Objective: To present a self-developed experimental system for basic studies of blood perfusion imaging and time-intensity evaluating based on ultrasound contrast agent. Methods: The experimental system performed the ...Objective: To present a self-developed experimental system for basic studies of blood perfusion imaging and time-intensity evaluating based on ultrasound contrast agent. Methods: The experimental system performed the image reconstruction and time-intensity processing with radio frequency signals. The system was comprised of ultra-high speed hardware data acquisition interface and low computational cost algorithms. The self-made contrast agent,blood mimic phantom and capillary phantom model were used to validate the experimental system. Results: The images acquired in blood phantoms with linear-array and curve-array transducers were given. The time-intensity curves corresponding to selected region of interested from image sequence were demonstrated. It was also shown the time-intensity based decay curves and a comparison of decay of ultrasound contrast agent under different ultrasound powers. Conclusion: Several experiments resulted from two in vitro phantom models show that the experimental system can be used to basic studies of blood perfusion and further clinical studies of microvasculature perfusion.展开更多
A learner’s stages of L2 development are connected by his or her L1 and culture.It is,accordingly,of paramount importance to understand the second language learners’culture and learning process and better assist the...A learner’s stages of L2 development are connected by his or her L1 and culture.It is,accordingly,of paramount importance to understand the second language learners’culture and learning process and better assist them through this process in the way of teaching them English.Similarly,inter-language theory(IL)and contrastive rhetoric are affected by factors,such as learner’s L1,learning experiences,and culture.This paper talks about these two theory’s characteristics,constructs,and importance,so language instructors may better understand the L2 learning phenomena and think out better methods to help language learners improve their language skills.展开更多
A comprehensive contrast of ore-forming geological background and ore-forming fluid features, especially fluid ore-forming processes, has been performed between the Tianmashan and the Datuanshan ore deposits in Tongli...A comprehensive contrast of ore-forming geological background and ore-forming fluid features, especially fluid ore-forming processes, has been performed between the Tianmashan and the Datuanshan ore deposits in Tongling, Anhui Province. The major reasons for the formation of the stratabound skarn Au-S ore deposit in Tianmashan and the stratabound skarn Cu ore deposit in Datuanshan are analyzed in accordance with this contrast. The magmatic pluton in Tianmashan is rich in Au and poor in Cu, but that in Datuanshan is rich in Cu and Au. The wallrock strata in Tianmashan contain Au-bearing pyrite layers with some organic substance but those in Datuanshan contain no such layers. Moreover, the ore-forming fluids in Tianmashan are dominantly magmatic ones at the oxide and sulfide stages, but those with high content of Cu in Datuanshan are mainly groundwater fluids. In addition, differences in compositional evolution and physicochemical condition variation of the ore-forming fluids result in gradual dispersion展开更多
针对红外图像增强过程中容易饱和、细节丢失等问题,提出一种参数自设定的双直方图均衡化方法。根据灰度级累积概率密度黄金比例值将原始图像划分为两个独立的子图像。结合原始图像曝光度和子图像灰度级区间信息,对每个子图像的直方图进...针对红外图像增强过程中容易饱和、细节丢失等问题,提出一种参数自设定的双直方图均衡化方法。根据灰度级累积概率密度黄金比例值将原始图像划分为两个独立的子图像。结合原始图像曝光度和子图像灰度级区间信息,对每个子图像的直方图进行多尺度自适应加权校正。基于校正后的直方图,对每个子图像分别作均衡化映射变换,最后合并子图像获得增强图像。在红外图像公开数据集INFRARED100上进行的测试显示,与亮度保持双直方图均衡化(Brightness Preserving Bi-Histogram Equalization,BBHE)、带平台限制的双直方图均衡化(Bi-histogram Equalization with a Plateau Limit,BHEPL)、基于曝光度的双直方图均衡化(Exposure based Sub-image Histogram Equalization,ESIHE)方法相比,所提方法增强的图像具有合适的平均对比度和更大的平均信息熵,在峰值信噪比(Peak Signal-to-Noise Ratio,PSNR)、结构相似度(Structural Similarity,SSIM)、绝对平均亮度偏差(Absolute Mean Brightness Error,AMBE)指标上平均提升至少17.2%、4.0%、56.2%。实验结果表明,所提方法对不同亮度特征的红外图像都有良好的适应性,可有效增强红外图像对象和背景之间的对比度,在噪声抑制、亮度和细节保持等方面优于同类方法。展开更多
Objective: To study the effective computerized image processing of underexposed and overexposed X-rays of bones and joints. Methods: Ninety-nine conventional X-ray images (82 were overexposed and 17 were underexposed)...Objective: To study the effective computerized image processing of underexposed and overexposed X-rays of bones and joints. Methods: Ninety-nine conventional X-ray images (82 were overexposed and 17 were underexposed),scanned by an UMAX Astra 4000U Scanner, were converted into digital images on the basis of their analog images. A computerized imaging processing program consisting of five functional modules such as Contrast Stretch, Fast Flourier Transform (FFT), Image Smoothing Modules, Inverse Fast Flourier Transform (IFFT) and Nonlinear Transform performed image contrast stretch and smoothing. Three senior doctors from hospital image sections made their evaluation of all the processed images. Results: Of 82 overexposed films, 71 met the clinical requirements after image processing, and 11 were unable to be applied to clinical diagnosis, accounting for 87% and 13% respectively. Of the other 17 underexposed X-ray images, 11 met the clinical requirements while 6 were not, making a percentage of 64 and 35. Conclusion: Image contrast stretch and smoothing processing are significantly effective on conventional X-ray images which were inappropriately exposed, and can avoid more X-ray radiation caused by handling of radiological photograph again. This method can decrease hospital cost and provide acute and effective X-ray examinations for the treatment and cure for critical patients.展开更多
国际疾病分类(International Classification of Diseases,ICD)编码任务是将疾病编码分配给电子病历,每份电子病历分配一个或多个ICD编码。现有的方法大多考虑临床文本中症状与诊断之间的关系,而对诊断与诊断间关系以及症状与症状间关...国际疾病分类(International Classification of Diseases,ICD)编码任务是将疾病编码分配给电子病历,每份电子病历分配一个或多个ICD编码。现有的方法大多考虑临床文本中症状与诊断之间的关系,而对诊断与诊断间关系以及症状与症状间关系缺乏考量。针对这一现状,对于诊断与诊断间关系,构造编码共现任务,采用多任务的形式使得预测结果不依赖于标签之间的顺序关系,且不会进行错误预测的传播;对于症状与症状间关系,使用对比学习获取有意义的表征,学习同一临床文本中的症状一致性。通过以上任务的组合,构建基于多任务学习的ICD自动编码模型框架。在MIMIC-Ⅲ数据集上的实验表明,所提出的方法相较于优异模型在Micro-f1指标上提高了1.0%,在Micro-auc指标上提高了0.3%,在P@5指标上提高了0.7%。展开更多
基金Supported by the National Natural Science Foundation of China(30270404)Specialized Research Fund for the Doctoral Program of Higher Education(2003069816)
文摘Objective: To present a self-developed experimental system for basic studies of blood perfusion imaging and time-intensity evaluating based on ultrasound contrast agent. Methods: The experimental system performed the image reconstruction and time-intensity processing with radio frequency signals. The system was comprised of ultra-high speed hardware data acquisition interface and low computational cost algorithms. The self-made contrast agent,blood mimic phantom and capillary phantom model were used to validate the experimental system. Results: The images acquired in blood phantoms with linear-array and curve-array transducers were given. The time-intensity curves corresponding to selected region of interested from image sequence were demonstrated. It was also shown the time-intensity based decay curves and a comparison of decay of ultrasound contrast agent under different ultrasound powers. Conclusion: Several experiments resulted from two in vitro phantom models show that the experimental system can be used to basic studies of blood perfusion and further clinical studies of microvasculature perfusion.
文摘A learner’s stages of L2 development are connected by his or her L1 and culture.It is,accordingly,of paramount importance to understand the second language learners’culture and learning process and better assist them through this process in the way of teaching them English.Similarly,inter-language theory(IL)and contrastive rhetoric are affected by factors,such as learner’s L1,learning experiences,and culture.This paper talks about these two theory’s characteristics,constructs,and importance,so language instructors may better understand the L2 learning phenomena and think out better methods to help language learners improve their language skills.
基金financially supported by the Ministry of Science and Technology of China(Grant No.1999043206)the National Natural Science Foundation of China(Grant Nos.40272034 and 40133020).
文摘A comprehensive contrast of ore-forming geological background and ore-forming fluid features, especially fluid ore-forming processes, has been performed between the Tianmashan and the Datuanshan ore deposits in Tongling, Anhui Province. The major reasons for the formation of the stratabound skarn Au-S ore deposit in Tianmashan and the stratabound skarn Cu ore deposit in Datuanshan are analyzed in accordance with this contrast. The magmatic pluton in Tianmashan is rich in Au and poor in Cu, but that in Datuanshan is rich in Cu and Au. The wallrock strata in Tianmashan contain Au-bearing pyrite layers with some organic substance but those in Datuanshan contain no such layers. Moreover, the ore-forming fluids in Tianmashan are dominantly magmatic ones at the oxide and sulfide stages, but those with high content of Cu in Datuanshan are mainly groundwater fluids. In addition, differences in compositional evolution and physicochemical condition variation of the ore-forming fluids result in gradual dispersion
文摘针对红外图像增强过程中容易饱和、细节丢失等问题,提出一种参数自设定的双直方图均衡化方法。根据灰度级累积概率密度黄金比例值将原始图像划分为两个独立的子图像。结合原始图像曝光度和子图像灰度级区间信息,对每个子图像的直方图进行多尺度自适应加权校正。基于校正后的直方图,对每个子图像分别作均衡化映射变换,最后合并子图像获得增强图像。在红外图像公开数据集INFRARED100上进行的测试显示,与亮度保持双直方图均衡化(Brightness Preserving Bi-Histogram Equalization,BBHE)、带平台限制的双直方图均衡化(Bi-histogram Equalization with a Plateau Limit,BHEPL)、基于曝光度的双直方图均衡化(Exposure based Sub-image Histogram Equalization,ESIHE)方法相比,所提方法增强的图像具有合适的平均对比度和更大的平均信息熵,在峰值信噪比(Peak Signal-to-Noise Ratio,PSNR)、结构相似度(Structural Similarity,SSIM)、绝对平均亮度偏差(Absolute Mean Brightness Error,AMBE)指标上平均提升至少17.2%、4.0%、56.2%。实验结果表明,所提方法对不同亮度特征的红外图像都有良好的适应性,可有效增强红外图像对象和背景之间的对比度,在噪声抑制、亮度和细节保持等方面优于同类方法。
文摘Objective: To study the effective computerized image processing of underexposed and overexposed X-rays of bones and joints. Methods: Ninety-nine conventional X-ray images (82 were overexposed and 17 were underexposed),scanned by an UMAX Astra 4000U Scanner, were converted into digital images on the basis of their analog images. A computerized imaging processing program consisting of five functional modules such as Contrast Stretch, Fast Flourier Transform (FFT), Image Smoothing Modules, Inverse Fast Flourier Transform (IFFT) and Nonlinear Transform performed image contrast stretch and smoothing. Three senior doctors from hospital image sections made their evaluation of all the processed images. Results: Of 82 overexposed films, 71 met the clinical requirements after image processing, and 11 were unable to be applied to clinical diagnosis, accounting for 87% and 13% respectively. Of the other 17 underexposed X-ray images, 11 met the clinical requirements while 6 were not, making a percentage of 64 and 35. Conclusion: Image contrast stretch and smoothing processing are significantly effective on conventional X-ray images which were inappropriately exposed, and can avoid more X-ray radiation caused by handling of radiological photograph again. This method can decrease hospital cost and provide acute and effective X-ray examinations for the treatment and cure for critical patients.
文摘国际疾病分类(International Classification of Diseases,ICD)编码任务是将疾病编码分配给电子病历,每份电子病历分配一个或多个ICD编码。现有的方法大多考虑临床文本中症状与诊断之间的关系,而对诊断与诊断间关系以及症状与症状间关系缺乏考量。针对这一现状,对于诊断与诊断间关系,构造编码共现任务,采用多任务的形式使得预测结果不依赖于标签之间的顺序关系,且不会进行错误预测的传播;对于症状与症状间关系,使用对比学习获取有意义的表征,学习同一临床文本中的症状一致性。通过以上任务的组合,构建基于多任务学习的ICD自动编码模型框架。在MIMIC-Ⅲ数据集上的实验表明,所提出的方法相较于优异模型在Micro-f1指标上提高了1.0%,在Micro-auc指标上提高了0.3%,在P@5指标上提高了0.7%。