Mode Of Scanning Research Articles

Composite scanning mechanism based onan aperiodic optical phased array.

A composite scanning mechanism is proposed based on an aperiodic optical phased array (OPA). The OPA of this scheme has a two-stage scanning mode of sub-aperture multi-beam and single-beam high-resolution scanning. The scanning mode can be adaptively switched according to different environmental conditions. While retaining the advantages of high-speed and multi-target detection of sub-aperture multi-beam steering, a high-resolution scanning of the region of interest is realized. Simultaneously, the array distribution of the phased array is optimized using the adaptive-reference-point-based multi-objective evolutionary algorithm to reduce the grating lobe. The research conducted provides ideas for OPAs in practical applications.

PD-CPS: A practical scheme for detecting covert port scans in high-speed networks

Port scanning is a commonly used technique to discover the vulnerabilities of network systems. Since many existing methods can detect fast port scans effectively, some advanced attackers perform slow port scans to avoid suspicion. Highly covert slow scans can last for tens of days, which poses a great challenge to current intrusion detection methods. In addition, the existing port scanning detection methods are all based on full traffic. They are difficult to apply to high-speed networks due to the huge consumption of computing and storage resources. This paper proposes PD-CPS, which is a Practical scheme for Detecting Covert Port Scans in high-speed networks. Based on the protocol characteristics and the connection mode of port scanning, we construct a traffic feature set that can not only distinguish the specific scan types but also remain valid for the sampled traffic. Furthermore, we customize a data structure Scan Detection Sketch (SDS) for rapid feature extraction. Experimental results using real-world traces demonstrate the feasibility of PD-CPS in detection accuracy and resource consumption. And the proposed method still works well for slow port scans that last for over 60 days.

Preliminary Study on Automatic Detection of Hard Defects in Integrated Circuits Based on Thermal Laser Stimulation

Locating the fault position is a crucial part of the failure mechanism analysis of integrated circuits. This paper proposes a hard defect locating system based on Thermal Laser Stimulation (TLS) technology. The equation for laser-induced changes in the electrical parameters of semiconductor devices is a good guide to the hardware and software design of the hard defect locating system. The scanning mode of fast total scanning combined with slow point-to-point scanning can quickly locate abnormal areas. A modified median absolute difference (MAD) method is applied to the extraction of anomalous data. The system software can automatically and collaboratively control the 3D mobile station, laser, and signal acquisition unit. It also can intuitively display the distribution of abnormal points on the infrared image. Using a failure MRAM chip and a good one to conduct a comparative test, the abnormal points distributed on the infrared image of the chip indicate that the failure area is in the digital module or eFuse module of the chip, and the Emission Microscopy (EMMI) experiment also verifies the accuracy of the test system.

Processes of ablation and structures growth under the action of femtosecond laser pulses on the gallium surface in an ammonia medium

In this paper, we present the results of processing metallic gallium in an ammonia vapor medium at 2 bar pressure by femtosecond laser pulses. The influence of the ammonia concentration and the mode of laser beam scanning on the result of laser action is considered. It has been established that an increase in the concentration of ammonia vapor and a change in the scanning regime lead to a radical change in the laser ablation process. A decrease in the scanning speed leads to the cessation of the ablation process and the development of the nitridation process of the gallium surface, accompanied by the formation of columnar structures up to 12 mm long and about 100 μm in diameter. The synthesized nanoparticles and structures were studied using scanning electron microscopy, Raman spectroscopy, and X-ray analysis. Keywords: laser ablation, gallium nitride, gallium nitride nanoparticles manufacturing, ablative synthesis of gallium nitride nanoparticles.

Процессы абляции и роста структур при воздействии фемтосекундных лазерных импульсов на поверхность галлия в среде аммиака

In this paper, we present the results of processing metallic gallium in an ammonia vapor medium at 2 bar pressure by femtosecond laser pulses. The influence of the ammonia concentration and the mode of laser beam scanning on the result of laser action is considered. It has been established that an increase in the concentration of ammonia vapor and a change in the scanning regime lead to a radical change in the laser ablation process. A decrease in the scanning speed leads to the cessation of the ablation process and the development of the nitridation process of the gallium surface, accompanied by the formation of columnar structures up to 12 mm long and about 100 μm in diameter. The synthesized nanoparticles and structures were studied using scanning electron microscopy, Raman spectroscopy, and X-ray analysis.

Justification of electromagnetic scanning of oil-filled formation using downhole matrix antenna arrays

An overview of methods for mapping disturbances in a rock mass is given on the example of determining hydraulic fracture systems in an oil-filled formation. Methods of passive and active microseismic monitoring, as well as electromagnetic examining of rock masses for the presence of inhomogeneities in it are considered. A promising option for the development of hydraulic fracture mapping systems is proposed - creation of downhole logging probes representing ground penetrating radars that implement the mode of electrical scanning of the rock mass under study. The calculation of downhole antenna array based on the Butler matrix is performed. The calculated parameters of a phased antenna array with a Butler matrix can be used to design a downhole logging probe for mapping hydraulic fractures, as well as for surveying engineering structures, for example, foundations of buildings.

Linear four-element cylindrical helix antenna array in boreside and scanning radiation modes

A cylindrical equidistant helix antenna has been created. The helix geometry of the antenna determined its central frequency of the operating band, equal to 1 GHz. This frequency corresponds to the maximum spectra of a bipolar voltage pulse with duration of 1 ns. Helixes identical to those of a single antenna were used in horizontal four-element linear arrays. Antenna arrays with different periods of d were studied in the axial mode with simultaneous excitation of elements by a bipolar voltage pulse of 1 ns duration and in the mode of scanning at a fixed angle in the horizontal plane. Experimental measurements were carried out in the frequency and time domains.

Algorithm of ultrasonographic examination of patency of venous stents

Analysed in the article are the results of ultrasonographic examination of patency of venous stents implanted in 86 patients with obstructive lesions of the iliofemoral segment of deep veins. The authors proposed an algorithm of triplex scanning, making it possible to optimize ultrasonographic examination, as well as increasing the accuracy of assessing the state of the stent and patency of the stented segments of veins. The first stage was to examine the state of the stented venous segment in the mode of grey-scale scanning (B-mode), for which purpose the study was performed in the longitudinal and transverse projections. This made it possible to determine the qualitative state of the stent as either presence or absence of its migration and deformation, completeness of expansion, extravasal compression. The second stage was to locate the venous stent in the mode of colour Doppler mapping (CD-mode), thus making it possible to assess stent patency. The third stage was examination in the spectral Doppler mode with the use of the distal compression test. Ultrasonographically detected phasic, respiration-synchronized blood flow with an increase of its linear velocity proximal to the stent in distal compression (positive compression test) is suggestive of no obstructive alterations in the stent's lumen. Determination of the blood flow velocity makes it possible to evaluate the stent patency or stenotic alterations. Monophasic low-velocity blood flow in the ipsilateral common femoral artery may also be indirectly indicative of impaired stent patency (pronounced stenosis, thrombosis, occlusion). The proposed algorithm of ultrasonographic triplex study of patency of venous stents may be used in out-patient conditions repeatedly and safely for the patient.

Capability of doppler ultrasonography in prevention of hemorrhagic complications of prostate biopsy

The article presents the results of a comparative study of the frequency and severity of bleeding after prostate biopsy performed under the control of Doppler mode of vascular scanning and without its use. Compared with the usual mode of ultrasound scanning of the prostate, the use of Doppler imaging mode of intraprostatic vessels reduces the number of hemorrhagic complications of prostate biopsy, which confirms the feasibility of using the Doppler mode when taking biopsy material.

On the Combined Application of Raman Spectroscopy and Photoluminescence Spectroscopy for the Diagnostics of Multilayer Heterostructures

The results of studying GaInAs/GaInP/GaAs photodiode structures grown by metal–organic vapor-phase epitaxy are reported. A procedure for the diagnostics of such multilayer structures is developed. The procedure is based on the application of Raman spectroscopy in combination with photoluminescence spectroscopy in the mode of the lateral scanning of transverse cleavages. The compositions of the GaInAs and GaInP solid solutions are determined.

Influence of single-beam expanding scanning laser circumferential detection system parameters on detection capability

Aiming at the high requirement for pulse-repetition frequency of the existing single-beam synchronous scanning circumferential detection, which is difficult to use practically. The method of single-beam expanding scanning laser circumferential detection is proposed. Based on the principle of single-beam expanding scanning laser circumferential detection, the mode of scanning has an inherent defect of periodic detection blind area in the detection field. The method of one-way spreading laser line beam into fan-shaped beam is proposed. The analytical expression of the lowest scanning frequency and the pulse frequency are derived. Echo characteristics of cylindrical target and the section attenuation coefficient are analyzed. Mathematic model of cylindrical target echo power of pulsed expanding laser beam is established. The mathematical model of section attenuation coefficient of cylindrical object is established, and the variation of the section attenuation coefficient when the center line and the edge of the beam have different positions relative to the cylindrical target is analyzed. The expression of the position having the smallest section attenuation coefficient and the expression of largest angle between the adjacent pulse laser beams are obtained, then the influence of system parameters on the section attenuation coefficient is also discussed. The emphasis is placed on the influence of pulse frequency, beam angle and incidence angle on the ability to detect different diameter targets. As the laser pulse frequency increases, the detectable target diameter is smaller and the detection ability is stronger. Increasing the beam angle and lowering the laser incident angle are beneficial to reducing the minimum laser pulse frequency required to discover the target. The methods of calculating maximum beam angle and minimum pulse frequency under typical conditions of the detection system are presented. When the incident angles are <inline-formula><tex-math id="M1">\begin{document}${\text{π}}/3$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="7-20181860_M1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="7-20181860_M1.png"/></alternatives></inline-formula>, <inline-formula><tex-math id="M2">\begin{document}${\text{π}}/4$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="7-20181860_M2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="7-20181860_M2.png"/></alternatives></inline-formula> and <inline-formula><tex-math id="M3">\begin{document}${\text{π}}/6$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="7-20181860_M3.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="7-20181860_M3.png"/></alternatives></inline-formula>, the maximum beam angle and the lowest pulse frequency are calculated for a cylindrical target with a diameter of 0.18 m at a detection distance of 6 m, the minimum pulse frequency decreases effectively after beam expansion. The results show that the pulse repetition frequency will be effectively reduced by slightly expanding the beam. This study may provide theoretical basis for designing and optimizing the single-beam pulsed laser circumferential detection.

Adaptive possibilities of the cardiovascular system in adolescents with non-inflammatory diseases of the myocardium, taking into account the functioning of the right ventricle of the heart

Adaptation of the cardiovascular system to physical activity implies the development of functional or structural changes that should ensure the most efficient and economical use of energy during muscular contraction. The most studied data reactions in individuals engaged in various sports. The aim of our study was to study the functional changes of the heart, taking into account the functioning of the right and left ventricles of the heart and the adaptive capacity of the cardiovascular system in children with non-inflammatory diseases of the myocardium. Were examined 62 patients with non-inflammatory myocardial diseases, whose mean age was 14.56 ± 0.24 years. The control group consisted of 41 practically healthy peers. The functional state of the myocardium was assessed according to the results of the ultrasonic Doppler study of the heart in the “M” and “B” - modes, as well as in the mode of constant-wave and color scanning with a convex sensor using the standard method. To study tolerance to the minimum physical activity and its influence on the state of the cardiovascular system in children, a six-minute walk test was conducted. To assess the functional intensity of the cardiovascular system before and after the six-minute walk test, the following vegetative indices were calculated: an endurance coefficient according to the formula A. Quaasa and a double product. The vegetative Kerdo index and adaptation potential were calculated at rest. As a result of the study, it was found that in children with myocardial pathology, stress is observed in the adaptation mechanisms of the cardiovascular system, accompanied by a weakening of its functional capabilities and an increase in the work of the cardiac muscle at rest. This happens against the background of a decrease in the functioning of the left ventricle and an increase in the functioning of the right ventricle of the heart. These changes are accompanied by activation of the parasympathetic division of the autonomic nervous system in patients in all the studied groups, which indicates a more economical mode of functioning of the body systems.

Комплексное применение спектроскопии комбинационного рассеяния света и фотолюминесценции для диагностики многослойных гетероструктур

AbstractThe results of studying GaInAs/GaInP/GaAs photodiode structures grown by metal–organic vapor-phase epitaxy are reported. A procedure for the diagnostics of such multilayer structures is developed. The procedure is based on the application of Raman spectroscopy in combination with photoluminescence spectroscopy in the mode of the lateral scanning of transverse cleavages. The compositions of the GaInAs and GaInP solid solutions are determined.

Surgical treatment of gemangioma of the small intestine complicated by recurrent bleedings and blood losses of heavy severity

The frequency of gastrointestinal bleeding in the modern structure of emergency surgical pathology still occupies a leading position. In this case, the predominant localization of sources-the stomach and duodenum, as well as the colon and rectum. The literature describes a few observations of severe life-threatening bleeding from tumours of the small intestine. Hemangioma of the small intestine in the structure of tumours of the gastrointestinal tract occurs only up to 0,3% of cases, which is probably due to its rare complications, in particular - bleeding. Presents a case of rare recurrent bleeding from the small intestine hemangioma into the lumen of the gastrointestinal tract with the development of severe posthemorrhagic anaemia. The features of diagnosis and surgical tactics in these cases are discussed. It was established that the classical standards of examination of the patient with signs of gastrointestinal bleeding will not allow establishing the source in the case of bleeding from the small intestine hemangioma. In this observation, using multiphase computed tomography in the mode of two-energy scanning followed by the construction of iodine maps, it was possible to diagnose the source of bleeding, establish its localization and perform a resection of the affected area of the small intestine.

Determination of N-nitrosodiphenylamine in meat canned food for children by the method of chromato-massspectrometry

This study demonstrates the results obtained from the GC/MS experimental determination of low concentrations of N-nitrosodiphenylamine in meat canned baby food in the concentration range of 0.027-3.89 mg/kg. The perfect conditions of sample preparation (extraction with organic solvent and solid phase extraction) as well as the application of the chromatography-mass spectrometry allowed us to detect N-nitrosodiphenylamine in samples of the meat canned baby food with high selectivity in concentrations ranged from 0.016 to 5 mg/kg when an error of 23% was assumed. The use of the reaction of transesterification of fatty acids by potassium methylate, the removal of the ester generated from the samples of canned meat by organic solvent (hexane), concentrating of N-nitrosodiphenylamine in the aqueous layer on the cartridges of an automatic solid-phase extraction system provided 99.94% extraction of N-nitrosodiphenylamine from the canned meat samples. The experiment has made evident the presence of N-nitrosodiphenylamine in the samples of canned meat (beef + chicken) with the help of mass-spectrometry method in the mode of full ion scanning using the AMDIS automatic mass-spectral identification system.

Welding of Low-Alloy Steels with Fiber Laser in the Mode of Beam Scanning

Metallographic studies and mechanical tests of welded joints formed by a fiber laser in the mode beam scanning in two passes are performed. The laws of formation of the joint, the process of laser beam welding in the mode of scanning, and the effect of the thermal action of the second welding pass on the metal of the weld are described. The process of laser welding with beam scanning is shown to have advantages.

AFM study of charging of the Au–n-GaAs contact

Effect of charging of structural elements of a metal–semiconductor Au–n-GaAs contact on the behavior of the contact potential difference (CPD) and other properties of the contact is investigated by AFM method. The change of the CPD caused by charging reaches the values of ∼0.5V and depends on the bias value, duration of exposure, scanning speed, and thickness and area of the metal. It is assumed that the above change is mainly due to the accumulation of an induced charge at the metal–semiconductor interface. However, it is not excluded that accumulation of charge occurs also at the grain boundaries of the metal. This is evidenced by the changes in properties of the gold film caused by charging: the rate of the film etching increases. This makes it possible to form a relief on the surface of the metal, which is set by the mode of the probe scanning over the surface of the metal during charging.

Film Thickness of Lithium Battery Fast De-Noising Based on Atomic Sequence Template Library

The natural frequency and scanning vibration frequency of C-dynamic scanning system of laser sensors are acquired for film thickness of lithium battery de-noising based on multi-resolution wavelet algorithm. For this reason, fast de-noising based on atomic sequence template library is present .First, under various mode of scanning, best atomic sequence template is built by sparse decomposition. Secondly, at the given mode, film thickness data is match to the best atomic sequence to de-nosing. Experimental results show that template-matching pursuit(MP) algorithm is effective and algorithm speed is higher than MP 57 times .

The evolution of pediatric tele-echocardiography: 15-year experience of over 10,000 transmissions.

Telemedicine transmission of echocardiograms, either in real-time or using store-and-forward technology, is used to evaluate infants with suspected heart disease. The impact of Internet protocol (IP) technology on telecardiology utilization is unknown. This study evaluated the impact of IP expansion on telecardiology utilization and mode of scanning. The telemedicine database from 1998 to 2012 at our institution was reviewed. Tele-echocardiography transmissions between 1998 to 2012 were identified. IP technology was introduced in 2006. The database was reviewed to compare telecardiology utilization and mode of scanning of transmission (live, store-and-forward, or both). As a secondary aim, indications for telemedicine echocardiograms, outcomes of studies, effectiveness, and efficiency were recorded. Between 1998 and 2012, 11,890 telemedicine transmissions were performed. After IP expansion, telecardiology utilization increased significantly with no adverse effect on efficiency or diagnostic accuracy. IP expansion paralleled a change from live transmissions to store-and-forward transmissions. Abnormalities were detected in over 40% of studies. The average from time of request to completion of teleconsultation was under 30 min. Over 90% of echocardiograms were performed during the videoconference in the first 2 years. This fell to under 60% during the 2 most recent years of the program without impact on accuracy. Use of IP technology at a single center corresponded to a dramatic increase in volume of telemedicine echocardiograms, with no significant differences in efficiency.

Detection of diatoms in water and tissues by combination of microwave digestion, vacuum filtration and scanning electron microscopy

The detection of diatoms has been proposed to be useful in the diagnosis of drowning. In the presented paper, we describe a novel method for qualitative and quantitative analysis of diatoms in water and organs. Samples were treated by microwave digestion. The fluid obtained was vacuum-filtrated; its sediment on the membrane was coated and examined under the scanning electron microscope with the mode of automatic field scanning; and qualitative and quantitative diatom analysis was performed based on the images captured automatically and on manual identification of the suspected diatoms at a required higher magnification. The method is rapid, sensitive, labor-saving, and accurate for qualitative and quantitative diatom analysis. However, further scientific research in the field of automatic diatom identification using SEM images has to be done in order to automate the process of detection and identification of diatoms in water and tissues for the diagnosis of drowning.