Effect Of Offset Research Articles

Spectroscopic Investigation of the Effect of Microstructure and Energetic Offset on the Nature of Interfacial Charge Transfer States in Polymer: Fullerene Blends.

Despite performance improvements of organic photovoltaics, the mechanism of photoinduced electron–hole separation at organic donor–acceptor interfaces remains poorly understood. Inconclusive experimental and theoretical results have produced contradictory models for electron–hole separation in which the role of interfacial charge-transfer (CT) states is unclear, with one model identifying them as limiting separation and another as readily dissociating. Here, polymer–fullerene blends with contrasting photocurrent properties and enthalpic offsets driving separation were studied. By modifying composition, film structures were varied from consisting of molecularly mixed polymer–fullerene domains to consisting of both molecularly mixed and fullerene domains. Transient absorption spectroscopy revealed that CT state dissociation generating separated electron–hole pairs is only efficient in the high energy offset blend with fullerene domains. In all other blends (with low offset or predominantly molecularly mixed domains), nanosecond geminate electron–hole recombination is observed revealing the importance of spatially localized electron–hole pairs (bound CT states) in the electron–hole dynamics. A two-dimensional lattice exciton model was used to simulate the excited state spectrum of a model system as a function of microstructure and energy offset. The results could reproduce the main features of experimental electroluminescence spectra indicating that electron–hole pairs become less bound and more spatially separated upon increasing energy offset and fullerene domain density. Differences between electroluminescence and photoluminescence spectra could be explained by CT photoluminescence being dominated by more-bound states, reflecting geminate recombination processes, while CT electroluminescence preferentially probes less-bound CT states that escape geminate recombination. These results suggest that apparently contradictory studies on electron–hole separation can be explained by the presence of both bound and unbound CT states in the same film, as a result of a range of interface structures.

Effect of Frequency Offset on Power Measurement Error in Digital Input Electricity Meters

The realization principle of digital input electricity meters and the present situation of the conventional power algorithm in the field of signal processing are introduced. According to the onsite operating conditions, formulas are derived for changes in active power and reactive power with frequency offset or phase change, aiming at the influence of nonsynchronization sampling created by the frequency offset. The corresponding analysis was simulated. The theory and simulated analysis indicate that the influence caused by frequency offset could cause excessive errors in digital input electricity meters at substation sites. A weighted algorithm is proposed to effectively reduce the influence to a negligible level. Error measurements of the frequency offset in the laboratory verify the analysis results. Finally, rationalization proposals are given for the software algorithm in digital input electricity meters.

A Novel Hybrid Filter-Based PLL to Eliminate Effect of Input Harmonics and DC Offset

Synchronous reference frame phase locked loop (SRF-PLL) is widely used for grid synchronization and control in grid-connected applications. A major problem with SRF-PLL is how to improve its dynamic performance and filtering capability under complex grid conditions such as unbalance, distortion, and dc offset mixing without affecting its phase tracking performance and stability. In order to achieve this goal, a novel second-order generalized integrator (NSOGI) and a modified NSOGI (MNSOGI) with dc offset rejection capability based on NSOGI are proposed, and then, an effective hybrid filter is designed and incorporated into the inner loop of a SRF-PLL. The proposed hybrid filter is a combination of a dual MNSOGI and a moving average filter (MAF), it can block the fundamental frequency negative sequence component, dc offset component, and the rest of harmonic components in the SRF-PLL input three-phase voltages at the same time with a simple complexity. The proposed PLL in this paper has a faster transient response due to reducing the window length of the MAF. A small-signal model of the proposed PLL is derived. The stability is analyzed, and parameters design guidelines are given. The effectiveness of the proposed PLL is confirmed through simulation experimental results.

Theoretical and Experimental Investigations on the Effect of Overlap and Offset on the Design of a Novel Quadrotor Configuration, VOOPS

The theoretical and experimental investigations of a novel configuration for a Vertical Take Off and Landing (VTOL) quadrotor system with a Vertically Offset Overlapped Propulsion System (VOOPS) is presented in this paper. The objective of the VOOPS concept is to improve the load carrying capability of the VTOL system without any increase in the footprint or reduction in endurance. This has been accomplished by overlapping the propeller blades with a vertical offset such that they don’t intersect. This way VOOPS can accommodate a larger propeller size without increase in footprint. The aerodynamics of the overlap and offset on the quadrotor performance has been analyzed using Blade Element and Momentum Theory (BEMT) and a methodology has been proposed to find their effects on thrust, drag, and power. The important design constraints for VOOPS are offset and overlap of the propellers, whose limits are evaluated using the blade-bending profile and the geometry of the propeller, respectively. The mathematical model and the design of a VOOPS quadrotor system is also presented. A quadrotor with VOOPS configuration has been designed and experimental studies have shown that the theoretical results obtained are in good agreement with the experiments. The practical implementation of VOOPS configuration and the consequences of the design changes are also presented.

Influence of Plugging DC Offset Estimation Integrator in Single-Phase EPLL and Alternative Scheme to Eliminate Effect of Input DC Offset and Harmonics

In this paper, the dynamic expressions of the amplitude and frequency estimated by the standard enhanced phase-locked loop (EPLL) and the ones with input dc offset estimation integrator (DCEI) are derived originally and reveal that the DCEI enlarges the amplitude of the periodic ripples caused by the dynamic disturbances and prolongs the dynamic process. To achieve correct estimation when the input signal contains dc offset and harmonics but without deteriorating the dynamic performance, an improved EPLL combined with delayed signal cancellation (DSC) is proposed. A DSC operator is employed to the input of the EPLL to eliminate dc offset and even-order harmonics. A cascaded DSC (CDSC) module is applied in both frequency and amplitude loops to remove the effect of most of the residual odd-order harmonics. The structure of the CDSC module and delay coefficients are designed in detail. Experimental results of all the three PLLs are presented and compared to validate the theoretical analysis results and the proposed EPLL.

Data Tracking and Effect of Frequency Offset to Simultaneous Collecting Method for Wireless Sensor Networks

In the packet access of wireless sensor networks, a distributed access protocol is employed to avoid packet collision but it also causes delay. Therefore, real time data collection is difficult. In wireless communication for simultaneous multidata collection (WC-SDC), sensed data are projected onto the parameters of the wireless communication. The specific feature of the sensed data appears in received signals. Even if the transmitted signal from each sensor collides by simultaneous access, the mixture sensed can be separated by using the specific features. Therefore, the real time data collection is achieved. However, frequency mismatch causes the fluctuation of sensed data, which gives the adverse impact to data separation. In this paper, a data tracking method is used for the data separation in the WC-SDC. We clarify the accuracy of data separation and the impact from the frequency offset. We propose a method for coping with the frequency offset and the error tracking. From the numerical results, our proposed method accurately achieves data separation even under 7% frequency offset normalized by the minimum frequency resolution.

Biologic Width Around Different Implant-Abutment Interface Configurations. A Radiographic Evaluation of the Effect of Horizontal Offset and Concave Abutment Profile in the Canine Mandible

The purpose of this experimental study was to analyze radiographically in a dog model how different implant-abutment interface configurations influence alveolar crestal bone changes. Six different experimental implant-abutment connections were evaluated in six mixed-breed dogs. The following parameters were tested: absence of microgap, microgap proximal to bone crest, and microgap distant from bone crest. In addition, two different cervical abutment profiles, one straight and one featuring a supracrestal concavity, were evaluated. Implants were based on a cylindrical full-body screw design and made from cold-worked grade IV commercially pure titanium. The diameter (at thread tips) measured 4.1 mm, whereas the inner diameter was 3.5 mm. Standardized periapical digital radiographs were obtained for comparative analysis at baseline and at 3, 4, 5, 6, 7, 8, and 9 months after implant placement. Radiographs were randomized and calibrated for linear measurements. For statistical analysis, mixed-model repeated-measures analysis of variance was used. All implants integrated successfully and remained stable during the entire period of the study. Radiographically, when comparing groups with straight profiles, crestal bone remodeling in group C (one-piece design) was significantly less than in group A (matching diameters) and B (nonmatching diameters). In fact, implant group C showed the least crestal bone remodeling of all groups. When comparing groups with a concave profile but different microgap configurations, all three designs demonstrated bone loss with no significant differences among the three groups. A nonsubmerged one-piece implant design demonstrated the least amount of bone remodeling of all groups. Implant-abutment connections with a concave profile established crestal bone levels immediately apical to the concavity regardless of the microgap variable.

Effect of Tool Pin Offset on Mechanical and Metallurgical Properties of Dissimilar FSW Joints of 6061t6 AL Alloy to Copper Material

In the present investigation effect of tool pin offset on mechanical and metallurgical properties of dissimilar FSW joints of 6061T6 Al alloy and Copper material was studied. Keeping other FSW variables constant, tool pin offset was varied from 1mm, 2mm and 3mm.The plunge load value decreases with increase in tool pin offset, because of the tool pin is immersed into soft material (Al), while at lower pin offset the plunge load increased. Tensile Strength (TS) values decreases with increase the tool pin offset. Poor tensile properties were obtained at the very large pin offsets, due to the insufficient reaction between the Cu and Al material. Sufficient reaction was achieved in the FSW Al-Cu joints produced at pin offsets of 1mm and 2mm, resulting in the good tensile properties. The distribution, amount and size of Cu particles strongly depend on tool pin offset. It is observed that content of dispersed particles decreases at larger tool pin offset. When the pin offset was larger, only few Cu pieces with relatively small size were scratched from the Cu bulk. It was easy for the small Cu pieces to mix into the Al base and react with the Al base in the nugget zone, and therefore no proper mixing of Cu with Al matrix. On the other hand, when the pin offset was smaller, more Al-Cu IMCs would be formed because the more Cu pieces were stirred into the nugget zone. Thus the joining between the Al and Cu became poor due to the brittle nature of the IMCs. Research investigation also highlights the fracture location at different tool pin offsets.

Effect of Tool Pin Offset on Mechanical and Metallurgical Properties of Dissimilar FSW Joints of 6061t6 AL Alloy to Copper Material

In the present investigation effect of tool pin offset on mechanical and metallurgical properties of dissimilar FSW joints of 6061T6 Al alloy and Copper material was studied. Keeping other FSW variables constant, tool pin offset was varied from 1mm, 2mm and 3mm.The plunge load value decreases with increase in tool pin offset, because of the tool pin is immersed into soft material (Al), while at lower pin offset the plunge load increased. Tensile Strength (TS) values decreases with increase the tool pin offset. Poor tensile properties were obtained at the very large pin offsets, due to the insufficient reaction between the Cu and Al material. Sufficient reaction was achieved in the FSW Al-Cu joints produced at pin offsets of 1mm and 2mm, resulting in the good tensile properties. The distribution, amount and size of Cu particles strongly depend on tool pin offset. It is observed that content of dispersed particles decreases at larger tool pin offset. When the pin offset was larger, only few Cu pieces with relatively small size were scratched from the Cu bulk. It was easy for the small Cu pieces to mix into the Al base and react with the Al base in the nugget zone, and therefore no proper mixing of Cu with Al matrix. On the other hand, when the pin offset was smaller, more Al-Cu IMCs would be formed because the more Cu pieces were stirred into the nugget zone. Thus the joining between the Al and Cu became poor due to the brittle nature of the IMCs. Research investigation also highlights the fracture location at different tool pin offsets.

Effect of Tool Offset and Tool Rotational Speed on Enhancing Mechanical Property of Al/Mg Dissimilar FSW Joints

Friction stir welding (FSW) is a promising solid-state joining technique for producing effective welds between Al alloy and Mg alloy. However, previously reported Al/Mg dissimilar FSW joints generally have limited strength or barely any ductility with relatively high strength, which was blamed on the brittle intermetallics formed during welding. In this study, effective joints with comparably high strength (163 MPa) and large elongation (~6 pct) were obtained. Three crucial/weak zones were identified in the welds: (1) Al/Mg bottom interface (BI) zone that resulted from the insufficient materials’ intermixing and interdiffusion; (2) banded structure (BS) zone which contains intermetallic particles possibly formed by constitutional liquation; and (3) softened Al alloy to the retreating side (SAA-RS) zone due to the dissolution and coarsening of the strengthening precipitates. Three fracture modes observed in the tensile specimens perpendicular to the weld seam were found closely related to these zones. Their microstructure evolution with the change of tool rotational speed and tool offset was characterized and the consequent effect on the fracture mode alteration was studied. It turned out that enhancing the strengths of all these zones, but keeping the strength of the SAA lowest, is an effective way for enhancing ductility while keeping comparatively high strength in Al/Mg FSW joints. Also, suggestions for further improving the mechanical property of the Al/Mg dissimilar FSW joints were made accordingly for practical applications.

Effect of Frequency Offset in OFDM Systems with Distributed Beamforming

Effect of Frequency Offset in OFDM Systems with Distributed Beamforming

Effect of Femoral Offset on Pain and Function After Total Hip Arthroplasty

The effects of altering patients’ femoral offset (FO) during total hip arthroplasty on postoperative pain and function have not been well described. This study compared clinical outcomes as assessed by the Short Form 12 Health Survey and Western Ontario and McMaster University Osteoarthritis Index between patients who had their FOs restored to varying degrees (compared to the contralateral normal hip [CL]). We retrospectively measured postoperative FOs on standard anteroposterior pelvis radiographs and compared to the CL. Patients were categorized into one of 3 groups: decreased offset (< −5 mm compared to CL), normal offset (between −5 and +5 mm), and increased offset (> +5 mm). The decreased offset group exhibited Western Ontario and McMaster University Osteoarthritis Index Physical Function scores that were less than those of the normal offset and increased offset groups (72.03, 82.23, and 79.51, respectively [P = .019]). In conclusion, reducing a patients’ native FO led to inferior functional outcome scores.

Effect of Tool Material and Offset on Friction Stir Welding of Al Alloy to Carbon Steel

In this research, effect of tool material and tool offset on tool erosion and metallurgical and mechanical properties of dissimilar friction stir welding of Al alloy to carbon steel are investigated. As the tool erosion is one of the important parameters on the defect-free friction stir welding, especially in butt joint of Al alloy to steel. In present work, different tool material and offset are used in friction stir welding at Al alloy to carbon steel with a constant tool speed and feed rate named as 710 rpm and 28 mm/min respectively. The result of experimental observation is shown better performance by tungsten carbide (WC) tool material with 1 mm offset on Al alloy area.

Effect of Tool Material and Offset on Friction Stir Welding of Al Alloy to Carbon Steel

In this research, effect of tool material and tool offset on tool erosion and metallurgical and mechanical properties of dissimilar friction stir welding of Al alloy to carbon steel are investigated. As the tool erosion is one of the important parameters on the defect-free friction stir welding, especially in butt joint of Al alloy to steel. In present work, different tool material and offset are used in friction stir welding at Al alloy to carbon steel with a constant tool speed and feed rate named as 710 rpm and 28 mm/min respectively. The result of experimental observation is shown better performance by tungsten carbide (WC) tool material with 1 mm offset on Al alloy area.

13-9 送り返し用STBC伝送に与える送信機間搬送波周波数オフセットの影響に関する検討(第13部門無線・光伝送)

13-9 送り返し用STBC伝送に与える送信機間搬送波周波数オフセットの影響に関する検討(第13部門無線・光伝送)

Effect of Valence Band Offset and Surface Passivation Quality in the Silicon Heterojunction Solar Cells

We fabricated hydrogenated amorphous silicon/crystalline silicon (a-Si:H/c-Si) heterojunction solar cells with different intrinsic buffer layers, to elucidate the effect of the energy band gap, as well as passivation quality on the performance of the a-Si:H/c-Si heterojunction solar cells. Deformation (S-shaped) of J-V characteristics are observed in defiance of surface passivation quality for heterojunction solar cells with intrinsic buffer layers of high energy band gap (Eg > 3.0 eV). The deformation of J-V characteristics could be recovered when the energy band gap does not exceed 1.72 eV. In this given energy band gap, it seem to be that the surface passivation quality plays a role in heterojunction solar cell performance. The electrical-optical simulator, AFORS-HET, is used to determine the probable cause of the change in device performance. We find that the band discontinuities at the a-Si:H/c-Si interface are responsible for such an S-shaped behavior in the high energy band gap of intrinsic buffer layers.

Analysis of Piston Slap Induced Noise and Vibration of Internal Combustion Engine (Effect of Piston Profile and Pin Offset)

This paper presents the analytical method to evaluate the impact force and engine noise induced by piston slap considering the detailed piston profile and dynamic characteristics of the piston. This method was applied to examine the effect of the piston profile and piston pin offset on the piston slap impact force and its induced engine noise. Present numerical method showed that increasing the upper clearance of the piston skirt enlarged the higher frequency components of the piston impact force and engine noise and this was verified by the experimental results. The analysis revealed that piston movement at the vicinity of the combustion top dead center was governed by the friction moment around the piston pin and the additional piston pin offset moment induced by combustion pressure could cancel this friction moment and reduce the piston impact force if the piston pin was offset to the major thrust side. This analytical results was confirmed by the measured results of actual diesel engine.

Effect of Carrier Frequency Offset on Single-Carrier CDMA With Frequency-Domain Equalization

Single-carrier code-division multiple access (SC-CDMA) with frequency-domain equalization (FDE) has attracted renewed interest in CDMA due to its lower peak-to-average power ratio (PAPR) and higher frequency diversity than orthogonal frequency-division multiple access (OFDMA), increased robustness to asynchronous multipath and multiuser interference than RAKE-based CDMA, and a reduced need for timing and frequency coordination than time-division multiple access, frequency-division multiple access, and OFDMA. However, existing studies on SC-CDMA are mostly conducted based on an optimistic assumption of perfect carrier frequency estimation; hence, the carrier frequency offset (CFO) effect on the performance of SC-CDMA has not adequately been addressed and is not well understood. In this paper, the system performance of SC-CDMA with FDE is evaluated in terms of the average bit error rate (BER) and signal-to-interference-plus-noise ratio (SINR) obtained through an analytical approach for downlink transmission over a frequency-selective fading channel. The results show that CFO gives rise to three effects: 1) a net phase rotation; 2) fading-like signal power reduction; and 3) intercode interferences (ICIs) due to the loss of code orthogonality. How the CFO-induced BER degradation varies with the number of active users, the number of virtual subcarriers, and constellation size is also investigated. We further show that, in practice, to prevent the BER performance from dramatically deteriorating, the residual CFO after synchronization should be kept within 5% of the virtual subcarrier spacing, irrespective of the constellation size.

Two Case Studies for the Effect of Beam Offset in Finite Element Calculations

This paper describes the effect of beam offsetting in finite element calculations. The effect is evaluated by considering two case studies involving beams, in which finite element analysis is performed with solid elements and with shell elements. It is seen that, under certain conditions, ignoring the beam offset can lead to erroneous results. Although the beam offsetting feature is available in most commercial codes, it is not always well documented.

ピストンスラップによるエンジン振動・騒音の研究 : ピストン形状やピンオフセットの影響

ピストンスラップによるエンジン振動・騒音の研究 : ピストン形状やピンオフセットの影響