Extending the Frequency Range of Surface Plasmon Polariton Mode with Meta-Material

The frequency range that surface plasmon polariton(SPP) mode exists is mainly limited by the metal material.With high permittivity dielectrics above metal surface, the SPP mode at high frequency has extremely large loss or can be cutoff, which limits the potential applications of SPP in the field of optical interconnection, active SPP devices and so on.To extend the frequency range of SPP mode, the surface mode guided by metal/dielectric multilayers meta-material has been studied based on the theory of electromagnetic field. It is demonstrated that surface mode not only could be supported by the meta-material but also extends the frequency to where conventional metal SPP cannot exist. Meanwhile, the characteristics of this surface mode, such as dispersion relation, frequency range, propagation loss and skin depth in metamaterial and dielectrics, are also studied. It is indicated that, by varying the structure parameters, the meta-material guided SPP mode presents its advantages and flexibility over traditional metal one.

Effect of bonding interface on delamination behavior of drawn Cu/Al bar clad material

Cu/Al bar clad material was fabricated by a drawing process and a subsequent heat treatment.During these processes,intermetallic compounds have been formed at the interface of Cu/Al and have affected its bonding property.Microstructures of Cu/Al interfaces were observed by OM,SEM and EDX Analyser in order to investigate the bonding properties of the material.According to the microstructure a series of diffusion layers were observed at the interface and the thicknesses of diffusion layers have increased with aging time as a result of the diffusion bonding.The interfaces were composed of 3-ply diffusion layers and their compositions were changed with aging time at 400 °C.These compositional compounds were revealed to be η2,(θ+η2),(α+θ) intermetallic phases.It is evident from V-notch impact tests that the growth of the brittle diffusion layers with the increasing aging time directly influenced delamination distance between the Cu sleeve and the Al core.It is suggested that the proper holding time at 400 °C for aging as post heat treatment of a drawn Cu/Al bar clad material would be within 1 h.

Electroencephalogram evidence for mirror neuron activity during the observation of drawn hand motion

The present study used electroencephalography to examine mu rhythm suppression （a putative index of human mirror neuron system activation） at frontal sites （F3, Fz and F4）, central sites （C3, Cz and C4）, parietal sites （P3, Pz and P4） and occipital sites （O1 and O2）, while subjects observed real hand motion （real hand motion condition） and illustrative depictions of hand motion （drawn hand motion condition）. Experimental data revealed that mu rhythm suppression was exhibited in the mirror neuron system when subjects observed both real and drawn hand motion. Moreover, the mu rhythm recorded at the F3, Fz, F4, and Pz poles was significantly suppressed while observing both stimulus types, but no obvious mu suppression occurred at the O1, 02 and 03 poles. These results suggest that the observation of drawings of human hand actions can activate the human mirror neuron system. This evidence supports the hypothesis that the mirror neuron system may be involved in intransitively abstract action understanding.

Temperature dependence of microstructure and texture in cold drawn aluminum wire

The effect of strain and drawing temperature on the evolution of microstructure and fiber textures of aluminum wiresdrawn at room temperature and cryogenic temperature was investigated by TEM and EBSD observations.The results show that lowangle boundaries frequency increases and high angle boundaries frequency decreases with strain increasing when the strain is low.Athigh strain,most of grain and dislocation boundaries are parallel to the drawn direction and low angle boundaries frequencydecreases and high angle boundaries frequency increases with strain increasing.The decrease of deformation temperature leads tomicrostructure finer and low angle boundaries frequency increasing.Texture analysis indicates that volume fraction of complextexture component decreases with strain increasing and a mixture of?111?and?100?fiber texture forms at high strain.?111?is stableat low strains but?100?becomes stable at high strain.The decrease of temperature can enhance the stability of?111?orientation athigh strain.

Recrystallization Kinetics and Microstructure Evolution of Annealed Cold-Drawn Low-Carbon Steel

The recrystallization behavior of cold-drawn 0.12 wt% C steel during annealing at temperatures 600°C and 650°C was investigated. Hardness tests were used to characterize the recrystallization kinetics. The micrographs of the steel were obtained using optical microscopy (OM) to characterize the grain microstructure of the non-treated and the annealed steel samples. Annihilation of dislocation defects occur within the soaking time of 5 - 10 minutes for all the deformed steel after annealing at 650°C. Specifically at 5 minutes soaking time the grains elongation is still observed indicating that reformation of grains is not taking place but recovery of the deformed grains. At the 10 minutes annealing time, new grains are observed to begin and full recrystallization is achieved at 15 minutes annealing time. At annealing time between 20 - 25 minutes, grains coarsening are observed indicating the onset of grain growth. The hardness of the material reduces with increasing annealing temperature for all the degree of cold drawn deformation. On the basis of the experimentally obtained hardness values, recrystallization increases with increasing degree of cold drawn deformation for the annealed steel. Recovery process was found to prolong in the 20% cold drawn steel as compared to the 55% cold drawn steel. The prolong recovery process is due to reduction in the driving force. Full recrystallization of the annealed steel is achieved at different soaking time depending on the degree of the cold drawn steel.

Effect of Prior-Heat Treatments on the Creep Behavior of an Industrial Drawn Copper

The effect of prior-heat treatments at 500℃, 600℃ and 700℃ on the creep behavior of an industrial drawn copper has been studied under constant stresses (98, 108 and 118 MPa) and temperatures (290℃ and 340℃). The results revealed that the creep behavior and the creep life of the material depend strongly on these prior-heat treatments. The apparent activation energy Qc for different creep tests of a drawn copper wire was calculated. The fracture mechanism of the material is characterized using optical microscopy.

Optimization of the Annealing Parameters for Improved Tensile Properties in Cold Drawn 0.12 wt% C Steel

Drawn low carbon steel is characterized by brittle fracture. These defects are associated with the poor ductility and high strain hardening due to the cold work. There is a need therefore to determine optimum heat treatment parameters that could ensure improved toughness and ductility. Determining the optimum annealing parameters ensures valued recrystallization and also minimizes grain growth that could be detrimental to the resulting product. 40% and 55% cold drawn steels were annealed at temperatures 500℃ to 650℃ at intervals of 50℃ and soaked for 10 to 60 minutes at interval of 10 minutes to identify the temperature range and soaking time where optimum combination of properties could be obtained. Tensile test and impact toughness experiments were done to determine the required properties of the steel. Polynomial regression analysis was used to fit the properties relationship with soaking time and temperatures and the classical optimization technique was used to determine the minimum soaking time and temperature required for improved properties of the steel. Annealing treatment at 588℃ for 11 minutes at grain size of 44.7 mm can be considered to be the optimum annealing treatment for the 40% cold drawn 0.12 wt% C steel and 539℃ for 17 minutes at grain size of 19.5 mm for the 55% cold drawn 0.12 wt% C steel.

DEFORMATION AND STRENGTHENING OF COLD-DRAWN STEEL WIRES

It was shown by the study of TEM that the fine lamellar pearlite becomes a ductile phase dur- ing cold drawing.There exist many ledges to emit dislocations at Fe_3C/Fe interface.It is one of the reasons that high density of dislocations emerges at the Fe_3C/Fe interface. Furthermore,there are some evidences to support that dislocation cuts through Fe_3C.There- fore,it is necessary to consider the contribution of cementite being sheared strengthening.

Labeling Line Drawings with Hidden-Part-Drawn of Planar Object with Trihedral Vertices

Although line drawings consist of only line segments on a plane, they convey much information about the three-dimensional object structures. For a computer interpreting line drawings, some intelligent mechanism is required to extract three-dimensional information from the two-dimensional line drawings. In this paper, a new labeling theory and method are proposed for the two-dimensional line drawing with hidden-part-draw of a three-dimensional planar object with trihedral vertices. Some rules for labeling line drawing are established. There are 24 kinds of possible junctions for line drawing with hidden-part-draw, in which there are 8 possible Y and 16 W junctions. The three problems are solved that Sugihara＇s line drawing labeling technique exists. By analyzing the projections of the holes in manifold planar object, we have put forward a labeling method for the line drawing. Our labeling theory and method can discriminate between correct and incorrect hidden-part-draw natural line drawings. The hidden-part-draw natural line drawings can be labeled correctly by our labeling theory and method, whereas the labeling theory of Sugihara can only label the hidden-part-draw unnatural line drawings in which some visible lines must be drawn as hidden lines, and some invisible lines must be drawn as continuous lines.

基于断裂力学的腐蚀钢丝疲劳S-N曲线研究

高强冷拔钢丝因其优异的力学性能被广泛应用于缆索承重结构,服役过程中钢丝腐蚀与断裂威胁着结构安全。钢丝腐蚀后表面的蚀坑因应力集中效应易产生疲劳裂纹,因此腐蚀钢丝剩余疲劳寿命主要取决于裂纹的扩展阶段,且裂纹扩展受到腐蚀程度(初始损伤)的显著影响。精确表征腐蚀程度并准确评估服役期钢丝腐蚀后的剩余寿命,仍是亟待解决的维修难题。首先采用蚀坑最大深度表征钢丝腐蚀程度,以应力强度因子幅作为裂纹扩展驱动力指标,基于断裂力学的Paris公式建立受拉钢丝裂纹扩展理论模型,进而推导腐蚀钢丝的疲劳S-N曲线。大量既有的腐蚀钢丝疲劳试验结果与理论预测值的比较验证了所提理论模型及疲劳S-N曲线的合理性和有效性。含多个蚀坑的钢丝裂纹扩展有限元模拟表明,等效单裂纹适用于多腐蚀坑钢丝疲劳寿命的简化分析。参数分析表明,蚀坑深度和腐蚀环境是腐蚀钢丝疲劳强度的关键影响因素,而应力比和疲劳加载频率影响较小,所提出的S-N曲线在钢丝常规服役条件下适用于评估其剩余寿命,可得到合理的预测结果。基于断裂力学所提的理论方法和疲劳S-N曲线可为腐蚀钢丝的疲劳强度和寿命评估提供参考。

INSPIRATIONS DRAWN FROM ONE OF OUR RESEARCH ACHIEVEMENTS

In January 1985, our Institute formed a topic research team aimed at treating underwater soft foundations with explosive techniques. Its research target was the West Seawall in the Harbour of Lianyungang in northern Jiangsu Province. The West Seawall is a key engineering project in the construction and development of the Harbour.

I Never Saw Another Butterfly——Pictures Drawn by the Jewish Children in Terezin Concentration Camp in Czech

From 1942 to 1945 more than 15,000 Jewish children passed through Terezin,a former military garrison set up as a ghetto.It soon became a transition station for hundreds of thousands of Jews on their way to the gas chambers of Auschwitz.While most of the children imprisoned at Terezin perished at Auschwitz,some of their stories of life during the Holocaust are preserved in drawings and poems,published in the book,I Never Saw Another Butterfly. When Terezin was liberated in 1945,only about 100 children were alive to return to what was left of their lives.

Effect of Soaking Time on the Mechanical Properties of Annealed Cold-Drawn Low Carbon Steel

The paper presents the results of investigation on the effect of soaking time on the yield strength, ductility and hardness properties of annealed cold-drawn low carbon steel. The low carbon steel cold-drawn at 40% deformation was annealed at 900 deg Celsius for soaking times of 10, 20, 30, 40, 50 and 60 minutes. Tensile, charpy and Brinnel hardness tests were conducted to determine the yield strengths, tensile strengths, impact strengths, ductility and hardness of the annealed steel with increasing soaking time. The yield strength, tensile strength, hardness and impact strength of the steel showed a continuous drop in value with increasing soaking time up to 60 minutes with a steep drop between 30 and 40 minutes. Ductility values followed the same decreasing trend up to 40 minutes soaking time after which the values started increasing again till 60 minutes soaking time. There was a linear relationship between the tensile strength and hardness of the material for different soaking times. This linear relationship was also observed for yield strength and hardness of the material.

基于移动互联网的手绘图谱微课教学在专业学习中的探索

本研究旨在探索与研究基于移动互联网络的渐进式手绘图谱微课教学模式在骨科专业学习中的应用价值,以期进一步优化教学模式,提高学生学习效果和满意度,改善学习态度。本研究选取iPad应用程序Procreate及其他方式进行手绘,采用录屏和手机俯拍方式进行视频录制,从而保证了微课教学的互动性、灵活性和流畅性。在教学内容方面,着重介绍了膝关节半月板损伤、膝关节置换和骨折治疗等课程,以期为学生提供更加专业、实用和全面的学习资源。此外,本研究还对教学效果进行了全面评估和反馈,以便不断完善教学方法和内容。研究结果显示,基于移动互联网络的渐进式手绘图谱微课教学对学生学习效果、学习态度和满意度都产生了积极影响。学生在参与手绘微课教学后的成绩普遍提升,对教学方式和内容表达出积极态度,并对教学方式感到满意。因此,本研究为骨科专业学习提供了一种创新的教学模式,具有较好的应用前景。

手绘支气管导航图联合径向超声在肺外周病变患者诊断中的应用价值研究

探讨手绘支气管导航图联合径向超声在肺外周病变患者诊断中的应用价值.选取2022年1月-2023年4月于济宁市第一人民医院接受手绘支气管导航图联合径向超声支气管镜检查的51例肺外周病变患者为研究对象,分析气管镜检查的诊断阳性率及并发症的发生情况.结果显示,51例患者均完成了气管镜检查及活检,确诊肿瘤共28例,其中腺癌24例,鳞癌两例,小细胞癌1例,肉瘤样癌1例,结核3例,炎症8例,阴性结果12例,诊断阳性率为76.46%.并发症发生情况包括气胸1例,发生率为1.96%;术中出血7例,发生率为13.73%,但均为少量出血.研究发现,手绘支气管导航图联合径向超声检查可以用于肺外周病变的诊断,并且该技术的诊断阳性率较高,并发症(出血及气胸)的发生率低.

新型粉煤灰泡沫混凝土墙体轴心受压性能试验研究

利用工业固废粉煤灰制备节能与承重一体的新型墙体,对无冷弯薄壁C型钢外包内置钢丝网片固废粉煤灰泡沫混凝土墙体FW、外包1mm厚冷弯薄壁C型钢内置钢丝网片固废粉煤灰泡沫混凝土墙体CW1、外包2mm厚冷弯薄壁C型钢内置钢丝网片固废粉煤灰泡沫混凝土墙体CW2分别在轴压作用下的破坏形态、荷载-位移曲线及墙体极限承载力进行试验研究。研究结果表明:从破坏形态度角度,FW、CW1及CW2在破坏时,冷拔钢丝、冷弯薄壁C型钢发生屈服,泡沫混凝土破裂;FW大面积泡沫混凝土挤压破碎剥落,破坏严重;CW2破坏时完整性优于FW、CW1。从变形角度,CW1、CW2外包的C型钢能够对墙体内部的泡沫混凝土起到约束作用,墙体的刚度得到提升。从承载力角度,CW2较CW1提升了17.4%,较FW提升了23.7%。对墙体的轴压承载力进行理论计算,与墙体轴心受压试验的实测值相比,二者误差在10%以内且小于实测值,满足国家现行规范、行业技术标准相关要求。

加捻及干湿热处理对大有光PET FDY光泽度的影响

分别以圆形、三角形、扁平形截面的83.3 dtex/36 f大有光聚对苯二甲酸乙二醇酯(PET)全拉伸丝(FDY)为原料,在捻线机上采用直接加捻和合股后反向复捻的方法分别制得单股加捻丝和双股复捻丝;对不同截面形态的PET FDY分别进行不同温度、时间的干热处理,以及沸水中不同时间的湿热处理;研究加捻、干湿热处理条件对PET FDY光泽度的影响。结果表明:随加捻捻度增大,不同截面形态单股加捻丝的光泽度均呈下降趋势,在较低捻度下加捻对三角形、扁平形截面PET FDY光泽度的影响更为明显;双股复捻丝的光泽度主要取决于单股加捻丝初捻捻度,初捻及复捻方向对丝线光泽度无影响;在80~120℃、1~3 h干热处理条件下,随干热处理温度及时间的增加,PET FDY的光泽度均逐渐下降,干热处理温度的影响比干热处理时间更显著;在100℃沸水中湿热处理1~3 h,圆形截面PET FDY的光泽度稳定在9.7~9.8,而三角形及扁平形截面PET FDY的光泽度均随处理时间的增加呈明显下降趋势。

涤纶FDY纺丝油剂的研究进展

为了跟踪涤纶FDY纺丝油剂的行业动态,为相关研发人员提供参考,文章综述了国内外涤纶FDY纺丝油剂的研发进展。首先,介绍了涤纶FDY纺丝油剂生产中所采用的关键油剂单体的研发状况,主要包括平滑剂、乳化剂、润湿剂、集束剂、抗静电剂等;其次,探讨了国内外主要涤纶FDY纺丝油剂产品的研究和应用情况,并对不同产品性能特点进行了对比;最后,展望了涤纶FDY纺丝油剂的未来发展趋势。随着全球环保意识的增强和技术的创新,未来的纺丝油剂产品将朝着环保型、原油型、专用型等方向发展。

560 dtex/72 f三叶形阻燃尼龙66 FDY生产工艺探讨

以相对黏度2.28的尼龙66切片为原料,共混添加氮系阻燃剂三聚氰胺氰尿酸盐(MCA)质量分数50%的阻燃母粒,在切片纺生产线上通过熔融纺丝生产560 dtex/72 f三叶形阻燃尼龙66全拉伸丝(FDY),探讨了主要生产工艺条件。结果表明:较佳的生产工艺条件为添加阻燃母粒质量分数5%,采用18孔喷丝板、三叶形喷丝孔呈菱形排布,熔体管道温度270℃,纺丝箱体温度281℃,侧吹风速度0.5~0.6 m/s,第三热辊温度190℃,卷绕速度2600~2800 m/min;在较佳生产工艺条件下,生产过程稳定,产品优等品率为91%、满筒率为82%,纤维具有良好的力学性能及阻燃性能,其断裂强度4.4 cN/dtex、断裂伸长率40.7%、干热收缩率6.1%、条干不匀率1.2%、极限氧指数27.5%。

Ceramic-based meta-material absorber with high-temperature stability

With the continuous exploration of uncharted and extreme environments,enhanced temperature robustness of passive devices has become particularly important.In this study,a ceramic-based meta-material absorber with exceptional temperature stability is developed using a fusion design approach that combines rare metal-based tungsten bronze structural ceramics and meta-materials.Specifically,the absorbance of the meta-material array based on Mie resonance exceeds 49.0%in both waveguides and free space,approaching the theoretical limit.According to impedance analysis,the absorption performance can be distinctly correlated with the dielectric loss(Q_(f)).Notably,the high-temperature robustness is verified to still be effective at 400℃.These advancements in our design allow for the use of monolithic materials in fabricating temperature-stable perfect absorbers,providing greater freedom in the dielectric performance and expanding their potential applications,including in space exploration and 5G millimeter-wave scenarios.