Extra Width Research Articles

Transport of a topologically protected photonic waveguide on-chip

We propose a design on integrated optical devices on-chip with an extra width degree of freedom by using a photonic crystal waveguide with Dirac points between two photonic crystals with opposite valley Chern numbers. With such an extra waveguide, we demonstrate numerically that the topologically protected photonic waveguide retains properties of valley-locking and immunity to defects. Due to the design flexibility of the width-tunable topologically protected photonic waveguide, many unique on-chip integrated devices have been proposed, such as energy concentrators with a concentration efficiency improvement of more than one order of magnitude, and a topological photonic power splitter with an arbitrary power splitting ratio. The topologically protected photonic waveguide with the width degree of freedom could be beneficial for scaling up photonic devices, and provides a flexible platform to implement integrated photonic networks on-chip.

The influence of altered foot placement and cognitive load on balance control during walking in healthy young adults

BackgroundClinical populations often walk with altered foot placement, which can adversely affect balance control. However, it is unknown how balance control during walking is influenced when combining a cognitive load with altered foot placement. Research QuestionIs balance control during walking adversely affected by the combination of a more complex motor task, such as walking with altered foot placements, with a cognitive load? MethodsFifteen young healthy adults walked on a treadmill with and without a spelling cognitive load during normal walking, with step width targets (self-selected width, narrow, wide and extra wide), or with step length targets (self-selected length, short and long). ResultsCognitive performance, measured by correct spelling response rate, decreased from self-selected (2.407 ± 0.6 letters/s) to the extra wide width (2.011 ± 0.5 letters/s). The addition of the cognitive load caused a decrease in frontal plane balance control across all step lengths (15% change) and at the wider step widths (16% change), but only caused a slight decrease in the sagittal plane for the short step length (6.8% change). SignificanceThese results suggest that when combining a cognitive load with walking at non-self-selected widths, a threshold exists at wider steps where attentional resources become insufficient and balance control and cognitive performance decrease. Because decreased balance control increases the risk of falling, these results have implications for clinical populations who often walk with wider steps. Furthermore, the lack of changes to sagittal plane balance during altered step length dual-tasks further supports that frontal plane balance requires more active control.

Effect change of extra-wide concrete self-anchored suspension bridge under blast loads and its prediction considering time-dependent effect

In order to study the dynamic response of self-anchored suspension bridge with extra-wide concrete girder under explosive load, a real bridge was taken as the background, which is the widest on in China at present. Firstly, the refined finite element model (FEM) of the whole bridge was established. The reliability of numerical simulation method was validated by the measured data of the bridge at completion state and explosive test results of scaled girder specimen. The vertical displacement, reinforcement strain, acceleration and failure characteristics of the girder specimen under the explosive load of 3 kg TNT were analyzed. Through parametric simulation, the effects of different scale distance, concrete strength and reinforcement ratio on the explosion response of girder specimen were studied. Secondly, the dynamic responses of girder were studied. Finally, the change law of dynamic response at different ages was analyzed. The results show that the elliptical crack is formed on girder top plate. The maximum girder vertical displacement reaches 135.9 mm under 1000 kg, and the maximum increasing ratio of hanger force is 27%. The influence brought by the extra width of girder is significant. The girder vertical displacement changes along transverse direction and the concrete breach sizes are different. In addition, with the increase of service age, the girder displacement increases from 60.50 mm to 106.16 mm under the same explosive load. The research results can provide an important basis for the anti-explosion protection and reinforcement of similar extra-wide concrete self-anchored suspension bridge.

Compact Bandstop Microstrip Line Filter Using U-Shaped Slot

A bandstop filter is proposed, where the resonant element is a slot that is folded to the shape of the letter U and embedded into the microstrip line so that no extra width is required. Moreover, the folding of the slot reduces its length to ¼ the effective wavelength. This is a considerable size reduction in comparison with the filters using the resonant elements like rings or coupled short-circuited and open-circuited stubs. The designed prototype at the WLAN frequency of 2.45 GHz was investigated using the CST software package and showed low insertion loss at the passbands and high rejection across the stopband. The folding of the slot offered very low radiation at the stopband. The simulation results are validated by measurements on the fabricated prototypes.

External Electromagnet FPCB Micromirror for Large Angle Laser Scanning.

An external electromagnet plus moving PM (permanent magnet) FPCB (flexible printed circuit board) micromirror is proposed in this paper that can overcome two limitations associated with the previous FPCB micromirror with a configuration of an external PM plus moving coil, i.e., (1) it reduces the overall width beyond the mirror plate, and (2) increases the maximum rotation angle. The micromirror has two external electromagnets underneath an FPCB structure (two torsion beams and a middle seat) with two moving PM discs attached to the back and a metal-coated mirror plate bonded to the front of the FPCB middle seat. Modeling and simulation were introduced, and the prototype was fabricated and tested to verify the design. The achieved performance was better than that of the previous design: a maximum resonant rotation angle of 62° (optical) at a driving voltage of ±3 V with a frequency of 191 Hz, the required extra width beyond the mirror plate was 6 mm, and an aperture of 8 mm × 5.5 mm with a roughness of <10 nm and a flatness of >10 m (ROC, radius of curvature). The previous FPCB micromirror’s performance was: strain limited maximum rotation angle was 40° (optical), the extra width beyond the mirror plate was 14.7 mm, and had an aperture of 4 mm × 4 mm with a similar roughness and flatness.

Wave packet propagation through branched quantum rings under applied magnetic fields

We investigate the effect of opening and closing pathways on the dynamics of electron wave packets in semiconductor quantum rings with different geometries. Our analysis is based on the time evolution of an electron wave packet, within the effective-mass approximation. We demonstrate that opening an extra channel in the quantum ring does not necessarily improve the electron transmission and, depending on the extra channel width, may even reduce it, either due to enhancement of quantum scattering or due to interference. In the latter case, transmission reduction can be controlled through the Aharonov-Bohm phase of the wave function, via an applied magnetic field. It is also shown that, closing one of the channels of the quantum ring, system improves the transmission probability under specific conditions, an effect which is a quantum analog of the Braess paradox.

Pseudo-static scaled-down experiments on dry stone retaining walls: Preliminary implications for the seismic design

Dry stone retaining walls (DSRWs) are vernacular structures which can be found all over the world. Most of them have been built in the 19th century but they can be as old as two hundred years. Because of decades of neglect, many of these walls are highly damaged; however, in the absence of national rules for this peculiar heritage, any intervention on these constructions is made difficult. A number of former studies in France have tried to settle the bases for a standard aimed at designing slope DSRWs. This paper complement those works in order to give clues for a seismic design of slope DSRWs following the simplified approach proposed by the Eurocode 8 and denoted pseudo-static approach.Firstly, scaled-down experiments have been carried out using a mock-up composed of a wall made of clay bricks retaining a sandy backfill. This mock-up was then tilted and the characteristics of the system at failure were reported and analysed. A particularity of failure in DSRWs is that the failure surface crosses the wall leaving a part of it intact. Secondly, an analytic method based on the limit equilibrium using the Coulomb wedge theory has been designed to predict the tilting angle and validated on the basis of these experimental results. Finally, some preliminary implications for the seismic design of DSRWs have been proposed for walls built in moderate seismicity areas which is typical of mainland France. In low seismicity zones, the extra width required to bear the seismic motion does not exceed 25% of the width identified through the static design. Results are also given for more critical cases associated to zones of higher seismicity as well as for different wall configurations.

Tsu-Esaki modeling of tunneling currents in ferroelectric tunnel junctions

We model tunneling currents through step barrier structures representative of ferroelectric tunnel junctions wherein one of the electrodes contributes to the barrier potential profile or an extra layer is grown between the ferroelectric barrier and one of the electrodes. We study current density–voltage (J–V) and tunneling electroresistance (TER) curves using the Tsu-Esaki formula with numerically calculated transmission. This method is computationally robust, and the same results cannot be obtained with the standard methods usually applied for interpreting experimental I–V curves. Our results predict that the effect of resonant tunneling produces asymmetry in the J–V curves and negative differential resistance characteristics. We show that the asymmetry of the J–V curves can be tuned by adjusting the barrier heights and widths and that changing the extra barrier width affects the asymmetry the most. The barrier widths and the main barrier height affect the magnitude of the tunneling current the most. The change in the tilt of the main barrier is suggested to produce a significant TER of the order of 102. Our numerical method provides a systematic way to study trends in tunneling currents through step barrier structures across a wide range of barrier parameters and bias voltages, in contrast to the necessity of employing several different approximations when using analytical formulae. Therefore, our method provides the means for interpreting existing and future experiments and can be used as a tool for designing new devices with desired functionalities.

Test and numerical investigations on static and dynamic characteristics of extra-wide concrete self-anchored suspension bridge under vehicle loads

The present work is aimed at studying the mechanic properties of the extra-wide concrete self-anchored suspension bridge under static and dynamic vehicle loads. Based on the field test using 12 heavy trucks and finite element simulations, the static deformations of different components, stress increments and distributions of the girder, as well as the vibration characteristics and damping ratio of the Hunan Road Bridge were analyzed, which is the widest self-anchored suspension bridge in China at present. The dynamic responses were calculated using the Newmark-β integration method assisted by the simulation models of bridge and vehicles, the influences on the dynamic impact coefficient (DIC) brought by the vehicle parameters, girder width, eccentricity travel and deck flatness were also researched. The spatial effect of the girder is obvious due to the extra width, which performs as the stress increments distribute unevenly along the transverse direction, and the girder deflections and stress increments of the upper plate change as a “V” and “M” shape respectively under the symmetrical vehicle loads affected by the shear lag effect, cross slope and local effect of the wheels, the maximum of stress increments are located in the junctions with the inner webs. The obvious girder torsional deformation and the apparent unevenness of the hanger forces between the two cable planes under the eccentric vehicle loads, together with the mode shapes such as the girder transverse bending and torsion which appear relatively earlier, all reflect the weakened torsional rigidity of the extra-wide girder. The transverse displacements of towers are more obvious than the longitudinal ones. As for the influences on the DIC, the static effect of the heavier vehicles plays a major role when pass through with a higher speed and the changes of vehicle suspension stiffness generate greater impacts than the suspension damp. The values of DIC in the vehicle-running side during the eccentric travel, affected by the restricts from the static effects of the eccentric moving trucks, are significantly smaller than the vehicle-free side, the increase in the road roughness is the most sensitive one among the above influential factors. The results could provide references for the design, static and dynamic response analysis of the similar extra-wide suspension bridges.

Wavy Channel TFT-Based Digital Circuits

We report a wavy channel (WC) architecture thin-film transistor-based digital circuitry using ZnO as a channel material. The novel architecture allows for extending device width by integrating vertical finlike substrate corrugations giving rise to 50% larger device width, without occupying extra chip area. The enhancement in the output drive current is 100%, when compared with conventional planar architecture for devices occupying the same chip area. The current increase is attributed to both the extra device width and 50% enhancement in field-effect mobility due to electrostatic gating effects. Fabricated inverters show that WC inverters can achieve two times the peak-to-peak output voltage for the same input when compared with planar devices. In addition, WC inverters show 30% faster rise and fall times, and can operate up to around two times frequency of the planar inverters for the same peak-to-peak output voltage. WC NOR circuits have shown 70% higher peak-to-peak output voltage, over their planar counterparts, and WC pass transistor logic multiplexer circuit has shown more than five times faster high-to-low propagation delay compared with its planar counterpart at a similar peak-to-peak output voltage.

Zinc Oxide Integrated Wavy Channel Thin-Film Transistor-Based High-Performance Digital Circuits

High-performance thin film transistor (TFT) can be a great driving force for display, sensor/actuator, integrated electronics, and distributed computation for the Internet of Everything applications. While semiconducting oxides, such as zinc oxide (ZnO), present promising opportunity in that regard, still wide area of improvement exists to increase the performance further. Here, we show a wavy channel (WC) architecture for ZnO integrated TFT, which increases transistor width without chip area penalty, enabling high performance in material agnostic way. We further demonstrate digital logic NAND circuit using the WC architecture and compare it with the conventional planar architecture. The WC architecture circuits have shown 2× higher peak-to-peak output voltage for the same input voltage. They also have 3× lower high-to-low propagation delay times, respectively, when compared with the planar architecture. The performance enhancement is attributed to both extra device width and enhanced field-effect mobility due to higher gate field electrostatics control.

One-Millimeter Cancer-Free Margin Is Curative for Colorectal Liver Metastases

To investigate the influence of clear surgical resection margin width on disease recurrence rate after intentionally curative resection of colorectal liver metastases. There is consensus that a histological positive resection margin is a predictor of disease recurrence after resection of colorectal liver metastases. The dispute, however, over the width of cancer-free resection margin required is ongoing. Analysis of observational prospectively collected data for 2715 patients who underwent primary resection of colorectal liver metastases from 2 major hepatobiliary units in the United Kingdom. Histological cancer-free resection margin was classified as positive (if cancer cells present at less than 1 mm from the resection margin) or negative (if the distance between the cancer and the margin is 1 mm or more). The negative margin was further classified according to the distance from the tumor in millimeters. Predictors of disease-free survival were analyzed in univariate and multivariate analyses. A case-match analysis by a propensity score method was undertaken to reduce bias. A 1-mm cancer-free resection margin was sufficient to achieve 33% 5-year overall disease-free survival. Extra margin width did not add disease-free survival advantage (P > 0.05). After the propensity case-match analysis, there is no statistical difference in disease-free survival between patients with negative narrow and wider margin clearance [hazard ratio (HR) 1.0; 95% (confidence interval) CI: 0.9-1.2; P = 0.579 at 5-mm cutoff and HR 1.1; 95% CI: 0.96-1.3; P = 0.149 at 10-mm cutoff]. Patients with extrahepatic disease and positive lymph node primary tumor did not have disease-free survival advantage despite surgical margin clearance (9 months for <1-mm vs 12 months for ≥1-mm margin clearance; P = 0.062). One-mm cancer-free resection margin achieved in patients with colorectal liver metastases should now be considered the standard of care.

Evaluation of the accuracy of shoe fitting in older people using three‐dimensional foot scanning

BackgroundIll-fitting footwear is a common problem in older people. The objective of this study was to determine the accuracy of shoe fitting in older people by comparing the dimensions of allocated shoes to foot dimensions obtained with a three-dimensional (3D) scanner.MethodsThe shoe sizes of 56 older people were determined with the Brannock device®, and weightbearing foot scans were obtained with the FotoScan 3D scanner (Precision 3D Ltd, Weston-super-mare, UK). Participants were provided with a pair of shoes (Dr Comfort®, Vista, CA, USA), available in three width fittings (medium, wide and extra wide). The dimensions (length, ball width and ball girth) of the allocated shoes were documented according to the last measurements provided by the manufacturer. Mean differences between last dimensions and foot dimensions obtained with the 3D scanner were calculated to provide an indication of shoe fitting accuracy. Participants were also asked to report their perception of shoe fit and comfort, using 100 mm visual analogue scales (VAS).ResultsShoe size ranged from US size 7 to 14 for men and 5.5 to 11 for women. The allocated shoes were significantly longer than the foot (mean 23.6 mm, 95% confidence interval [CI] 22.1 to 25.2; t55 = 30.3, p < 0.001), however there were no significant differences in relation to ball width (mean 1.4 mm, 95% CI −0.1 to 2.9 mm; t55 = 1.9, p = 0.066) or ball girth (mean −0.7 mm, 95% CI −6.1 to 4.8 mm; t55 = −0.2, p = 0.810). Participants reported favourable perceptions of shoe fit (mean VAS = 90.7 mm, 95% CI 88.4 to 93.1 mm) and comfort (mean VAS = 88.4 mm, 95% CI 85.0 to 91.8 mm).ConclusionShoe size selection using the Brannock device® resulted in the allocation of shoes with last dimensions that were well matched to the dimensions of the foot. Participants also considered the shoes to be well fitted and comfortable. Older people with disabling foot pain can therefore be dispensed with appropriately-fitted shoes using this technique, provided that the style and materials used are suitable and extra width fittings are available.

Structure Design and Simulation of a Pulsar Navigation-Oriented X-Ray Detector

Based on the advantages silicon drift detector (SDD) and avalanche photo diode (APD), a droplet-like avalanche drift diode detector (DADD) is proposed. Firstly, the overall structure of the DADD has been designed considering the parameters of bow-shaped curves, distance of drift ring, extra biased voltage and width of drift ring. Secondly, the surface potential of DADD has been simulated and obtained the relation of dark current of drift ring and voltage drops between different drift rings. In addition, static structure analysis and steady state thermal analysis have been implemented. The simulation results show that, the DADD has a good structure and features with high gain, smaller output capacitance and high photon counting capacity, which is appropriate for the pulsar navigation system.

Probing the steric requirements of the γ-aminobutyric acid aminotransferase active site with fluorinated analogues of vigabatrin

We have synthesized three analogues of 4-amino-5-fluorohexanoic acids as potential inactivators of γ-aminobutyric acid aminotransferase (GABA-AT), which were designed to combine the potency of their shorter chain analogue, 4-amino-5-fluoropentanoic acid (AFPA), with the greater enzyme selectivity of the antiepileptic vigabatrin (Sabril®). Unexpectedly, these compounds failed to inactivate or inhibit the enzyme, even at high concentrations. On the basis of molecular modeling studies, we propose that the GABA-AT active site has an accessory binding pocket that accommodates the vinyl group of vigabatrin and the fluoromethyl group of AFPA, but is too narrow to support the extra width of the distal methyl group in the synthesized analogues.

연료전지 채널 내 균일한 유량분배를 위한 연료전지 스택의 매니폴드 디자인 최적화 연구

The main function of fuel cell manifold is to render reactants distribution as uniform as possible into a fuel cell stack. The purpose of this study is to numerically investigate the effects of stack manifold design on reactants distribution within a fuel cell stack. Four manifold designs with different manifold entrance shapes (expansion or diffuser) and different values of the extra width between the cell outer channel and manifold side wall are considered and applied to the fuel cell stack consisting of 50 cells. Since the fuel cell stack geometry involves several millions of grid points for numerical calculations, a parallel computing methodology is employed to substantially reduce the computational time and overcome the memory requirement. The numerical simulations are carried out and calculated results clearly demonstrate that both the manifold entrance shape and extra width have a substantial influence on manifold performance, controlling the degree of flow separation and entrance length for fully developed flow in the manifold channel. Finally, we suggest the optimum design of fuel cell manifold based on the simulation results.

The Orphan and the Polar Bear by S. Qaunaq

Qaunaq, Sakiasi. The Orphan and the Polar Bear. Iqaluit: Inhabit Media, Inc., 2011. Print.One of the common themes in Inuit stories is that of the orphan child alone on the land. In this version, told by Arctic Bay elder Sakiasi Qalinaq, who learned his stories from his grandmother, the orphan is abandoned by hunters from his village and adopted by a village of polar bears. The bears teach him to hunt and survive on the land and, when he is grown, return him to his people. The image on the cover of the book showing the child riding the polar bear is an iconic one. This mythological relationship between child and polar bear is also found in non-Inuit literature, most notably in Philip Pullman’s The Golden Compass. In the bears’ village the orphan is trained to hunt and survive on the land. The bears also teach him their traditional wisdom. For example, when one of the bears wants to go “push down” some humans because they “look so silly standing on their skinny legs”, a wiser elder bear says, “Never talk that way…don’t make humans our enemy. Stay clear of them and their camps.” The book is primarily a picture-book. Unlike many of the other books of Inuit legends published by Inhabit Media, the pictures are not scary. Rather they are quite beautiful. The extra width of the landscape format gives artist, Eva Widermann, the opportunity to spread her illustrations across two pages reflecting the wide expanses of the Arctic. Text usually takes up one corner or a few lines of a page. Widermann’s images are realistic. However, because this story is from a time when animals could shape-shift into human form, she sometimes gives the bears human postures and gestures. For example, in the image on page 15, the polar bear is standing with a harpoon grasped in its front paws, handing it to the orphan. Bears are also shown in their human form in three images. In the image on page 20, depicting the inside of an igloo in the bears’ village, a woman with human form is tending the fire.Overall this is a lovely rendition of the story. While designed for an elementary school audience, anyone with an interest in traditional Arctic tales will enjoy it. Recommended for elementary schools and public libraries. Recommendation: 4 out of 4 starsReviewer: Sandy CampbellSandy is a Health Sciences Librarian at the University of Alberta, who has written hundreds of book reviews across many disciplines. Sandy thinks that sharing books with children is one of the greatest gifts anyone can give.

Hybrid method for global optimization using more accuracy interval computation

In this paper, a novel hybrid method is presented for finding global optimization of an objective function. Based on the interval computation, this hybrid method combines interval deterministic method and stochastic evolution method. It can find global optimization quickly while ensuring the deterministic and stability of the algorithm. When using interval computation, extra width constraints accuracy of interval computation results. In this paper, a splitting method to reduce the extra width is introduced. This method is easy and it can get a more precise interval computation result. When finding the global optimization, it can increase the efficiency of pruning. Several experiments are given to illustrate the advantage of the new hybrid method.

Wide stopband compact microstrip lowpass filter using circular ring resonator and split ring resonators

In this contribution, a microstrip low-pass filter with a wide stop-band using split ring resonators and a circular ring resonator is introduced. The passband ripple of proposed filter was measured 0.6 dB and minimum insertion loss of passband is about 0.75 dB at 0.5 GHz frequency. Moreover, the 1.0 dB cut off frequency of proposed filter is 1.45 GHz in measurement. Designing this type of low-pass filter requires a high impedance transmission-line. However, the microstrip line width cannot be taken less than 0.2 mm in practical implementation. This causes to a small mismatch in passband. Furthermore, these results show wide stop-band up to 9.0 GHz with more than 30 dB rejection. The dimensions of proposed compact filter are about 12.5×30 mm2 (excluding extra substrate width). The proposed filter is a microstrip filter and can compete with defected ground structure (DGS) or defected microstrip structures lowpass filters in miniaturizing and wide stopband. However, the DGS or DGS filters have some problems in manufacturing applications such as radiation fields from defected structures and requiring a specific box. In addition, a distributed equivalent circuit model based on geometrical filer parameters is introduced, and good agreement can be seen between EM simulation and distributed equivalent circuit model up to 6.0 GHz frequency. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26203

Medical grade footwear: does it prevent ulcer recurrence? An Australian perspective

Medical grade footwear is frequently used in the prevention and treatment of ulceration in the high risk foot. Many factors can contribute to the breakdown of tissue in the foot which leads to ulceration. Foot deformity, reduced joint mobility, mechanical stress and strain, peripheral neuropathy, vascular disease and increased pressure are common factors. The right footwear can aid in reducing the effects of these factors and assist in prevention of tissue breakdown. The St Vincent’s (Melbourne) Podiatry Department introduced an in house footwear range 18 months ago. This study is to determine the effect this range of extra depth and width footwear has had on patient’s foot health. The St Vincent’s Podiatry Department is conducting a retrospective study on 40 high risk patients over a 12 month period in an acute hospital setting. All patients have been prescribed medical grade footwear. Patients who were determined high risk are assigned a risk classification 0 (low risk) – 3 (high risk). The aim of this study was to identify those patients who had a poor outcome such as further ulceration or amputation since being issued with medical grade footwear within this time frame. From this retrospective study we hope to be able to conclude that therapeutic footwear can assist in prevention of foot ulcers if fitted correctly.