闪存器与移动电子设备

闪存器技术于上世纪80年代中期面世,在不到20年的时间里,就出现了迅猛增长,其应用范围从个人电脑的引导代码存储一直到近期出现的PDA、数码相机和手机中的代码和数据存储。随着移动电子的持续增长,我们对在移动电子中获得成功应用的闪存器功能和优点进行一次回顾。闪存器的历史沿革“闪存(Flash)”这一名称,是源于该存储器件只需单步操作即能擦除其中所有内容的能力。军用装备很早就从这一能力中获益,军用装备都包含机密信息,一旦即将落入敌手,就应该迅速予以破坏。与EEPROM类似,Flash的数据存储也是通过向其晶体管栅区存入电荷来实现…     

Calcium Phosphate Biomaterials: An Update

1Introduction Archaeologicalfindingsdatingbacktothe4thcentury BCshowedthatmissinghumanteethhavebeenreplaced bymaterialswhichincluded:animalteeth,coral,shells,ivory(elephanttusk),wood,andmetals[1].Inmodern times,autografts(boneobtainedfromanothersiteinthe …     

A generalization of Vidyasagar's theorem on stabilizability using state detection

In this paper we generalize the Vidyasagar's well known theorem on the local stabilizability problem of nonlinear systems using state detection [11]. Our purpose is to prove that if a system is weakly detectable and stabilizable by means of a continuous state feedback u = γ(x), for which no differentiability assumption is imposed, then the system is also stabilized by the law u = γ(z), where z is the output of a weak detector for the state x. The result above is applicable to several cases not covered by other works.     

Sorption of Acid Green 25 on chitosan: Influence of experimental parameters on uptake kinetics and sorption isotherms

Acid Green 25, which is a diazoic dye bearing two sulfonic groups, is efficiently sorbed on chitosan. The protonation of chitosan may explain the electrostatic attraction of this anionic dye and that its optimum pH is close to 3. Preliminary protonation of amine groups (obtained by contact with a sulfuric acid solution) reduced the variation of solution pH following sorbent addition but significantly reduced sorption performance: the maximum sorption capacity of raw chitosan, 525 mg dye/g (0.84 mmol dye/g), was halved by acidic preconditioning. The acidic conditioning also reduced the kinetic rate—the time necessary to reach equilibrium increased up to threefold depending on the experimental conditions. The size of sorbent particles influenced sorption kinetics and equilibrium because of resistance to intraparticle diffusion, but the sorption appeared to occur not only at the surface of the sorbent but also in the intraparticle network of the polymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1073–1080, 2003     

Vortices in anisotropic type-II superconductors

We present a generalized variational model of an isolated vortex, valid in the anisotropic case when the external magnetic field is along one of the symmetry directions. We discuss the effects of the field anisotropy on the core and magnetic pinning of individual vortices.     

Tourism‐related waterfront development in historic cities: Malta's Cottonera Project

The emergence of new tourism‐related land uses within historic port cities has brought a range of physical, economic and social benefits. However, there are often associated tensions between the need for economic development and the need to maintain the unique heritage resource that may be a large part of the attraction for visitors. The case of Malta's Cottonera Project—for the waterfront of part of the historic ‘Grand Harbour’—throws these tensions into sharp relief; indeed, the controversy generated by the proposal led to a successful vote of no confidence in the Maltese government. The case illustrates the problematic role of the spatial planning system in seeking to mediate between interests with opposing aims in historic port cities, and the need to apply principles of sustainable regeneration.     

High-performance liquid chromatography of human milk triacylglycerols and gas chromatography of component fatty acids

Human milk triacylglycerols were separated by high-performance liquid chromatography. A 5-μ Supelcosil LC-18 column (Supelco, Inc., Bellefonte, PA) was used with acetone/acetonitrile (64∶36, vol/vol) as mobile phase. Triacylglycerols were tentatively identified based on theoretical carbon number and relative retention time. Despite changes resulting from dietary fat variation, the major component triacylglycerols were those composed of palmitic, oleic and linoleic acids. Triacylglycerols with palmitic, stearic and oleic acids were present as minor components. Fatty acids were quantified by gas chromatography relative to an internal standard. Ratios of n−6/n−3 fatty acids were found to be high than previously reported. Based on a paper presented at the Symposium on Milk Lipids held at the AOCS Annual Meeting, Baltimore, MD, April 1990.     

A new minimum zone method for evaluating flatness errors

A new minimum zone method for flatnes error analyis is proposed in this article. Based on the criteria for the minimum zone solution and strict rules for data exchange, a simple and rapid algorithm, called the control plane rotation scheme, is developed for the flatness analysis of a flat surface. Experimental work was performed, and some examples are given in terms of the minimum zone and least-squares solutions.