Two-tone suppression in the cricket, Eunemobius carolinus (Gryllidae, Nemobiinae)

Sounds with frequencies >15 kHz elicit an acoustic startle response (ASR) in flying crickets (Eunemobius carolinus). Although frequencies <15 kHz do not elicit the ASR when presented alone, when presented with ultrasound (40 kHz), low-frequency stimuli suppress the ultrasound-induced startle. Thus, using methods similar to those in masking experiments, we used two-tone suppression to assay sensitivity to frequencies in the audio band. Startle suppression was tuned to frequencies near 5 kHz, the frequency range of male calling songs. Similar to equal loudness contours measured in humans, however, equal suppression contours were not parallel, as the equivalent rectangular bandwidth of suppression tuning changed with increases in ultrasound intensity. Temporal integration of suppressor stimuli was measured using nonsimultaneous presentations of 5-ms pulses of 6 and 40 kHz. We found that no suppression occurs when the suppressing tone is >2 ms after and >5 ms before the ultrasound stimulus, suggesting that stimulus overlap is a requirement for suppression. When considered together with our finding that the intensity of low-frequency stimuli required for suppression is greater than that produced by singing males, the overlap requirement suggests that two-tone suppression functions to limit the ASR to sounds containing only ultrasound and not to broadband sounds that span the audio and ultrasound range.     

Acoustical analysis of the auditory system of the cricket Teleogryllus commodus (Walker)

The basic auditory physiology of crickets, and particularly of Teleogryllus commodus (Walker) is examined and its behavior simulated by electrical analog networks, beginning from the simplest possible model and progressing by stages to the full system found in the real insect. It is found that the attenuation of sound in the auditory trachea plays a crucial role in the mechanism for directional hearing in even the simplest model and that the tracheal diameter is in fact appropriate to produce the desired attenuation. In a more complex model in which it is recognized that the auditory system probably responds to pressure changes in the tracheal sacs underlying the tympana rather than simply to tympanic motion, it is found that the phase shift produced by the combined effects of the central septum and the adjoining cavities leading to the spiracles is also important to hearing directionality. The final model which includes both tympana and spiracles is able to simulate both the hearing directionality and, in part, the frequency selectivity of the system. It appears, however, that a large measure of the observed frequency selectivity is due to some form of selectivity in the neural transducers themselves rather than in the simple acoustic components of the system.     

Ultrasound (US) enhances the hydration of sorghum (Sorghum bicolor) grains

The water activity (Aw) reduction technique is widely used to preserve different food products, which are further rehydrated in order to be processed or consumed. The food hydration is time-consuming and, thus, a limiting unit operation during process. Therefore, there is an ongoing need to enhance the mass transfer phenomena during processing. The ultrasound technology (US) has been widely studied to improve different mass transfer processes of food. However, there is a lack of knowledge in relation to its application in the hydration process. This work evaluated the hydration process of sorghum seeds, comparing the effect of heating and ultrasound application in order to improve the hydration rate. The sorghum hydration kinetic was described by Peleg Model, whose parameters were evaluated for both processes. The US increased both water uptake rate (related to Peleg k₁ parameter) and equilibrium moisture content (related to Peleg k₂ parameter). The time for reach 90% of the control process equilibrium moisture content was 40% lower when the US was applied. The effect of processing at 53 °C was higher than applying US at the evaluated power, and its limitations were discussed. The effect of combining both ultrasound and heating application was negligible when it was compared to the heated process. The obtained results highlighted that the US technology can be successfully used to optimize the hydration process of grains with directly industrial application.     

Ultrasound liberates nitric oxide (NO) from the caged NO compound N,N'-bis(carboxymethyl)-N,N'-dinitroso-p-phenylenediamine sodium salt

To determine whether nitric oxide (NO) can be released from a cage compound N,N'-bis(carboxymethyl)-N,N'-dinitroso-p-phenylenediamine sodium salt (BNN 5 Na), we sonicated different concentrations of BNN 5 Na solutions containing an NO spin trap, (MGD)2Fe2+, and then measured (MGD)2Fe2+-NO signal using electron paramagnetic resonance (EPR). We also investigated the role of cavitation by saturating the solutions with Ar, He or Xe gases before sonication. The result showed that ultrasound can liberate NO from caged NO compound at rates highest with Xe and lowest with He. These results suggest that high-temperature due to cavitations induced by ultrasound are capable of releasing NO from caged NO compounds. This finding also opens up to a new possibility for the use of ultrasound in a controlled release of active compound (e.g. drug) from its caged form for therapeutic purposes.     

Red thermoluminescence (RTL) sensitivity change in quartz

This study investigated changes in the thermoluminescence sensitivity of volcanic and plutonic quartz following irradiation and annealing treatments with the aim of improving the accuracy of red thermoluminescence (RTL) dating. The response to X-ray irradiation (49 Gy) and RTL readout to 450 °C at a rate of 1 °C s^?1 was repeated 12 times and the sensitivity change induced by doses ranging from 49 to 293 Gy was examined. The results of these two experiments revealed that the final enhanced ratio of the sensitivity of plutonic quartz is 2.1–2.8 and 2.2–2.3 for two types of analyzed samples, much greater than that of volcanic quartz. To examine the thermal stability of quartz, several annealing treatments were performed from 300 to 900 °C for 100 min. An annealing treatment of 500 °C for 100 min resulted in a strong enhancement of RTL emission intensity for plutonic quartz, approaching the level for volcanic quartz. Finally, the single aliquot regeneration (SAR) method was applied to evaluate the absorbed dose, D_e, for aliquots irradiated with a known-dose ranging from 195 to 1952 Gy. All SAR D_e values obtained with volcanic quartz were in good agreement with the known dose values; whereas for plutonic quartz large uncertainties in D_e were obtained due to a marked sensitivity change. The magnitude of the RTL sensitivity change of quartz depends on dose and annealing treatment, and is clearly dependent on a classification of quartz based on thermal history.     

高强度聚焦超声软组织损伤超声监控成像与评价方法

提出基于超声射频信号的数字减影损伤区域成像方法,并根据成像结果采用对数谱差衰减系数估计法对高强度聚焦超声引起的软组织损伤程度进行评价。通过离体牛肉和牛肝组织实验,获得了绝对差值法、绝对差值求和法以及平方差值求和法的数字减影结果,分析了这些算法的性能以及阈值和窗宽的选取对算法的影响。在此基础上,比较了用于损伤程度评价的三种声衰减估计参量,证实了采用超声换能器带宽范围内的平均衰减系数的改变△(ā)进行组织损伤程度评价的有效性。     

高强聚焦超声(HIFU)无创外科─21世纪治疗肿瘤的新技术

本文从简要回顾超声治疗的发展历史开始,重要介绍了90年代初在国际上兴起的HIFU无创外科技术及我国在该领域中的成就。文章继而对HIFU“切除”肿瘤的机理,治疗质量及其发展前景做了讨论。     

超声波辐照下N,N,N’,N’-四甲基二氨基二苯 甲烷的合成研究

本文报道了Ｎ,Ｎ,Ｎ’,Ｎ’－四甲基二氨基二苯甲烷的催化合成反应研究,讨论了超声空化场对氨基苯磺酸和阴离子表面活性剂等条件对该反应的催化作用。     

Development of auditory sensitivity in budgerigars (Melopsittacus undulatus)

Auditory feedback influences the development of vocalizations in songbirds and parrots; however, little is known about the development of hearing in these birds. The auditory brainstem response was used to track the development of auditory sensitivity in budgerigars from hatch to 6 weeks of age. Responses were first obtained from 1-week-old at high stimulation levels at frequencies at or below 2 kHz, showing that budgerigars do not hear well at hatch. Over the next week, thresholds improved markedly, and responses were obtained for almost all test frequencies throughout the range of hearing by 14 days. By 3 weeks posthatch, birds' best sensitivity shifted from 2 to 2.86 kHz, and the shape of the auditory brainstem response (ABR) audiogram became similar to that of adult budgerigars. About a week before leaving the nest, ABR audiograms of young budgerigars are very similar to those of adult birds. These data complement what is known about vocal development in budgerigars and show that hearing is fully developed by the time that vocal learning begins.     

Ultrasound assisted hydration of navy beans (Phaseolus vulgaris)

The use of ultrasound to enhance the transport phenomena in food processes has been well recognised in recent times. The objective of this study was to evaluate the effect of sonication on hydration rate and pasting profile of navy beans. The hydration kinetics for control and ultrasound assisted soaking was mathematically described using mechanistic (Fickian diffusion) and empirical (Peleg’s equation, Weibull model and First Order equation) models. Ultrasound enhanced the rate of hydration which was evident from the plot of kinetic data and model parameters. The effective diffusivities for water transport without and with ultrasound application were estimated to be 1.36 × 10⁻¹⁰ m²/s and 2.19 × 10⁻¹⁰ m²/s respectively, considering Fickian diffusion. The Weibull model was concluded to best predict the hydration kinetics of navy beans in an ultrasonic field. Significant increase in peak viscosity of sonicated bean powder was observed compared to control.     

Ultrasound enhances lipase-catalyzed synthesis of poly (ethylene glutarate)

The present work explores the best conditions for the enzymatic synthesis of poly (ethylene glutarate) for the first time. The start-up materials are the liquids; diethyl glutarate and ethylene glycol diacetate, without the need of addition of extra solvent. The reactions are catalyzed by lipase B from Candida antarctica immobilized on glycidyl methacrylate-ter-divinylbenzene-ter-ethylene glycol dimethacrylate at 40 °C during 18 h in water bath with mechanical stirring or 1 h in ultrasonic bath followed by 6 h in vacuum in both the cases for evaporation of ethyl acetate. The application of ultrasound significantly intensified the polyesterification reaction with reduction of the processing time from 24 h to 7 h. The same degree of polymerization was obtained for the same enzyme loading in less time of reaction when using the ultrasound treatment. The degree of polymerization for long-term polyesterification was improved approximately 8-fold due to the presence of sonication during the reaction. The highest degree of polymerization achieved was 31, with a monomer conversion of 96.77%. The ultrasound treatment demonstrated to be an effective green approach to intensify the polyesterification reaction with enhanced initial kinetics and high degree of polymerization.     

Ultrasound production by the long haired rat of Australia (Rattus Villosissimus)

The ultrasonic vocalizations produced by the long haired Australian rat Rattus villosissimus, during agonistic behaviour were investigated using a commercial ultrasonic receiver with earphones, a microphone and storage oscilloscope, and a tape recorder and sonograph. The rats were found to produce one audible call with ultrasonic components up to 64 kHz, the limit of the detecting apparatus used, and one pure ultrasound. Suggestions are made as to their behavioural significance.     

拓展傅里叶幅度敏感性检验(EFAST)在陆面过程模式中参数敏感性分析的应用探索

本文旨在探讨拓展傅里叶幅度敏感性检验(EFAST)在陆面参数敏感性分析中的应用. 基于2008年吉林通榆观测值站的退化草地观测资料,针对通用陆面过程模式(CoLM)的关键陆面参数, 使用地表感热通量、潜热通量作为检验变量,尝试将EFAST方法运用到陆面过程模式参数敏感性试验中. 在充分考虑单个参数敏感性的基础上,将参数间的耦合作用考虑进来, 研究了相互影响制约下的多参数变化对非线性系统的影响,并且对这种非线性影响进行了定量分析. 敏感性分析结果表明:土壤砂土比例、最小水分透过孔隙度为影响地表感热通量与潜热通量的关键参数, 验证了EFAST方法在陆面过程模式参数敏感性分析方面的可行性.本项研究对于外场观测试验的设计 和发展陆面模式物理过程参数化方案具有积极的指导意义. 关键词： 陆面过程模式 陆面参数 EFAST方法 参数敏感性     

Understanding the Effects of Ultrasound (408 kHz) on the Hydrogen Evolution Reaction (HER) and the Oxygen Evolution Reaction (OER) on Raney-Ni in Alkaline Media

The hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) occurring at the Raney-Ni mesh electrode in 30 wt.-% aqueous KOH solution were studied in the absence (silent) and presence of ultrasound (408 kHz, ∼54 W, 100% acoustic amplitude) at different electrolyte temperatures (T = 25, 40 and 60 °C). Linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) experiments were performed to analyse the electrochemical behaviour of the Raney-Ni electrode under these conditions. Under silent conditions, it was found that the electrocatalytic activity of Raney-Ni towards the HER and the OER depends upon the electrolyte temperature, and higher current densities at lower overpotentials were achieved at elevated temperatures. It was also observed that the HER activity of Raney-Ni under ultrasonic conditions increased at low temperatures (e.g., 25 °C) while the ultrasonic effect on the OER was found to be insignificant. In addition, it was observed that the ultrasonic effect on both the HER and OER decreases by elevating the temperature. In our conditions, it is suggested that ultrasound enhances the electrocatalytic performance of Raney-Ni towards the HER due to principally the efficient gas bubble removal from the electrode surface and the dispersion of gas bubbles into the electrolyte, and this effect depends upon the behaviour of the hydrogen and oxygen gas bubbles in alkaline media.     

t(1) noise and sensitivity in pulsed field gradient experiments

In this paper, a calculation routine based on product operator formalism and coherence pathway is presented, which describes t(1) noise and sensitivity in pulsed field gradient experiments. Several examples including the absolute value mode pulsed field gradient COSY, MQF-COSY, MQC, HMQC, and NOESY sequences are investigated to study the t(1) noise stemming from the phase errors of radiofrequency (RF) pulses and the sensitivity affected by RF pulse rotation angles. Our theoretical results indicate that the t(1) noises in P-type COSY, multiple-quantum-filtered (MQF)-COSY, and multiple-quantum coherence (MQC) are lower than those in the N-type corresponding experiments, while in HMQC and NOESY there is no difference in t(1) noise effects between P-type and N-type spectra. Meanwhile, from the calculations, we obtained the optimized RF pulse rotation angles in those sequences. In MQF-COSY, an increase in sensitivity of about 4(cos(2)θ sin(q-1)2θ)(2) - 1 (θ = arc cot can be achieved by using the optimized angles. In MQC, the increase is 2 cos(2)θ sin(q-1)2θ - 1 (θ = arc cot. MQF-COSY experiments are also carried out to support our corresponding theoretical results.     

The sensitivity of the transition temperature to changes in α2 F(ω)

The transition temperature of a superconductor depends on α² F(ω), the spectral function of the effective interaction due to phonon exchange. We discuss how strongly the transition temperature is influenced by different frequency parts of α² F(ω). For this purpose the functional derivative δT _c /δα² F(ω) is calculated. It is shown that all frequency regions of α² F(ω) yield a positive contribution toT _c and that the most effective range covers frequencies, slightly above 2πT _c . The functional derivative is calculated numerically for several superconductors from their measured α² F(ω)-spectra. Finally, we discuss the change in transition temperature due to the softening of α² F(ω) which has been observed in amorphous superconductors.     

Polarization and fundamental sensitivity of ~(39)K(~(133)Cs)-~(85)Rb-~(21)Ne co-magnetometers

The hybrid optical pumping spin exchange relaxation free(HOPSERF)atomic co-magnetometers make ultrahigh sensitivity measurement of inertia achievable.The wall relaxation rate has a big effect on the polarization and fundamental sensitivity for the co-magnetometer,but it is often neglected in the experiments.However,there is almost no work about the systematic analysis of the influence factors on the polarization and the fundamental sensitivity of the HOPSERF co-magnetometers.Here we systematically study the polarization and the fundamental sensitivity of 39K-85Rb-21Ne and 133Cs-85Rb-21Ne HOPSERF co-magnetometers with low polarization limit and the wall relaxation rate.The 21Ne number density,the power density and wavelength of pump beam will affect the polarization greatly by affecting the pumping rate of the pump beam.We obtain a general formula on the fundamental sensitivity of the HOPSERF co-magnetometers due to shot-noise and the fundamental sensitivity changes with multiple systemic parameters,where the suitable number density of buffer gas and quench gas make the fundamental sensitivity highest.The fundamental sensitivity 7.5355×10^-11 rad·s^-1·Hz^-1/2 of 133Cs-85Rb-21Ne co-magnetometer is higher than the ultimate theoretical sensitivity 2×10^-10 rad·s^-1·Hz^-1/2 of K-21Ne co-magnetometer.