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991.
Shiteng Suo Xiaoxi Chen Lianming Wu Xiaofei Zhang Qiuying Yao Yu Fan He Wang Jianrong Xu 《Magnetic resonance imaging》2014
Purpose
To evaluate the non-Gaussian water diffusion properties of prostate cancer (PCa) and determine the diagnostic performance of diffusion kurtosis (DK) imaging for distinguishing PCa from benign tissues within the peripheral zone (PZ), and assessing tumor lesions with different Gleason scores.Materials and Methods
Nineteen patients who underwent diffusion weighted (DW) magnetic resonance imaging using multiple b-values and were pathologically confirmed with PCa were enrolled in this study. Apparent diffusion coefficient (ADC) was derived using a monoexponential model, while diffusion coefficient (D) and kurtosis (K) were determined using a DK model. Differences between the ADC, D and K values of benign PZ and PCa, as well as those of tumor lesions with Gleason scores of 6, 7 and ≥ 8 were assessed. Correlations between parameters D and K in PCa were analyzed using Pearson’s correlation coefficient. ADC, D and K values were correlated with Gleason scores of 6, 7 and ≥ 8, respectively.Results
ADC and D values were significantly (p < 0.001) lower in PCa (0.79 ± 0.14 μm2/ms and 1.56 ± 0.23 μm2/ms, respectively) compared to benign PZ (1.23 ± 0.19 μm2/ms and 2.54 ± 0.24 μm2/ms, respectively). K values were significantly (p < 0.001) greater in PCa (0.96 ± 0.20) compared to benign PZ (0.59 ± 0.08). D and K showed fewer overlapping values between benign PZ and PCa compared to ADC. There was a strong negative correlation between D and K values in PCa (Pearson correlation coefficient r = − 0.729; p < 0.001). ADC and K values differed significantly in tumor lesions with Gleason scores of 6, 7 and ≥ 8 (p < 0.001 and p = 0.001, respectively), although no significant difference was detected for D values (p = 0.325). Significant correlations were found between the ADC value and Gleason score (r = − 0.828; p < 0.001), as well as the K value and Gleason score (r = 0.729; p < 0.001).Conclusion
DK model may add value in PCa detection and diagnosis. K potentially offers a new metric for assessment of PCa. 相似文献992.
利用电沉积法在ITO导电玻璃上沉积的BR紫膜薄膜,制作ITO/BRPMFILM/PARYLENEFILM/AL电池结构系统。在可见光的照射下,光电池系统对光强的变化产生微分响应电流信号,其上升时间不随光强变化量大小而变;并且光电流与光强的变化量呈线性关系。但是与文献1不同的一点是:在光强以相等的改变量增大或减小时产生的正、反微分响应电流(与质子泵方向相比)幅值并不相等,而是存在一定关系。 相似文献
993.
By using Lanczos exact diagonalization and quantum Monte Carlo combined with stochastic analytic continuation, we study the dynamical properties of the S = 1 antiferromagnetic Heisenberg chain with different strengths of bond disorder. In the weak disorder region, we find weakly coupled bonds which can induce additional low-energy excitation below the one-magnon mode. As the disorder increases, the average Haldane gap closes at δ∆ ~ 0.5 with more and more low-energy excitations coming out. After the critical disorder strength δc ~ 1, the system reaches a random-singlet phase with prominent sharp peak at ω = 0 and broad continuum at ω > 0 of the dynamic spin structure factor. In addition, we analyze the distribution of random spin domains and numerically find three kinds of domains hosting effective spin-1/2 quanta or spin-1 sites in between. These “spins” can form the weakly coupled longrange singlets due to quantum fluctuation which contribute to the sharp peak at ω = 0. 相似文献
994.
Xiangli Qian Huiying Sun Tianlu Chen Danzengluobu Youliang Feng Qi Gao Quanbu Gou Yiqing Guo Hongbo Hu Mingming Kang Haijin Li Cheng Liu Maoyuan Liu Wei Liu Bingqiang Qiao Xu Wang Zhen Wang Guangguang Xin Yuhua Yao Qiang Yuan Yi Zhang 《Frontiers of Physics》2022,17(6):64602
The High Altitude Detection of Astronomical Radiation (HADAR) experiment is a refracting terrestrial telescope array based on the atmospheric Cherenkov imaging technique. It focuses the Cherenkov light emitted by extensive air showers through a large aperture water-lens system for observing very-high-energy γ-rays and cosmic rays. With the advantages of a large field-of-view (FOV) and low energy threshold, the HADAR experiment operates in a large-scale sky scanning mode to observe galactic sources. This study presents the prospects of using the HADAR experiment for the sky survey of TeV γ-ray sources from TeVCat and provids a one-year survey of statistical significance. Results from the simulation show that a total of 23 galactic point sources, including five supernova remnant sources and superbubbles, four pulsar wind nebula sources, and 14 unidentified sources, were detected in the HADAR FOV with a significance greater than 5 standard deviations (σ). The statistical significance for the Crab Nebula during one year of operation reached 346.0 σ and the one-year integral sensitivity of HADAR above 1 TeV was ~1.3%–2.4% of the flux from the Crab Nebula. 相似文献
995.
基于AlxNy绝缘介质膜的新型窗口大功率半导体激光器 总被引:1,自引:1,他引:1
提升半导体激光器的腔面抗光学灾变(COD)损伤的能力,改善半导体激光器的工作特性,一直是大功率半导体激光器器件工艺研究的难点.基于薄膜应力使基底半导体材料带隙变化的原理,采用直流磁控溅射方法在不同条件下溅射生成不同内应力的AlxNy绝缘介质膜.通过研究大功率半导体激光器腔面退化机理,借助AlxNy等应力膜设计制作了一种新型非吸收透明窗口结构的宽条形半导体激光器,使器件平均最大输出功率提高46.5%,垂直发散角达到21°,水平发散角达到6.1°,2000 h加速老化试验,其千小时退化速率小于0.091%. 相似文献
996.
997.
The effects of CuO addition on phase composition, microstructure, sintering behavior, and microwave dielectric properties of 0.80Sm(Mg0.5Ti0.5)O3-0.20 Ca0.8Sr0.2TiO3(8SMT-2CST) ceramics prepared by a conventional solid-state ceramic route have been studied. CuO addition shows no obvious influence on the phase of the 8SMT-2CST ceramics and all the samples exhibit pure perovskite structure. Appropriate CuO addition can effectively promote sintering and grain growth, and consequently improve the dielectric properties of the ceramics. The sintering temperature of the ceramics decreases by 50°C by adding 1.00 wt.%CuO. Superior microwave dielectric properties with a ε r of 29.8, Q × f of 85,500 GHz, and τ f of 2.4 ppm/°C are obtained for 1.00 wt.%CuO doped 8SMT-2CST ceramics sintered at 1500°C, which shows dense and uniform microstructure as well as well-developed grain growth. 相似文献
998.
999.
基于TDLAS的长光程环境大气痕量CO监测方法研究 总被引:2,自引:0,他引:2
CO作为大气中重要的污染物和煤矿、油田等环境的危险气体,CO浓度的实时监测对生产生活安全具有重要意义。筛选出CO位于2334 nm附近的R(6)吸收谱线,搭建了基于可调谐半导体激光吸收光谱技术的长光程开放光路大气CO监测系统。采用直接吸收技术,吸收光程为700 m,借助离轴抛物面镜实现了收发同光路;低功耗、小型化的测量控制系统,在单块电路板上实现了激光器驱动、光谱信号处理等功能,单板体积为120 mm×100 mm×25 mm,功耗小于5 W。上位机对光谱数据进行多峰拟合处理,分离出CO和CH4的吸收光谱,反演CO浓度。通过分析光谱数据标准差可知,在1 s响应时间下的检测限为0.06×10-6。对大气中的CO浓度进行了连续监测,测量结果和CO点式分析仪结果一致性良好,验证了该系统仪器化的可行性。 相似文献
1000.