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A robust technique to reconstruct sound field for all wave-numbers

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Science China(Technological Sciences) 2004年第5期47卷 505-517页

作者： yu Fei chen jian LI Weibing chen Xinzhao School of Mechanical and Automotive Engineering Hefei University of Technology Hefei 230009 China School of Mechanical and Automotive Engineering Hefei University of Technology Hefei 230009 China School of Mechanical and Automotive Engineering Hefei University of Technology Hefei 230009 China School of Mechanical and Automotive Engineering Hefei University of Technology Hefei 230009 China

A robust technique has been proposed for reconstructing sound field for all wave-numbers, which is suitable for the radiation analysis on an arbitrarily-shaped body. According to the wave superposition formulation, the spatial sound field of an actual radiator can be represented equivalently by superposing the fields generated by some fictitious sources interior to the actual radiator. Meanwhile, the strength density on the fictitious sources can be obtained by matching the sound pressures of a finite number of field points. Once the strength density is calculated, the acoustic information at any field point can be obtained subsequently. Finally, some typical numerical examples are given to validate the theoretical analysis, and some investigations are made to analyze the influence of sound frequency and the fictitious source position on the reconstruction precision, which are helpful to the application of the proposed technique to real industrial measurements.

关键词： sound field reconstruction, wave superposition, hybrid layer potential theory, non-uniqueness,robustness.

NEAR-FIELD ACOUSTIC HOLOGRAPHY FOR SEMI-FREE ACOUSTIC FIELD BASED ON WAVE SUPERPOSITION APPROACH

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Chinese Journal of Mechanical Engineering 2006年第3期19卷 455-459页

作者： LI Weibing chen jian yu Fei chen Xinzhao Institute of Sound and Vibration Research Hefei University of Technology Hefei 230009 China

In the semi-free acoustic field, the actual acoustic pressure at any point is composed of two parts： The direct acoustic pressure and the reflected acoustic pressure. The general acoustic holographic theories and algorithms request that there is only the direct acoustic pressure contained in the pressure at any point on the hologram surface, consequently, they cannot be used to reconstruct acoustic source and predict acoustic field directly. To take the reflected pressure into consideration, near-field acoustic holography for semi-free acoustic field based on wave superposition approach is proposed to realize the holographic reconstruction and prediction of the semi-free acoustic field, and the wave superposition approach is adopted as a holographic transform algorithm. The proposed theory and algorithm are realized and verified with a numerical example, and the drawbacks of the general theories and algorithms in the holographic reconstruction and prediction of the semi-free acoustic field are also demonstrated by this numerical example.

关键词： Near-field acoustical holography Semi-free acoustic field Wave superposition approach

Unimolecular artificial transmembrane channel with terminal dihydrogen phosphate groups showing transport selectivity for ammonium

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Chinese Chemical Letters 2020年第1期31卷 77-80页

作者： jian-yu chen Qi Xiao Harekrushna Behera Jun-Li Hou Department of Chemistry Fudan University

A new artificial transmembrane channel molecule bearing dihydrogen phosphate groups has been *** terminal dihydrogen phosphate groups enable the channel to be highly negatively charged at both ends of the channel *** artificial channel could incorporate into the lipid bilayer efficiently under low *** channel displays high NH4+/K+selectivity due to the electrostatic interaction and hydrogen bonding between NH4+and the terminal dihydrogen phosphate groups.

关键词： Artificial transmembrane channel Ammonium transport Dihydrogen phosphate Pillararene Transmembrane transport Transport selectivity

Automatic Normalization and Equivalent-Width Measurement of High-Resolution Stellar Spectra

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Chinese Journal of Astronomy and Astrophysics 2006年第6期6卷 689-696页

作者： Jing-Kun Zhao Gang Zhao yu-Qin chen jian-Rong Shi yu-Juan Liu Ju-Yong Zhang National Astronomical Observatories Chinese Academy of Sciences Beijing 100012

It is well known that normalization, radial velocity correction and equivalent-width measurement of high-resolution stellar spectra are time-consuming work. In order to improve the efficiency we present an automatic method for these routines. The continuum is determined by fitting the ＇high points＇ in the spectrum. After continuum normalization, the program automatically searches for the position of the Ha line and obtains a rough radial velocity, then computes an accurate radial velocity by cross-correlation between the given spectrum and the solar spectrum. In this method, the equivalent-width is automatically measured using Gaussian fitting. A comparison between our results and those from traditional analysis shows that the typical error for equivalent width is around 3.8% in our method. Developing such automatic routines does not mean to replace the interactive reduction method： it is just for a quick extraction of information from the spectra, especially those obtained in large sky surveys.

关键词： techniques radial velocities - stars abundances

Neural network technology in the plant fault diagnosis software application

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通讯和计算机（中英文版） 2008年第5期5卷 32-35页

作者： SONG yu chen jian-jun North China Electric Power University Baoding 071003 China

Reconstruction and prediction of coherent acoustic field with the combined wave superposition approach

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Chinese Journal of Acoustics 2006年第2期25卷 124-138页

作者： LI Weibing chen jian yu Fei chen Xinzhao Institute of sound and vibration research Hefei University of Technology Hefei 230009

The routine wave superposition approach cannot be used in reconstruction and prediction of a coherent acoustic field, because it is impossible to separate the pressures generated by individual sources. According to the superposition theory of the coherent acoustic field , a novel method based on the combined wave superposition approach is developed to reconstruct and predict the coherent acoustic field by building the combined pressure matching matrixes between the hologram surfaces and the sources. The method can reconstruct the acoustic information on surfaces of the individual sources, and it is possible to predict the acoustic field radiated from every source and the total coherent acoustic field can also be calculated spontaneously. The experimental and numerical simulation results show that this method can effectively solve the holographic reconstruction and prediction of the coherent acoustic field and it can also be used as a coherent acoustic field separation technique. The study on this novel method extends the application scope of the acoustic holography technique.

关键词： wave superposition acoustic field holographic reconstruction separation technique acoustic holography simulation results application scope used in

Primary clear cell carcinoma in the liver: CT and MRI findings

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World Journal of Gastroenterology 2011年第7期17卷 946-952页

作者： Qing-yu Liu Hai-Gang Li Ming Gao Xiao-Feng Lin Yong Li jian-yu chen Department of Radiology The Second Affiliated Hospitalof Sun Yat-sen University Guangzhou 510120 Guangdong Prov-ince China Department of Pathology The Second Affiliated Hospital of Sun Yat-sen University Guangzhou 510120Guangdong Province China

AIM: To retrospectively analyze the computed tomography (CT) and magnetic resonance imaging (MRI) appearances of primary clear cell carcinoma of the liver (PCCCL) and compare the imaging appearances of PCCCL and common type hepatocellular carcinoma (CHCC) to determine whether any differences exist between the two groups. METHODS: Twenty cases with pathologically proven PCCCL and 127 cases with CHCC in the Second Affiliated Hospital of Sun Yat-sen University were included in this study. CT or MRI images from these patients were retrospectively analyzed. The following imaging findings were reviewed: the presence of liver cirrhosis, tumor size, the enhancement pattern on dynamic contrast scanning, the presence of pseudo capsules, tumor rupture, portal vein thrombosis and lymph node metastasis. RESULTS: Both PCCCL and CHCC were prone to occur in patients with liver cirrhosis, the association rate of liver cirrhosis was 80.0% and 78.7%, respectively (P > 0.05). The mean sizes of PCCCL and CHCC tumors were (7.28 ± 4.25) cm and (6.96 ± 3.98) cm, respectively. Small HCCs were found in 25.0% (5/20) of PCCCL and 19.7% (25/127) of CHCC cases. No significant differences in mean size and ratio of small HCCs were found between the two groups (P = 0.658 and 0.803, respectively). Compared with CHCC patients, PCCCL patients were more prone to form pseudo capsules (49.6% vs 75.0%, P = 0.034). Tumor rupture, typical HCC enhancement patterns and portal vein tumor thrombosis were detected in 15.0% (3/20), 72.2% (13/18) and 20.0% (4/20) of patients with PCCCL and 3.1% (4/127), 83.6% (97/116) and 17.3% (22/127) of patients with CHCC, respectively. There were no significant differences between the two groups (all P > 0.05). No patients with PCCCL and 2.4% (3/127) of patients with CHCC showed signs of lymph node metastasis (P > 0.05). CONCLUSION: The imaging characteristics of PCCCL are similar to those of CHCC and could be useful for differentiating these from other liver tumors (such as h

关键词： Clear cell carcinoma Hepatocellular carcinoma Pathology Magnetic resonance imaging Computed Tomography X-ray

Off-line analysis of single-unit neuronal discharge in the globus pallidus region in Parkinson＇s disease

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Chinese Medical Journal 2010年第14期123卷 1884-1887页

作者： ZHAO Ya-qun ZHOU Jing-an WANG Yong yu jian-chen ZHANG Hui Department of Neurosurgery 309th Clinical Department of Chinese People's Liberation Army General Hospital Beijing 100091 China Institute of Biomedicine Xi'an Jiaotong University of China Xi'an 710054 China

Background The accuracy of microelectrode-guided localization can make the operation safe and effective, but only experienced neurosurgeons are capable of performing this operation. A good index to identify neuronal discharges between globus pallidus interna and globus pallidus externa is needed. The aim of this research was to establish a good and practical electrophysiologic index to distinguish neuronal discharge in the interior globus pallidus from neuronal discharge in the exterior globus pallidus region of the brain in Parkinson＇s disease. The effect of neurons having an atypical discharge on successful surgical localization was also quantitatively evaluated Methods The study included 30 patients with primary Parkinson＇s disease who underwent pallidotomy between September 2000 and October 2002. During each pallidotomy, the neuronal discharges in the pallidum and its vicinity were recorded. The recorded spikes were used to calculate the frequency, burst index, pause index, and pause ratio of the single-unit discharge. The interior and exterior globus pallidus regions were compared in terms of frequency, burst index, pause index, and pause ratio. The sensitivity, specificity, false-negative ratio, false-positive ratio, and accuracy of those indices were then evaluated. Results The values of frequency, burst index, pause index, and pause ratio in the interior globus pallidus were （96±43） Hz, 2.31±1.81, 0.05±0.05, and 0.27±0.28, respectively, and in the exterior globus pallidus were （59±27） Hz, 0.88±0.63, 0.20±0.14, and 1.54±1.17, respectively. Use of the four indices to distinguish the two neuron types produced a sensitivity of 0.84, 0.78, 0.77, and 0.93 with a specificity of 0.64, 0.79, 0.88, and 0.87, respectively. The false-positive ratio was 0.36, 0.21, 0.12, and 0.13 and the false-negative ratio was 0.16, 0.22, 0.23, and 0.07 while the accuracy was 0.72, 0.79, 0.80, and 0.90, respectively. Conclusions Pause ratio is a relatively reliable index to distinguish

关键词： Parkinson's disease globus pallidus neural discharge intraoperative localization comparative study

STUDY ON THE SYNTHESIS OF A NEW TYPE OF PHOSPHORUS HETEROCYCLIC COMPOUNDS-PYRAZOLO[3,4-d]-1,3,2-DIAZAPHOSPHORIN-6-ONE

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Chinese Chemical Letters 1990年第1期1卷 59-60页

作者： Ru yu chen jian Wu WANG Institute of Elemento-Organic Chemistry,Nankai University,Tianjin 300071,China

1-substituted-5-benzoylamino-4-pyrazolecarboxamides(2)were prepared by the reaction of 1-substituted pyrazolo[3,4-d]-oxazinone(1) with amines in *** compound 2 was refluxed with excess LiAlH_4 in a mixture of THF and ether,one of the two carbamoyl groups in the molecule 2 was reduced *** the results,1-substituted-5- benzylamino-4-pyrazolecarboxamides(3)were *** 3 reacted with Cl_2PPh-X,or P(NET_2)_3,producing the title compounds(4). The conditions of the reactions were studied.

关键词： DIAZAPHOSPHORIN-6-ONE STUDY ON THE SYNTHESIS OF A NEW TYPE OF PHOSPHORUS HETEROCYCLIC COMPOUNDS-PYRAZOLO[3,4-d