Xem 1-20 trên 24 kết quả Probe techniques
  • About 400 years ago, the invention of telescopes and microscopes not only extended our sense of seeing but also revolutionized our perception of the world. Extending this perception further and further has since been the driving force for major scientific developments. Local probe techniques extend our sense of touching into the micro- and nanoworld and in thisway provide complementary newinsight into theseworlds with microscopic techniques.

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  • Advances in nanotechnology over the past decade have made scanning electron microscopy (SEM) an indispensable and powerful tool for analyzing and constructing new nanomaterials. Development of nanomaterials requires advanced techniques and skills to attain higher quality images, understand nanostructures, and improve synthesis strategies. A number of advancements in SEM such as field emission guns, electron back scatter detection (EBSD), and X-ray element mapping have improved nanomaterials analysis.

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  • Progress in modern science is impossible without reliable tools for characterization of structural, physical, and chemical properties of materials and devices at the micro-, nano-, and atomic scale levels. While structural information can be obtained by such established techniques as scanning and transmission electron microscopy, high-resolution examination of local electronic structure, electric potential and chemical functionality is a much more daunting problem.

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  • The invention of scanning tunneling microscope (STM) by Binnig and his colleagues in 1982 opened up the possibility of imaging material surfaces with spatial resolution much superior to the conventional microscopy techniques. The STM is the first instrument capable of directly obtaining three-dimensional images of solid surfaces with atomic resolution. Even though STM is capable of achieving atomic resolution, it can only be used on electrical conductors. This limitation has led to the invention of atomic force microscope (AFM) by Binnig and his co-workers in 1986.

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  • The use of scientific techniques in materials conservation has notably expanded in recent decades. There is much interest in identifying the materials used in culturally important objects. Of great importance is a clear understanding of the state and mechanisms of degradation of objects susceptible to deterioration with time and exposure to environmental factors. An understanding of the state of materials at a molecular level can provide valuable information for conservators, enabling them to decide on a conservation procedure....

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  • An overview of PTB’s activities in the field of dimensional nanometrology using scanning probe microscopes (SPMs) is presented. The chapter is divided into two parts: the development of (1) high-resolution probing systems and (2) complete SPM metrology systems. The subject of SPM-probing system design comprises, among other things, the concept of the “sensor objective” to combine conventional microscopy with scanning probe techniques.

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  • Nanotips have been in increasing demand over the last two decades, owing to their crucial role in the main nanotechnology instruments, like scanning probe microscopes and scanning electron and transmission microscopes. Well-defined ultrasharp tips have also attracted a growing interest in molecular electronics, as they are needed for fabrication and characterization of molecular structures. In this chapter we present several methods that have been explored so far for fabricating such ultrasharp tips, with an emphasis on the most recent technique.

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  • Intrusion detection is not for the faint at heart. But, if you are a network administrator chances are you're under increasing pressure to ensure that mission-critical systems are safe--in fact impenetrable--from malicious code, buffer overflows, stealth port scans, SMB probes, OS fingerprinting attempts, CGI attacks, and other network intruders.

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  • A suite of emerging techniques, known collectively as “molecular imaging,” now offer scientists an unprecedented opportunity to identify, follow, and quantify biologic processes at the cellular level with molecular specificity in intact organisms. For instance, it is now possible to evaluate, with imaging, the distribution, magnitude, and timing of gene expression in genetically altered animals (1–3).

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  • Since the subject of nuclear magnetic resonance (NMR) was awarded its first Nobel Prize in 1952 due to its successful detection by Bloch and Purcell in 1945, the technology and its applications have developed tremendously. The first two decades were focused on technical developments of instrumentation and methodologies to apply to the structure determination of compounds. During the late 1970s, several research groups developed modifications of NMR probes to convert them to an online mode for the analysis of sample mixtures....

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  • Association studies from north India probing multiple loci across the spectrum of candidate cytokine genes are scanty. The present study, therefore, was aimed to bring in focus certain unexplored polymorphisms in the context of tuberculosis susceptibility in north Indian population. The role and importance of genetic background in tuberculosis has now become univocal with ethnicity playing a crucial role. Probing new loci relating to tuberculosis susceptibility could suggest novel approach in pharmacogenomics and therapy to combat this pathogen.

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  • IP Address Scans scan the range of addresses looking for hosts (ping scan) Port Scans scan promising ports for openness (80, 21, …) Service Evaluation determine the OS Target Selection pick the most vulnerable host, most running services... Vulnerability Probes Automated password attacks FTP, HTTP, NetBIOS, VNC PCAnywhere…. Application specific attacks try known vulnerabilities on present services

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  • The efficient engineering of enzymes with novel activities remains an ongoing challenge. Towards this end, genetic selection techniques provide a method for finding rare solutions to catalytic problems that requires only a limited foreknowledge of structure–function relationships. We have used genetic selections to extensively probe the structure and mechanism of chorismate mutases. The insights gained from these investigations will aid future enzyme design efforts.

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  • U.S. Sensor is a world class manufacturer of an extensive variety of the highest quality thermistors as well as thermistor probes and assemblies. The company’s products include NTC and PTC thermistors which are produced using proprietary state of the art processing techniques. Customers worldwide use U.S. Sensor thermistors in their most demanding applications.

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  • Microscopic and imaging techniques: – Optical microscopy – Confocal microscopy – Electron microscopy (SEM and TEM, related methods) – Scanning probe microscopy (STM and AFM, related methods) Surface spectrometric techniques: – X-ray fluorescence (from electron microscopy) – Auger electron spectrometry – X-ray photoelectron spectrometry (XPS/UPS/ESCA)

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  • The idea of using ultrasonic waves in medical and engineering fields came from military applications of sound waves in sonar systems. Sokolov, Firestone, Simons, and several other researchers are among the ones who studied this high frequency kind of wave in the first half of twentieth century. Ultrasonic waves are defined as those with frequencies higher than 20 kHz. The constant development of data acquisition systems and probes seems to work, removing the upper limit of the wave frequency that can be acquired.

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  • The last decade has seen an explosive increase in both the volume and the accuracy of data obtained from cosmological observations. The number of techniques available to probe and cross-check these data has similarly proliferated in recent years.

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  • Applications of FISH The majority of FISH applications involve hybridization of one or two probes of interest as an adjunctive procedure to conventional chromosomal banding techniques. In this regard, FISH can be utilized to identify specific chromosomes, characterize de novo duplications or deletions, and clarify subtle chromosomal rearrangements. Its greatest utilization, however, is in the detection of microdeletions (see below). Though conventional cytogenetic studies can detect some microdeletions, initial detection and/or confirmation with FISH is essential.

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  • Welcome to the second half of the network based intrusion detection tutorial, where we will discuss more advanced analysis techniques based on Indications and Warnings as well as correlation. For every attack that really gets our attention, there are twenty or thirty probes or mapping attempts. Some of the common efforts are DNS zone transfers, DNS queries, SNMP queries, portmapper access attempts, and NetBIOS name lookups.

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  • Additional reduction of the leaflet height could be achieved by folding the leaflet edge toward the ventricle before deploying the U- clip. The remaining loops were distributed at equal distance along the edge of the prolapsed segment by applying the same technique. After the pledget platform was secured, the 2 free suture needles were placed through the anterior prolapse. The correct apposition was confirmed with saline test. The assistan, at the patient side, tied the knots. Annuloplasty was performed at the surgeon's discretion.

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