component parts are discussed. The main algorithm and software features are presented. The technique of ground spectrometer tests and calibrations in various measurement modes at atmospheric cosmic particle flows, both in autonomous laboratories and in interface tests as part of a satellite, is also described.     

Testing the accuracy of smartphones and sound level meter applications for measuring environmental noise

This paper reports on experimental tests undertaken to assess the capability of noise monitoring applications to be utilized as an alternative low cost solution to traditional noise monitoring using a sound level meter. The methodology consisted of testing 100 smartphones in a reverberation room. Broadband white noise was utilized to test the ability of smartphones to measure noise at background, 50, 70 and 90 dB(A) and these measurements were compared with true noise levels acquired via a calibrated sound level meter. Tests were conducted on phones using the Android and iOS platforms. For each smartphone, tests were completed separately for leading noise monitoring apps culminating in 1472 tests. The results suggest that apps written for the iOS platform are superior to those running on the Android platform. They show that one of the apps tested – SLA Lite – is within ±1 dB of true noise levels across four different reference conditions. The results also show that there is a significant relationship between phone age and its ability to measure noise accurately. The research has implications for the future use of smartphones as low cost monitoring and assessment devices for environmental noise.     

An evaluation of three helium speech unscramblers to a depth of 1000 feet

This paper presents the results of speech intelligibility tests conducted during two simulated dives in a helium-oxygen environment and in a tri-mixture environment of helium, nitrogen, and oxygen at depths from 800 to 1000 feet of sea water. In order to avoid the narcotic effect of nitrogen at these depths, a large percentage of the nitrogen is replaced by helium. The introduction of helium into the breathing mixture seriously distorts the speech signal (primarily due to the greatly increased sound velocity in this mixture). To correct this problem, a number of devices (helium speech “unscramblers”) have been designed to return this distorted speech to a more natural and intelligible form. In the present study, it was found that several of these units are effective at depths near 1000 feet of sea water; however, their effectiveness is strongly influenced by the electroacoustic characteristics of the microphone. In addition, a significant four-way interaction among the diver/talkers, listeners, microphones, and unscramblers was discovered. This would seem to indicate that communications training of diving teams, consisting of both divers and surface personnel, would be desirable.     

用于浅层肿瘤重离子治疗的终端束流诊断控制系统

 设计了中国科学院近代物理研究所利用兰州重离子研究装置（HIRFL）进行浅层肿瘤临床治疗试验研究中所使用的束流诊断安全控制系统。该系统包括束流强度监测及保护、剂量测量、扫描波形监测及保护3个部分。系统基于PXI系统及LabVIEW软件,给出了该系统的各部分结构。从系统建立时的多次测试结果以及实际临床治疗试验研究时的长期运行结果来看,该束流诊断控制系统在控制辐照剂量以及安全保护方面能够满足当前重离子加速器浅层肿瘤临床治疗试验的基本要求,为试验研究的顺利进行提供了可靠的保证。     

Wide-range structurally optimized channel for monitoring the certified power of small-core reactors

The results of tests of a prototype version of a channel for monitoring the certified power of small-core reactors performed at the BR-K1 reactor at the All-Russian Scientific Research Institute of Experimental Physics are reported. An SNM-11 counter and commercial KNK-4 and KNK-3 compensated ion chambers were used as neutron detectors in the tested channel, and certified NCMM and CCMM measurement modules controlled by a PC with specialized software were used as measuring instruments. The specifics of metrological assurance of calibration of the channel in the framework of reactor power monitoring are discussed.     

氦语音增强算法的研究

当潜水员深海作业时，由于生理方面的原因，需要以氦氧混合气体为呼吸介质替代空气，但这时会出现所谓的“氦语音”现象，语音产生很大畸变，清晰度极低。本文给出了氦语音的基本变化规律，介绍了两种分别基于短时傅立叶变换和线性预测模型的增强算法。我们的实验结果表明，两种算法均能显著校正氦语音，提高清晰度。     

飞参系统实时监视技术研究

针对飞机研制阶段各系统交联试验时故障定位慢、检查测试手段匮乏的问题,设计了飞参系统的实时监视功能。飞参系统中的机载设备与地面设备通过以太网进行数据交互,实现飞机状态的实时监视。分析了实时监视功能的作用与优势,并从某型飞参系统功能需求出发,阐述了机载设备的硬件配置及软件架构。基于UDP通信协议,提出了一种机载设备与地面设备交互的数据收发策略。该策略通过地面设备控制数据通信周期,机载设备采集的数据按周期发送给地面设备还原显示,实现了飞行数据的一边记录一边监视。实际应用表明,飞参系统的实时监视功能丰富了试验测试手段,提高了各个系统试验效率,实现了对飞机实时状态的监测,为航前快速检测技术的发展奠定了基础,具有很高的工程实用价值。     

海豚声散射特性的理论建模及实验研究

国内对蛙人和大型海洋哺乳动物声散射特性的研究很少,无法满足现代的防御需要。论文分析了海豚的回波机理,建立了海豚反向散射目标强度的球壳散射模型。采用比较法测得海豚对75kHz的声波反向散射目标强度为-25.8dB。根据实验结果,球壳散射模型对75kHz声波是适用的。     

水下蛙人被动探测技术实验研究

为了探测携带呼吸器的水下蛙人目标,实验研究了蛙人呼吸辐射声信号的基本原理,提出了基于蛙人呼吸周期性特征的水下蛙人被动检测方法。水池实验获得了蛙人呼吸的周期性声信号,论证了被动探测的可行性。由于蛙人呼吸声信号所具有的显著频带,所以分别利用了带通滤波法和匹配滤波法获取周期信号的包络,并提取包络信号频谱的四类特征用于判决。三亚湖试结果表明:四类特征对蛙人的探测距离存在差异,最远能在40 m附近检测到蛙人,并且匹配滤波法的检测性能明显优于带通滤波法。结论:受限于辐射源的能量级,被动方法对蛙人的探测距离有限。      

双余度发动机状态监测技术的研究与应用

在飞机、舰艇、装甲、汽车电子控制系统中采用双余度发动机状态监测技术,能够有效提高飞机、舰艇、装甲、汽车运行的安全性和可靠性,以某型涡轴发动机为研究对象,对双余度发动机状态监测技术进行了深入研究,研制了双余度发动机状态监测系统,介绍了系统的总体设计、软硬件设计、余度设计,虚拟仪表设计,并在双余度发动机状态监测系统的设计中引入了嵌入式PC/104模块;为了使状态监测系统具有更好的扩展性和适应性,将系统设计成可以在两种方式下工作:机载运行方式和地面试车方式,通过这两种方式对发动机状态进行自动监测,为发动机的状态趋势分析、故障诊断和视情维修提供科学的依据;采用双余度发动机状态监测技术研制的某型涡轴发动机状态实时监测系统经过了大量的地面试验和某型直升机上试飞试验,功能、性能满足要求,目前该系统已在某型直升机上得到应用。     

Physical and crystallographical properties of bornite,Cu5FeS4 and digenite Cu7S4

Correlations in metal shifts constitute an important feature of these sulfides. We have found these in the course of the crystal structure analysis of an ordered phase of bornite. Digenite undergoes one transition and bornite two transitions. The divers phases are more or less ordered and the phase changes are order disorder transitions. The magnetic properties of bornite depends only on the ordering of iron atom whose magnetic moments are ordered at low temperature.     

Facile,efficient and one-pot access to diverse new functionalized aminoalkyl and amidoalkyl naphthol scaffolds via green multicomponent reaction using triethylammonium hydrogen sulfate ([Et3NH][HSO4]) as an acidic ionic liquid under solvent-free conditions

Molecular Diversity - An efficient, clean and one-pot multicomponent synthesis of divers kind of new functionalized aminoalkyl naphthol and amidoalkyl naphthol derivatives via tandem condensation...     

Possibilities of Practical Use of Historical Distributions of Ash,Sulfur and Mercury Contents in Commercial Steam Coal of the USCB

In the process of extracting hard coal, extensive databases are created on its quality parameters. A statistical assessment was made of the ash, sulfur, and mercury content of commercial coals produced in the Upper Silesian Coal Basin (USCB). The statistical methods applied: non-parametric tests of compatibility for two populations, parametric significance tests, and non-parametric tests of compatibility for the three populations, showed that the distributions of ash and sulfur content in 2014 and 2015 are comparable and the average values are similar. Statistical tests indicated significant differences in the mercury content distributions and their variances. This demonstrates the need for ongoing monitoring of mercury content in commercial coals, as a prediction of mercury content from historical data is hardly possible.     

Characteristics of noise attenuators for use in acoustic emission studies

The background noise generated by servo-hydraulic machines commonly used in laboratory tests of materials prevents the extraction of the maximum amount of acoustic emission data during fatigue experiments. Some of the solutions for removing background noise during monotonic tests are not applicable, and modern acoustic emission (ae) monitoring systems cannot detect all ae generated in the presence of continuous background noise. The best technique for reducing the background noise appears to be the insertion of a noise attenuating barrier between the noise source and the test specimen.Multilayer sound transmission theory is outlined to show that noise attenuators must be designed for the particular frequency at which the ae system is to operate. The theoretical basis for obtaining (for a given application) the optimum attenuation from attenuators constructed on an acoustic impedance mismatch basis is provided. Finally, physical properties of materials suitable for use in attenuator construction are tabulated.     

Experimental research on distributed fiber sensor for sliding damage monitoring

A distributed optical fiber sensor (DOFS) with the principle of microbend loss has been developed for concrete or rock-sliding damage measurement. The combination of multiple microbend sensors can form a sensor array for distributed sensing application in monitoring local slippage or deformation along the rock mass of the high slope, and the optical time-domain reflectometry (OTDR) can be conveniently used for interrogation of each sensor point. The sensor sensitivity can be obtained at a specific range according to the requirement of the model test condition. Connected with multiplexed sensing processing schemes, its sliding range of dynamic sensing response reached 0–3.6 mm and semi-empirical formula was fitted according to data from model tests. The DOFS array may find a potential application in real-time monitoring and damage detection of large and critical slope engineering structures.     

基于安卓平台的糖尿病监护系统的研究及实现

基于目前针对糖尿病的研究主要集中在健康管理及血糖浓度监测方面,在糖尿病病情控制方面并不乐观的现状,设计开发了一套能够实时监护老年患者注射药物情况的远程家庭医疗系统。该系统由智能检测硬件系统,手机客户端和WEB信息管理端组成,不仅可以解决独孤老人时常忘记注射胰岛素的问题,也有利于解决我国老年患者糖尿病监护难的问题,同时也能提醒青壮年实时携带注射针剂盒,缓解糖尿病并发症的发生。通过实时实验测试,该糖尿病监护系统可靠、稳定,且具有良好的实际应用价值。