轻质水泥基隔声砂浆性能试验研究

本文分析对比使用不同掺量水泥、玻化微珠、胶粉、减水剂对水泥基隔声砂浆抗压强度、软化系数、线收缩率性能的影响,同时研究了胶粉、减水剂掺量对砂浆力学性能、产品状态稳定性的影响。结果表明:水泥掺量增加,砂浆体积密度增大,抗压强度、软化系数、线收缩率均增高;而隔声砂浆的脆性随着轻骨料玻化微珠掺量的增加而增大,砂浆的体积密度、抗压强度、软化系数、线收缩率均呈反向降低的趋势。轻质水泥基隔声砂浆材料的最佳掺量为水泥45%~50%,玻化微珠15%~18%,可再分散乳胶粉0.2%~0.3%,减水剂0.05%~0.1%。

声敏型脂质纳米粒联合低功率聚焦超声对HepG2细胞增殖的影响及其体外CT成像的实验研究

目的制备一种载血卟啉单甲醚(hematoporphyrin monomethyl ether,HMME)包裹全氟溴辛烷(1-Bromoheptadecafluorooctane,PFOB)及阿霉素(doxorubicin,DOX)的声敏型脂质纳米粒(sound sensitive nano-liposomes,SNLs),探究其联合低功率聚焦超声(low intensity focused ultrasound,LIFU)体外释药、产生活性氧的能力以及对HepG2细胞增殖的影响,和其体外CT成像的能力。方法采用薄膜水化法制备SNL;检测其一般性质;高效液相色谱法检测其体外释药;荧光分光光度计和激光共聚焦显微镜观察其产生活性氧的能力; CCK-8实验检测其对HepG2细胞增殖的影响,CT观察其体外CT成像。结果成功制备SNL,粒径为(282. 53±6. 95) nm; LIFU处理8h内SNL释放阿霉素达(83. 45±2. 97)%,释药速度随LIFU强度提高而加快;以DPBF(1,3-二苯基异苯并呋喃)为活性氧探针,产生活性氧的相对量随SNL中血卟啉单甲醚增加及LIFU强度增高而增多;以DCFH-DA(2’,7’-二氯荧光黄双乙酸盐)为活性氧探针,激光共聚焦观察显示SNL+LIFU组较SNL组绿色荧光强; CCK-8检测结果显示SNL+LIFU组的细胞存活率明显较DOX组,载血卟啉单甲醚包裹全氟溴辛烷的脂质纳米粒(hematoporphyrin monomethyl ether nano-liposomes,HNL)+LIFU组和SNL组低(P <0. 05),可见SNL+LIFU明显增强了对HepG2细胞生长的抑制作用; CT成像结果显示SNL的CT值较对照组和空白组高,且CT值随PFOB浓度增大而增高。结论成功制备的声敏型脂质纳米粒的声动力效果呈HMME浓度及LIFU强度依赖性,药物释放速度受LIFU控制,可联合化疗及声动力治疗增强HepG2细胞生长的抑制效果,同时具有良好的CT成像效果。

热声泵质

分析了混合工质在热声边界层内发生分离的机理及热声循环中的泵质微循环过程 。

E型轻质防水保温隔声系统施工工艺

建筑物的防水和保温是建筑的两大热点问题,用传统的建筑材料所形成的屋面很难兼顾防水性能和保温性能。E型轻质防水保温隔声系统,优点非常显著,如保温性好、防水性强、附着力强、不易裂开、不易出现空鼓等。并且,该系统具有突出的节能环保特性,顺应工程建筑的发展趋势,发展前景良好。鉴于该文以E型轻质防水保温隔声系统为研究对象来进行分析,并指出了对应改进措施,旨在为类似项目提供参考。

秦振声二三事

秦振声二三事丁毅，木澄一把酒壶１９９０年中秋节前夕，不知是何人给雅县原政协副主席秦振声家里送了一把鸳鸯转香壶。这把壶特别小巧伶成精美别致．一把壶不但能倒两种酒．倒酒时还能发出“十五的月亮”、“谢谢”、“再见”、“您好”等动人的乐曲和语言。秦主席发现酒...

室外流行音乐的声控制——以香港中心露天音乐会为例(英文)

只要符合噪音管制标准和在指定的时间内结束,在香港一般情况下是允许举办露天音乐会的.由环境保护署对此类活动引起的噪声加以监测和评估.作为六次葛莱美奖得主,被2005时代周刊选为世界100位最具影响的人物,霹雳舞创作人、歌手、歌曲作者Kanye West于2006年11月28日在香港举办其在亚洲唯一的一场演唱会.该演唱会在维多利亚港中心地带的西九龙全新户外场地HK Outdoor Drive-In举行,名为"轩尼诗V.S.O.P Kanye West"Touch the Sky Tour"Live in Hong Kong",由管弦乐队伴奏并邀请本港Hip Hop界代表陈冠希作开幕演出.位于香港中心区的演唱会场地被多层可俯瞰美丽港湾的豪华住宅环绕.演出要符合严格的噪音管制条例.音乐会期间,在距舞台45m的控制台处连续监测到的声压级达到107dB(A).对此,代替传统上通常采用的依赖于声屏障的降噪技术或采用吸声内衬的方法,利用新的轻质材料和沙包成功地控制了这次音乐会的声溢出.

铜锣峡气田长兴气藏增压工程厂房噪声治理

文章叙述了天然气压缩机增压工程降噪厂房的噪声、轻钢、通风设计问题,可为工作实践提供参考。

Correlations of transcranial sonography of substantia nigra characteristics with MRI iron deposition on substantia nigra in patients with Parkinson disease

Objective To explore the correlations of transcranial sonography of substantia nigra(SN-TCS)characteristics with MRI iron deposition on substantia nigra in patients with Parkinson disease(PD).Methods Data of SN-TCS and craniocerebral MRI in 120 PD patients were retrospectively analyzed.The patients were divided into iron deposition positive group(positive group,n=46)and iron deposition negative group(negative group,n=74)according to quantitative susceptibility mapping(QSM)value.Then parameters of SN-TCS and MRI were compared between groups(both P<0.05),and correlation analysis were also performed.Results The proportion of high echo positive,strong echo area and QSM value of substantia nigra,as well as of hyper-substantia nigra area/midbrain area(S/M)in positive group were all higher than those in negative group(all P<0.001).No significant difference of midbrain area was found between groups(P>0.05).Strong echo area of substantia nigra and S/M based on SN-TCS were both low-medium positively correlated with substantia nigra QSM value showed on MRI(r=0.497,0.529,both P<0.001).Conclusion SN-TCS characteristics of PD patients were correlated with MRI iron deposition on substantia nigra,among which strong echo area and S/M were valuable for evaluating iron deposition on substantia nigra.

Dynamic response characteristics of muddy sandstone in pumped storage mine under action of high-stress dynamic disturbance

During the construction and operation of the abandoned mine pumped storage power station,the underground space surrounding rock body faces the complex stress environment under the action of mining disturbance,frequent pumping,water storage and other dynamic disturbances.The stability of the abandoned mine surrounding rock body is the basis for guaranteeing the safety and effectiveness of water storage in the underground space of the abandoned mine.By considering the two main factors of different stress levels and disturbance amplitudes,the mechanical properties,damage characteristics and acoustic emission characteristics of the abandoned mine perimeter rock body under dynamic disturbance were investigated using a creep-disturbed dynamic impact loading system.The experimental results show that:1)The stress level is considered to be the major contributing factor of the failure of muddy sandstone,followed by the amplitude of the disturbances;2)The time required for the destruction of muddy sandstone decreases with the increase of amplitude.When the stress level is 80%,the sandstone specimens have a decreasing number of cycles as the disturbance amplitude increases.The disturbance amplitude is sequentially increased from 4 MPa to 5,6,7,and 8 MPa,the number of cycles required for specimen destruction decreases significantly by 96.71%,99.13%,99.60%,and 99.93%,respectively;3)Disturbance amplitude and stress level have a significant effect on muddy sandstone damage and damage occurs only after a certain threshold is reached.With the increase of stress level and disturbance amplitude,the macroscopic damage of muddy sandstone is mainly conical,with obvious flake spalling and poor damage integrity;4)According to the time-dependent changes in AE energy and ringing counts,the acoustic emission activity during the failure process could be divided into three phases,namely,weakening period,smooth period,and surge period,corresponding to the compaction phase,elastic rise phase and post-peak damage phase.The research results are of reference significance for the damage evolution analysis of muddy sandstone under dynamic disturbance and the safety and stability of abandoned mine perimeter rock body.

Deep learning models semi-automatic training system for quality control of transthoracic echocardiography

Objective To explore the value of deep learning(DL)models semi-automatic training system for automatic optimization of clinical image quality control of transthoracic echocardiography(TTE).Methods Totally 1250 TTE videos from 402 patients were retrospectively collected,including 490 apical four chamber(A4C),310 parasternal long axis view of left ventricle(PLAX)and 450 parasternal short axis view of great vessel(PSAX GV).The videos were divided into development set(245 A4C,155 PLAX,225 PSAX GV),semi-automated training set(98 A4C,62 PLAX,90 PSAX GV)and test set(147 A4C,93 PLAX,135 PSAX GV)at the ratio of 5∶2∶3.Based on development set and semi-automatic training set,DL model of quality control was semi-automatically iteratively optimized,and a semi-automatic training system was constructed,then the efficacy of DL models for recognizing TTE views and assessing imaging quality of TTE were verified in test set.Results After optimization,the overall accuracy,precision,recall,and F1 score of DL models for recognizing TTE views in test set improved from 97.33%,97.26%,97.26%and 97.26%to 99.73%,99.65%,99.77%and 99.71%,respectively,while the overall accuracy for assessing A4C,PLAX and PSAX GV TTE as standard views in test set improved from 89.12%,83.87%and 90.37%to 93.20%,90.32%and 93.33%,respectively.Conclusion The developed DL models semi-automatic training system could improve the efficiency of clinical imaging quality control of TTE and increase iteration speed.

Low palladium content CeO_(2)/ZnO composite for acetone sensor with sub-second response prepared by ultrasonic method

In practical applications,noble metal doping is often used to prepare high performance gas sensors,but more noble metal doping will lead to higher preparation costs.In this study,CeO_(2)/ZnO-Pd with low palladium content was prepared by ultrasonic method with fast response and high selectivity for acetone sensing.With the same amount of palladium added,the selectivity coefficient of CeO_(2)/ZnO-Pd is 1.88 times higher than that of the stirred sensor.Compared with the pure PdO-doped CeO_(2)/ZnO-PdO material,the content of Pd in CeO_(2)/ZnO-PdO is about 30%of that in CeO_(2)/ZnO-PdO,but the selectivity coefficient for acetone is 2.56 times higher.The CeO_(2)/ZnO-Pd sensor has a higher response(22.54)to 50×10^(−6) acetone at 300℃and the selectivity coefficient is 2.57 times that of the CeO_(2)/ZnO sensor.The sensor has a sub-second response time(0.6 s)and still has a 2.36 response to 330×10^(−9) of acetone.Ultrasonic doping makes Pd particles smaller and increases the contact area with gas.Meanwhile,the composition of n-p-n heterojunction and the synergistic effect of Pd/PdO improve the sensor performance.It shows that ultrasonic Pd doping provides a way to improve the utilization rate of doped metals and prepare highly selective gas sensors.

Effects of Blood Cell Membrane Disruption by Ultrasonic Technology on the Quality of Duck Blood Tofu

[Objective] The aim was to improve the quality of the duck blood tofu by ultrasonic technology. [Method] Ultrasonic technology was used to break the blood cell membrane. The optimal ultrasonic condition was determined by single factor de- sign, and the differences in sensory quality and nutritional value between the duck blood tofu treated with and without ultrasonication were studied. [Result] The optimal ultrasonic power was 400 W and the optimal ultrasonic time was 6 min. Under these conditions, the content of duck blood haemoglobin increased by 43.46%, the content of iron increased by 10.85%, and the breakage rate was 100%. The a＊ value of the duck blood tofu increased significantly under ultrasonic treatment. Both internal micro-structure and texture parameters proved that the ultrasonic contributed to the formation of gel structure. After treatment by artificial gastric juice and artifi- cial intestinal juice, the total amino acids in the digestive juice were 9.25% higher than that of the duck blood tofu without ultrasonic treatment. [Conclusion] The duck blood tofu under ultrasonic treatment would be beneficial to human body absorption, and the nutrition value would be higher as well.

Modeling of rock failure based on physical cellular automata

To analyze the effects of heterogeneous material characteristics on rock failure,a micro-heterogeneous physical cellular automata （Mh-PCA） model is introduced according to the cellular automata theory from a general power view.In this model,the neighbor is the Moore pattern and the Weibull distribution is adopted to simulate the rock heterogeneousness.Using this model,the evolvements and acoustic emission of rock failure are simulated for four materials of different degree of homogeneousness （m＝1,5,10,15）.The results show that the heterogeneous characteristic has a great effect on the rock failure,the more the homogeneousness,the fewer the crack branches and the more concentrated acoustic emissions.The physical cellular automata theory gives a new idea for studying rock failure.

Novel Ka-band low-noise down-converter assembly

An efficient way to design a down-converter assembly for the Ka-band millimeter system is presented, in which dielectric resonators （DR＇s） are adopted in the Schottky barrier diode image recovery mixer and the local oscillator （LO）. DR structures guarantee high frequency stability with an acceptable volume. The configurations of low noise amplifier, mixer and oscillator in the assembly are described and fabricated to estimate the chain performance. According to the verification results, the assembly exhibits the noise figure of less than 5 dB over 1 GHz frequency range, and the single-sideband phase noise （200 kHz offset from carrier frequency） of - 70 dBc/Hz. Utilizing the DR structure, the frequency stability of the local oscillator is less than 60 × 10^-6/℃.

An Analysis of the Hoarse Speech Signals by the Three Mass Model of Vocal Cords *

A three mass model of vocal cords as well as mathematical expression of the model are discussed. Different kinds of typical hoarse speech due to laryngeal diseases are simulated on microcomputer and the effects of different pathological factors of vocal cords on model parameters are studied. Some typical spectrum distribution of the simulated speech signals are given. Moreover, hoarse speech signals of some typical cases are analyzed by the methods of digital signal processing, including FFT, LPC, Cepstrum technique, Pseudocolor encoding, etc. The experiment results show that the three mass model analysis of vocal cords is an efficient method for analysis of hoarse speech signals.

Acoustic evaluation of cementing quality using obliquely incident ultrasonic signals

Ultrasonic cement bond logging is a widely used method for evaluating cementing quality. Conventional ultrasonic cement bond logging uses vertical incidence and cannot accurately evaluate lightweight cement bonding. Oblique incidence is a new technology for evaluating cement quality with improved accuracy for lightweight cements. In this study, we simulated models of acoustic impedance of cement and cementing quality using ultrasonic oblique incidence, and we obtained the relation between cementing quality, acoustic impedance of cement, and the acoustic attenuation coeffi cient of the A0-mode and S0-mode Lamb waves. Then, we simulated models of different cement thickness and we obtained the relation between cement thickness and the time difference of the arrival between the A0 and A0′ modes.

Effect of ultrasonic on structure and electrochemical performance of α-Ni(OH)_2 electrodes

Al/Co co-doped α-Ni（OH）2 samples were prepared by either ultrasonic co-precipitation method （Sample B） or co-precipitation method （Sample A）. The crystal structure and particle size distribution of the prepared samples were examined by X-ray diffraction （XRD） and laser particle size analyzer, respectively. The results show that Sample B has more crystalline defects and smaller average diameter than Sample A. The cyclic voltammetry and electrochemical impedance spectroscopy measurements indicate that Sample B has better electrochemical performance than Sample A, such as better reaction reversibility, lower charge-transfer resistance and better cyclic stability. Proton diffusion coefficient of Sample B is 1.96×10-10cm2/s, which is two times as large as that （9.78×10-11cm2/s） of Sample A. The charge-discharge tests show that the discharge capacity （308 mA·h/g） of Sample B is 25 mA·h/g higher than that of Sample A （283 mA·h/g）.