بزرگترین منبع مقالات فارسی و انگلیسی
جمعه 25 بهمن 1387
جمعه 25 بهمن 1387
Active File Recovery is a simple easy to use, yet powerful tool for recovering files and folders that have been lost or deleted from your Windows system. It allows you to recover data after formatting or loss of partitions. Active File Recovery will also undelete files that have been lost by damage, virus or directory destruction.
Active File Recovery can be installed on and run from a floppy disk, so that the risk of overwriting your data is minimized.
Active File Recovery Professional is an enhanced version of Active File Recovery software that includes Active@ Partition Recovery for Windows that can detect and restore accidentally deleted partitions (volumes, drives) on Hard Disk Drives, external USB drives, and memory cards (SunDisk, MemoryStick, CompactFlash, etc...)
Active File Recovery will help you to restore data residing on hard drives or floppy drives formatted in any of the following file systems:
NTFS + EFS
Active File Recovery supports for:
All types of hard drives: IDE, ATA, SCSI and floppy disks
Removable devices (CompactFlash, SmartMedia, Secure Digital / MultiMediaCard, Sony Memory Sticks etc. ...)
Large sized drives (more than 8 GB)
Long file names and local language (non-English) file names
Recovery of compressed, encrypted (EFS) and fragmented files on NTFS
Detection and recovery from deleted or damaged file partitions
Exact file name or partial file name search
Disk Image creation and restoring (restores from a backup file that represents a drive)
جمعه 25 بهمن 1387
Acronis True Image Home 2009 complete PC protection: back up your entire PC, including the OS plus your data, applications, pictures, video, financial documents, settings and everything!
Acronis True Image Home 2009 is an award-winning backup and recovery solution for a good reason: it protects your PC after just one click and allows you to recover from viruses, unstable software downloads, and failed hard drives. Create an exact copy of your PC and restore it from a major failure in minutes, or back up important files and recover them even faster.
* New!One-click™ protection
Initially, you decide what, where and when to back up. After that, backups occur automatically or with just one click.
* New! Full text search
You will be able to search for files through multiple archives by name or by a part of the name and then restore individual files easily and quickly. You can also perform searches of the files content.
* New! Zip archive format support available
In addition to Acronis' powerful TIB data compression backup format, one of the most densely compressed backup file types available to consumers, Acronis True Image Home 2009 also supports the popular ZIP® format.
* New! Windows Vista® -style interface
The new, sleek interface of this product works on Microsoft® Windows XP and Vista operating systems.
* New! Auto backup based on destination availability
Users can decide to back up automatically or as soon as a destination drive is available. Works jointly with existing scheduling.
* New! Automatic computer shutdown after backup or restoration finishes
You can now perform a backup at night and go to sleep without bothering about turning off the computer. The PC will shut down when the back up is complete.
* New! Archive to various places
You can save full, incremental and differential backups almost anywhere. You now you have ultimate flexibility in choosing a place to store from the same data series: on a network share, CD/DVD, USB stick, FTP-server, any local internal or external hard drive. You can now also give meaningful names to incremental and differential backups, for example, "C-drive-before-repartitioning".
* Making reserve copies of your backups
You can make reserve copies of your backups and save them on a network drive, or a USB storage device. You have a choice of making a reserve copy as regular (flat) files, a zip compressed file, and a tib file.
You can define rules for consolidating your archives to reduce storage space. Merge an older full backup with several incremental backups to quickly create a new full backup; subsequent backups are based on the newly-created full backup.
* Exclude Files and Folders
Back up only the data you want to keep and save disk space.
* Migration tools
Make upgrades easier with built-in PC cloning and migration tools.
* Migration tools make upgrades easier
PC cloning or adding a new disk is simple with Acronis True Image Home 2009's built-in migration tools. No longer must you reinstall the operating system, applications, or re-key user settings when you clone your PC or increase its storage capacity.
* Security, performance and privacy tools
When you replace a hard drive on your PC, Acronis ensures you don't inadvertently give personal or organizational data to cyber thieves. Acronis Drive Cleanser, a $50 value is included at no charge. It protects sensitive data from view by wiping a disk clean of all data. If you don't need to erase the entire disk, File Shredder safely destroys individual files so they can't be resurrected. A System clean-up utility restores system efficiency.
جمعه 25 بهمن 1387
Acronis Disk Director Suite 10.0 is a comprehensive workstation partition and disk management suite that combines a number of previous Acronis products into one solution:
• Create individual partitions for your system and your data using Acronis Disk Director Suite.
• Image your system partition using Acronis True Image only before applying system changes, such as installing new software and the like.
• And make scheduled data backups from your data partition by selecting specific files you need to backup.
• Thus, using the combination of two great Acronis products you will always have an image of your system and backup of your data. This will greatly save you time and reduce your storage requirements.
Acronis Disk Director Suite 10.0 adds new key features making it easier than ever before to modify your partition structure and boot new operating systems.
• New! Split partitions — Split one partition into two and leave your data intact
• New! Merge partitions — Merge two partitions into one and leave your data untouched, even if file systems on the partitions are different
• New! Explore partitions — Windows-like explorer interface to view partition data before performing partitioning operations
• New! Boot from an additional hard disk drive — Select the hard disk drive you want to boot from
• New! Boot from CD/DVD — Insert a bootable CD/DVD and it will automatically be detected and displayed as a boot option by Acronis OS Selector
• New! Automatic operating system detection — Detect operating systems that became unbootable due to some accidental reasons with the Acronis OS Selector detection tool
جمعه 25 بهمن 1387
پنجشنبه 24 بهمن 1387
M. Hessaby, University of Tehran
The difficulties with which the concept of point-like particles is beset, such as the infinities encountered in the existing theories of elementary particles, suggest a different approach to the study of these particles. Instead of restricting ourselves to the concept of point-like particles, we should extend our investigation to the implications of the concept of particles having infinite extension. Such a particle should consist of a continuous distribution of energy over all space, the energy density tending to zero at infinity.
To achieve this aim, we introduce into the theory of general relativity the postulate that the gravitational, electric and nuclear fields are special cases of a more general field. An expression is obtained for the gravitational potential which differs from the usual expression of the potential accepted in general relativity, and which gives an energy density for the particle at every point of space, the integral of which over all space is equal to the mass of the particle, the greatest part of the mass being concentrated near the center of the spherical pattern constituting the particle.
The particle is thus seen to consist of the energy of its field. No infinities are encountered in the integration's. The same result is obtained for a charged particle.
The charge density is spread out over all space and the integrals of the charge density and energy density are respectively equal to the charge and mass of the particle. The electric potential thus obtained is inserted in Diary's wave equation, and gives a sales of equations of increasing degree, the first of which gives the mass of the muon.In addition to the expressions obtained for the electric and gravitational potentials, an expression is found for a potential which has the form of a dipole potential.
When inserted in Dirac's wave equation, this potential gives the values of the masses of baryons. When inserted in the Klein-Gordon equation, this potential gives the values of the masses of mesons.
دوشنبه 21 بهمن 1387
The Milky Way is the galaxy which is the home of our Solar System together with at least 200 billion other stars (more recent estimates have given numbers around 400 billion) and their planets, and thousands of clusters and nebulae including at least almost all objects of Messier's catalog which are not galaxies on their own (the only possible exception may be M54 which may belong to SagDEG, a small galaxy which is currently in a close encounter with the Milky Way, and thus our closest known intergalactic neighbor).
As a galaxy, the Milky Way is actually a giant, as its mass is probably between 750 billion and one trillion solar masses, and its diameter is about 100,000 light years. Radio astronomial investigations of the distribution of hydrogen clouds have revealed that the Milky Way is a spiral galaxy of Hubble type Sb or Sc. Therefore, out galaxy has both a pronounced disk component exhibiting a spiral structure, and a prominent nuclear reagion which is part of a notable bulge/halo component. It is still not clear if it has a bar structure (so that it would be type SB) or not , but an increasing number of investigations
has given some evidence for this, so that the Milky Way may look like M61 or M83, and is perhaps best classified as SABbc ?
The Milky Way Galaxy belongs to the Local Group, a smaller group of 3 large and over 30 small galaxies,
and is the second largest (after the Andromeda Galaxy M31) but perhaps the most massive member of this group. M31, at about 2.9 million light years, is the nearest large galaxy, but a number of faint galaxies are much closer: Many of the dwarf Local Group members are satellites or companions of the Milky Way. The closest of all is above-mentioned SagDEG at about 80,000 light years from us and some 50,000 light years from the Galactic Center, followed by the more conspicuous Large and Small Magellanic Cloud at 179,000 and 210,000 light years, respectively.
The spiral arms of our Milky Way contain interstellar matter, diffuse nebulae, and young stars and open star clusters emerging from this matter. On the other hand, the bulge component consists of old stars and contains the globular star clusters; our galaxy has probably about 200 globulars, of which we know about 150. These globular clusters are strongly concentrated toward the Galactic Center: From their apparent distribution in the sky, Harlow Shapley has concluded that this center of the Milky Way lies at a considerable distance (which he overestimated) in the direction of Sagittarius and not rather close to us, as had been thought previously.
Our solar system is thus situated within the outer regions of this galaxy, well within the disk and only about 20 light years above the equatorial symmetry plane but about 28,000 light years from the Galactic Center. Therefore, the Milky Way shows up as luminous band spanning all around the sky along this symmetry plane, which is also called the "Galactic Equator". Its center lies in the direction of the constellation Sagittarius, but very close to the border of both neighbor constellations Scorpius and Ophiuchus. The distance of 28,000 light years has recently (1997) been confirmed by the data of ESA's astrometric satellite Hipparcos. Other investigations published consequently have disputed this value and propose a smaller value of some 25,000 light years, based on stellar dynamics; a recent investigation (McNamara et.al 2000, based on RR Lyrae variables) yields roughly 26,000 light years. These data, if of significance, wouldn't immediately effect values for distances of particular objects in the Milky Way or beyond.
The solar system is situated within a smaller spiral arm, called the Local or Orion Arm, which is merely connection between the inner and outer next more massive arms, the Sagittarius Arm and the Perseus Arm.
Similar to other galaxies, there occur supernovae in the Milky Way at irregular intervals of time. If they are not too heavily obscurred by interstellar matter, they can be, and have been seen as spectacular events from Earth. Unfortunately, none has yet appeared since the invention of the telescope (the last well observed supernova was studied by Johannes Kepler in 1604).
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