Magnetic and Structural Properties in Co/Cu/Co Sandwiches with Ni and Cr Buffer Layers

The magnetic and structural properties in Co/Cu/Co sandwiches with Ni and Cr buffer layers were investigated. It was found that the coercivity in Ni layer buffered samples decreases with increasing Ni layer thickness, while that in Cr layer buffered ones increases with increasing Cr layer thickness, leading to a large difference in field sensitivity of their giant magnetoresistance (GMR) properties. X-ray diffraction and high resolution transmission electron microscope images exhibited that there is a strong fcc (111) texture in the samples with Ni buffer layer. But there are only randomly oriented potycrystalline grains in Cr buffered sandwiches. According to atomic force microscope topography, the surface roughness of Cr buffered sandwiches is smaller than that of Ni buffered ones. It is demonstrated that buffer layer influences both magnetic and structural properties in Co/Cu/Co sandwiches as well as their GMR characteristics.

Prevalence of Methicillin-Resistant <i>Staphylococcus aureus</i>in Raw Hamburgers and Ready-to-Eat Sandwiches Commercialized in Supermarkets and Fast Food Outlets in Brazil

Although well known, Staphylococcus aureus is a bacterium that remains widely studied because of its high pathogenic potential and its ability to develop resistance to antibiotics routinely used in clinical practice. The present study investigated the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) in hamburgers and sandwiches sold in supermarkets and fast food outlets in Salvador, BA, Brazil. Fifty samples of frozen raw hamburgers (25: beef and 25: chicken) and 50 samples of ready-to-eat sandwiches (25: beef and 25: chicken) were collected and investigated for the presence of MRSA. MRSA was present in 32% of the hamburgers and 8% of the sandwiches. The frequency of MRSA was higher in the samples containing chicken meat. However, the statistical analysis showed no association between MRSA presence and the type of meat investigated (P > 0.05). The high prevalence of MRSA in hamburgers and the presence of the microorganism in ready-to-eat sandwiches are worrying and indicate the need for better control during food preparation to prevent the spread of bacteria.

Influence of Si buffer layer on the giant magnetoresistance effect in Co/Cu/Co sandwiches

The Co/Cu/Co sandwiches with a semiconductor Si buffer layer were prepared by high vacuum electron-beam evaporation. The influence of the Si buffer layer with different thickness on the giant magnetoresistance (GMR) effect in the Co/Cu/Co sandwiches was investigated. It was found that the GMR showed an obvious anisotropy when the thickness of Si buffer layer was larger than or equal to 0.9 nm, and that the GMR was basically isotropic with an Si buffer layer thinner than 0.9 nm. The anisotropic behavior of GMR can be ascribed to the in-plane magnetic anisotropy in the sandwiches. Due to the interdiffusion at the Si buffer/Co interface, a Co2Si interface layer with a good (301) texture formed and induced the in-plane magnetic anisotropy in the sandwiches. The dependence of the crystalline texture of the sandwiches on the thickness of Si buffer layer was also studied.

THE ELECTRONIC CONFIGURATION OF 5-MEMBERED AND 6-MEMBERED RING SANDWICHES

In this paper, a method of local symmetry is applied to metallo-organic 5-membered and 6-membered ring poly-decker sandwiches (briefly called 5-membered sandwich Ⅰ and 6-membered sandwich Ⅱ), and the nature of their chemical bond is discussed by means of the HMO theory. The stable electronic configuration for these sandwiches is obtained. A working rule for the total number of valence electrons being 6(2n+l)+4t is proposed. It is reasonable to suggest some potential synthetic goals of poly-decker sandwiches. The discovery in 1951 of the transition metal π-complex, ferrocene, created a new research field of metalloorganic sandwiches. Since then, a lot of bis-decker sandwich-

MARKET 101 BY GOGA Epic sandwiches from Brad Turley on Changle Lu

As anyone who's paid a visit to veteran restaurant Goga on Yueyang Lu will tell you,proprietor Brad Turley is a man who knows good America-style food-Luckily these values seem to be in place at Market 101,his new San Franciscan delicatessen on Changle Lu.

RISE OF THE ULTRA SANDWICHES A Whos Who of Shanghai's Most Badass Carbohydrate

The'KFC'(Korean Fried Chicken)Why we love it:All the ftm of KFC minus the food scandals,this sandwich takes ultra-crunchy secret recipe fried chicken,sesame vinaigrette,shredded cabbage and Sriracha-laced mayonnaise,and puts it between a toasted sesame bun.What's not to love?

PBL-Sandwich混合教学模式在临床分子生物学检验技术实习教学中的应用

目的 探讨以问题为基础的教学法(PBL)-Sandwich混合教学模式在临床分子生物学检验技术实习教学中的应用效果。方法 选取2018-2019年进入该院分子生物学实验室实习的82例实习生作为研究对象。以2018年的42例实习生作为对照组,采用传统教学模式;以2019年的40例实习生作为试验组,采用PBL-Sandwich混合教学模式。实习结束后,采用理论考试、操作考核和问卷调查等形式评价实习生的教学效果。结果 试验组的理论考试成绩与操作考核成绩均明显高于对照组,差异均有统计学意义(P<0.05)。共发放调查问卷82份,回收有效问卷80份,其中试验组39份,对照组41份,有效回收率为97.56%(80/82)。试验组在提高学习主动性、激发学习兴趣、增强师生间的交流和互动、提升分析解决临床实际问题能力和教学方法实施满意度方面均优于对照组,差异均有统计学意义(P<0.05)。结论 PBL-Sandwich混合教学模式能有效激发实习生学习兴趣,培养实习生自主学习的主观能动性,提高分析、解决临床实际问题能力,教学质量得到提升。

Sandwich联合角色扮演教学法在住培医师医患沟通能力培训中的应用

目的 以腰椎穿刺术前谈话为例,探讨Sandwich联合角色扮演教学法在住院医师规范化培训(住培)学员医患沟通能力培训中的应用价值。方法 选取2019年3月至2023年1月在该院神经外科进行住培的40名学员,将其分为A、B组,每组20名。A组通过传统教学方法进行腰椎穿刺术前谈话的教学,B组运用Sandwich联合角色扮演教学法进行教学,在教学前、中、后期分别使用医患沟通技能评价量表对2组学员进行考评,最后对2组学员进行满意度问卷调查,对比2组教学效果及学员对教学的满意度。结果 2组学员在教学前测评得分均较低,在教学后测评较教学前均有提升,差异均有统计学意义(P<0.05);与A组比较,B组在教学中期测评得分明显更高,差异有统计学意义(P<0.05);2组在教学后期测评得分比较,差异无统计学意义(P>0.05)。B组住培学员的满意度高于A组,差异有统计学意义(P<0.05)。结论 Sandwich联合角色扮演教学法能快速提升学员的术前谈话沟通能力,也能提高学员的教学满意度,适合在相关教学活动中推广。

基于CBL+PBL联合Sandwich教学法在神经病学本科教学中的探索

神经病学是一门理论性和实践性较强的综合性学科,对从业人员的专业知识和操作技能均有较高要求。传统神经病学本科教育存在教师单方面授课无法激发学生学习兴趣、学生学习有效性不足等问题,使神经病学专业人才的培养存在一定难度。该文基于神经病学本科教学的实际情况,探讨以CBL、PBL联合Sandwich教学法在神经病学专业本科教育体系中的应用前景。

案例教学法联合Sandwich教学法在老年科教学中的应用

目的探讨案例教学法联合Sandwich教学法在老年科教学中的应用效果。方法选取2022年3月—2023年6月潍坊医学院附属医院的60名参加老年科教学的学生为研究对象,按照随机数表法分为两组,各30名。对照组行常规教学,观察组行案例教学法联合Sandwich教学法教学,比较两组教学效果。结果观察组各项模拟出科考试成绩高于对照组,差异有统计学意义(P均<0.05);观察组对实习教学效果的各项满意度评分高于对照组,差异有统计学意义(P<0.05)。结论案例教学法联合Sandwich教学法可提升老年科教学的效果,并提高学生对实习教学效果的满意度。

Sandwich教学法融入思政教育在超声诊断学中的应用

研究Sandwich教学法融入思政教育模式在超声诊断学教学中应用效果。方法 选择2022年11月-2023年11月在本院接受超声诊断学教学的学生40名,随机分组法分作试验组(Sandwich教学法融入思政教育模式)和对照组(传统教学模式),每组20名,分析不同教学模式的实施效果评价。结果 出科时,试验组考核成绩明显高于对照组,P<0.05;试验组综合能力和批判性思维能力均优于对照组,P<0.05。结论 超声诊断学教学中实施Sandwich教学法融入思政教育模式,可明显提升学生考核成绩、综合素质以及批判性思维能力,可以应用于超声诊断学教学。

Sandwich教学方法在非本专业医学本科生临床见习中的应用效果

目的:探讨Sandwich教学方法应用于非麻醉专业本科生在麻醉临床见习中的应用效果。方法:本研究选择2021年4月在首都医科大学附属北京佑安医院参与临床麻醉学见习的51名本科护理学专业学生作为观察对象,根据随机表随机分为对照组(n=26)和试验组(n=25)。其中对照组采用常规的见习教学方法,而试验组采用Sandwich教学方法,最后两组采用理论知识试卷和满意度调查表进行教学效果和教师满意度评价。结果:理论知识掌握方面,试验组和对照组的平均得分分别是(81.80±5.02)分与(66.56±5.13)分,差异具有统计学意义(P<0.05);对见习带教老师满意度方面,试验组显著高于对照组,差异具有统计学意义(P<0.05)。结论:Sandwich教学方法不仅有利于见习生掌握教学大纲内容,而且还有利于提高学生对带教老师的满意度。

Mechanical Performance of Bio-inspired Bidirectional Corrugated Sandwich Pressure Shell Under External Hydrostatic Pressure

This paper aims to enhance the compression capacity of underwater cylindrical shells by adopting the corrugated sandwich structure of cuttlebone.The cuttlebone suffers uniaxial external compression,while underwater cylindrical shells are in a biaxial compressive stress state.To suit the biaxial compressive stress state,a novel bidirectional corrugated sandwich structure is proposed to improve the bearing capacity of cylindrical shells.The static and buckling analysis for the sandwich shell and the unstiffened cylindrical shell with the same volume-weight ratio are studied by numerical simulation.It is indicated that the proposed sandwich shell can effectively reduce the ratio between circumferential and axial stress from 2 to 1.25 and improve the critical buckling load by about 1.63 times.Numerical simulation shows that optimizing and adjusting the structural parameters could significantly improve the advantage of the sandwich shell.Then,the hydrostatic pressure tests for shell models fabricated by 3D printing are carried out.According to the experimental results,the overall failure position of the sandwich shell is at the center part of the sandwich shell.It has been found the average critical load of the proposed sandwich shell models exceeds two times that of the unstiffened shell models.Hence,the proposed bio-inspired bidirectional corrugated sandwich structure can significantly enhance the pressure resistance capability of cylindrical shells.

含根量对SANDWICH形加筋土界面剪切强度影响--以红叶石楠为例

SANDWICH形加筋土是一种采用粘土夹砂层以及土工格栅而形成的混合填料形式的加筋土结构。采用一系列直接剪切试验研究含根量、竖向应力等因素对筋土界面强度的影响。试验证明,根系的加入对SANDWICH形加筋土界面最大剪应力有所提升且随着竖向应力的增大,土体抗剪强度增幅大。随着粘土中含根量的增加,筋土界面最大剪应力在不同竖向应力作用下出现先增后减的趋势。根据试验数据,利用拟合软件提出了评价筋土界面剪切强度的经验公式,得出理论上含根量的最优值为4.2%。并通过试验验证了拟合公式的有效性和正确性。

基于岗位胜任力的WebQuest联合Sandwich教学法在超声医学本科教学的探索

超声医学是一门理论性和实践性较强的综合性学科,对从业人员的专业知识和操作技能均有较高要求。传统超声医学本科教育存在教师单方面授课无法激发学生学习兴趣以及学生实践时间严重不足等问题,超声医学专业人才岗位胜任力的培养存在一定难度。本文基于超声医学本科教学的实际情况,探讨以岗位胜任力为导向的WebQuest联合Sandwich教学法在超声医学专业本科教育体系中的应用前景。

Combining video and GPS-tracking to study the spatial foraging distribution of a single-prey loading seabird

Seabirds are valuable indicators of marine ecosystem processes and studying seabird diets can shed light on natural or human-induced variability in food-web composition.Specifically single-prey loading seabird species such as terns have the potential to act as visual sentinels of prey availability offshore.However,obtaining diet information from remote bird colonies is often challenging and time consuming.In this pilot study we present a novel approach to combine two established methods to study seabird foraging ecology,providing a powerful and cost-effective tool to study the distribution of prey items available to seabirds.We combined GPS tracking data of Sandwich Terns(Thalasseus sandvicensis)with prey-observations from a hide in 2012 and 2013,and from semicontinuously recorded camera footage in 2017.By doing so,we identified 115 approximate catch locations of prey(86 herring/sprat Clupeidae,29 sandeel Ammodytidae).Combining GPS-data and prey observations yielded detailed knowledge on the movements and chick diets of tracked birds as well as the spatial origin and lengths of captured prey items.Further catch distances of both Clupeidae and Ammodytidae resulted in deliveries of larger prey items and thus higher energy yield per trip,but also a higher energy expenditure per trip.We discuss the limitations and potential of our methodological approach to study foraging energetics during chick-provisioning of seabirds that carry prey items visible in their beaks.

Sandwich structures with tapered tubes as core:A quasi-static investigation

In this article,the experimental and finite element analysis is utilized to investigate the quasi-static compression features of sandwich constructions built with tapered tubes.3D printing technology was utilized to create the hollow centers of the tapering tubes,with and without corrugations.The results demonstrate that the energy absorption(EA)and specific energy absorption(SEA)of the single corrugated tapered tube sandwich are 51.6% and 19.8% higher,respectively,than those of the conical tube sandwich.Furthermore,the results demonstrate that energy absorbers can benefit from corrugation in order to increase their efficiency.Additionally,the tapered corrugated tubes'resistance to oblique impacts was studied.Compared to a straight tube,the tapered tube is more resistant to oblique loads and has a lower initial peak crushing force(PCF),according to numerical simulations.After conducting a parametric study,it was discovered that the energy absorption performance of the sandwich construction is significantly affected by the amplitude,number of corrugations,and wall thickness.EA and SEA of DTS with corrugation number of 8 increased by 17.4%and 29.6%,respectively,while PCF decreased by 9.2% compared to DTS with corrugation number of 10.

Dynamic Resistance and Energy Absorption of Sandwich Beam via a Micro-Topology Optimization

The current research of sandwich structures under dynamic loading mainly focus on the response characteristic of structure.The micro-topology of core layers would sufficiently influence the property of sandwich structure.However,the micro deformation and topology mechanism of structural deformation and energy absorption are unclear.In this paper,based on the bi-directional evolutionary structural optimization method and periodic base cell(PBC)technology,a topology optimization frame work is proposed to optimize the core layer of sandwich beams.The objective of the present optimization problem is to maximize shear stiffness of PBC with a volume constraint.The effects of the volume fraction,filter radius,and initial PBC aspect ratio on the micro-topology of the core were discussed.The dynamic response process,core compression,and energy absorption capacity of the sandwich beams under blast impact loading were analyzed by the finite element method.The results demonstrated that the overpressure action stage was coupled with the core compression stage.Under the same loading and mass per unit area,the sandwich beam with a 20%volume fraction core layer had the best blast resistance.The filter radius has a slight effect on the shear stiffness and blast resistances of the sandwich beams.But increasing the filter radius could slightly improve the bending stiffness.Upon changing the initial PBC aspect ratio,there are three ways for PBC evolution:The first is to change the angle between the adjacent bars,the second is to further form holes in the bars,and the third is to combine the first two ways.However,not all three ways can improve the energy absorption capacity of the structure.Changing the aspect ratio of the PBC arbitrarily may lead to worse results.More studies are necessary for further detailed optimization.This research proposes a new topology sandwich beam structure by micro-topology optimization,which has sufficient shear stiffness.The micro mechanism of structural energy absorption is clarified,it is significant for structural energy absorption design.

Nonlinear vibration of Timoshenko FG porous sandwich beams subjected to a harmonic axial load

In this study,the instability and bifurcation diagrams of a functionally graded(FG)porous sandwich beam on an elastic,viscous foundation which is influenced by an axial load,are investigated with an analytical attitude.To do so,the Timoshenko beam theory is utilized to take the shear deformations into account,and the nonlinear Von-Karman approach is adopted to acquire the equations of motion.Then,to turn the partial differential equations(PDEs)into ordinary differential equations(ODEs)in the case of equations of motion,the method of Galerkin is employed,followed by the multiple time scale method to solve the resulting equations.The impact of parameters affecting the response of the beam,including the porosity distribution,porosity coefficient,temperature increments,slenderness,thickness,and damping ratios,are explicitly discussed.It is found that the parameters mentioned above affect the bifurcation points and instability of the sandwich porous beams,some of which,including the effect of temperature and porosity distribution,are less noticeable.

Experimental study of 3D printed carbon fibre sandwich structures for lightweight applications

Honeycomb sandwich structures are widely used in lightweight applications.Usually,these structures are subjected to extreme loading conditions,leading to potential failures due to delamination and debonding between the face sheet and the honeycomb core.Therefore,the present study is focused on the mechanical characterisation of honeycomb sandwich structures fabricated using advanced 3D printing technology.The continuous carbon fibres and ONYX-FR matrix materials have been used as raw materials for 3D printing of the specimens needed for various mechanical characterization testing;ONYX-FR is a commercial trade name for flame retardant short carbon fibre filled nylon filaments,used as a reinforcing material in Morkforged 3D printer.Edgewise and flatwise compression tests have been conducted for different configurations of honeycomb sandwich structures,fabricated by varying the face sheet thickness and core cell size,while keeping the core cell thickness and core height constant.Based on these tests,the proposed structure with face sheet thickness of 3.2 mm and a core cell size of 12.7 mm exhibited the highest energy absorption and prevented delamination and debonding failures.Therefore,3D printing technology can also be considered as an alternative method for sandwich structure fabrication.However,detailed parametric studies still need to be conducted to meet various other structural integrity criteria related to the lightweight applications.