String Type Research Articles

Study on the Influencing Factors of Insulator on the Back-Flashover Lightning Withstand Performance of ±800 kV UHVDC Transmission Lines

The current research results indicate that the insulator’s insulation performance has a very important influence on the back-flashover lightning withstand performance of UHVDC transmission lines, especially for ±800 kV voltage level. However, it is not clear which factors will influence the insulation performance of the insulator, and the influencing mechanism is also not clear yet. To figure out this problem, the insulator’s insulation performance under different conditions has been deeply analyzed and considered to reveal the influence mechanism in this paper, such as the surface hydrophobicity, pollution degree, and the string type. Firstly, the insulator’s model is established using COMSOL software, and the lightning impulse voltage of insulator is calculated and verified with the corresponding experimental data. Then, the ±800 kV UHVDC transmission lines model is constructed using PSCAD software, and back-flashover lightning withstand level and back-flashover rate are calculated by considering the above lightning impulse voltage as the threshold of flashover. Finally, the back-flashover lightning withstand performance of ±800 kV UHVDC transmission lines is deeply analyzed based on different insulators. The simulation results demonstrate that the back-flashover lightning withstand performance of ±800 kV UHVDC transmission lines is obviously weakened with the increase of the pollution degree and slightly weakened with the decrease of the surface hydrophobicity. Considering the same pollution degree, the V-type string insulator has the least influence, while the II-type string insulator has the greatest influences on the back-flashover lightning withstand performance of ±800 kV UHVDC transmission lines. The research results are beneficial for providing theoretical basis for stable operation and reliable power supply of ±800 kV UHVDC transmission lines.

Temporal Profiles of Neuroimaging Features of Non-haemorrhagic and Non-ischemic Vertebral Artery Dissections for Conservative Treatment

Most patients with non-hemorrhagic and non-ischemic vertebral artery dissections(VADs)are likely to recover with good outcomes. In contrast, some cases of uneventful outcomes have also been reported. Therefore, whether surgical treatment or prolonged follow-up should be utilized for each case remains controversial. In this study, we retrospectively investigated the radiological features and changes in non-hemorrhagic and non-ischemic VADs during the follow-up period. We reviewed the medical records of 15 consecutive patients with VADs without hemorrhage or ischemic lesions diagnosed between 2008 and 2017; all patients reported severe occipital headache. All hemorrhagic and ischemic lesions were categorized into morphological types according to the initial radiological findings. The following morphological types of dissections were observed: six cases, pearl and string type; six cases, dilatation type; two cases, stenosis type; and one case, occlusion type. We observed morphological aggravation in four cases, and among them, three underwent surgical interventions. Seven patients recovered during the follow-up period, and five of them showed marked radiological changes within 2 months. One patient died fromethe clinical onset. Therefore, careful follow-up radiological imaging is presumably necessary for patients with non-hemorrhagic and non-ischemic VADs, within at least 2 months of the clinical onset because of the tendency of VADs for rapid morphological changes during that period.

Generalized Gibbs Ensemble and string-charge relations in nested Bethe Ansatz

The non-equilibrium steady states of integrable models are believed to be described by the Generalized Gibbs Ensemble (GGE), which involves all local and quasi-local conserved charges of the model. In this work we investigate integrable lattice models solvable by the nested Bethe Ansatz, with group symmetry SU(N)SU(N), N\ge 3N≥3. In these models the Bethe Ansatz involves various types of Bethe rapidities corresponding to the “nesting” procedure, describing the internal degrees of freedom for the excitations. We show that a complete set of charges for the GGE can be obtained from the known fusion hierarchy of transfer matrices. The resulting charges are quasi-local in a certain regime in rapidity space, and they completely fix the rapidity distributions of each string type from each nesting level.

SYNTHESIS OF QUASI BAND LADDER TRANSFORMING HIGH ORDER FILTERS

The purpose of the work, the results of which are presented in the article, was to develop a computerized mathematical model of the ladder filter to study the features of the synthesis of matching chains of any order on its basis. To achieve this goal, all the synthesis tasks were solved, including the choice of the prototype, frequency transposition, calculation of the poles of the transfer function of the prototype, calculation of the poles of the transfer function of the filter, calculation of the reflection coefficient of the filter, the calculation of the input resistance of the filter, the implementation of the ladder chain by the Cauer method and denormalization of the values of the elements of the ladder chain. Modeling of characteristics of ladder filters of any high order with frequency characteristic of Chebyshev on the computer with 32-bit operating system is carried out. It is shown that the use of standard mathematics leads to a significant increase in the error of matching of loads at increasing the order of the chain. To increase the accuracy of calculations it is proposed to use software that allows implementing mathematical operations on variables with any length of the mantissa. There are computer libraries where numbers are presented in the form of string type variables and arithmetic operations are carried out on them according to school rules “ in a column ” . Once the calculations are completed, the strings are converted back to normal numbers. The article considers the application of the variant of BigNumber library for high level JavaScript language. To estimate the accuracy of the calculation it is proposed to apply the property of antimetric ladder structure. From the presented results of the calculation it follows that in order to obtain not less than 15 reliable digits after the decimal point for the parameters of the n-th order filter it is necessary to increase the length of the variable mantissa to the value 2n.

An occasional ornament, part of clothes or just a gift for ancestors? The results of traceological studies of teeth pendants from the Subneolithic sites in Šventoji, Lithuania

This article presents the results of a zooarchaeological, technological and functional analysis of a collection of animal tooth pendants from the Subneolithic sites in Šventoji, Lithuania. The technological research carried out on the artefacts showed minimal interference in the material and the use of three basic techniques for drilling the holes. Traseological research of the use-wear traces legible on the pendants established a long period of use and was a premise for making inferences on the likely differences in their way of use. These inferences were tested with an experimental programme testing different ways of wearing pendants and with different types of strings. The article also presents the results of the analysis of the spatial distribution of pendants of different types at the site Šventoji 23. The discussion compares the results of the analyses carried out with the results of studies of other European collections of animal tooth pendants of similar chronology.

Evaluation of microplastics in beach sediments along the coast of Dubai, UAE

Microplastic contamination in beach sediments along coast of Dubai is un-documented. In this study, microplastic contamination in beach sediments collected from the wrack lines of 16 beaches in Dubai was evaluated. Five samples were collected from each beach along a 100 m stretch using a 0.5 m by 0.5 m, quadrant. The number, color, and shape of microplastics were documented. The polymer types of large fibers and strings were identified through FT-IR analysis. 480 microplastics from each of the 16 beaches were selected to detect heavy metals using XRF analysis. The results showed that the average weight of microplastic is 0.33 mg per gram of dry sediment (or 953 mg·m−2) and the number of microplastic is 59.71 items per kg of dry sediment (or 165 items·m−2). Blue and fibrous microplastics were dominant. Polyethylene strings and fibers were abundantly found. 13 heavy metals were identified of which five are priority pollutants.

Design of air-cooled waste heat removal system with string type direct contact heat exchanger and investigation of oil film instability

Abstract A new air-cooled waste heat removal system with a direct contact heat exchanger was designed for SMRs requiring 200 MW of waste heat removal. Conventional air-cooled systems use fin structure causing high thermal resistance; therefore, a large cooling tower is required. The new design replaces the fin structure with a vertical string type direct contact heat exchanger which has the most effective performance among tested heat exchangers in a previous study. The design results showed that the new system requires a cooling tower 50% smaller than that of the conventional system. However, droplet formation on a falling film along a string caused by Rayleigh-Plateau instability decreases heat removal performance of the new system. Analysis of Rayleigh-Plateau instability considering drag force on the falling film surface was developed. The analysis results showed that the instability can be prevented by providing thick string. The instability is prevented when the string radius exceeds the capillary length of liquid by a factor of 0.257 under stagnant air and 0.260 under 5 m/s air velocity.

Comparison study of Fibonacci code algorithm and Even-Rodeh algorithm for data compression

The need for greater storage capacity is the cause of various compression techniques. By compressing, large data will be reduced in size to save storage capacity. This research will use Even-Rodeh code algorithm and Fibonacci code algorithm to compress the data. The performance of algorithms will be measured by Bitrate, Compression Ratio, Space Saving, and Compression Time (millisecond) and Time Decompression (millisecond). Compression is done by reading String in the text file, then Even-Rodeh Code algorithm and Fibonacci code algorithm create String code and perform compression process. The result of compression is the file with extension *. C and *. Fib which contains character information and String Bit. The results of compression can be decompressed to the original text file. The system test used a sample of Strings consisting of one type of character (Homogen String) and String comprising more than one kind of character (Heterogenous String) is stored in the text file by extension * .doc, * .docx, * .pdf. From the compression process on the homogenous String, the Fibonacci code algorithm is more efficient about the compression ratio of 0.25 and decompression time is 0.011 milliseconds compared with the Even-Rodeh code algorithm. While in the compression process on heterogeneous String Fibonacci Code algorithm is better than the Even-Rodeh code algorithm with an average Compression Ratio of 0.65 and decompression time faster with an average of 0.293 milliseconds.

Model for data codification in hierarchical classifications with application to the biodiversity domain

The conception and treatment of complex classifications or typologies (as hierarchical tables), mainly of nature components, has for long constituted a major concern for researchers. Hence, several codification methods were developed in order to address and facilitate the management of such tables. Most of these methods uses alphanumeric codes, that remain specific to each case (type of entity), in the sense that their transposition to other cases is rarely feasible.This article proposes a new standardized codification method, applicable to various hierarchical schemas. Implemented in the development of a complex system of biodiversity data management, this method consists in creating for each table a fixed number of levels, coded using the same type of strings, based on ’numeric characters’.This method makes it possible to manage different tables with the same module and facilitates the automatic incrementation and updating of the code (=position). The new model has the advantage of offering possibilities to generate, update or delete a code, without disrupting the codes of the other elements, in addition to the gain in response time of the requests. It gives hope that in some cases (as geo-databases) to merge different tables whose merger was not previously obvious.

Visual Search for Letters in the Right Versus Left Visual Hemifields.

The current study investigated the relationships between attention, word processing, and visual field asymmetries. There is a discussion on whether each brain hemisphere possesses its own attentional resources and on how attention allocation depends on hemispheric lateralization of functions. We used stimuli with lateralized processing in an attentional task presented across the two visual hemifields. Three experiments investigated the visual search for a prespecified letter in displays containing words or nonwords, placed left and right to fixation, with a variable target letter position within the strings. In Experiment 1, two letter strings of the same type (words or nonwords) were presented to both visual hemifields. In Experiment 2, there was only one letter string presented right or left to fixation. In Experiment 3, two letter strings of different type were presented to both hemifields. Response times and accuracy data were collected. The results of Experiment 1 provide evidence for letter-by-letter search within a word in the left visual field (LVF), within a nonword in the right visual field (RVF), and for position-independent access to letters within a nonword in LVF and within a word in RVF. Experiment 3 produced similar results except for letter-by-letter search within words in RVF. In Experiment 2, for all types of letter strings in both hemifields, we observed the same letter-by-letter search. These results demonstrate that presence of stimuli in both one or two hemifields and the readiness to process a certain string type might contribute to the search for a letter within a letter string.

Magnetic quivers, Higgs branches and 6d mathcal{N} = left(1,kern0.5em 0right) theories

The physics of M5 branes placed near an M9 plane on an A-type ALE singularity exhibits a variety of phenomena that introduce additional massless degrees of freedom. There are tensionless strings whenever two M5 branes coincide or whenever an M5 brane approaches the M9 plane. These systems do not admit a low-energy Lagrangian description so new techniques are desirable to shed light on the physics of these phenomena. The 6-dimensional mathcal{N} = left(1,kern0.5em 0right) world-volume theory on the M5 branes is composed of massless vector, tensor, and hyper multiplets, and has two branches of the vacuum moduli space where either the scalar fields in the tensor or hyper multiplets receive vacuum expectation values. Focusing on the Higgs branch of the low-energy theory, previous works suggest the conjecture that a new Higgs branch arises whenever a BPS-string becomes tensionless. Consequently, a single theory admits a multitude of Higgs branches depending on the types of tensionless strings in the spectrum. The two main phenomena discrete gauging and small E8instanton transition can be treated in a concise and effective manner by means of Coulomb branches of 3-dimensional mathcal{N} = 4 gauge theories. In this paper, a formalism is introduced that allows to derive a novel object from a brane configuration, called the magnetic quiver. The main features are as follows: (i) the 3d Coulomb branch of the magnetic quiver yields the Higgs branch of the 6d system, (ii) all discrete gauging and E8 instanton transitions have an explicit brane realisation, and (iii) exceptional symmetries arise directly from brane configurations. The formalism facilitates the description of Higgs branches at finite and infinite gauge coupling as spaces of dressed monopole operators.

SPSR-FSPG: A Fast Simulative Password Set Generation Algorithm

Identity authentication is a main line of defense for network security, and passwords have long been the mainstream of identity authentication. In the field of password security research, large-scale password datasets have played an important role in the efficiency evaluation of password attack algorithms, the feasibility detection of password strength meters, and the correction of password probability models. However, due to user privacy, timeliness, effectiveness and other factors, it is still very difficult for researchers to obtain real large-scale user plaintext passwords. Based on this, this paper proposes a fast simulative password set generation algorithm based on structure partitioning and string recombination, denoted as SPSR-FSPG. The algorithm uses the probability context-free grammar to model the structure of the password, and constructs a string generation model based on the recurrent neural network to generate different types of strings, so as to learn the character composition of the password in the original dataset. In addition, the model fully considers the user's password reuse and modification behavior. Finally, the method is verified by experiment on six real Chinese and English password sets. The results show that the generation rate of SPSR-FSPG is faster than other algorithms. In terms of true password coverage, the SPSR-FPSG simulative password set is increased by 11.36% and 17.5, respectively, relative to SPPG and PCFG, and is increased by about 122.73% and 130.3%, respectively, compared to OMEN and 4-Markov. And the fit of the Zipf distribution is maintained at a level above 0.95, it is better than 0.9 of SPPG. At the same time, the SPPR-FPSG simulative password set is closer to the real password set in terms of length and character composition.

Strongly intensive observable between multiplicities in two acceptance windows in a string model

The strongly intensive observable between multiplicities in two acceptance windows separated in rapidity and azimuth is calculated in the model with quark-gluon strings acting as sources. The dependence of this observable on the two-particle correlation function of a string, the width of observation windows and the rapidity gap between them is analyzed. In the case with independent identical strings the model calculation confirms the strongly intensive character of this observable: it is independent of both the mean number of string and its fluctuation. For this case the peculiarities of its behaviour for particles with different electric charges are also analyzed. In the case when the string fusion processes are taken into account and a formation of strings of a few different types takes place in a collision, this observable is proved to be equal to a weighted average of its values for different string types. Unfortunately, in this case through the weight factors this observable becomes dependent on collision conditions and, strictly speaking, can not be considered any more as strongly intensive variable. For a comparison the results of the calculation of considered observable with the PYTHIA event generator are also presented.

Formelhaft oder nicht? Die wichtigsten Merkmale der formelhaften Sequenzen

Formulaic sequences constitute a large protection of any discourse and, furthermore, they exist in so many forms that it is difficult to develop an adequate definition of this phenomenon. The term formulaic sequences encompasses verious types of world strings which appear to be stored and retrieved as holistic units from the memory. This article outlines some improtant aspects of formulaic sequences; it also shows the variety of definitions which appear in the research literature, and tries to find some specific criteria by means of which formulaic sequences could be identified in a discourse or a text.

How different strings affect violin qualities

The brand and model of strings used on violins are considered to play a significant role in their playability and sound quality. An experiment was designed to test the perceptual quality of different violin strings. A professional violinist selected two violins, from a set of the same make/model, that had similar sound and playing qualities. Three different types of strings were chosen for this study: Dominant, Kaplan and Pro-Arte strings. Professional and advanced student violinists were invited to play and evaluate the violins. Two violins were both strung with Dominant strings initially (session labelled D1-D2). Subjects rated the difference between the two violins (violin 2 compared to violin 1) according to eight criteria. Then the strings of violin 2 were changed to a different type. Subjects rated the difference between the two violins again. In Oberlin, subjects compared Dominant and Kaplan strings in two sessions (called respectively D1-D2 and D1-K2). In Montreal, subjects compared Dominant, Kaplan and Pro-Arte strings in three trials (D1-D2, D1-K2 and D1-P2). Results showed no significant differences between the experiment conditions in either place except that the brightness difference ratings in D1-D2 were found to be significantly higher than in D1-P2 based on the Montreal results.

In vitro single-cell dissection revealing the interior structure of cable bacteria

Filamentous Desulfobulbaceae bacteria were recently discovered as long-range transporters of electrons from sulfide to oxygen in marine sediments. The long-range electron transfer through these cable bacteria has created considerable interests, but it has also raised many questions, such as what structural basis will be required to enable micrometer-sized cells to build into centimeter-long continuous filaments? Here we dissected cable bacteria cells in vitro by atomic force microscopy and further explored the interior, which is normally hidden behind the outer membrane. Using nanoscale topographical and mechanical maps, different types of bacterial cell-cell junctions and strings along the cable length were identified. More important, these strings were found to be continuous along the bacterial cells passing through the cell-cell junctions. This indicates that the strings serve an important function in maintaining integrity of individual cable bacteria cells as a united filament. Furthermore, ridges in the outer membrane are found to envelop the individual strings at cell-cell junctions, and they are proposed to strengthen the junctions. Finally, we propose a model for the division and growth of the cable bacteria, which illustrate the possible structural requirements for the formation of centimeter-length filaments in the recently discovered cable bacteria.

What makes a word so attractive? Disclosing the urge to read while bisecting.

Expert readers have been repeatedly reported to misperceive the centre of visual stimuli, shifting systematically to the left the bisection of any lines (pseudoneglect) while showing a cross-over effect while bisecting different types of orthographic strings (Arduino etal., 2010, Neuropsychologia, 48, 2140). This difference has been attributed to asymmetrical allocation of attention that visuo-verbal material receives when lexical access occurs (e.g., Fischer, 2004, Cognitive Brain Research, 4, 163). The aim of this study was to further examine which visual features guide recognition of potentially orthographic materials. To disentangle the role of orthography, heterogeneity, and visuo-perceptual discreteness, we presented Italian unimpaired adults with four experiments exploiting the bisection paradigm. The results showed that a cross-over effect emerges in most discrete strings, especially when their internal structure, that is being composed of heterogeneous elements, is suggestive of orthographically relevant material. Interestingly, the cross-over effect systematically characterized the processing of letter strings (Experiment 2) and words (Experiments 3 and 4), whether visually discrete or not. Overall, this pattern of results suggests that neither discreteness nor heterogeneity per se are responsible for activating visual scanning mechanisms implied in text exploration, although both contribute to increasing the chance of a visual stimulus undergoing a perceptual analysis dedicated to pre-lexical processing.

Polymer Flooding Separate Injection and High Efficiency Measurement and Adjustment Technology

Daqing Oilfield is the largest onshore oil field in China. Polymer flooding plays an important role in the development of Daqing oil field, producing more than 10 million tons of oil for 11 consecutive years. If the injection is not carried out separately, polymer solution will advance along the high permeability layer, which will lead to the serious ineffective and low efficiency cycle, and reduce the production degree of the low and medium permeability layers, which will affect the overall development effect of polymer flooding. Therefore, stratified injection must be carried out, and a new type of delamination injection process string should be developed.1 The whole process integrated separate injection column was designed. The throttle element adopted the streamline annular pressure reducer structure. When the polymer solution passed, the molecular chain expanded and contracted, forming the effective throttling pressure difference and the flow rate 70m3/d. The maximum throttling pressure difference can reach 2.5 MPa, which can effectively control the injection amount into the high permeability layer and improve the production degree of the reservoir. The structural design of streamline ring pressure reducer can effectively control the degradation of polymer solution and reduce the viscosity loss rate from 12.3% to 8%, which ensures the maximum economic benefit of injecting polyacrylamide dry powder. The oil displacement effect of polymer solution is improved effectively. Developed a complete set Electric direct and high efficiency measuring and adjusting technology are used in this paper. From the manual to the cable controlled direct reading mechatronics, the injection test is developed from the manual trial to the cable controlled direct reading era. This technique has been applied in 6464 wells in Daqing Oilfield. The success rate of one salvage operation has been raised from 75% to 96.4% and the testing time of the 3-5 interval wells has been reduced from 5.2 days to 2.5 days, and the injection profile has been obviously improved. The effective production thickness ratio is increased from 62.8% to 74.7%, the oil production ratio is increased from 52.1% to 68.7%, and the oil recovery factor is increased by 2 percentage points. It is especially suitable for the old oil field to enter into the high water cut development. Effective technology for further improving oil recovery after stage.

Aspects of using ground and above-ground transport for urban passenger transportation

Abstract A need for having high-speed and cost-effective transportation systems in large cities is substantiated. A potential dramatic decrease in power consumed by public and private transport means in large cities is outlined due to reducing the number of transport means per citizen. It is established that the risk of fatal outcome is much higher for road accidents involving automobiles than for road accidents involving alternative types of transport. Above-ground transport means allowing increasing passenger transportation safety and significantly reducing power consumption are listed as a group of innovative transport technologies. Cable and light-weight overhead road or string types of above-ground transport are distinguished as the most promising. A comparative analysis of transportation systems, most popular in large cities, is given comprising the subway, monorail, high-speed tram, tram, trolleybus, bus, cable car, and string transport, using three technical and economic parameters: costs for the construction of one km of a transportation system line, average speed of transport means and specific reduced power consumption. Specifics in applying light-weight overhead road transport (also referred to as string transport) are outlined. Currently, this type of transport is at the design stage, i.e. it is not as developed as other types of transport featuring greater or lesser implementation degree. According to development engineers, string transport rails will have a bunch of stressed steel wires or carbon fibers in the cross-section. In order to implement the principle of gravity energy recovery, claimed by developers of string transport, anchor supports-stations in string transportation systems should be located at a significant height, thus, increasing construction costs. Average speeds for string transport modules are established based on the gravity energy recovery principle. Graphic images are plotted for transportation system indicators. Potential advantages and disadvantages of cable and string transport are examined. A conclusion is made that, under modern conditions, limited construction of cable and light-weight overhead transportation lines to supplement and duplicate the existing roads in large cities is expedient.

Repairment of skin defects of penetrating palm wound by application of free string-type dorsalis pedis flap and anterior malleolus flap

Objective To investigate the clinical outcome of the feasible method of the free string type dorsalis pedis flap and anterior malleolus flap in the repairement of skin defects caused by penetrating wound of palm. Methods From May, 2011 to January, 2017, the anterior combined ankle flap of the ankle were used to repair skin defects of 16 cases who sutained penetrating wounds of palm. Results All 32 flaps in the 16 cases survived. Follow-up were done from 2 months to 2 years after operation. Bone healing was achieved in all cases. Two-point discrimination recovered to 6-8mm. Total active range of motion of the fingers reached 75% of the normal side. Both appearance and texture of the flaps were good. Both the appearances of the repaired palms and the functional recovery were satisfactory. The function assessment of the hand was excellent in 8 cases, good in 5 cases, fine in 2 cases and poor in 1 case. The eligible rate was 81.25%. Conclusion The anatomy of the dorsalis pedis flap and anterior malleolus flap is rare variant, which facilitate the dissection of the flaps during operation. The repairement of skin defects at two sides, both the palm and the back of hand, can be achieved via one operation. Therefore, the free string type dorsalis pedis flap and anterior malleolus flaps offer an ideal procedure to repair skin defects secondary to penetrating wound of palm. Key words: Anterior malleolus flap; Dorsalis pedis flap; Penetrating wound of palm; Reconstruction