Irradiated rare‐earth‐doped powellite single crystal probed by confocal Raman mapping and transmission electron microscopy

The irradiation‐induced damages and structure modifications of rare earths doped powellite single crystal have been precisely studied using optical and electron microscopy techniques, including optical interferometry, confocal micro‐Raman spectroscopy and transmission electron microscopy. The surface of powellite crystal pops out anisotropically after exposing under Ar ion beam, with a saturation swelling value of 2.0% along a‐axis and 1.3% along the c‐axis of powellite at high dose. Raman mapping on focused ion‐beam sections (5 × 3 µm²) perpendicular to the irradiated surface reveals that irradiation damage induces orientation‐dependent compressive stresses in powellite. However, no significant anisotropic effect has been found on the irradiation‐induced structural disorder in powellite. At low dose (0.012 dpa), the main irradiation‐induced defects created in powellite crystal are small defect clusters. By comparison, the dominant kinds of defects in high‐dose (5.0 dpa) sample are dislocations loops and networks. Copyright © 2014 John Wiley & Sons, Ltd.     

Generalized algebraic transformations and exactly solvable classical-quantum models

The rigorous approach aimed at providing exact analytical results for hybrid classical-quantum models is elaborated on the grounds of generalized algebraic mapping transformations. This conceptually simple method allows one to obtain novel interesting exact results for the hybrid classical-quantum models, which may for instance describe interacting many-particle systems composed of the classical Ising spins and quantum Heisenberg spins, the localized Ising spins and delocalized electrons, or many other hybrid systems of a mixed classical-quantum nature.     

Introducing navigated transcranial magnetic stimulation as a refined brain mapping methodology

A major intrinsic limitation of transcranial magnetic stimulation (TMS) to map the human brain lies in the unclear relationship between the position of the stimulating coil on the scalp and the underlying stimulated cortex. The relationship between structure and function as the major feature constituting a brain mapping modality can therefore not be established. Recent advances in image processing allowed us to refine TMS by combining magnetic resonance imaging (MRI) modalities with TMS using a neuronavigation system to measure the position of the stimulating coil and map this position onto a MRI data set. This technique has several advantages over recent TMS mapping strategies. The position of the coil on the scalp can be held constant as verified by real time visual guidance. When evaluating higher cortical functions, the relationship between underlying cortical anatomy and the scalp stimulation site can be accurately assessed. Cortical motor output maps can be easily obtained for preoperative planning and decision making for mass lesions near rolandic cortex in patients. In conclusion, navigated TMS is a reliable alternative for localizing cortical functions and therefore may be a useful adjunct or in selected patients even a helpful alternative to other functional neuroimaging methods. Electronic Publication     

Mapping the Gastrointestinal Quality of Life Index to Short-Form 6D utility scores

Purpose

The Gastrointestinal Quality of Life Index (GIQLI) is a disease-specific quality of life instrument that is commonly used in gastrointestinal disorders. However, no preference weights, which are used to calculate quality-adjusted life years for cost-effectiveness analyses, for this instrument have been assigned. Therefore, the objective of this study was to develop a mapping function to derive utility scores for the GIQLI.

Methods

Patients undergoing elective laparoscopic cholecystectomy completed the short-form 6D (SF-6D), a preference-weighted utility measure, and the GIQLI at baseline and at 1 wk and 1 mo postoperatively. The responsiveness of the SF-6D to expected postoperative changes as well as the correlation between the SF-6D and the GIQLI was investigated. Ordinary least squares regression was performed to derive a mapping function using the baseline values, which was then validated using postoperative values. Adjusted r², mean absolute error, and root mean square error was used to determine model performance.

Results

A total of 50 patients were included in the study (mean age 51.1 [standard deviation 16.8], 28% male). The SF-6D and GIQLI domains were responsive to expected postoperative changes, and there was high correlation between the SF-6D and four of the five GIQLI domains (excluding treatment effects). The final mapping function explained 63% of the variance in the derivation sample but had relatively high mean absolute error (0.075 and 0.067 in the 1-wk and 1-mo samples, respectively) and adjusted root mean square error (13.1% and 12.0% in the 1-wk and 1-mo samples, respectively).

Conclusions

The GIQLI can be accurately mapped to SF-6D preference weights at the group level but may be too inexact at the individual level.     

Finite difference method for 2-D and 3-D nonlinear free surface wave problems

A finite difference method is developed for the numerical modelling of the 2-D and 3-D unsteady potential flow generated by transient disturbances on the free surface, on which the nonlinear boundary conditions are fully satisfied. The unknown function is computed with an iteration scheme processing in a transformed time-invariant space. After the velocity is calculated, the location of the free surface is renewed and so is the value of velocity on it. The boundary-value problem of the governing equation is then solved at the next time step. The present method incorporates the FFT. Consequently, a tri-diagonal equation system is obtained which could be readily solved. The feasibility of this method has been demonstrated by 2-D and 3-D examples corresponding to different initial disturbances. This work is supported by the science foundation of Academia Sinica. The paper had been accepted by the XVIth International Congress of IUTAM, Lyngby, Denmark, August, 1984.     

调和映射在线性非平衡热力学中的应用

本文将一类线性非平衡热力学系统归结为调和映射问题.文中将昂塞格系数从常数推广成状态变量的函数,并应用调和映射讨论了系统的定态及其稳定性问题,给出了判定系统定态稳定性的判据.最后讨论了这些结果与原有的最小熵产生定理间的关系.     

一种降低DMT系统发送信号峰值的非线性映射方法

针对DMT ADSL（DMT线路码非对称数字用户环路）传输系统发送信号幅值尖峰问题。本文提出了一种降低发送信号最大峰值同时又不损失系统 传送信息的非线性映射方法。通过最优化方法合理地设计一组可逆映射器,该方法比目前ADSL系统的硬限幅方法能较大幅度地压缩系统的动态范围或在相同的动态范围下获得更好的传输性能。     

Mappings of Domains in Rn and Their Metric Tensors

We consider quasi-isometric mappings of domains in multidimensional Euclidean spaces. We establish that a mapping depends continuously in the sense of the topology of Sobolev classes on its metric tensor to within isometry of the space. In the space of metric tensors we take the topology determined by means of almost everywhere convergence. We show that if the metric tensor of a mapping is continuous then the length of the image of a rectifiable curve is determined by the same formula as in the case of mappings with continuous derivatives. (Continuity of the metric tensor of a mapping does not imply continuity of its derivatives.)     

基于USB密钥和映射的网上银行认证方法

基于指纹比对和USB-Key认证技术,通过把客户的十个手指指纹一一映射对应为0到9这十个数字,对USB-Key接收到的收款账号通过刷入代表不同数字的指纹进行复核比对,提出一种即使客户的交易信息被秘密篡改的情况下仍然能够保证客户账户安全的网上银行身份认证方法.在某网上银行测试系统进行的实验结果表明,该方法有效、安全.