An unsupervised learning method with a clustering approach for tumor identification and tissue segmentation in magnetic resonance brain images

Malignant and benign types of tumor infiltrated in human brain are diagnosed with the help of an MRI scanner. With the slice images obtained using an MRI scanner, certain image processing techniques are utilized to have a clear anatomy of brain tissues. One such image processing technique is hybrid self-organizing map (SOM) with fuzzy K means (FKM) algorithm, which offers successful identification of tumor and good segmentation of tissue regions present inside the tissues of brain. The proposed algorithm is efficient in terms of Jaccard Index, Dice Overlap Index (DOI), sensitivity, specificity, peak signal to noise ratio (PSNR), mean square error (MSE), computational time and memory requirement. The algorithm proposed through this paper has better data handling capacities and it also performs efficient processing upon the input magnetic resonance (MR) brain images. Automatic detection of tumor region in MR (magnetic resonance) brain images has a high impact in helping the radio surgeons assess the size of the tumor present inside the tissues of brain and it also supports in identifying the exact topographical location of tumor region. The proposed hybrid SOM-FKM algorithm assists the radio surgeon by providing an automated tissue segmentation and tumor identification, thus enhancing radio therapeutic procedures. The efficiency of the proposed technique is verified using the clinical images obtained from four patients, along with the images taken from Harvard Brain Repository.     

FKM/MVQ/FSR共混胶的性能研究

研究氟橡胶(FKM)与硅橡胶(MVQ)并用以及采用氟硅橡胶(FSR)为增容剂制作耐高低温耐油胶料的性能。结果表明：FKM并用MVQ后,热力学相容性差,因此共混胶的物性较差,但低温性能明显改善,耐油性能有所下降。随着氟硅橡胶(FSR)用量的增加,共混胶的拉伸强度和拉断伸长率均有明显的提高,耐油性略有改善,低温性能变化不大。对并用胶拉伸断裂试样断面进行电子显微镜扫描,观察到FKM/MVQ硫化胶基体断面凹凸不平,出现明显的层状分离状态,加入FSR后,可以看出FKM/MVQ/FSR硫化胶断面较为均匀,没有明显分层现象,说明FSR对FKM/MVQ 2相相容性有所改善。热失重曲线分析可看到FKM/MVQ/FSR共混胶分解温度高于FKM硫化胶的主链热分解温度,说明FKM/MVQ/FSR共混胶的耐热性优于氟橡胶。     

水滑石在氟橡胶中的应用研究

讨论了以水滑石替代氢氧化钙作为碱催化剂的硫化特性,研究了水滑石/氧化钙组合对消除氟橡胶硫化试样气泡的作用。研究了水滑石对双酚硫化氟橡胶的耐水性能的影响。     

硅藻土在高硬度彩色氟橡胶中的应用

研究了硅藻土MW-25和FP-22在彩色氟橡胶中的补强效果,对高硬度氟橡胶的硫化特性、物理及力学性能、热老化性能和压缩永久变形性能进行了测试。结果表明:两种硅藻土在氟橡胶中有很好的补强作用,添加量为40份时,胶料硬度即可达到87~89度(邵尔A硬度),拉伸强度达15 MPa,同时胶料具有较好的耐热老化性能和压缩永久变形性能。     

Festigkeitsberechnung scharf gekerbter Bauteile

Strength calculation of sharp notched components In this report the strength calculation of sharp notched components under static and cyclic loading is investigated and compared to the FKM code “Analytical strength assessment for machine components”. The calculation of the strength of sharp notched components according to the guideline does not lead to satisfying solutions. Therefore different concepts of strength calculation with consideration of scale and notch effects are examined e.g. the gradient concept of Siebel/Stieler. This concept is implemented in the FKM code for the calculation of the notch sensitivity factor. In order to evaluate the numerical results, experimental tests with various sharp notched specimens under static and cyclic loading were carried out. Based on these experimental results the FKM code is extended to sharp notched components.     

共混比对ACM／FKM共混胶性能的影响

采用硫化剂TCY为共硫化剂,研究了共混比对丙烯酸酯橡胶／氟橡胶共混胶的硫化特性、力学性能、耐热老化性能和耐油性能的影响。结果表明：TCY可以同时硫化两种橡胶;ACM／FKM共混比为20／80时．硫化胶具有较好综合力学性能和耐热老化性能;随着ACM用量的增加,硫化胶耐油性能逐渐下降。     

提高硫化温度对氟橡胶硫化胶性能的影响

本文讨论了采用高温硫化对氟橡胶性能的影响。结果表明，可以缩短硫化时间，提高生产效率     

氟橡胶外露骨架油封的研制

介绍了氟橡胶外露骨架油封的新式结构、配方设计、生产工艺及产品性能。     

高性能氟橡胶密封垫片的研制

研究了不同填料和短纤维对氟橡胶性能的影响,尤其是产品耐高温高压的性能。结果表明：R300取代部分N990填充的氟橡胶试样,其拉伸强度和伸长率以及撕裂强度方面具有更好的平衡性能。以N990、R300和芳纶浆粕并用填充氟橡胶能够得到综合物理机械性能优异,耐高温高压冲击寿命长的产品。