自动删除任意目录下的空文件

本文讨论了VAX计算机系统中无用文件的类型及清理方法，特别讨论了文件长度为来的空文件的删除方法，并提供一个可删除任意指定目标下全部空文件的DCL，命令过程，可以简化系统管理，方便系统管理员和系统操作员。

Jx4层控文件结构设计的研究

对向量测图有关的层控文件间相互关系的研究并与JX4数字摄影工作站相结合得出初步结论,可达到不同的作业单位、人员能够自如的设计符合生产要求的层控文件,减少了不必要的操作,节省了作业时间,提高了生产效益。

Effect of Polyvinylpyrrolidone on the Morphologies of Latex Films and Air Permeability of the Latex Finished Fabrics

Low air permeability is a common problem happening to the coating finished and pigment dyed fabrics.To tackle the problem,styrene and butyl acrylate copolymer latex was prepared and used as substitute for the binder.Then,polyvinylpyrrolidone(PVP)was fed into the latex.It was expected that pores could form in the resulting latex film after being rinsed.The morphologies of the latex films were analysized by scanning electric microscope(SEM).It was found that the continuity of the latex films decreased greatly because of the addition of PVP,leading to the loss of the stress at break of the films.After rinsing with methanol aqueous solution,PVP was easily leached off and(macro)void was formed in the latex films.The size of the void decreased with the increase of the PVP concentration.Then,the latex with and without PVP was used to finish the cotton fabrics and engaged as binder in pigment dyeing.After PVP was rinsed out,the air permeability of the fabrics improved greatly,which recovered to that of the unfinished one.In the meantime,the color fastness to rubbing was little affected.So,the method of PVP addition could be termed as an efficient way to improve the air permeability in coating and dyeing industry.

Approximation Properties For Modified Kantorovich-Type Operators

We introduce a modification of Kantorovich-type operators in polynomial weighted spaces of functions. Then we study some approximation properties of these operators. We give some inequalities for these operators by means of the weighted modulus continuity and also obtain a Voronovskaya-type theorem. Furthermore, in our paper show that the operators give better degree of approximation of functions belonging to weighted spaces than classical Szaisz- Kantorovich operators.

Meaningful String Extraction Based on Clustering for Improving Webpage Classification

Since webpage classification is different from traditional text classification with its irregular words and phrases,massive and unlabeled features,which makes it harder for us to obtain effective feature.To cope with this problem,we propose two scenarios to extract meaningful strings based on document clustering and term clustering with multi-strategies to optimize a Vector Space Model(VSM) in order to improve webpage classification.The results show that document clustering work better than term clustering in coping with document content.However,a better overall performance is obtained by spectral clustering with document clustering.Moreover,owing to image existing in a same webpage with document content,the proposed method is also applied to extract image meaningful terms,and experiment results also show its effectiveness in improving webpage classification.

A new coordination method for multi-robot system

This paper proposes a new coordination method for multi-robot system.The state space for a multi-robot system is constructed according to the task requirements and system characteristics.Reachable statefor the system is constrained by the system s internal and external constraints,under which the task isexecutable if there exists a state transition trajectory from the initial to the goal state in its state space.Ifthe task is realizable,the feasible or the optimal strategy for task execution could then be investigated inthe state space.Otherwise,the task could be modified to be realizable via adjusting system s configura-tions and/or task constraints,which provides critical guidance for system reconstructions.This con-tributes to the designing and planning of the robotic tasks.Experiments of multi-robot formation movementare conducted to show the validity of the proposed method.

Laser Ablation of Silver Artifacts in Vacuum： Solution to Silver Tarnishing Problem

This work is a study of effect of laser ablation in different medium on silver artifacts. The effectiveness of laser ablation cleanness methods was evaluated in air, water and vacuum condition. The samples were subjected to HC1 treatment for several hours to simulate the formation of chloride patina on marine archeological artifacts. Laser ablation removes the patina in all medium, reducing its thickness from 300 to few microns in air and water and eliminating completely the chlorine in vacuum conditions. However, it was observed the formation, during cleanness of a white patina in air and water and an increasing of oxygen amount on surface. This indicate that in ambient reach in oxygen laser ablation favorite the oxygen absorbance on surface and the formation of a thin layer of AgO which dulls the surface. This hypothesis is confirmed by the results of laser ablation in vacuum conditions where surface tarnishing was not observed. So, laser ablation in vacuum condition was indicated as the most effective procedure to clean silver artifacts.

INDEX OF DIRECTION CHANGE OF ZONALLY AVERAGED WIND AND CHANGE OF SEASON

In this paper, a Wind Direction Change Index (WI), which can describe four-dimensional spatiotemporal changes of the atmospheric circulation objectively and quantitatively, is defined to study its evolution and seasonal variation. The first four modes can be obtained by EOF expansion of the zonally averaged WI. The first mode reveals the basic spatial distribution of the annually averaged WI. The second mode reflects the quasi-harmonic parts of the WI deviations. Tropical, subtropical and extratropical monsoon areas can be clearly reflected by this mode. The third mode reflects the non-harmonic parts of the WI deviations. It shows the so-called February reverse in stratospheric atmosphere as well as the asymmetric seasonal changes from spring to fall and from fall to spring due to both the land-sea distribution contrast between the Northern and Southern Hemispheres and the nonlinear effect of atmospheric and ocean fluids. The fourth mode reveals the northward advancing of the global reversed wind fields from spring to summer and their southward withdrawal from summer to autumn.

巧用WIN98

1.防止别人使用你的电脑要防止别人用你的电脑,不妨试试以下方法:用任一编辑软件创建一个空文件,把它命名为WIN.BAT并存放在C盘的根目录下。这样当您启动机器时,系统将自动地直接进入到DOS状态下(而此时要进入到Win98的界面,您只需再键入Win后回车就行了)。再在此基础上改进一下:您可以把C:Windows目录下的Win.com文件重命名为其它,如yourname.com。这样您就可以阻止任何人访问您的Windows系统了,因为只有您一个人知道要在DOS状态下输入yourname.com才能进入Windows。是不是挺有效?

常见影响计算机(初级)考核的误操作

计算机应用能力(初极)考核是由上海首创,很快便被全国许多省、市所仿效。这种形式的计算机考试不同于以往的笔试,它要求考生既有全面的书本知识,还要有娴熟的操作技能,但作为考生,大多数是初学者。

ImgFS： a transparent cryptography for stored images using a filesystem in userspace

Real-time encryption and decryption of digital images stored on end-user devices is a challenging task due to the inherent features of the images. Traditional software encryption applications generally suffered from the expense of user con- venience, performance efficiency, and the level of security provided. To overcome these limitations, the concept of transparent encryption has been proposed. This type of encryption mechanism can be implemented most efficiently with kernel file systems. However, this approach has some disadvantages since developing a new file system and attaching it in the kernel level requires a deep understanding of the kernel internal data structure. A filesystem in userspace （FUSE） can be used to bridge the gap. Never- theless, ctwrent implementations of cryptographic FUSE-based file systems suffered from several weaknesses that make them less than ideal for deployment. This paper describes the design and implementation of ImgFS, a fully transparent cryptographic file system that resides on user space. ImgFS can provide a sophisticated way to access, manage, and monitor all encryption and key management operations for image files stored on the local disk without any interaction from the user. The development of ImgFS has managed to solve weaknesses that have been identified on cryptographic FUSE-based implementations. Experiments were carried out to measure the performance of ImgFS over image files＇ read and write against the cryptographic service, and the results indicated that while ImgFS has managed to provide higher level of security and transparency, its performance was competitive with other established cryptographic FUSE-based schemes of high performance.

Water wettability in nanoconfined environment

Water confined in nanoscale space behaves quite differently from that in the bulk.For example,in biological aquaporins and in carbon nanotubes,the traversing water molecules form a single file configuration.Water would stay in vapor state in extremely hydrophobic narrow nanopores owing to the physicochemical interactions between the water molecules and the surface of the nanopore.A spontaneous wet-dry transition has been identified in both biological and artificial nanopores.The nanopore is either fulfilled with liquid water or completely empty.Based on this mechanism,the wetting and dewetting processes inside nanopores have been further developed into highly efficient nanofluidic gates that can be switched by external stimuli,such as light irradiation,electric potential,temperature,and mechanical pressure.This review briefly covers the recent progress in the special wettability in nanoconfined environment,water transportation through biological or artificial nanochannels,as well as the smart nanofluidic gating system controlled by the water wettability.

Impact of Stagger Angle Nonuniformity on Turbine Aerodynamic Performance

The assembling error may lead to variation in stagger angles,which would affect the aerodynamic performance of the turbine.To investigate this underlying effect,two parallel numerical experiments on two turbines with the same profile,but uniform and nonuniform vane stagger angle respectively,were conducted in both steady and unsteady methods.The results indicate that certain changes in the detailed flow field of the turbine occur when the stagger angles are nonuniform,further,the blade loading distribution of the vane and rotor become markedly different from that in uniform vane stagger angle situation.Then these consequences caused by nonuniformity mentioned above enhance the unsteadiness of the flow,finally,the aerodynamic performance changes dramatically.It also shows that,compared with steady simulation,the unsteady numerical simulation is necessary in this investigation.