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101.
中国医学物理学的过去、现在与未来 总被引:2,自引:0,他引:2
医学物理(medical physics,MP)是把物理学的原理和方法应用于人类疾病的预防、诊断、治疗和保健的一门交叉学科,是物理学与医学实践相结合的一门独立的分支学科.它是研究人类疾病诊、治过程中的物理现象,并用物理方法表达这种现象.医学物理包括放射肿瘤物理(rsdiation oncdogy physics,ROP)、医学影像物理(medical imaong physics,MIP)、核医学物理(nuclear medicine physics,NMP),其他非电离辐射如核磁、超声、微波、射频、激光等物理因子在医学中的应用,和保健物理(heath physics,HP)等分支内容.医学物理学和生物医学工程学(biomedical engineefing,BME)是一对栾生的兄弟学科,分别从物理学的角度(前者)和工程学的角度(后者)研究人类疾病诊断、治疗及健康保健过程中的生命现象和采取相应的物理措施和工程手段。医学物理学与物理医学(physical medicine,PM)是完全两个不同的概念,前者是物理学的分支,后者是医学的分支.自上世纪60年代以来,中国医学物理学有了很大的进展,推动了中国现代放射肿瘤学、核医学和医学影像学的发展;成立了自己的学术组织,并成为国际医学物理组织(IOMP)的成员国组织.随着中国逐步奔入小康社会,为适应人民大众对健康的需求和现代化医院发展的需要,中国医学物理应该加快发展. 相似文献
102.
对近年各地区高考物理实验试题命题改革趋势进行了分析,以具体类型题为例,对2007年高考物理实验试题设计趋势作以预测. 相似文献
103.
P.R. Drake K.A. Miller 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2013,19(3):307-311
The use of a range of values for the self-feedback gains in the context layer of a modified Elman neural network is shown to reduce RMS error when modelling a non-linear dynamic system. 相似文献
104.
测量和减小纳米凹凸面摩擦力的分子新技术 总被引:1,自引:1,他引:0
报道了美国用原子力显微镜可直接检测超微型设备内发动机转子与外表表面上凸点之间摩擦力的大小的研究成果,介绍了降低了时机的摩擦力的方法。 相似文献
105.
106.
Zhiqin Peng Yoichiro Yoshida Sachiko Sukigara 《Journal of Polymer Science.Polymer Physics》2010,48(1):1-14
A novel macro/nano blended nonwoven with excellent physical properties was prepared by electrospinning polyurethane (PU) nanofibers onto the surface of ramie webs under different weight ratios of N,N‐dimethylacetamide (DMAc)/acetone cosolvents. The ratio of cosolvents has a significant influence on the morphology, tensile properties, resilience, and thermal properties of the resultant samples. Bead‐free and fine interconnected nanofibers were obtained with an increase of acetone content up to 60 wt%. The total physical properties of the blended nonwovens were optimal for a DMAc/acetone ratio of 40/60, in which the tensile load at break, extension at break and Young's modulus were 441, 54, and 256% higher than that of pure ramie web, respectively. The resilience of the blended nonwovens was ~20% higher than that of nonblended ramie web. The significant improvement of physical properties may be due to the good connection between PU nanofiber membranes and ramie webs and the molecular chain structure differences, interconnected structural differences, and high extensibility of PU nanofibers, according to the results of crystallization by differential scanning calorimetry (DSC) and morphological observation by scanning electronic microscopy (SEM). © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1–14, 2010 相似文献
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108.
The fluorescent spectrum and the excitation spectrum were used to present the cluster molecular structure feature in ethanol-water solutions.Through analyzing the fluorescent characteristics of an excimer,it is proposed that the excimers are formed between the ethanol-water cluster molecules in the excited state and in the ground state.The fluorescent lifetime and the fluorescent intensity decay process give information about the photo-physical and photo-chemical processes of the formation and the dissociation of an excimer.The theoretical calculation and physical analysis coincide with the experimental results.The preliminary conclusion about the structure feature of ethanol-water cluster molecule is that it has a planar one like a sandwich. 相似文献
109.
Xiao‐Lin Wang Yan‐Dong He Li‐Yan You Zhong‐Yuan Lu Ze‐Sheng Li 《Journal of Polymer Science.Polymer Physics》2009,47(4):353-365
Dissipative particle dynamics simulations are applied to investigate the monolayer and multilayer film formations on different solid substrates by physical deposition. The influences of the polymer concentration, the polymer chain length, the solvent quality, and the interactions between the polymer solution and the solid substrate surface on the film formation dynamics and the mechanism are studied in detail. The results are analyzed in terms of the thickness and the shape of the deposited film, the kinetics of phase separation in the polymer solution, and the contact angle formed between the polymer aggregations and the substrate surface. Moreover, we suggest two strategies, designing a deposition process analogous to “chemical titration” and physically blocking interlayer diffusion by a simple crosslinked network barrier, to deposit the compact monolayer and multilayer films with better quality, respectively. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 353–365, 2009 相似文献
110.
Chaoying Wan Feng Zhao Xujin Bao Bala Kandasubramanian Matt Duggan 《Journal of Polymer Science.Polymer Physics》2009,47(2):121-129
Polyamide 12/Trisilanolphenyl‐POSS (PA 12/POSS) composites were prepared via melt‐compounding. The effect of polyhedral oligomeric silsesquioxane (POSS) on crystalline structure and crystalline transition of PA 12 was investigated by wide‐angle X‐ray diffraction (WAXD) and real time fourier transform infrared spectroscopy (FTIR). WAXD results indicated that PA 12 crystallized into γ‐form as slowly cooling from melt and the presence of POSS did not influence the crystalline structure of PA 12. Both PA 12 and PA 12/POSS composites underwent Brill transitions when they were heated from room temperature to melt point. Real time FTIR patterns showed that an absorption band at 697 cm?1 ascribed to Amide V (α) mode was emerged along with the disappearance of Amide VI (γ) band at 628 cm?1 with the increase of the temperature for PA 12 and PA 12/POSS composites, which suggested that the γ‐form crystalline has transformed into α form. The Brill bands were identified and the transformed mechanism was discussed based on the real FTIR results. The addition of POSS enhanced the tensile strength and thermal stability of PA 12. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 121–129, 2009 相似文献