DIGITAL FILTER FOR SINGLE FREQUENCY SINUSOID SERIES

The sinusoid curve fit is widely applied in the evaluation of digitized measurement equipment, such as data acquisition system, digital storage oscilloscope, waveform recorder and A/D converter,etc. Because of the distortion and noise of sinusoid signal generator, the digitizing and the non linearity errors in measurement, it is impossible to avoid the distortion and the noise in sinusoid sampling series. The distortion and the noise limit the accuracy of curve fit results. Therefore, it is desirable to find a filter that can filter out both distortion and noise of the sinusoid sampling series, and in the meantime, the filter doesn′t influence the amplitude, the frequency, the phase and DC bias of fitting curve of the sine wave. And then, the uncertainty of fitting parameter can be reduced. This filter is designed and realized. Its realization in time domain is described and its transfer function in frequency domain is presented.

男性叙事中的女性“默言”——谈莫言中短篇小说中的女性声音

莫言中短篇小说叙事中女性声音有几种特殊形态:第一,美人"失声"。部分女性人物在莫言小说中被剥夺叙事权力,失去话语权,这时女性成为无言的"物"或非理性的象征,表现出男性对女性欲望想象的矛盾心理。第二,藏在"匣子"里的声音。在《金发婴儿》等小说中,女性以"假言"的方式隐匿自己的真实情感,传达出在男权文化语境中女性言说之艰难。第三,女性被"禁言"。莫言的部分小说中,女性话语若符合男性的性别期待,则给予发声权力,否则,要么被禁言,要么人物承担悲剧的命运。莫言小说中这些女性叙事声音的处理,呈现出男性写作的性别潜意识。

Application of BDRM Theory in the Two-AXIS Underwater Channel

Two-axis underwater channel often exists in deep ocean. Because of the coupling between surface channel and SOFAR channel, sound propagation in the two-axis underwater channel is complex and so its calculations of acoustic fields are difficult. The beam-displacement ray-mode （BDRM） theory is a normal mode method for propagation modeling in the common horizontally stratified shallow water. We improve the theory, proposing a new method for computing the upper boundary reflection coefficient, and apply it to calculate the acoustic fields of two-axis underwater channel. Transmission losses in the two-axis underwater channel are calculated by the BDRM theory. The results are in good agreement with the KRAKEN code and the computational speed excels those of the other methods.

黄侃《手批尔雅义疏》声训失误拾零

《手批尔雅义疏》是黄季刚先生从事语源研究实践的重要成果之一。黄氏运用声训,系联了大量可信的同族词,阐释了一些事物得名的由来,但也存在一些失误。疏证这些"声训失误"现象,可以辨正一些事物名称词语的得名之由。

Correction of buckling distortion by ultrasonic shot peening treatment for 5A06 aluminum alloy welded structure

Ultrasonic shot peening treatment （USPT） was proposed to correct welding buckling distortion. The residual stress distribution along the depth direction of the peened zone was measured by an X-ray diffractometer. The microstructure of the treated specimens was investigated by scanning electron microscopy （SEM）. The Vickers microhardness was measured in different areas of welded joint before USPT and along the depth direction of the weld after USPT. The experimental results indicated that the welding buckling distortion of 5A06 aluminum alloy butt joint can be essentially corrected by USPT; the average correction rate reached 90.8% in this study. Furthermore, USPT enhanced specimens by work hardening. The microstructure of the peened zone was improved; moreover, the distribution of the precipitates and grains presented an apparent orientation.

Recent Possibilities for the Diagnosis and Pharmacological Control of Pregnancy Loss in Dairy Cow

One of the most recent techniques for the diagnosis of EP （early pregnancy） in cattle on the farm is B-mode ultrasonography. Under field conditions, acceptable results may be achieved with ultrasonography from days 25 to 30 post-AI. The reliability of the test greatly depends on the frequency of the transducer used, the skill of the examiner, the criterion used for a positive PD （pregnancy diagnosis） and the position of the uterus in the pelvic inlet. Pregnancy protein assays （PAG, PSPB） may provide an alternative method to ultrasonography for determining EP or LEM/EFM （late embryonic/early foetal mortality） in the cow. Although early pregnancy factor is the earliest specific indicator for fertilization, its detection is entirely dependend on the use of the RIT （rosette inhibition test）, therefore its use in the field needs further inventions. Preventive pharmaceutical treatments with hCG （human chorionic gonadotropin）, GnRH （gonadotropin realising hormone）, PRID （progesterone-releasing intravaginal device） or CIDR （controlled internal drug release） inserts at different time periods at or post-AI may have some benefit in decreasing PL （pregnancy loss）, however further examinations are warranted to determine how and when these treatments may influence PL in the field.

Compensation for diffusion loss of sound wave in sonar system

Sound pressure amplitude will be attenuated with propagation distance in a certain rule when sound wave is propagated in shallow sea.When processing the attenuated signal,time-variant gain circuit is usually used to compensate its diffusion loss.In this paper,spherical diffusion loss is compensated by digital potentiometer and operational circuit and further investigation is also made on compensation of cylindrical diffusion loss and transition from spherical diffusion loss to cylindrical diffusion loss.Finally,a new compensation model is proposed for unknown propagation loss for the purpose of adjusting the dynamic range of signal to meet the requirement of A/D conversion.

Sound Insulation Performance of Acoustic Metamaterials Based on Attachable Helmholtz Resonators

To address the control of low frequency noises,we propose an new perforated thin-plate acoustic metamaterials with the attachable Helmholtz resonator(AHR)which can be directly attached to the existing structure to suppress acoustic radiation.Sound transmission loss of the aluminium plate with AHR has been simulated using the finite element method under a normal incident plane sound wave.The results show that AHR works well in the 50—500 Hz frequency band,with two peaks of insulation occurring and the corresponding frequency of the first insulation peak dropping to around 120 Hz.The study of the effects of plate thickness,cavity depth,perforation radius and perforation length on the sound insulation performance of metamaterials demonstrates that the effective suppression of acoustic radiation at specific frequencies can be achieved by changing the acoustic radiation properties of the structure.

Effects of different pull-out loading rates on mechanical behaviors and acoustic emission responses of fully grouted bolts

Due to the influence of mining disturbance stress,it is of great significance to better understand the bearing characteristics of fully grouted bolts under different pull-out loading rates.For this purpose,a series of laboratory pull-out tests were conducted to comprehensively investigate the effects of different pull-out loading rates on the mechanical performance and failure characteristics of fully grouted bolts.The results show that the mechanical performance of the anchored specimen presents obvious loading rate dependence and shear enhancement characteristics.With the increase of the pull-out loading rates,the maximum pull-out load increases,the displacement and time corresponding to the maximum pull-out load decrease.The accumulated acoustic emission(AE)counts,AE energy and AE events all decrease with the increase of the pull-out loading rates.The AE peak frequency has obvious divisional distribution characteristics and the amplitude is mainly distributed between 50-80 dB.With the increase of the pull-out loading rates,the local strain of the anchoring interface increases and the failure of the anchoring interface transfers to the interior of the resin grout.The accumulated AE counts are used to evaluate the damage parameter of the anchoring interface during the whole pull-out process.The analytical results are in good agreement with the experimental results.The research results may provide guidance for the support design and performance monitoring of fully grouted bolts.

Advanced imaging and visualization in gastrointestinal disorders

Advanced medical imaging and visualization has a strong impact on research and clinical decision making in gastroenterology. The aim of this paper is to show how imaging and visualization can disclose structural and functional abnormalities of the gastrointestinal (GI) tract. Imaging methods such as ultrasonography, magnetic resonance imaging (MRI), endoscopy, endosonography, and elastography will be outlined and visualization with Virtual Reality and haptic methods. Ultrasonography is a versatile method that can be used to evaluate antral contractility, gastric emptying, transpyloric flow, gastric configuration, intragastric distribution of meals, gastric accommodation and strain measurement of the gastric wall. Advanced methods for endoscopic ultrasound, three-dimensional (3D) ultrasound, and tissue Doppler (Strain Rate Imaging) provide detailed information of the GI tract. Food hypersensitivity reactions including gastrointestinal reactions due to food allergy can be visualized by ultrasonography and MRI. Development of multi-parametric and multi-modal imaging may increase diagnostic benefits and facilitate fusion of diagnostic and therapeutic imaging in the future.

Designing and implementation of variance-dependent Goldstein radar interferogram filtering

The variance-dependent Goldstein radar interferogram filter takes into account the information of both interferometric coherence and multilook factors,and can produce very consistent results for interferograms generated under a wide variety of multilook factors and with very different noise level.However,the filter is a bit complicated and its application is still very limited.We present the designing and implementation of the variance-dependent Goldstein radar interferogram filtering,emphasizing on the logic flow,the generation of look-up table,the determination of filtering parameter,and the handling of edge information loss.Experiments with real interferograms are provided to demonstrate the applications of the designed filtering.Comparisons with the result of the coherence-dependent Goldstein filter show that improvements from 18.4% to 36.9% are achieved when the variance-dependent filter is used,and the noisier the interferogram,the greater the improvement.

Referral for anorectal function evaluation is indicated in 65% and beneficial in 92% of patients

AIM: To determine the indicated referrals to a tertiary centre for patients with anorectal symptoms, the effect of the advised treatment and the discomfort of the tests.METHODS: In a retrospective study, patients referred for anorectal function evaluation (AFE) between May 2004 and October 2006 were sent a questionnaire, as were the doctors who referred them. AFE consisted of anal manometry, rectal compliance measurement and anal endosonography. An indicated referral was defined as needing AFE to establish a diagnosis with clinical consequence (fecal incontinence without diarrhea, 3rd degree anal sphincter rupture, congenital anorectal disorder, inflammatory bowel disease with anorectal complaints and preoperative in patients for re-anastomosis or enterostoma, anal fissure, fistula or constipation). Anal ultrasound is always indicated in patients with fistula, anal manometry and rectal compliance when impaired continence reserve is suspected. The therapeutic effect was noted as improvement, no improvement but reassurance, and deterioration.RESULTS: From the 216 patients referred, 167 (78%) returned the questionnaire. The referrals were indicated in 65%. Of these, 80% followed the proposed advice. Improvement was achieved in 35% and a reassurance in 57% of the patients, no difference existed between patient groups. On a VAS scale (1 to 10) symptoms improved from 4.0 to 7.2. Most patients reported no or little discomfort with AFE. CONCLUSION: Referral for AFE was indicated in 65%. Beneficial effect was seen in 92%: 35% improved and 57% was reassured. Advice was followed in 80%. Better instruction about indication for AFE referral is warranted.

Characteristics of acoustic emission temporal sequences during the failure of a concrete structure under loading

The characteristics of acoustic emission (AE) signals given off in the course of the failure of a concrete structure is explored based on the laboratory experiments with concrete specimens. It is observed that the failure of a concrete structure experiences three stages divided by two inflexion points on the AE event curve, which are sequentially no damage, damage initiation and propagation, and major failure stages. In the first stage, existing micro cracks and defects are compacted by loading, but no damage propagated, hence few AE signals are detected, and it appears that there exists a nearly linear relationship between the relative stress and relative strain. In the second stage, the AE event frequency increases, implying that micro cracks begin to emerge inside the concrete structure, which is consistent with the damage mechanics. When the load is over 80 % of that breaks the structure, i.e. the maximum load, there is a vertical jump on the AE event count curve, which suggests that the failure propagation speeds up. After the second inflexion point, the AE event density increases faster than before, and there is another jump just before breaking, which indicates a quick propagation stage. These findings are valuable for evaluating the damage situations, and for studying and monitoring the dynamic process of the failure behaviors of a concrete structure.

Effect of carbonation-drying-wetting on durability of coral aggregate seawater concrete

Based on the drying-wetting cycles experiment and the carbonation-drying-wetting cycles experiment for coral aggregate seawater concrete(CASC)with different strength grades,the effects of carbonation-drying-wetting on the durability of CASC are studied with the surface state,mass loss rate,relative dynamic elastic modulus,ultrasonic wave velocity and cube compressive strength as indices.Results show that the mass loss rate of CASC increases gradually with the increase in cycle times in the drying-wetting and carbonation-drying-wetting cycles.The mass loss rate increases relatively slowly at the initial stage but it increases remarkably after 10 cycles.The relative dynamic elastic modulus and ultrasonic wave velocity decrease gradually with the increase in cycle times.After 6 cycles,the decrease rate of the relative dynamic elastic modulus and ultrasonic wave velocity of CASC tends to be flat and the surface is slightly damaged.Compared with the initial 28 d cube compressive strength,the cube compressive strength of CASC decreases by 8.8%to 11.0%.Drying-wetting cycles and carbonation can accelerate seawater erosion on CASC,and drying-wetting cycles result in salting-out and accelerate the destruction of concrete.Therefore,the carbonation-drying-wetting accelerates the destruction of CASC.

Optimal filtering for uncertain systems with stochastic nonlinearities, correlated noises and missing measurements

The globally optimal recursive filtering problem is studied for a class of systems with random parameter matrices,stochastic nonlinearities, correlated noises and missing measurements. The stochastic nonlinearities are presented in the system model to reflect multiplicative random disturbances, and the additive noises, process noise and measurement noise, are assumed to be one-step autocorrelated as well as two-step cross-correlated.A series of random variables is introduced as the missing rates governing the intermittent measurement losses caused by unfavorable network conditions. The aim of the addressed filtering problem is to design an optimal recursive filter for the uncertain systems based on an innovation approach such that the filtering error is globally minimized at each sampling time. A numerical simulation example is provided to illustrate the effectiveness and applicability of the proposed algorithm.

Simultaneous Perineal Ultrasound and Vaginal Pressure Measurement Proves Electroacupuncture Pudendal Nerve Stimulation

Purpose： To prove that electroacupuncmre pudendal nerve stimulation （EPNS） can exactly excites the pudendal nerve, by simultaneous measurements of pelvic floor muscle （PFM） movements （perineal ultrasound）, vaginal pressure and pelvic floor surface myoelectricity. Methods： Long needles （acupuncture needles） were deeply inserted into four sacral points and electrified to stimulate the pudendal nerves. When EPNS was performed, perineal ultrasound B-mode images of PFM movements （contractions）, M-mode PFM movement curves; vaginal pressure and pelvic floor surface electromyogram were recorded simultaneously by use of an urodynamic instrument with video suite （Medtronic Duet Encompass）. Simultaneous records were also obtained under three conditions in the process of the nerve stimulation： 1） pausing electric stimulation; 2） reducing the intensity of electric stimulation （to about 2/7 of the original）; 3） drawing back the two lower needles to make the tips 1-2 cm away from the original position. Results： Thirty-five female patients with stress incontinence （aged 54.9±9.8） received EPNS and the simultaneous measurements. When EPNS was performed correctly, the patient felt rhythmic and cephalad PFM contractions with the urethra as the center. Simultaneous records showed the following： 1） cranio-caudal PFM movements on the B-mode image; 2） the M-mode curves indicating the PFM contractions （amplitude： about 1 mm, n=31, 14 cases ） 1 mm and 17 cases 〈1 mm）; 3） A sawtooth curve of changes in vaginal pressure [amplitude： 2.61＋1.69 （0.7-5.6） cmH20, n=34]; 4） pelvic floor myoelectric waves [amplitude： 23.9＋25.3 （5-96） gV, n=34]. The amplitude ofa PFM movement curve conformed basically to that of a vaginal pressure curve. If the electric current was stopped or its intensity was reduced to about 2/7 of the original or during the process of the nerve stimulation the two lower needles were gradually drawn back until the tips were 1-2 cm away from the original positions, then B-mode PFM movements, M-mode curves and sawtooth changes in vaginal pressure disappeared. Conclusion： Electroacupuncture pudendal nerve stimulation can exactly excites the pudendal nerve and effectively contract the pelvic floor muscles.

Study on the Relation Between MRI Findings and Acupuncture Effect in Trigeminal Neuralgia Patients

Objective： To observe the relationship between acupuncture and MRI （Magnetic Resonance Imaging） findings in patients with trigeminal neuralgia （TN）. Methods： A total of 32 idiopathic TN patients who completed acupuncture treatment protocol were recruited in this trial. The relationship between acupuncture effect and MRI findings were analyzed by using MRI-B-FFE （Balanced Fast Field Echo） technique to record MRI information, such as the distance from the brainstem to the contact point of offending vessels and trigeminal nerve, the contact angle of offending vessels and trigeminal nerve, and the ratio of the diameter of the contact vessel to trigeminal nerve width. Results： After acupuncture treatment, 9 cases got marked effect, 19 got improvement, and 4 got no effect. Acupuncture effect was neither associated with the distance from the brainstem to the contact point of the offending vessel and trigeminai nerve （P〉0.05） nor the ratio of the diameter of the offending vessel to trigeminal nerve width （P〉0.05）; however, it was indeed associated with the running course of the offending vessels （P〈0.05）. Conclusion： The bigger the angle between the offending vessels and trigeminal nerve, the poorer the acupuncture effect. The B-FFE technique can be used for screening acupuncture-indicated TN patients.