十二指肠间质瘤的影像学表现与病理对照分析

目的:分析十二指肠间质瘤的CT、MRI表现,旨在提高对十二指肠间质瘤的诊断水平.方法:回顾性分析16例经免疫组化证实的十二指肠间质瘤的CT和MRI表现,其中12例患者行CT检查,4例行MRI检查,将影像学表现与手术病理结果对照.结果:16例患者中,病理诊断交界性或交界性偏低度恶性潜能5例,低度恶性4例,中-高度恶性7例...     

胆囊增大的MRCP和常规MRI诊断

目的：探讨磁共振胰胆管成像（MRCP）和常规MRI对胆囊增大的诊断价值。方法：回顾性分析经腹腔镜或外科手术证实的29例胆囊增大病人的临床和影像资料。对每一例患者在术前行MRCP和常规轴面T1WI与T2WI联合检查,将影像诊断与手术所见及病理诊断结果对照,评价术前MRCP和MRI对胆囊增大病因的诊断正确率。结果：①本组增大胆囊的长径范围为8.01～18.13cm（平均11.93cm±3.20）,横径范围为4.12～7.05cm（平均4.59cm±0.91）;②29例胆囊增大的病因诊断如下：与胆道结石相关的良性病变17例（胆总管结石7例、急性与慢性胆囊炎伴胆囊结石4例、胆囊腺肌瘤病和Mirizzi综合征各3例）,低张力胆囊1例,MRCP和MRI的诊断敏感度为83.33%（15/18）,特异度为72.22%（13/18）;由肿瘤性病变引起的胆囊增大11例（胆囊癌1例、肝门胆管癌1例、胆总管癌5例及壶腹周围癌4例）,MRCP和MRI的诊断敏感度为90.90%（10/11）,特异度为81.81%（9/11）。结论：胆囊增大可由良、恶性胆囊疾病与肝外胆管梗阻性病变引起,MRCP和常规MRI联合检查有助于明确病因诊断。     

核磁共振T2谱反演影响因素

为了进一步改进完善核磁共振T2谱反演算法,利用核磁共振正演模拟信号,研究回波间隔、原始回波采集数量、信噪比等因素对反演结果的影响,同时在不同信噪比下对最优化T2谱反演算法、奇异值分解反演算法进行比较分析。研究表明:采集弛豫信号时,回波间隔大小的设置与回波数量、组分大小相匹配,才能得到最佳的反演效果;信噪比越高反演效果越好,当信噪比大于25时反演谱与构造谱基本吻合;在反演不同信噪比理论回波数据时,最优化反演方法对信噪比要求不高,奇异值分解反演方法对信噪比要求高,而奇异值分解反演速度较快。     

Dynamic analysis of tension leg platform for offshore wind turbine support as fluid-structure interaction

Tension leg platform (TLP) for offshore wind turbine support is a new type structure in wind energy utilization.The strong-interaction method is used in analyzing the coupled model,and the dynamic characteristics of the TLP for offshore wind turbine support are recognized.As shown by the calculated results:for the lower modes,the shapes are water’s vibration,and the vibration of water induces the structure’s swing;the mode shapes of the structure are complex,and can largely change among different members;the mode shapes of the platform are related to the tower’s.The frequencies of the structure do not change much after adjusting the length of the tension cables and the depth of the platform;the TLP has good adaptability for the water depths and the environment loads.The change of the size and parameters of TLP can improve the dynamic characteristics,which can reduce the vibration of the TLP caused by the loads.Through the vibration analysis,the natural vibration frequencies of TLP can be distinguished from the frequencies of condition loads,and thus the resonance vibration can be avoided,therefore the offshore wind turbine can work normally in the complex conditions.     

基于核磁共振技术的海水盐度测量研究探讨

为了进一步提高测量海水盐度的准确度,提出了一种新的测量方法.该方法改进了测量原理,利用核磁共振适合于液体的性质,对海水样品内所含元素进行精确的定量分析,通过建立数学模型并进一步分析处理后得到海水盐度的精确值.这种方法是由实际工作中得到的一种创新思想,目前仍然处于理论研究阶段,而且国内外还没有开展这方面的研究工作.今后会...     

地下人防工程地面勘测定位的三种方法

重力勘探、空腔谐振法和主动源电磁信号寻踪法三种地下人防工程地面勘测定位方法。对主动源电磁信号寻踪法做了较详细的介绍。用上述方法对城市地下人防工程进行地面勘测定位是行之有效的方法，并用实例展示了该方法的应用前景。     

平面贴片天线的研究

介绍了半波谐振贴片的理论,并利用HFSS分别对采用微带和同轴两种方式馈电的中心频率为12GHZ的平面贴片天线进行了仿真.仿真结果表明:当改变微带与同轴传输线馈电位置时,对于微带馈电方式,要实现单频点,取贴片的长边中点效果较好;如果偏离该中心点,将具有双频点特性.而采用同轴馈电时,所研究的几个馈电点位置中也是贴片长边中点相对较好,如偏离该中心点,频率将偏离中心频率.     

The specific molecular identification of life experiment (SMILE)

We describe a compact, highly integrated instrument concept for the detection and identification of a wide range of molecules associated with extinct/extant life or potential life processes. The Specific Molecular Identification of Life Experiment (SMILE) will be sensitive to the presence of a range of target molecules using both electrical and optical transduction techniques, and incorporates molecular imprinted polymers in addition to traditional biological receptors such as antibodies. A number of versions of the concept are possible depending on available resources e.g. mass, volume, etc. The full concept utilises a novel imaging interferometer where a large number of molecular receptors are deposited on the measurement plane of an imaging interferometer and read out by an imaging detector, enabling multiple targets—biomarkers—within a sample to be measured simultaneously. The optics can also form the basis of an UV-NIR imaging Fourier spectrometer allowing basic mineralogy studies to be conducted using optical properties to assist in the determination of the geological context of the samples. By incorporating micro-fabricated transducer arrays, micro-fluidics and artificial molecular recognition systems, as well as recombinant antibody technology with appropriate integration methods, SMILE forms a compact and robust “Life Marker Chip” which has been proposed for future planetary missions including ESA's ExoMars mission, where the instrument offers the possibility of conducting a direct in situ search for signs of past or present biological activity on Mars. In addition to its role in planetary exploration, derivatives of SMILE have multiple terrestrial applications in fields such as forensic analysis and environmental monitoring.     

Phase Diagram in Asteroidal Motion

In order to study the dynamical behaviour of asteroids in commensurability with a planet, we propose a phase diagram obtained by short computer time. We test this numerical procedure by analyzing the behaviour of real and fictitious asteroids in first order commensurabilities with Jupiter. We have also studied the evolution time of the orbital elements and other variables to compare these results with those obtained in the phase diagram. The results obtained with our numerical technique were compared to similar results previously obtained by other authors. This revised version was published online in July 2006 with corrections to the Cover Date.     

The Resonance Region of Plutinos under the Perturbation of Outer Planets

Three resonances, the 3:2 exterior mean motion resonance with Neptune, Kozai resonance and 1:1 super resonance, are known to govern concurrently the stability of the motion of Pluto. We explore numerically the resonance zones in which the three resonance coexist. There might exist plutinos with relatively large masses in these zones. Considering that Pluto's perturbation is important to the long-term evolution of plutinos, the resonance zone is mainly explored in the mirror region of Pluto, which is a mirror image of the region around Pluto with respect to the invariant plane of the solar system. We find six resonance zones in the mirror region. The orbit elements at the centers of the six zones and the corresponding heliocentric distances, longitudes and latitudes on July 1, 2003 have been computed and listed for the reference of observation.