一种快速高效的二维超声CT成像的正演算法研究

超声CT成像是采用散射场数据来重建物体内部结构的一种定量化的超声技术。本课题采用快速傅里叶变换(ffT)加速扩展波恩近似(EbA),进而基于EbA来预处理共轭梯度-快速傅里叶变换(Cg-ffT)的方法来实现正演成像的过程。该算法是在传统超声成像领域和商业超声软件中没有使用过的;同时,在保持同等计算精度的条件下,该算法对比传统超声成像正演算法具有速度更快等优点

The comparison of underwater acoustic FM speech communication methods in shallow water channels

水声语音通信在海洋工程、海洋科考、水下搜救等领域具有广泛应用。与单边带通信、数字编码调制通信相比,调频水声语音通信具有实现简单方便、抗幅度衰落性能好的特点,但浅海水声信道具有的复杂多径效应及噪声严重影响其获得的语音音质,容易出现语音含混、语义难辨等问题。本文通过浅海不同距离、不同多径信道下的海试实验比较了采用非线性解调法和正交解调法的调频语音通信性能,并通过客观语音质量评估PESQ（Perceptual evaluation of speech quality）方法对调频水声语音通信音质进行量化评估。Underwater acoustic speech communication plays an important role in mar/ne engineering, marine research, underwater search and rescue, and related fields. Compared with the classic single side band communication and digital code modulation communication, frequency modulation （FM） underwater acoustic voice communication has a good performance in amplitude fading resistance and low implementation complexity. However, shallow water channels featured by complicated multipath and noise will seriously degrade the speech communication quality of FM systems, leading to the problem of ambiguous speech and semantic ambiguity. This paper compares the performance of the underwater acoustic FM speech communication system used nonlinear demodulation method and orthogonal demodulation method by the field experiment in different shallow water channels, and performs quantitative assessment to the speech communication quality through PESQ （Perceptual evaluation of speech quality） method.国家自然科学基金资助项目（11274259;11574258

Video-assisted Thoracoscopic 3D Mode Operation for Solitary Pulmonary Nodules

目的探讨三维胸腔镜手术(3d VIdEO-ASSISTEd THOrACIC SurgEry,3d-VATS治疗孤立性肺结节(SOlITAry PulMOnAry nOdulE,SPn)的效果。方法回顾性分析2013年3月~2014年3月50例SPn的资料,采用3d-VATS手术模式楔形切除结节,根据快速病理结果决定是否行肺叶切除加淋巴结清扫术。统计手术时间(去除快速冰冻时间)、术后24 H引流量、总引流量、引流管拔除时间、淋巴结清扫数及术后并发症等。结果 3d-VATS模式下,50例均行肺结节楔形切除,其中23例病理为恶性,继续行肺癌根治术,手术顺利。肺癌根治术手术时间(62±12)MIn,术中出血量(35±5)Ml,清扫淋巴结(19±3)个,术后24 H引流量(120±20)Ml,术后胸管引流时间(4±1)d,术后住院时间(7±2)d。并发症3例,其中术后肺炎2例,阵发性心房纤颤1例,均治愈。无围手术期死亡。随访2~12个月,平均6.3月。1例术后3个月脑转移,1例术后5个月肺癌复发。结论胸腔镜3d模式下治疗SPn是一种新的选择方式,安全可行,值得推广应用。Objective To evaluate the effects of surgical treatment for solitary pulmonary nodules under thoracoscopic 3D mode(3D-VATS).Methods A total of 50 cases of solitary pulmonary nodules from March 2013 to March 2014 were retrospectively analyzed.Intraoperative wedge pulmonary resection with 3D-VATS was utilized.According to intraoperative pathological findings,lobectomy plus lymph node dissection was given or not.Intraoperative time( minus fast freezing time),drainage volume for 24 h,total drainage volume,drainage tube removal time,number of lymph node dissected,and postoperative complications were recorded.Results Under 3D-VATS mode,50 cases of solitary pulmonary nodules were treated with wedge resection,including 23 cases of malignant pathology receiving radical resection, which was smoothly.The radical resection time( lung lobectomy plus lymphadenectomy) was(62 ± 12) min,the bleeding volume was(35 ± 5) ml,the lymphadenectomy number was 19 ± 3,the drainage volume for 24 h was(120 ± 20) ml,the postoperative chest tube removal time was(4 ± 1) days,and the postoperative hospital stay was(7 ± 2) days.Postoperative complications occurred in 3 cases,including 2 cases of pneumonia and 1 case of paroxysmal atrial fibrillation.No perioperative deaths were observed.All the cases were followed up for 2- 12 months,with an average of 6.3 months.Brain metastases was found in 1 case at the third postoperative month and recurrence of lung cancer was noted in 1 case at the fifth postoperative month.Conclusion Thoracoscopic 3D mode treatment for solitary pulmonary nodules is a new,safe,and feasible alternative and should be widely applied

Combined Use of Thoracoscopy and Laparoscopy in Total Laryngectomy for Cervical Esophageal Carcinoma

目的探讨胸、腹腔镜联合全喉切除治疗颈段食管的可行性和疗效。方法 2009年1月~2014年7月胸、腹腔镜联合全喉切除治疗33例颈段食管癌。胸腔镜下分离食管、腹腔镜下管胃成形、全喉切除、气管永久造口、胃咽吻合术。结果胸部手术时间40~66 MIn,平均53 MIn;腹部手术时间35~51 MIn,平均44 MIn;颈部手术时间128~150 MIn,平均139 MIn。术中出血量130~270 Ml,平均150 Ml。术后住院时间8~14 d,平均12 d。病理均为鳞状细胞癌,其中高分化2例,中分化19例,中-低分化7例,低分化5例。切缘病理学检查无癌组织残留。31例淋巴结转移。并发症:吻合口漏2例,喉返神经损伤3例,肺部感染6例,胃排空障碍2例,吻合口狭窄1例,无死亡病例。33例随访1个月~5年,术后1、3、5年生存率分别为87.9%、54.5%、45.5%。结论颈段食管癌应采取积极的手术治疗,胃咽吻合术是颈段食管癌切除后较为理想的修复手段。Objective To investigate clinical feasibility and efficacy of combined use of thoracoscopy and laparoscopy in total laryngectomy for cervical esophageal carcinoma.Methods Clinical data of 33 patients with cervical esophageal carcinoma undergoing surgical treatment in our department from January 2009 to July 2014 were analyzed retrospectively.The esophagus was separated under thoracoscopy.And laparoscopic gastroplasty,total laryngectomy,tracheal permanent colostomy,and gastric pharyngeal anastomosis were performed.Results The thoracoscopic operation time was 40- 66 min( mean,53 min),the laparoscopic operation time was 35- 51 min( mean,44 min),and the cervical operation time was 128- 150 min( mean,139 min).The blood loss was 130- 270 ml( mean,150 ml).The postoperative hospital stay was 8- 14 d( mean,12 d).Pathological examinations showed squamous cell carcinoma in all the cases,including 2 cases of highly differentiated carcinoma,19 cases of moderately differentiated carcinoma,7 cases of moderately or lowly differentiated carcinoma,and 5 cases of lowly differentiated carcinoma.No residual cancer was found at cutting edges pathologically.Among the 33 cases,lymph node metastasis was found in 31 cases.Complications included 2 cases of anastomotic fistula,3 cases of recurrent laryngeal nerve injury,6 cases of pulmonary infection,2cases of delayed gastric emptying,and 1 case of anastomotic stenosis.There was no death.All the patients were followed up for 1months to 5 years.The survival rates at 1,3,and 5 postoperative year were 87.9%,54.5%,and 45.5%,respectively.Conclusions Cervical esophageal carcinoma should be surgically treated actively.Gastric pharyngeal anastomosis is an ideal option for the repair of cervical esophageal cancer resection

numerical simulation of Marangoni effect induced by unsteady interphase mass transfer to single drops in liquid-liquid extraction systems by the level set method

在自然界和许多工程技术中存在许多多相体系的传热和传质过程，表现为丰富的多层次、多尺度的物理和化学现象，Marangoni效应是其中机理十分复杂、涉及众多应用问题的现象之一。Marangoni效应的研究无论在理论研究上，还是在工业应用上都具有十分重要的价值。 本文用水平集方法建立了单液滴非稳态运动萃取传质过程的控制方程，该控制方程是在一个建立在运动液滴的坐标系中数值求解的。利用萃取传质实验测定了四个体系的传质速率，数值模拟了四个体系的传质过程，数值模拟结果同实验研究作了对比，发现两者吻合较好。还比较了运动方程和浓度方程耦合的算法和解耦算法的优劣性，本文的耦合算法的结果比解耦算法更符合实验结果。 用水平集方法数值模拟单液滴萃取传质中的Marangoni效应时，由于表面力的计算误差，极易出现表面“寄生”流。为此，基于对CSF（Continuum surface force）方法的理解，在原有的CSF方法的基础上, 本文提出了一个改进的离散表面力的新方法，即权重积分方法。用权重积分方法计算了中性液滴以及运动气泡和液滴的速度场，验证了该方法能有效地克制“寄生”流，从而为数值模拟Marangoni效应提供必要的基础。 在权重积分方法的基础上，用水平集方法建立了单液滴非稳态萃取传质中Marangoni效应的控制方程，运动方程和浓度方程相耦合。其中，表面张力和浓度的关系为简单的线性模型，数值模拟结果同经典的文献基本相符。 利用萃取传质实验和CCD方法，测定了典型单液滴传质中Marangoni效应。实验测定了MIBK-HAc-H2O体系的传质速率以及MIBK液滴在水中上升的速度。在建立水平集方法数值模拟非稳态的单液滴萃取传质的Marangoni效应的基础上，计算真实液液传质体系MIBK-HAc-H2O中的Marangoni效应。在MIBK-HAc-H2O中，表面张力和浓度的关系为二次多项式关系。数值模拟结果同实验测定结果比较，二者吻合较好，证实了模型方程和数值方法的准确性

视觉词汇加工的动态神经网络及其形成

揭示大脑加工的神经网络机制成为认知神经科学研究的最新取向。本研究以视觉词汇加工脑区(VWFA)的神经功能作为切入点,探讨视觉词汇加工神经网络的动态机制及其形成。研究一考察VWFA在刺激驱动和任务调节下的动态激活,及其与语音、语义脑区所组成神经网络的动态机制。研究二通过跨文化对比以及儿童阅读发展研究,阐明语言经验对视觉词汇加工网络的塑造作用。研究三对比功能网络、静息网络以及白质纤维束联结,探讨视觉词汇加工网络的动态联结及其形成。研究结果有助于建构视觉词汇加工的神经生理模型,为基于脑科学的阅读教学和阅读障碍矫治奠定理论基础,为认知神经科学研究提供了新的思路

THE WAVE ATTENUATION ON THE MUD BED

In the paper the wave attenuation in a two layer fluid system is studied.The fluid in the toplayer is ideal and that in the lower layer is the Voigt model of the viscoelastic medium.A dispersion relationis derived and the rate of the wave decay is computed.The approximate explicit expressions of..

The Dynamic Neural Network and Its Development of Visual Word Processing

揭示大脑加工的神经网络机制成为认知神经科学研究的最新取向。本研究以视觉词汇加工脑区(VWFA)的神经功能作为切入点,探讨视觉词汇加工神经网络的动态机制及其形成。研究一考察VWFA在刺激驱动和任务调节下的动态激活,及其与语音、语义脑区所组成神经网络的动态机制。研究二通过跨文化对比以及儿童阅读发展研究,阐明语言经验对视觉词汇加工网络的塑造作用。研究三对比功能网络、静息网络以及白质纤维束联结,探讨视觉词汇加工网络的动态联结及其形成。研究结果有助于建构视觉词汇加工的神经生理模型,为基于脑科学的阅读教学和阅读障碍矫治奠定理论基础,为认知神经科学研究提供了新的思路

水波在软淤泥底床上的衰减

本文研究了二层流体系统中波浪的衰减。上层为理想流体;下层为粘弹性Ｖｏｉｇｔ体。导出了色散关系;计算了波浪衰减系数。对于粘性或弹性很大或很小的情况;导出了各种水深情况下近似的显式的衰减系数表示式。与精确的数值结果比较;近似程度很好。可供工程设计者参考、使用

异丁基乙烯基醚/马来酸酐共聚物改性聚乙烯醇的研究

采用异丁基乙烯基醚/马来酸酐共聚物对聚乙烯醇(PVA)进行共混改性,研究了改性PVA的耐水性及力学性能,发现改性后的PVA的耐水性及力学性能有明显提高,其中当异丁基乙烯基醚/马来酸酐共聚物的含量为2%时,共混薄膜的断裂伸长率达到300%.同时从增塑性及结晶性等多方面对共混体系的改性机理进行了分析