采用37.5■锦纶开发多功能弹力Legging面料

文章以37.5■锦纶科技纱线4.4 tex/34 f消光DTY为主纱,夹入2.2 tex黑氨纶材料,采用双面互锁的织造方式,开发出一款集抗菌、凉感、远红外、吸湿速干、防紫外线功能为一体的多功能弹力Legging针织面料。详细介绍该面料的原料选择、织造工艺以及染整工艺,并对面料的基本性能进行测试。结果表明,该面料具有较好的多项功能以及优良的包覆性能,可以满足女子多场景的运动与穿着舒适性的相关需求。

Bionic lightweight design of limb leg units for hydraulic quadruped robots by additive manufacturing and topology optimization

Galloping cheetahs,climbing mountain goats,and load hauling horses all show desirable locomotion capability,which motivates the development of quadruped robots.Among various quadruped robots,hydraulically driven quadruped robots show great potential in unstructured environments due to their discrete landing positions and large payloads.As the most critical movement unit of a quadruped robot,the limb leg unit(LLU)directly affects movement speed and reliability,and requires a compact and lightweight design.Inspired by the dexterous skeleton–muscle systems of cheetahs and humans,this paper proposes a highly integrated bionic actuator system for a better dynamic performance of an LLU.We propose that a cylinder barrel with multiple element interfaces and internal smooth channels is realized using metal additive manufacturing,and hybrid lattice structures are introduced into the lightweight design of the piston rod.In addition,additive manufacturing and topology optimization are incorporated to reduce the redundant material of the structural parts of the LLU.The mechanical properties of the actuator system are verified by numerical simulation and experiments,and the power density of the actuators is far greater than that of cheetah muscle.The mass of the optimized LLU is reduced by 24.5%,and the optimized LLU shows better response time performance when given a step signal,and presents a good trajectory tracking ability with the increase in motion frequency.

Type Synthesis of Walking Robot Legs

Walking robots use leg structures to overcome obstacles or move on complicated terrains. Most robots of current researches are equipped with legs of simple structure. The specific design method of walking robot legs is seldom studied. Based on the generalized-function(GF) set theory, a systematic type synthesis process of designing robot legs is introduced. The specific mobility of robot legs is analyzed to obtain two main leg types as the goal of design.Number synthesis problem is decomposed into two stages, actuation and constraint synthesis by name,corresponding to the combinatorics results of linear Diophantine equations. Additional restrictions are discussed to narrow the search range to propose practical limb expressions and kinematic-pair designs. Finally, all the fifty-one leg structures of four subtypes are carried out, some of which are chosen to make up robot prototypes, demonstrating the validity of the method. This paper proposed a novel type synthesis methodology, which could be used to systematically design various practical robot legs and the derived robots.

Parametric Vibration Analysis of Submerged Floating Tunnel Tension Legs

According to the characteristics of submerged floating tunnel anchored by tension legs,simplifying the tube as point mass and assuming that the tension leg is a nonlinear beam model hinged at both ends,the nonlinear vibration equation of the tension leg is derived.The equation is solved by the Galerkin method and Runge Kutta method.Subsequently,numerical analysis of typical submerged floating tunnel tension leg is carried out.It is shown that,the parametric vibration response of the submerged floating tunnel tension leg is related to the amplitude and frequency of the end excitation.Without considering axial resonance and transverse resonance,it is reasonable that higher order modes are abandoned and only the first three modes are considered.The axial resonance amplitude of the second or third order mode is equivalent to the first order mode axial resonance amplitude,which should not be ignored.

基于CFD和热阻网络法的C型舱LEG船温度场分析及热应力计算

为解决C型舱LEG船进行温度场计算时,CFD方法难以计入结构细节以及热阻网络法处理热对流精度较低的问题,提出将2种方法相结合的船体结构温度场计算方法。在CFD计算时,只考虑主要结构,将计算结果作为热阻网络法的输入,而在热阻网络法中考虑结构细节。实船计算结果显示,该方法高效可靠,避免了2种方法的缺点,可以合理地求解船体结构的温度场,是一种工程上实用的方法。计算还表明,对于温度梯度大的关键结构区域,结构强度评估需要考虑热应力。

V-Shaped Monopole Antenna with Chichena Itzia Inspired Defected Ground Structure for UWB Applications

Due to rapid growth in wireless communication technology,higher bandwidth requirement for advance telecommunication systems,capable of operating on two or higher bands with higher channel capacities and minimum distortion losses is desired.In this paper,a compact Ultra-Wideband(UWB)V-shaped monopole antenna is presented.UWB response is achieved by modifying the ground plane with Chichen Itzia inspired rectangular staircase shape.The proposed V-shaped is designed by incorporating a rectangle,and an inverted isosceles triangle using FR4 substrate.The size of the antenna is 25 mm×26 mm×1.6 mm.The proposed V-shaped monopole antenna produces bandwidth response of 3 GHz Industrial,Scientific,and Medical(ISM),Worldwide Interoperability for Microwave Access(WiMAX),(IEEE 802.11/HIPERLAN band,5G sub 6 GHz)which with an additional square cut amplified the bandwidth response up to 8 GHz ranging from 3.1 GHz to 10.6 GHz attaining UWB defined by Federal Communications Commission(FCC)with a maximum gain of 3.83 dB.The antenna is designed in Ansys HFSS.Results for key performance parameters of the antenna are presented.The measured results are in good agreement with the simulated results.Due to flat gain,uniform group delay,omni directional radiation pattern characteristics and well-matched impedance,the proposed antenna is suitable for WiMAX,ISM and heterogeneous wireless systems.

RIGID-PLASTIC MECHANICAL MODEL FOR THE FORGING METHOD WITH HORIZONTAL V-SHAPED ANVIL

In order to decrease the anisotropy of mechanical properties, the rigid-plastic mechanical model for the forging method with horizontal V-shaped anvil is presented. The forging method, through the change of anvils shape, is able to control fibrous tissue direction, to improve the anisotropy of mechanical properties of axial forgings, to realize uniform forging. Therefore, the forging method can overcome the defect that conventional forging methods produce. The mechanism of the forging method with horizontal V-shaped anvil and the process of metal deformation are analyzed. The agreement of theoretical analysis with experimental study verifies the fact that the forging method with horizontal V-shaped anvil can control effectively the mechanical properties of axial forgings.

An experimental investigation of the fracturing behaviour of rock-like materials containing two V-shaped parallelogram flaws

The distribution characteristics and evolution law of rock mass fissures induced by mining are a key scientific issue in the study of deep rock mechanics.In this study,a series of uniaxial compression experiments was conducted on rock-like specimens containing double V-shaped prefabricated fissures at dip angles ofα=β=45°,α=45°<b=60°,α=β=60°,andα=60°<β=75°with a rock mechanics servocontrolled testing system.According to the experimental results,the effects of the dip angles of the double V-shaped prefabricated flaws with the same area on the mechanical parameters and fracturing process of the specimens were analysed in detail.Additionally,the crack initiation stress presented a nearly linear growth trend,which is generally similar to that of the crack peak stress with increasing flaw dip angle.By applying photographic monitoring to the crack initiation,propagation,coalescence,and failure modes in rock-like specimens,it was easily seen that the V-shaped flaw properties slightly influence the crack initiation positions but significantly influence the crack trajectories.The crack failure modes can be summarized into two distinct types.The study reported herein can provide a better understanding of the evolution of double V-shaped prefabricated fissures induced by coal mining.

Scattering of SH waves induced by a symmetrical V-shaped canyon: a unified analytical solution

This paper reports a series solution of wave functions for two-dimensional scattering and diffraction of plane SH waves induced by a symmetrical V-shaped canyon with different shape ratios. A half-space with a symmetrical V-shaped canyon is divided into two sub-regions by using a circular-arc auxiliary boundary. The two sub-regions are represented by global and local cylindrical coordinate systems, respectively. In each coordinate system, the wave field satisfying the Helmholtz equation is represented by the separation of variables method, in terms of the series of both Bessel functions and Hankel functions with unknown complex coefficients. Then, the two wave fields are described in the local coordinate system using the Graf addition theorem. Finally, the unknown coefficients are sought by satisfying the continuity conditions of the auxiliary boundary. To consider the phase characteristics of the wave scattering, a parametric analysis is carried out in the time domain by assuming an incident signal of the Ricker type. Surface and subsurface transient responses demonstrate the characteristics and mechanisms of wave propagating and scattering.

Finite Element Analysis of Deformed Legs of Offshore Platform Structures

The element stiffness matrix of the equivalent beam or pipe element of the deformed leg of the platform is derived by the finite element method. The stresses and displacements of some damaged components are calculated, and the numerical solutions agree well with those obtained by the fine mesh finite element method. Finally, as an application of this method, the stresses of some platform structures are calculated and analyzed.

The Calculating Model of Structural Analysis for Jack-Up Rig Legs

The selection or establishment of structural calculating model is a matter of primary importance in structural analysis. By analysing the irrationality of the calculating models used by some research organizations at home and abroad in structural analyses for truss jack-up rig legs, this paper introduces a new calculation model which is more reasonable. This model can simulate better the load situation of a rig reflecting more precisely the effects of the leg loads caused by the spring support of gearboxes of the jacking system and the secondary bending moment raised by hull displacement under extreme conditions. The rig conversion was completed in 1989. In July 1991 the rig safely stood the frontal hitting of Typhoon with the wind speed of 52 m / s, which shows that the checking on the structure is correct.

Management of restless legs syndrome in chronic liver disease:A challenge for the correct diagnosis and therapy

AIM To investigate the association between restless legs syndrome(RLS) and well-defined chronic liver disease, and the possible therapeutic options. METHODS Two hundred and eleven patients with chronic liver disease, complaining of sleep disturbances, painful leg sensation and daily sleepiness, were included. Patients with persistent alcohol intake, recent worsening of clinical conditions, or hepatitis C virus were excluded. Diagnosis of RLS was suggested by the Johns Hopkins questionnaire and verified by fulfilling the diagnostic criteria by Allen. All patients were tested, both at baseline and during follow-up, with the Hamilton rating scale for depression, sleep quality assessment(PSQI), Epworth sleepiness scale(ESS), International Restless Legs Syndrome Study Group evaluation, and international RLS severity(IRLS) scoring system. Ironfree level, ferritin, folate, vitamin B12 and D-OH25 were detected. Neurological examinations and blood testoccurred at the beginning of the therapy, after 2 wk, and at the 28^(th), 75 th, 105 th, 135 th, 165 th and 205 th day. Regarding therapy, pramipexole or gabapentin were used.RESULTS Patients were moderately depressed, with evident nocturnal sleep problems and concomitant daily sleepiness. Sleep problems and involuntary leg movements had been underestimated, and RLS s yndrome had not be e n c ons ide re d be fore t he neurological visit. All(211/211) patients fulfilled the RLS diagnostic criteria. Twenty-two patients considered their symptoms as mild, according to IRSL, but 189 found them moderate to very severe. No correlation was found between ammonium level and ESS or PSQI. Augmentation was rather precocious in our patients(135 th day), and more frequent(35%) than previous data(8.3%-9.1%). The dosage of dopamine agonists was found to be associated with augmentation and appears in range with the literature. Previous intake of alcohol and lower levels of vitamins have been related to the phenomenon in our study.CONCLUSION RLS is a common disorder, requiring rapid diagnosis and treatment. Further research is therefore fundamental.

Seismic analysis of high-speed railway irregular bridge–track system considering V-shaped canyon effect

To explore the effect of canyon topography on the seismic response of railway irregular bridge-track system that crosses a V-shaped canyon, seismic ground motions of the horizontal site and V-shaped canyon site were simulated through theoretical analysis with 12 earthquake records selected from the Pacific Earthquake Engineering Research Center(PEER) Strong Ground Motion Database matching the site condition of the bridge.Nonlinear seismic response analyses of an existing 11-span irregular simply supported railway bridge-track system were performed under the simulated spatially varying ground motions. The effects of the V-shaped canyon topography on the peak ground acceleration at bridge foundations and seismic responses of the bridge-track system were analyzed. Comparisons between the results of horizontal and V-shaped canyon sites show that the top relative displacement between adjacent piers at the junction of the incident side and the back side of the V-shaped site is almost two times that of the horizontal site, which also determines the seismic response of the fastener. The maximum displacement of the fastener occurs in the V-shaped canyon site and is 1.4 times larger than that in the horizontal site. Neglecting the effect of V-shaped canyon leads to the inappropriate assessment of the maximum seismic response of the irregular high-speed railway bridge-track system. Moreover, engineers should focus on the girder end to the left or right of the two fasteners within the distance of track seismic damage.

CLINICAL STUDY OF 108 RESTLESS LEGS CASES BY ACUPUNCTURE OR EAR ACUPUNCTURE

108 cases of restless legs syndrome were treated , out of which, 56 cases withacupuncture, 52 cases with ear acupuncture. The therapeutical effects of acupuncture are superior tothat of ear acupuncture.

Estimation of Standard Operation Time of Flight Legs Based on Clustering and Probability Analysis

A clustering algorithm and a probability statistics method were applied to different phases of a flight to analyze operation time during aircraft ground taxiing and airborne flight.And the clustering pattern,distribution characteristics and dynamically changing rules of the two phases were identified.Further,an estimate method was established to measure operation time of flight legs,with creative steps of calculating individual segment separately and then integrating them accordingly.The method can both objectively and dynamically measure operation time,and accurately reflect real situation.It helps to better utilize airport slot resources and provides a strong support for air traffic flow management when scheduling flight plan in strategic and pre-tactic phases.

New Methods of Determining the Mixed Mode Stress Intensity Factors for V-Shaped Notch

In this paper, on the basis of the stress field given by D.H.Chen, three new photoelastic methods are developed for determining the stress intensity factors K1 and K2 of V-shaped notch. Some photoelastic experiments are performed on a skew -symmetric 45° notch. Measurements of the coordinates components of r,θand fringe order N are made for progressively smaller fringes and used in the proposed methods to solve K1 and K2.Plots of apparent K vs. r/l are made and extrapolated to the notch tip to yield the true values of K1 and K2.The results obtained by the three methods are very close to each other. When the notch problem is simplified as a crack problem, the corresponding equation is identical to the one proposed by D.G. Smith, which shows that the proposed methods are applicable for both notch and crack problems.

Prevalence of Restless Legs Syndrome in Patients Treated with Peritoneal Dialysis: Clinical and Biochemical Characteristics among Patients with and without Restless Legs Syndrome

Introduction and Aims:This is a prospective study identifying prevalence of Restless Legs Syndrome (RLS) in patients ongoing peritoneal dialysis (PD) due to end stage renal disease (ESRD) and comparing clinical and biochemical characteristics among patients with and without RLS. Methods: Two hundred ESRD patients who received PD at least six months assessed by neurologist and nephrologist with regards to presence of RLS. Also, clinical and biochemical features of these patients are determined. One hundred and forty four patients were excluded from study because they had other secondary causes of RLS except for ESRD. Results: Thirteen of 56 patients (23.2%) had RLS. The use of vitamin B + folic acid supplements was significantly lower in patients with RLS than in those without RLS (69.2% vs 97.7%;p = 0.008). There was no significant difference between patient groups with and without RLS in terms of age, gender, body mass index, cause of ESRD, peritoneal membrane transport characteristic, smoking, consuming alcohol, use of erythropoietin, duration of PD, hemoglobin, serum calcium, serum phosphorus, serum albumin, levels of serum iron, total iron binding capacity, ferritin, folic acid and vitamin B12, transferrin saturation, weekly Kt/V urea value, and amount of residual urine volume (p > 0.05). Conclusion: RLS is more common among PD patients than general population. Although essential cause is not exactly known, use of folic acid and vitamin B complex decrease the RLS prevalence in this particular patient group.

Light-extraction efficiency and forward voltage in GaN-based light-emitting diodes with different patterns of V-shaped pits

We present a new method of making a textured V-pit surface for improving the light extraction efficiency in GaN- based light-emitting diodes and compare it with the usual low-temperature method for p-GaN V-pits. Three types of GaNbased light-emitting diodes （LEDs） with surface V-pits in different densities and regions were grown by metal-organic chemical vapor deposition. We achieved the highest output power and lowest forward voltage values with the p-InGaN V-pit LED. The V-pits enhanced the light output power values by 1.45 times the values of the conventional LED owing to an enhancement of the light scattering probability and an effective reduction of Mg-acceptor activation energy. Moreover, this new technique effectively solved the higher forward voltage problem of the usual V-pit LED.

Restless Legs Syndrome in Liver Transplant Recipients

Background: The prevalence of restless legs syndrome (RLS) is approximately 10% in general population. This condition is more prevalent in certain diseases and we previously reported the prevalence of RLS in chronic liver disease population to be 62%. Objectives: Our aim was to assess the self-reported prevalence of RLS using an RLS symptom specific questionnaire in liver transplant patients. Methods: Subjects were a convenience sample in transplant clinic. They completed a validated survey for core RLS symptoms and if positive went on to completed a telephone survey using the validated International RLS Severity Scale Questionnaire (IRLS) and the Johns Hopkins RLS QoL survey to measure the effect of RLS symptoms on daily activities. Results: 40 patients surveyed, RLS was found in 16 subjects (40%) with moderate severity {17 (SD + 7.2, high score 31)}. Hepatitis C as indication for liver transplant was more likely associated with RLS (p = 0.05). Calcium channel blockers were protective (p = 0.032) while antidopaminergic agent use was statistically significant for RLS symptom (p = 0.005). On multiple linear regression analysis, diabetes (p = 0.024) and use of antidepressants/antihistamines (p = 0.049) were associated with RLS. Quality of Life (QoL) surveys specific to RLS suggested RLS symptoms resulted in significantly diminished QoL, with an average QoL score of 80 (SD + 11.7). Conclusion: There was a very high prevalence of RLS in our liver transplant patients with majority experiencing moderate or severe symptoms. The explanation for this higher prevalence is likely due to combination of comorbidites as well as medications that can trigger RLS.

Wave Pressure Acting on V-Shaped Floating Breakwater in Random Seas

Wave pressure on the wet surface of a V-shaped floating breakwater in random seas is investigated. Considering the diffraction effect, the unit velocity potential caused by the single regular waves around the breakwater is solved using the finite-depth Green function and boundary element method, in which the Green function is solved by integral method. The Response-Amplitude Operator(RAO) of wave pressure is acquired according to the Longuet-Higgins' wave model and the linear Bernoulli equation. Furthermore, the wave pressure's response spectrum is calculated according to the wave spectrum by discretizing the frequency domain. The wave pressure's characteristic value corresponding to certain cumulative probability is determined according to the Rayleigh distribution of wave heights. The numerical results and field test results are compared, which indicates that the wave pressure calculated in random seas agrees with that of field measurements. It is found that the bigger angle between legs will cause the bigger pressure response, while the increase in leg length does not influence the pressure significantly. The pressure at the side of head sea is larger than that of back waves. When the incident wave angle changes from 0? to 90?, the pressure at the side of back waves decreases clearly, while at the side of head sea, the situation is more complicated and there seems no obvious tendency. The concentration of wave energy around low frequency(long wavelength) will induce bigger wave pressure, and more attention should be paid to this situation for the structure safety.