摘要：A theoretical model and mathematical description for silicon micromachined elec- trostatic or capacitive ultrasonic imaging transducers have been developed. Ac- cording to the model the basic performance parameters of such a transducer, such as natural frequencies, eigenfunctions, resonance and anti-resonance frequencies, and the mechanical impedance of the diaphragm can be predicted from the ge- ometry of the transducer and property parameters of materials used. The paper reveals that this type of transducers has two basic operation modes, correspond- ing to the resonance of a mass-spring oscillator comprised of the diaphragm and the air cushion, and the first-order bending mode of the diaphragm itself respec- tively, and presents an optimal method for extending the bandwidth by making the two modes coupled, and thereby provides a theoretical basis for the optimal de- sign.

摘要：Significant advances in imaging technology have changed the management of pancreatic cancer. In computed tomography (CT), this has included development of multidetector row, rapid, thin-section imaging that has also facilitated the advent of advanced reconstructions, which in turn has offered new perspectives from which to evaluate this disease. In magnetic resonance imaging, advances including higher field strengths, thin-section volumetric acquisitions, diffusion weighted imaging, and liver specific contrast agents have also resulted in new tools for diagnosis and staging. Endoscopic ultrasound has resulted in the ability to provide high-resolution imaging rivaling intraoperative ultrasound, along with the ability to biopsy via real time imaging suspected pancreatic lesions. Positron emission tomography with CT, while still evolving in its role, provides whole body staging as well as the unique imaging characteristic of metabolic activity to aid disease management. This article will review these modalities in the diagnosis and staging of pancreatic cancer.

摘要：该文提出一种Integral imaging和模拟退火相结合的深度测量方法。针对传统立体视深度测量的复杂性,采用全真三维显示技术Integral imaging成像技术记录空间三维信息。利用带约束的特征匹配算法并综合多种信息分析Integral imaging视图对之间的视差。将寻找匹配的问题设计为全局能量函数模型,并用模拟退火算法使该能量函数最小化,从而实现所有视图对中所有特征点的匹配。最后结合Integral imaging深度估算公式获得空间深度信息。仿真结果表明该方法的有效性。

摘要：A quasi-optical dielectric lens used for W-band focal plane array passive imaging has been developed. The imaging system requires the lens to form beam spot with 3 dB width less than 35 mm at distance of 3500 mm. The powerful optical design software ZEMAX was utilized to design the contours of the lens, and numerical method based on ray tracing and Huygens’ Principle was processed to verify the design result. Measurement result shows that the 3 dB width of the beam spot formed by the lens is 34 mm at distance of 3460 mm, and the beam pattern on imaging plane are equally arranged and the intensity decreases only 0.55 dB while the object lateral deviation increases to 300 mm.

摘要：The architecture of a multi-channel front-end system is important for realizing a high-resolution PET system. We propose a novel front-end readout electronic system with TDC to deal with time information for PET system which can easily design the timing control. Each channel consists of a charge preamplifier, slow/fast shaper, discriminator and an analog memory. There are an ADC and a TDC to process the energy information and time information for each channel at the same time. In this paper, the whole system signals flow is all simulated by MATLAB. The simulation results show that the proposed system can process slender current from the detector and achieve the energy and time information. The proposed architecture can be applied to high-resolution PET imaging systems with multi-channel ASICs.

摘要：设计并成功地研制了一台以螺绕环为激励源的新型随钻多模式电阻率成像测井仪样机,该仪器可在方位电阻率、侧向电阻率和钻头电阻率三种模式下进行测量。相比现有仪器,该仪器节省了时间成本和经济成本。文中将螺绕环激励源等效为延伸的电偶极子,推导了在均匀地层中的测井响应方程。利用3D有限元法模拟了设计的新仪器在三种不同测量模式下的探测深度、纵向分辨率、周向方位探测特性以及井眼尺寸、泥浆电阻率、目的层厚度、围岩层电阻率和泥浆侵入的影响。数值模拟结果表明,新仪器的三种测量模式之间具有不同的探测深度和纵向分辨率,可为井场实时决策提供更多的参考。方位纽扣周向探测能力取决于异常体与周围地层电阻率对比度和异常体周向张开角度。井眼在钻头处截断与否对模拟结果有较大影响。井眼、泥浆侵入对不同模式的影响都存在,而围岩层厚的校正只需要在侧向测量模式下进行。本文结果可为仪器的研发及随钻测井解释提供理论依据。

摘要：光动力疗法在抗菌领域中的应用备受关注.传统的光敏剂在水性介质中容易聚集,从而减少活性氧的产生并严重影响其光动力抗菌疗效.为了减少传统光敏剂的聚集,研究人员做出了许多努力.与之相反,聚集诱导发光型的光敏剂(AIE-PSs)利用其聚集的优势,不仅增加了活性氧产量,而且增强了荧光强度.然而目前有关抗菌型AIE-PSs的研究仍处在发展阶段,相关报道也非常有限.我们在此首次报道了系列基于硝基苯甲酸结构的高效抗菌型AIE-PSs.其中带负电荷的TTVBA不仅可选择性地灭杀球形细菌(如金黄色葡萄球菌),而且易于被扩展成多种带正电荷且具有广谱抗菌性能的AIE-PSs(如TTVBP1–3).我们发现,TTVBP2在125 nmol L^(-1)的低浓度下,即可灭杀3.0 log_(10)金黄色葡萄球菌;TTVBP3在1μmol L^(-1)浓度下可灭杀4.7 log_(10)表皮葡萄球菌,在5μmol L^(-1)浓度下可灭杀3.8 log_(10)大肠杆菌,成为目前已报道的最有效的抗菌AIE-PSs.此外,这些AIE-PSs直接与细菌混合后,即对细菌具有出色的免洗成像能力.因此,我们认为基于硝基苯甲酸结构的TTVBA为未来高效抗菌光敏剂的设计提供了崭新思路.

摘要：高质量的观测系统是获得高质量地震数据的关键,并能影响到数据处理成像的精度。本文在分析观测系统质量与四个采集参数(接收道数,跑线距,接收线距和接收线数)关系的基础上,提出了基于综合质量因子的观测系统质量评价方法,给出了观测系统质量随四参数变化的关系式。根据野外采集实际资料,利用综合质量因子评价方法,计算并给出了观测系统随四参数变化的关系曲线,分析结果显示,炮线距对观测系统质量影响最大,接收线距的增大可以适当的提高观测系统质量,接收道数增加可以提高观测系统质量,不同的采集参数对浅层和深层同相轴成像质量有不同的影响。并利用模型正演和叠前深度偏移方法生成不同采集参数的叠前深度偏移剖面,成像结果显示与上述计算分析结果一致。在实际生产中根据目的层深度,应用本文质量因子评价方法指导观测系统的设计,优选采集参数,达到提高地震数据成像精度的目的。

摘要：Magnetic core shell nanoparticles are composed of a highly magnetic core material surrounded by a thin shell of desired drug, polymer or metal oxide. These magnetic core shell nanoparticles have a wide range of applications in biomedical research, more specifically in tissue imaging, drug delivery and therapeutics. The present review discusses the up-to-date knowledge on the various procedures for synthesis of magnetic core shell nanoparticles along with their applications in cancer imaging, drug delivery and hyperthermia or cancer therapeutics. Literature in this area shows that magnetic core shell nanoparticle-based imaging, drug targeting and therapy through hyperthermia can potentially be a powerful tool for the advanced diagnosis and treatment of various cancers.

摘要：没有一张数字图片能够让每个人都觉得完美。也好，数字图片本来就可以方便地修改润色，我们每个人也因此能自由发挥各自的创意，体现当时的心情。所以我觉得优化是处理数字图片的一个必经过程一无论是DC拍摄、扫描、网上收集还是其他途径得到的数字图片，也无论你准备将这些图片用在什么地方，这个日臻完美的优化过程都是数字图片“人生经历”的重要一页。