At present, almost all the systems and products for speech recognition are working in quiet environment and their performances are degraded or even can′t work when they are operated in high noisy environment. In this...At present, almost all the systems and products for speech recognition are working in quiet environment and their performances are degraded or even can′t work when they are operated in high noisy environment. In this paper, after analyzing the features of speech and noise, a speech enhancement method for LPC autoregressive model for command words recognition used in noisy environment is proposed, and an experimental system is realized. In different background noisy environments, we conduct experiments about SNR, basic accuracy, noise resistant ability and system environment adaptability with different microphones. The experimental results show that the system has good recognition performance in high noisy environments. The system can resist many kinds of noises and meet the needs of application areas on the whole such as military, traffic, marketplace and factory etc.展开更多
A new type of linear ultrasonic motor with two degrees of freedom (DOF) motion is presented. The concept of the new typical motor is based on the combination of a longitudinal and two bending modes. The construction a...A new type of linear ultrasonic motor with two degrees of freedom (DOF) motion is presented. The concept of the new typical motor is based on the combination of a longitudinal and two bending modes. The construction and the operational principle of motor are described, and the elliptical motion of the driving point of the actuator is proved. Meanwhile, a prototype linear motor is designed by using the finite element method (FEM) and is constructed for experiments. The vibration modes are tested with the laser doppler vibrometer (PSV-300F), and the experimental results prove that the design requirements on the mode shape of the actuator and nature frequency are satisfied. The test run of the motor indicates that the operational principle of the motor and the design results are correct, and the output properties are also tested.展开更多
The properties of a bound polaron in a parabolic quantum dot with weak electron-LO-phonon coupling under a Coulomb field are studied. The ground state energy of the bound polaron is derived by using a linear combinati...The properties of a bound polaron in a parabolic quantum dot with weak electron-LO-phonon coupling under a Coulomb field are studied. The ground state energy of the bound polaron is derived by using a linear combination operator and the perturbation method. The influence of the interaction between phonons with different wave vectors in the recoil process on the ground state energy of the bound polaron is discussed. Numerical calculations are performed,and the results show that the ground state energy increases significantly as the effective confinement length of the quantum dot decreases,considering of the interaction between phonons. When l0〉1.0, the influence of the interaction between phonons on the ground state energy cannot be ignored.展开更多
Transarterial chemoembolization(TACE) is a widely used standard treatment for patients with hepatocellular carcinoma(HCC) who are not suitable candidates for curative treatments. The rationale for TACE is that intra-a...Transarterial chemoembolization(TACE) is a widely used standard treatment for patients with hepatocellular carcinoma(HCC) who are not suitable candidates for curative treatments. The rationale for TACE is that intra-arterial chemotherapy using lipiodol and chemotherapeutic agents, followed by selective vascular embolization, results in a strong cytotoxic effect as well as ischemia(conventional TACE). Recently, drugeluting beads(DC Beads?) have been developed for transcatheter treatment of HCC to deliver higher doses of the chemotherapeutic agent and to prolong contact time with the tumor. DC Beads? can actively sequester doxorubicin hydrochloride from solution and release it in a controlled sustained fashion. Treatment with DC Beads? substantially reduced the amount of chemotherapeutic agent that reached the systemic circulation compared with conventional, lipiodol-based regimens, significantly reducing drug-related adverse events. In this article, we describe the treatment response, survival, and safety of TACE used with drugeluting beads for the treatment of HCC and discuss future therapeutic possibilities.展开更多
Epoxidation of cyclohexene to cyclohexene oxide was studied in a new type reactor—the ultrasound airlift loop reactor. The influences of ultrasound intensity, molar ratio of isobutyraldehyde to cyclohexene and oxy-ge...Epoxidation of cyclohexene to cyclohexene oxide was studied in a new type reactor—the ultrasound airlift loop reactor. The influences of ultrasound intensity, molar ratio of isobutyraldehyde to cyclohexene and oxy-gen gas flow rate on the conversion of cyclohexene and selectivity of cyclohexene oxide were investigated and dis-cussed, and the optimal operation condition was found, under which 95.2% conversion of cyclohexene and 90.7% selectivity of cyclohexene oxide were achieved. The ultrasonic airlift loop reactor utilizes the synergistic effect of sonochemsitry and higher oxygen transfer rate. Possible reaction mechanisms were outlined and the reason of ul-trasound promotion of epoxidation reactionwas analyzed.展开更多
AIM： To evaluate the value of endoscopic ultrasono- graphy （EUS） in the preoperative TNM staging of gastric cancer. METHODS ： Forty-one patients with gastric cancer （12 early stage and 29 advanced stage） proved ...AIM： To evaluate the value of endoscopic ultrasono- graphy （EUS） in the preoperative TNM staging of gastric cancer. METHODS ： Forty-one patients with gastric cancer （12 early stage and 29 advanced stage） proved by esophagogastroduodenoscopy and biopsies preoperatively evaluated with EUS according to TNM （1997） classification of International Union Contrele Cancer （UICC）. Pentax EG-3630U/Hitachi EUB-525 echo endoscope with real-time ultrasound imaging linear scanning transducers （7.5 and 5.0 MHz） and Doppler information was used in the current study. EUS staging procedures for tumor depth of invasion （T stage） were performed according to the widely accepted five-layer structure of the gastric wall. All patients underwent surgery. Diagnostic accuracy of EUS for TNM staging of gastric cancer was determined by comparing preoperative EUS with subsequent postoperative histopathologic findings. RESULTS： The overall diagnostic accuracy of EUS in preoperative determination of cancer depth of invasion was 68.3% （41/28） and 83.3% （12/10）, 60% （20/12）, 100% （5/5）, 25% （4/1） for T1, T2, T3, and T4, respectively. The rates for overstaging and understaging were 24.4% （41110）, and 7.3% （4113）, respectively. EUS tended to overstage T criteria, and main reasons for overstaging were thickening of the gastric wall due to perifocal inflammatory change, and absence of serosal layer in certain areas of the stomach. The diagnostic accuracy of metastatic lymph node involvement or N staging of EUS was 100% （17/17） for NO and 41.7% （24/10） for N＋, respectively, and 66% （41127） overall.Misdiagnosing of the metastatic lymph nodes was related to the difficulty of distinguishing inflammatory lymph nodes from malignant lymph nodes, which imitate similar echo features. Predominant location and distribution of tumors in the stomach were in the antrum （20 patients）, and the lesser curvature （17 patients）, respectively. Three cases were found as surgically unresectable （T4 N＋）, and included as being correctly diagnosed by EUS. CONCLUSION： EUS is a useful diagnostic method for preoperative staging of gastric cancer for T and N criteria. However, EUS evaluation of malignant lymph nodes is still unsatisfactory.展开更多
Acoustic emission tests were performed using a split Hopkinson pressure bar system(SHPB) on 50-mm-diameter bars of granite, limestone, sandstone and skarn. The results show that the amplitude distribution of hits is n...Acoustic emission tests were performed using a split Hopkinson pressure bar system(SHPB) on 50-mm-diameter bars of granite, limestone, sandstone and skarn. The results show that the amplitude distribution of hits is not well centralized around 50 d B, and that some hits with large amplitudes, usually larger than 70 d B, occur in the early stages of each test, which is different from the findings from static and low-loading-rate tests. Furthermore, the dominant frequency range of the recorded acoustic emission waveforms is between 300 k Hz and 500 k Hz, and frequency components higher than 500 k Hz are not significant. The hit with the largest values of amplitude, counts, signal strength, and absolute energy in each test, displays a waveform with similar frequency characteristics and greater correlation with the waveform obtained from the elastic input bar of the split Hopkinson pressure bar system compared with the waveforms of the other hits. This indicates that the hit with the largest values of amplitude, counts, signal strength, and absolute energy is generated by elastic wave propagation instead of fracture within the rock specimen.展开更多
文摘At present, almost all the systems and products for speech recognition are working in quiet environment and their performances are degraded or even can′t work when they are operated in high noisy environment. In this paper, after analyzing the features of speech and noise, a speech enhancement method for LPC autoregressive model for command words recognition used in noisy environment is proposed, and an experimental system is realized. In different background noisy environments, we conduct experiments about SNR, basic accuracy, noise resistant ability and system environment adaptability with different microphones. The experimental results show that the system has good recognition performance in high noisy environments. The system can resist many kinds of noises and meet the needs of application areas on the whole such as military, traffic, marketplace and factory etc.
文摘A new type of linear ultrasonic motor with two degrees of freedom (DOF) motion is presented. The concept of the new typical motor is based on the combination of a longitudinal and two bending modes. The construction and the operational principle of motor are described, and the elliptical motion of the driving point of the actuator is proved. Meanwhile, a prototype linear motor is designed by using the finite element method (FEM) and is constructed for experiments. The vibration modes are tested with the laser doppler vibrometer (PSV-300F), and the experimental results prove that the design requirements on the mode shape of the actuator and nature frequency are satisfied. The test run of the motor indicates that the operational principle of the motor and the design results are correct, and the output properties are also tested.
文摘The properties of a bound polaron in a parabolic quantum dot with weak electron-LO-phonon coupling under a Coulomb field are studied. The ground state energy of the bound polaron is derived by using a linear combination operator and the perturbation method. The influence of the interaction between phonons with different wave vectors in the recoil process on the ground state energy of the bound polaron is discussed. Numerical calculations are performed,and the results show that the ground state energy increases significantly as the effective confinement length of the quantum dot decreases,considering of the interaction between phonons. When l0〉1.0, the influence of the interaction between phonons on the ground state energy cannot be ignored.
文摘Transarterial chemoembolization(TACE) is a widely used standard treatment for patients with hepatocellular carcinoma(HCC) who are not suitable candidates for curative treatments. The rationale for TACE is that intra-arterial chemotherapy using lipiodol and chemotherapeutic agents, followed by selective vascular embolization, results in a strong cytotoxic effect as well as ischemia(conventional TACE). Recently, drugeluting beads(DC Beads?) have been developed for transcatheter treatment of HCC to deliver higher doses of the chemotherapeutic agent and to prolong contact time with the tumor. DC Beads? can actively sequester doxorubicin hydrochloride from solution and release it in a controlled sustained fashion. Treatment with DC Beads? substantially reduced the amount of chemotherapeutic agent that reached the systemic circulation compared with conventional, lipiodol-based regimens, significantly reducing drug-related adverse events. In this article, we describe the treatment response, survival, and safety of TACE used with drugeluting beads for the treatment of HCC and discuss future therapeutic possibilities.
基金Supported by Qinglan Project Foundation of Jiangsu Province and Doctoral Dissertation Innovate Foundation of Nanjing Uni-versity of Technology (No.BSCS200508).
文摘Epoxidation of cyclohexene to cyclohexene oxide was studied in a new type reactor—the ultrasound airlift loop reactor. The influences of ultrasound intensity, molar ratio of isobutyraldehyde to cyclohexene and oxy-gen gas flow rate on the conversion of cyclohexene and selectivity of cyclohexene oxide were investigated and dis-cussed, and the optimal operation condition was found, under which 95.2% conversion of cyclohexene and 90.7% selectivity of cyclohexene oxide were achieved. The ultrasonic airlift loop reactor utilizes the synergistic effect of sonochemsitry and higher oxygen transfer rate. Possible reaction mechanisms were outlined and the reason of ul-trasound promotion of epoxidation reactionwas analyzed.
文摘AIM： To evaluate the value of endoscopic ultrasono- graphy （EUS） in the preoperative TNM staging of gastric cancer. METHODS ： Forty-one patients with gastric cancer （12 early stage and 29 advanced stage） proved by esophagogastroduodenoscopy and biopsies preoperatively evaluated with EUS according to TNM （1997） classification of International Union Contrele Cancer （UICC）. Pentax EG-3630U/Hitachi EUB-525 echo endoscope with real-time ultrasound imaging linear scanning transducers （7.5 and 5.0 MHz） and Doppler information was used in the current study. EUS staging procedures for tumor depth of invasion （T stage） were performed according to the widely accepted five-layer structure of the gastric wall. All patients underwent surgery. Diagnostic accuracy of EUS for TNM staging of gastric cancer was determined by comparing preoperative EUS with subsequent postoperative histopathologic findings. RESULTS： The overall diagnostic accuracy of EUS in preoperative determination of cancer depth of invasion was 68.3% （41/28） and 83.3% （12/10）, 60% （20/12）, 100% （5/5）, 25% （4/1） for T1, T2, T3, and T4, respectively. The rates for overstaging and understaging were 24.4% （41110）, and 7.3% （4113）, respectively. EUS tended to overstage T criteria, and main reasons for overstaging were thickening of the gastric wall due to perifocal inflammatory change, and absence of serosal layer in certain areas of the stomach. The diagnostic accuracy of metastatic lymph node involvement or N staging of EUS was 100% （17/17） for NO and 41.7% （24/10） for N＋, respectively, and 66% （41127） overall.Misdiagnosing of the metastatic lymph nodes was related to the difficulty of distinguishing inflammatory lymph nodes from malignant lymph nodes, which imitate similar echo features. Predominant location and distribution of tumors in the stomach were in the antrum （20 patients）, and the lesser curvature （17 patients）, respectively. Three cases were found as surgically unresectable （T4 N＋）, and included as being correctly diagnosed by EUS. CONCLUSION： EUS is a useful diagnostic method for preoperative staging of gastric cancer for T and N criteria. However, EUS evaluation of malignant lymph nodes is still unsatisfactory.
基金Projects(51204206,41272304,41372278) supported by the National Natural Science Foundation of ChinaProject(20110162120057) supported by Ph D Program Foundation of Ministry of Education ChinaProject(201012200232) supported by the Freedom Explore Program of Central South University,China
文摘Acoustic emission tests were performed using a split Hopkinson pressure bar system(SHPB) on 50-mm-diameter bars of granite, limestone, sandstone and skarn. The results show that the amplitude distribution of hits is not well centralized around 50 d B, and that some hits with large amplitudes, usually larger than 70 d B, occur in the early stages of each test, which is different from the findings from static and low-loading-rate tests. Furthermore, the dominant frequency range of the recorded acoustic emission waveforms is between 300 k Hz and 500 k Hz, and frequency components higher than 500 k Hz are not significant. The hit with the largest values of amplitude, counts, signal strength, and absolute energy in each test, displays a waveform with similar frequency characteristics and greater correlation with the waveform obtained from the elastic input bar of the split Hopkinson pressure bar system compared with the waveforms of the other hits. This indicates that the hit with the largest values of amplitude, counts, signal strength, and absolute energy is generated by elastic wave propagation instead of fracture within the rock specimen.
