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Graphene-based devices have initiated unprecedented breakthrough in nanoelectronics. Due to its intrinsic ultrathin 2-D nature, the unique structural, mechanical, electronic, optical, and magnetic properties of graphene are found to be extremely dependent on its substrate material. For the synthesis of graphene with pretailored features or fabrication of graphene-based device with tunable functionality, understanding of the graphene interfaces with other materials are of pivotal importance. Density-functional theory (DFT) computations have been proved to be a powerful tool in investigating the interface properties of graphene-crystalline solids and to subsequently correlate the experimental findings with underlying mechanisms, as well as to explore their potential applications. This paper presents a comprehensive review on utility of DFT-based analysis for graphene interfaces/heterostructures with other crystalline solid materials including metals, semiconductors, and insulators. DFT computational efforts to choose the appropriate material for substrate catalyst, probe, and electrode in graphene synthesis/graphene-based nanodevice design have been critically reviewed including the investigation of different combination of complex interfaces as well as unconventional materials. Salient features, advantages, and constraints of the approach have also been summarized. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate how Facebook use is leading to negative relationship outcomes such as cheating and breakup by assessing users' perceived relationship qualities. It was hypothesized that Facebook-related conflict will be negatively related with users' relationship length and will also be negatively related with their perceived relationship satisfaction, commitment, and love. Facebook-related conflict further mediates the relationship between relationship length and perceived relationship satisfaction, commitment, and love. Self-report data were gathered from participants (N = 101) in an online survey by employing standard questionnaires. A set of regression and mediation analyses confirmed all the hypotheses of the study. That is, Facebook-related conflict mediates the relationship between relationship length and perceived relationship satisfaction, commitment, and love. Moreover, the magnitude of mediation was highest for relationship satisfaction. Implications for future research and contributions are discussed. [ABSTRACT FROM AUTHOR]

It is our interest to design and develop a high-power pulser system employing an electrical discharge in a spark gap. The type of discharge generates short electric pulses capable of both the characteristics of a fast rise time and a high repetition rate. Such a switch pulser has wide applications in the industry. To generate the electrical discharge in the spark gap in an efficient manner is very important for the switching operation. The regime of the operation utilizes the residual plasma in the interpulse recovery of the spark gap to increase the repetition rate. Therefore, the mechanisms of the discharge in a controlled manner following the electrical breakdown of the spark gap, such as the plasma generation in the spark channel and the dielectric recovery process as well as the residual plasma in the post-spark-discharge period, are of great importance. The understanding of the type of the spark-gap discharge for the switching at a high repetition rate beyond 1 MHz has been the primary goal. The typical voltage and current ratings are below 1 kV and several amperes, respectively. In particular, this paper addresses the optimal set of several parameters, such as the spark-gap geometry, electrode gap distance, gas pressure, and gas type, in conjunction with a unique circuit scheme to drive the discharge in the controlled fashion. [ABSTRACT FROM PUBLISHER]

It is our endeavor to develop switching technology for the breakdown reliability and reproducibility at extremely high voltages above 1 MV. One of the key objectives of the endeavor is to derive precise breakdown criteria for use in high-voltage applications. We have developed empirical criteria by which the breakdown field strength of a high-pressure \SF6-filled spark gap can be computed. The validity of the computed result has been verified with several experimental data from different investigators. The computed result has shown good agreement in an extended range of pd (pressure times gap distance) and field enhancement factor of the spark gap geometry. Furthermore, a spark gap has been designed and constructed with particular intention of generating a high-pulsed-power source in Pohang Accelerator Laboratory. In parallel, field modeling has been performed to verify the appropriate shape of the highly stressed insulator and electrode design in the spark gap and to evaluate their field enhancements. A series of breakdown voltage tests has demonstrated the function of the spark gap switch as intended up to 9 bars of \SF6. Aside from this, the limitation of the switching behavior has been examined with an aim of operating the designed spark gap to its maximum capability. [ABSTRACT FROM PUBLISHER]

It is difficult to predict or measure the breakdown strength of SF6 gas in the high pressure range. Therefore, it is hard to find reference data of the high pressure SF6 gas breakdown strength. This paper attempts to provide empirically a novel criterion for the estimation of SF6 gas breakdown strength in a spark gap switch. For this purpose, J.C. Martin's breakdown field strength of non-uniform gap in air and Kuffel et al's breakdown field strength by exploiting streamer criterion of uniform field in SF6 gas are adopted. The research is made for the empirical method of predicting the high pressure SF6 breakdown strength and compared results have been ascertained with several experimental data from different investigators in a wide range of pd (pressure times distance) and field enhancement factor (FEF). For further confirmation of the empirical approach, we have designed and developed a high pressure spark gap switch to be closely coupled to a high voltage PFN-Marx system. The designed spark gap switch operates above 1 MV. Our tests have verified the prediction of the breakdown strength of the SF6 filled spark gap switch in a pd range of 0.27-1.62 MPa . cm (2.7 to 16.2 bar.cm). [ABSTRACT FROM AUTHOR]

It is difficult to predict or measure the breakdown strength of SF6 gas in the high pressure range. Therefore, it is hard to find reference data of the high pressure SF6 gas breakdown strength. This paper attempts to provide empirically a novel criterion for the estimation of SF6 gas breakdown strength in a spark gap switch. For this purpose, J.C. Martin's breakdown field strength of non-uniform gap in air and Kuffel et al's breakdown field strength by exploiting streamer criterion of uniform field in SF6 gas are adopted. The research is made for the empirical method of predicting the high pressure SF6 breakdown strength and compared results have been ascertained with several experimental data from different investigators in a wide range of pd (pressure times distance) and field enhancement factor (FEF). For further confirmation of the empirical approach, we have designed and developed a high pressure spark gap switch to be closely coupled to a high voltage PFN-Marx system. The designed spark gap switch operates above 1 MV. Our tests have verified the prediction of the breakdown strength of the SF6 filled spark gap switch in a pd range of 0.27-1.62 MPa . cm (2.7 to 16.2 bar.cm). [ABSTRACT FROM AUTHOR]

This paper presents an algebraic testing method for detecting stuck-at faults in the polynomial-basis (PB) bit-parallel (BP) multiplier circuits over GF(2m). The proposed technique derives the test vectors from the expressions of the inner product (IP) variables without any requirement of the ATPG tool. This low- complexity testing method requires (2m + 1) test vectors for detecting single stuck-at faults in the AND part and multiple stuck-at faults in the EXOR part of the multiplier circuits. The test vectors are independent of the multiplier's structure, as proposed in (11), but are dependent on m. For the multiplier circuits, the test set is found to be smaller in size than the ATPG-generated test set. The test set provides 100 percent single stuck-at fault coverage. [ABSTRACT FROM AUTHOR]

In Bangladesh prevalence of kidney diseases is increasing day by day and it was observed that renal medulla is affected less in earlier period of life but in late period it becomes affected more. Moreover renal mass changes with age which affecting the medullary mass and consequently the number of medullary pyramids. So the present study was carried out to evaluate anatomical features of medulla and to count the medullary pyramids with age related changes in the number of the pyramids in Bangladeshi people. Study type: Cross sectional analytical type of study. Place and period of study: Department of Anatomy, Mymensingh Medical College, Mymensingh, Bangladesh from January 2004 to June 2005. Materials and methods: A total of 70 fresh human kidneys of both sexes and sides were collected from the morgue of Mymensingh Medical College at postmortem. The selected cases were between 5 to 60 years of age. The samples were divided into 3 different age groups (A: 05-15 years, B: 16-35 years, C: 36- 60 years) to observe the variations in number of medullary pyramid of kidney in different age groups. Results: Among three groups, highly significant (<0.001) differences were found statistically in the number of medullary pyramid. Conclusion: There were changes in the number of medullary pyramid of kidney in different age groups. [ABSTRACT FROM AUTHOR]

A modular double gap pseudospark discharge based switch has been recently designed and developed for various pulsed power applications. The modular pseudospark geometry has two gaps that are separated by a cavity drift space region. It employs a single trigger unit in the cathode region to initiate discharge for the rapid breakdown of both the gaps. Successful experiments for the double gap pseudospark with typical coaxial arrangement of multichannel discharges were performed. The peak discharge currents at breakdown voltage of about 40 kV were 5 and 10 kA through resistive loads of 5.25 and 2.7 Ω, respectively. The design of the double gap pseudospark along with switching results is presented in this paper. [ABSTRACT FROM AUTHOR]

n optimal implementation of 128-Pt FFT/IFFT for low power IEEE 802.15.3a WPAN using pseudo-parallel datapath structure is presented, where the 128-Pt FFT is devolved into 8-Pt and 16-Pt FFTs and then once again by devolving the 16-Pt FFT into 4×4 and 2×8. We analyze 128-Pt FFT/IFFT architecture for various pseudo-parallel 8-Pt and 16-Pt FFTs and an optimum datapath architecture is explored. It is suggested that there exists an optimum degree of parallelism for the given algorithm. The analysis demonstrated that with a modest increase in area one can achieve significant reduction in power. The proposed architectures complete one parallel-to-parallel (i.e., when all input data are available in parallel and all output data are generated in parallel) 128-point FFT computation in less than 312.5 ns and thereby meet the standard specification. The relative merits and demerits of these architectures have been analyzed from the algorithm as well as implementation point of view. Detailed power analysis of each of the architectures with a different number of data paths at block level is described. We found that from power perspective the architecture with eight datapaths is optimum. The core power consumption with optimum case is 60.6 MW which is only less than half of the latest reported 128-point FFT design in 0.18u technology. Furthermore, a Single Event Upset (SEU) tolerant scheme for registers is also explored. The SEU tolerant scheme will not affect the performance, however, there is an increase power consumption of about 42 percent. Apart from the low power consumption, the advantages of the proposed architectures include reduced hardware complexity, regular data flow and simple counter based control. [ABSTRACT FROM AUTHOR]