Textured nickel tapes prepared from commercially available material

Textured Ni tapes were fabricated from commercially available nickel pellets (98.5% Ni). Ingots produced by a melt process were cold rolled to 150–400 μm thick tapes. Texturing was achieved by annealing in a reducing atmosphere (Ar + 6.5% v/v H₂). Sharp cubic biaxial textured Ni tapes were obtained by thermal treatment at 1000°C for 2 hours in a reducing atmosphere. The tapes were characterized by scanning electron microscopy, X-ray diffraction and by electron backscattering diffraction. The tensile strength, the thermal expansion behavior and the Vickers hardness for the cold rolled tapes and for the heat-treated tapes were measured.      

Structural transitions in model beta-sheet tapes

We present a molecular-scale simulation study of the structural transitions between helicoidal, helical, and tubular geometries in supramolecular beta-sheet tapes. Such geometries have been observed in different self-assembled amyloid systems (based on either natural or synthetic peptides) for which the beta-sheet tapes represent the simplest fibrillar aggregates. A coarse-grained model for the beta-sheet tapes is proposed, with chiral degrees of freedom and asymmetrical chemical properties, which provides a quantitative characterization of the structural transitions. A quantitative connection is established between the molecular properties and the elastic parameters of the supramolecular tapes.     

Biomimetic fabrication of 3D structures by spontaneous folding of tapes

This paper describes a biomimetic strategy for the fabrication of 3D structures-including an electrically functional light detector-modeled on the folding of biological macromolecules into globular shapes. The process started by fabricating precursors to 3D, millimeter-sized structures using flexible polymer tapes. These tapes were patterned with metal features supporting liquid solder, crimped into strings of 3D corrugations, and attached to flat polymer tapes to generate linear 3D structures. Capillary interactions between droplets of molten solder on adjacent faces of the crimped tapes resulted in folding of the precursors into quasi-3D and truly 3D structures.     

The application of isotope ratio mass spectrometry for discrimination and comparison of adhesive tapes

Forensic scientists are frequently requested to differentiate between, or compare, adhesive tapes from a suspect or a crime scene. The most common polymers used to back packaging tape are polypropylene and polyvinyl chloride. Much of the oriented polypropylene (OPP) needed to produce packaging tapes, regardless of the tape brand, is supplied by just a few polymer manufacturers. Consequently, the composition of the backing material varies little. Therefore, the discriminating power of classical methods (physical fit, tape dimensions, colour, morphology, FTIR, PyGC/MS, etc.) is limited. Analysis of stable isotopes using isotope ratio mass spectrometry (IRMS) has been applied in the broad area of forensics and it has been reported that isotope analysis is a valuable tool for the identification of adhesive tapes. We have tested the usefulness of this method by distinguishing different South Korean adhesive tapes produced by just a few manufacturers in the small South Korean market. Korean adhesive tapes were collected and analysed for their isotope signatures. The glue of the tapes was separated from the backing material and these sub-samples were analysed for their H- and C-isotope composition. The result shows the possibility for discriminating most tape samples, even from the same brand. Variations within single rolls have also been investigated, where no variations in H- and C-isotope composition significantly exceeding the standard deviation were found.     

YBa2Cu3O7-x涂层导体的研究进展

以YBa2Cu3O7-2（YBCO）超导涂层为导体的第二代高温超导带材由于其优异的本征性能，吸引着科学家不断探索和研究其实用成材技术。近年来，百米级长带的研制成功，使其成为当前国际上超导研究的热点。综述了近年来二代超导带材的发展状况，并对在镍和镍合金基带上制备涂层导体的工艺技术以及其基本结构特征做了较为系统的介绍，包括基带的制备技术、隔离层的生长、化学法和物理气相沉积法生长YBCO等。     

Photophysical properties of porphyrin tapes

The novel fused Zn(II)porphyrin arrays (Tn, porphyrin tapes) in which the porphyrin macrocycles are triply linked at meso-meso, beta-beta, beta-beta positions have been investigated by steady-state and time-resolved spectroscopic measurements along with theoretical MO calculations. The absorption spectra of the porphyrin tapes show a systematic downshift to the IR region as the number of porphyrin pigments increases in the arrays. The fused porphyrin arrays exhibit a rapid formation of the lowest excited states (for T2, approximately 500 fs) via fast internal conversion processes upon photoexcitation at 400 nm (Soret bands), which is much faster than the internal conversion process of approximately 1.2 ps observed for a monomeric Zn(II)porphyrin. The relaxation dynamics of the lowest excited states of the porphyrin tapes were accelerated from approximately 4.5 ps for the T2 dimer to approximately 0.3 ps for the T6 hexamer as the number of porphyrin units increases, being explained well by the energy gap law. The overall photophysical properties of the porphyrin tapes were observed to be in a sharp contrast to those of the orthogonal porphyrin arrays. The PPP-SCI calculated charge-transfer probability indicates that the lowest excited state of the porphyrin tapes (Tn) resembles a Wannier-type exciton closely, whereas the lowest excited state of the directly linked porphyrin arrays can be considered as a Frenkel-type exciton. Conclusively, these unique photophysical properties of the porphyrin tapes have aroused much interest in the fundamental photophysics of large flat organic molecules as well as in the possible applications as electric wires, IR sensors, and nonlinear optical materials.     

X7R型MLCC流延瓷膜显微结构的AFM研究

片式电容是由电介质陶瓷薄膜和内电极相互重叠而成的多层独石结构,又称多层陶瓷电容器(mul-tilayer ceram ic capacitors,简称MLCC)。具有体积小、内部电感低、绝缘电阻高及漏电流小、介质损耗低、价廉等优点,被广泛应用于各种电子整机中的振荡、耦合、滤波和旁路电路,尤其是高     

The effect of processing conditions on the mechanical properties and thermal stability of highly oriented PP tapes

It has previously been shown possible to use highly oriented polypropylene (PP) tapes to create self-reinforced (all-PP) composites. It is desirable to understand the relationship between tape processing parameters and the mechanical properties and thermal stability of the tapes, as these tape properties will govern the ultimate properties of the all-PP composite. In this paper, the effects of the tape drawing parameters such as draw ratio (λ), drawing temperature and thermal annealing on the final mechanical properties, density and dimensional thermal stability of the tapes are presented. PP tapes drawn to λ = 17 possess tensile moduli of ～15 GPa and tensile strengths of ～450 MPa. PP tapes with high draw ratios, λ > 9.3, show a decrease in density, a change from transparent to opaque appearance and increased dimensional thermal stability with increasing draw ratio. The results of an investigation into the effects of a thermal annealing step, targeted at improving the dimensional thermal stability of these highly oriented PP tapes, are also presented.     

Cyanuryl-PNA monomer: synthesis and crystal structure

[structure: see text] The chemical synthesis and crystal structure of the peptide nucleic acid (PNA) monomer 11 having cyanuric acid as the nucleobase is reported. The crystal structure of 11 shows molecular tapes arising from continuous intermolecular dimeric hydrogen bonding, with successive tapes held by single hydrogen bonds in the backbone.     

聚酰胺-胺树形分子对胶带上油潜指纹的显现研究

研究了不同pH值和光源波长条件下,荧光性聚酰胺-胺树形分子(PAMAM)水溶液对胶带粘面上油潜指纹的显现效果.结果显示:PAMAM树形分子水溶液pH值大于7时,指纹残留物被不同程度地溶解,因此显现效果不佳;pH值为4—7时,显现效果较好,处理过的指纹发出明亮的蓝色荧光,指纹纹路完整、特征明显,且与基底的对比度较高;但由于用365 nm紫外光激发时,PAMAM树形分子的蓝色荧光容易受胶带中杂质蓝色荧光的影响,因此对比度仅为28.8%左右;采用其它波段的可见光或者复合白光作为光源后,有效规避了胶带中杂质的同色系荧光干扰,指纹对比度可提高至90%,并且避免了紫外光使用过程中对人体的伤害.PAMAM树形分子水溶液是一种环保的、具有潜在应用价值的识别胶带粘面上油潜指纹的优良显现材料.     

Two-dimensionally extended porphyrin tapes: synthesis and shape-dependent two-photon absorption properties

We report the synthesis and characterization of L- and T-shaped porphyrin tapes as extensible structural motifs of two-dimensionally extended porphyrin tapes. The two-photon absorption (TPA) cross-section values (sigma((2))) for L- and T-shaped porphyrin tapes as well as those for linear trimeric and tetrameric porphyrin tapes were measured by an open-aperture Z-scan method at 2300 nm, a wavelength at which the one-photon absorption contribution is either zero or almost negligible. Under these conditions, the sigma((2)) values for the linear porphyrin tape trimer and tetramer were determined to be 18 500 and 41 200 GM, respectively. The sigma((2)) value for the L-shaped trimer was determined to be 8700 GM, which is only half that of the linear trimer, whereas the sigma((2)) value for the T-shaped tetramer was measured to be 35 700 GM. These results clearly indicate the dependence of the TPA cross-section on the molecular shape, which underscores the importance of directionality in the pi-conjugation pathway for the enhancement of TPA cross- section.     

Morphology and toughness of coextruded PS/PMMA multilayers

The micromechanical behaviour of multilayered tapes made of two brittle incompatible amorphous polymers PS and PMMA was studied by means of an optical and a High Voltage Electron Microscope (HVEM). Microlayers of PS and PMMA were coextruded with varying number of layers: 64, 512 and 4096 layers. Mechanical properties of the PS/PMMA tapes were also examined. An increase in layer numbers was found to lead to a decrease in layer thickness that, in turn, resulted in: a) formation of thicker and longer crazes and, therefore, increased volume of the material involved in the plastic deformation; b) a noticeable increase in strength and strain at break (i.e. of toughness) of the samples. Enhanced toughness of the multilayered tapes is accounted for by massive cooperating crazing and yielding of both PS and PMMA phases.     

Synthesis and properties of hybrid porphyrin tapes

Hybrid porphyrin tapes 3 and 4 , consisting of a mixture of 3,5‐di‐tert‐butylphenyl‐substituted donor‐type Zn^II–porphyrins and pentafluorophenyl‐substituted acceptor‐type Zn^II–porphyrins, were prepared by a synthetic route involving cross‐condensation reaction of a Ni^II–porphyrinyldipyrromethane and pentafluorophenyldipyrromethane with pentafluorobenzaldehyde followed by appropriate demetalation, remetalation, and oxidative ring‐closure reaction. The Ni^II‐substituted porphyrin tapes 5 (Ni‐Zn‐Ni) and 6 (Ni‐H₂‐Ni) were also prepared through similar routes. The hybrid porphyrin tapes 3 and 4 are more soluble and more stable than normal porphyrin tapes 1 and 2 consisting of only donor‐type Zn^II–porphyrins. The solid‐state and crystal packing structures of 3 , 4 , and 5 were elucidated by single‐crystal X‐ray diffraction analysis. Singly meso–meso‐linked hybrid porphyrin arrays 12 and 14 exhibit redox potentials that roughly correspond to each constituent porphyrin segments, while the redox potentials of the hybrid porphyrin tapes 3 and 4 are positively shifted as a whole. The two‐photon absorption (TPA) values of 1–6 were measured by using a wavelength‐scanning open aperture Z‐scan method and found to be 1900, 21 000, 2200, 27 000, 24 000, and 26 000 GM, respectively. These results illustrate an important effect of elongation of π‐electron conjugation for the enhancement of TPA values. The hybrid porphyrin tapes show slightly larger TPA values than the parent ones.     

High-velocity stretching of polyolefin tapes

Stretched polyolefin films and tapes are used in many packaging applications, such as BigBags. Stretching is elongation of polymer tapes in one direction, resulting in improved mechanical properties. Both, amorphous and crystalline polymers are in principle stretchable but linear, unbranched macromolecules are highly stretchable. Hence, the stretchability of e.g. branched low density polyethylene (PE-LD) is lower than of high-density polyethylene (PE-HD). Basic requirements for stretching of thermoplastics are known, but correlations between material parameters and stretching behaviour are scarce. Moreover, stretching of polymers is usually studied with tensile tests at stretching velocities much lower (1–500 mm/min) than in industrial processes (400–1000 mm/s), while results from high-velocity stretching tests or on production machines have not been published as of yet. We investigated high-velocity (800 mm/s) stretching of PE-LD, PE-HD and isotactic polypropylene films and tapes and which stretching parameters resulted in maximum mechanical properties. It was found that sample geometry, temperature, and the degree of stretching have a significant influence on the properties of stretched tapes, e.g. higher stretching temperature resulted in higher mechanical properties and orientation of crystallites. Furthermore, about 80% of the maximum stretching degree resulted in maximum mechanical properties.     

Mirror image supramolecular helical tapes formed by the enantiomeric-depsipeptide derivatives of the amyloidogenic peptide amylin(20-29)

Factors that determine the chirality of supramolecular helical tapes formed by a backbone-modified amylin(20-29) depsipeptide and inverso-depsipeptide, were studied by Fourier transform infrared spectroscopy, circular dichroism and transmission electron microscopy. Although β-sheet propensity was absent in both peptides, it was found that the l-depsipeptide formed left-handed and the enantiomeric d-depsipeptide right-handed helical tapes. Moreover, the backbone-modified depsipeptides, showed a certain degree of cross-recognition between both enantiomers, which might have implications in designing amyloid formation inhibitors.     

Textured tape substrates made of ternary alloys based on Cu–40%Ni–Me constantan for epitaxial deposition of buffer and superconducting layers

The structure was studied and the texture formation process was investigated in tapes made of Cu–Ni–Me ternary alloys (Me = Fe, Cr, V, or Mn) during cold deformation by rolling to a degree of ～99% with subsequent recrystallization annealing. It was shown that it is generally possible to create a perfect cubic texture in a thin ribbon made of ternary alloys based on copper and nickel to which a period 4 d-element (iron, chromium, or vanadium) was added. This makes these tapes promising as substrates in the technology for producing second-generation high-temperature superconductor tapes. The optimal annealing conditions were determined, under which, in the studied alloys, a perfect biaxial near-single-crystalline texture can be obtained with a content of cubic grains {001}〈100〉 ± 10° on the surface of the textured ribbon of above 99%.     

Evaluation of an HPLC Method for the Determination of Natural Moisturizing Factors in the Human Stratum Corneum

The levels of natural moisturizing factors in the skin can be used as a biomarker of hydration, for studying the effect of skin irritants, or as a biomarker of loss-of-function mutations in the filaggrin gene which are the main risk factor for atopic dermatitis. In this study the chromatographic performance and recovery of natural moisturizing factors and proteins from the skin were investigated using different extraction solvents and adhesive tapes. The uppermost layer of the skin stratum corneum, collected by using commercially available D-squame and corneofix adhesive tapes, was extracted by ammonia or potassium hydroxide. Protein levels used to correct for a variable stratum corneum amount on a tape were assessed by measuring optical density of a tape or indirectly by measuring proteins by a spectrophotometric assay. The measured natural moisturizing factors, pyrrolidone-5-carboxylic acid, histidine, tyrosine, trans-urocanic acid, and cis-urocanic acid were determined by ion pair reverse phase HPLC. Sample preparation and chromatographic performance were favorable when ammonia was used as an extraction solvent. Extraction of the natural moisturizing factors with ammonia avoids a time consuming neutralization step as required with extraction procedures using strong base or acid. The only drawback of the ammonia method is incomplete extraction of proteins from the tapes; however this can be avoided by measuring the optical density of stratum corneum-loaded tapes. The sensitivity of the method was sufficiently high to quantify the analytes even in homozygous filaggrin gene carriers. Reduced natural moisturizing factors levels found in the individuals with filaggrin gene mutation or after exposure to a skin irritant sodium lauryl sulfate were consistent with the previously reported studies.     

Burnout of Organic Components of Glass Ceramic Composite Tapes: Thermoanalytical investigations

Glass ceramic composite tapes are composed of inorganic raw materials (borosilicate glasses and inert fillers) and organic additives (polymer binder, plasticizer, dispergent, residues of solvent from the tape casting process). Burnout of organics in air is a complex process of vaporization, depolymerization and oxidation. Conditions of this process can be simulated by thermal analysis of plasticizer, various binders and binder/plasticizer mixtures with alumina, prepared by impregnation of alumina powder with corresponding solutions and subsequent drying. This allows a quantitative interpretation of the results of burnout of tapes.This revised version was published online in November 2005 with corrections to the Cover Date.     

One-dimensional array of two- and three-center cation-cation bonds in the structure of Li4[(UO2)10O10(Mo2O8)

Dark-red crystals of the new compound Li(4)[(UO(2))(10)O10(Mo(2)O(8))] (1) have been obtained by high-temperature solid-state reactions. The structure of 1 (monoclinic, P2(1)/c, a = 7.9426(4) A, b = 19.9895(9) A, c = 10.0796(5) A, beta = 90.575(2) degrees, V = 1600.24(13) A(3), Z = 4) consists of a framework of U and Mo polyhedra with Li+ cations in the channels. The framework contains seven-polyhedra-wide uranium oxide tapes interlinked by dimers of edge-sharing [4 + 1]-distorted MoO(5) polyhedra. The U-O tapes are parallel to the a axis, and their planes are oriented parallel to (021) and (02) so that they are cross-linked within the framework. The core of the tapes consists of unprecedented one-dimensional arrays of cation-cation-bonded uranyl ions. The arrays are constructed from eight-membered cycles with uranyl ions linked through two- and three-center cation-cation interactions.