Intermediate Contact Research Articles

S134016 ピコ秒パルスレーザによるガラスの微細溶接法の検討([S134]先進特殊加工技術)

Glass materials have been widely used in optics, MEMS, electronics and biomedical applications because of their excellent optical, mechanical and chemical properties. Fusion welding by ultrashort pulsed laser has been proposed as a promising technique for glass joining, since joining can be accomplished without any intermediate layer and mechanical contact. In this study, a method of evaluating the weld bead in the fusion welding of glass by picosecond pulsed laser was discussed, and its mechanical strength was investigated. A larger optical contact area had a great influence on the shear load of weld bead, while a smaller optical contact area could reduce the influence of the contact area on the measurement of shear load. Therefore, it was important to reduce the optical contact area to evaluate the shearing strength of weld bead accurately. The shear stress of weld bead decreased at a low pulse repetition rate, while it could increase at a proper pulse repetition rate.

Spot morphology of non-contact printed protein molecules on non-porous substrates with a range of hydrophobicities

Non-contact inkjet printing technology is one of the most promising tools for producing microarrays. The quality of the microarray depends on the type of the substrate used for printing biomolecules. Various porous and non-porous substrates have been used in the past, but due to low production cost and easy availability, non-porous substrates like glass and plastic are preferred over porous substrates. On these non-porous substrates, obtaining spot uniformity and a high signal to noise ratio is a big challenge. In our research work, we have modified pristine glass slides using various silanes to produce a range of hydrophobic glass substrates. The hydrophobicities of the slides expressed in the contact angle (θ) of a sessile drop of water were 49°, 61°, 75°, 88° and 103°. Using a non-contact inkjet printer, microarrays of biotinylated biomolecules (BSA and IgG) were produced on these modified glass substrates, pristine (untreated) glass and also on HTA polystyrene slides. The uniformity of the spots, reflecting the distribution of the biomolecules in the spots, was analyzed and compared using confocal laser scanning microscopy (CLSM). The quality of the spots was superior on the glass slide with a contact angle of ∼75°. We also investigated the influence of the hydrophobicity of the substrate on a two-step, real diagnostic antibody assay. This nucleic acid microarray immunoassay (NAMIA) for the detection of Staphylococcus aureus showed that on highly hydrophilic (θ < 10°) and hydrophobic substrates (θ > 100°) the assay signal was low, whereas an excellent signal was obtained on the substrates with intermediate contact angles, θ ∼ 61° and θ ∼ 75°, respectively.

Scale effects in convoluted thermal/spatial statistics of plasticity initiation in small stressed volumes during nanoindentation

The elastic–plastic transition of crystals at small length scales can be quantitatively evaluated by sudden discontinuities (pop-ins) on nanoindentation load–displacement curves. For defect free crystals under nanocontacts, pop-in stress fluctuations result purely from the thermally activated process of homogeneous dislocation nucleation, while at intermediate contact sizes, fluctuations can arise from the spatial statistics of pre-existing defects. Here, we find that the convolution of the above thermal and spatial effects exhibits a distinct dependence on the stressed volume size, dislocation density and geometric factors that describe crystallography and slip anisotropy. These essential features are captured in a unified model that includes both homogeneous dislocation nucleation and heterogeneous activation of pre-existing dislocations. Our theoretical predictions compare remarkably well with experimental findings. In particular, the model describes the observed strong and complex dependence of pop-in probability on indentation direction in NiAl. Implications for other small scale mechanical tests such as micropillar compression are discussed.

Cytocompatibility of polymer-based periodontal bone substitutes in gingival fibroblast and MC3T3 osteoblast cell cultures

ObjectivesInflammatory periodontal diseases are accompanied by destruction of periodontal tissue and alveolar bone. Infrabony lesions can be regenerated with adequate bone substitutes, which require high biocompatibility of the material. MethodsTo rate the biocompatibility of nine polymeric periodontal bone substitutes (Bio 1–Bio 9), cell viability and cytotoxicity assays were performed. For viability, human gingival fibroblasts (HGFs) and MC3T3 osteoblasts were cultured on the bone substitutes. For cytotoxicity, biomaterial extracts were prepared by incubation with culture medium for maximally 28days, and cells were exposed to the extracts for 1day. Polymers Bio 1 to Bio 5 were prepared by solvent casting, Bio 6 to Bio 9 by photopolymerization of the monomers at wavelengths of 400–500nm in the presence of a suitable photoinitiation system. ResultsBio 1, Bio 3, Bio 4, Bio 5, and Bio 7 showed moderate to excellent cytocompatibility for both HGFs and osteoblasts in viability tests. Together with the results of the cytotoxicity assays, four of the nine tested polymers were considered cytocompatible: Bio 1 (poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate; PVB)), Bio 4 and Bio 5 (functionalized oligolactones), and, to a limited degree, Bio 7 (urethane methacrylate). Except for Bio 7, the cytocompatible polymers showed intermediate water contact angles (74–85°) and therefore moderate to low hydrophilicity. SignificanceThe non-cross-linked polymers Bio 1, Bio 4, or Bio 5, and the photopolymerized polymeric network Bio 7 display good/excellent cytocompatibility and are therefore potential candidates for tissue engineering in alveolar bone substitution.

Proteksi Arus Bocor Pada Instalasi Listrik Dengan Saklar Arus Bocor 30 mA

This research was conducted in order to provide data, information, and earth leakage current protection with ELCB 30 mA. Of this research is expected we all's benefit to know how big ability earth leakage current protection. ELCB really help life being if stung by electricity current. There is ways of working even from ELCB is while happens electricity intermediate contact with human body, therefore current will pass human body making for grounding. ELCB is protection of leak current, so current totaled amount one passes ELCB'S input terminal with terminal its different issue, the difference totaled that current triggers ELCB to decide instantaneous current so lurching aculeate electric gets to be avoided. There is sensitivity even ELCB to detect current is 15 mA, 30 mA and 50 mA. &amp;nbsp;&amp;nbsp;&amp;nbsp; The electric current wreck two vital body functions that are respiration and cardiac beat. Man most one stung electricity current having zoom robustness variably for age. But in general the effect depends on the amount of electricity current flow (ampere). Base on testing of leakage current protection with&amp;nbsp; ELCB 30 mA, it is known that ELCB will trip/off when load current 22,33 A, leakage current is 23.04 mA, and resistance 9.86 K-ohm.

Assessment of exposure to intermediate frequency electric fields and contact currents from a plasma ball

While electric fields at intermediate frequencies are not widely utilized for industrial technologies, surprisingly, certain toys emit the highest electric fields found in our living environment. These toys, plasma balls, are devices that use high voltage to create ionized light discharges. In this study, we assessed exposure to electric fields and contact/induced current from a recreational plasma ball device. The electric field strength was measured as a function of distance from the device, and the contact/induced current was measured with a current clamp in different exposure situations with point or grasping contact. The characteristic spectra of the electric field and contact current were measured, and both the multiple frequency rule and weighting of the spectra were applied according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) 1998 and 2010 guidelines. The results indicate that the recommended reference levels for the general public are exceeded at distances <1.2 m, and that the contact currents in the hand may be twice higher than recommended by the general public guidelines.

Wettability Control Mechanism of Highly Contaminated Hydrophilic Silica/Alumina Surfaces by Ethyl Cellulose

In a previous study (Feng et al. Langmuir2010, 26, 3050), a biodegradable ethyl cellulose (EC) was proven to be an effective demulsifier for water-in-diluted bitumen emulsions by flocculation-enhanced coalescence through the displacement of protective interfacial films. In the current study, the potential of EC in displacing the asphaltene or bitumen layers adsorbed on hydrophilic silica and alumina surfaces is investigated in an attempt to explore the applicability of EC as a chemical modifier to control the wettability of solids contaminated by heavy oils. The quartz crystal microbalance with dissipation (QCM-D) was used to determine the adsorption of EC on silica or alumina which has a thin layer of asphaltene contaminant (preadsorbed). For comparison, the adsorption of asphaltenes on silica or alumina which was preadsorbed with EC was also determined. The effect of EC on the wettability and morphology of the asphaltene- or bitumen-contaminated (coated) silica or alumina surfaces was determined by contact angle measurement and atomic force microscope (AFM) imaging. The measurements were conducted before and after soaking the asphaltene- or bitumen-coated silica and alumina wafers in EC-in-toluene solution. The results of QCM-D showed irreversible adsorption of asphaltenes on silica surface. However, EC was found to adsorb on and/or displace the irreversibly preadsorbed asphaltenes from silica and alumina surfaces. Atomic force microscope imaging confirmed a gradual displacement of the preadsorbed asphaltenes or bitumen by EC from silica wafer surfaces, in which the asphaltene/bitumen contaminants were forced into sporadic larger aggregates. After 7 h of contact with EC-in-toluene solutions, the majority of the silica substrate surfaces precontaminated by asphaltenes or bitumen were covered with EC. Correspondingly, the contact angle of water decreased from about 88° and 67° of the original asphaltene- and bitumen-coated surfaces, respectively, to final values in the range of 20–30° which are similar to that of the EC-coated surface. Effect of EC adsorption on increasing the wettability of chemically hydrophobized (silanized) silica surface with water contact angle from 80° to 100°, is more conservative, leading to an intermediate water contact angle of 60–70° due to its weak binding and different conformations of EC on hydrophobic surfaces from that on hydrophilic surfaces. These findings demonstrated the possibility of using EC to modify the wettability of hydrocarbon-contaminated inorganic solids (clays) to improve heavy oil processing.

Influence of Hydrophobicity on the Surface-Catalyzed Assembly of the Islet Amyloid Polypeptide

The islet amyloid polypeptide (IAPP) is a hormonal factor secreted by the β-cells in the pancreas. Aggregation of misfolded IAPP molecules and subsequent assembly of amyloid nanofibrils are critical for the development of type 2 diabetes mellitus. In the physiological environment, amyloid aggregation is affected by the presence of interfaces such as cell membranes. The physicochemical properties of the interface dictates the interaction of the peptide with the surface, i.e., electrostatic and hydrophobic interactions on hydrophilic and hydrophobic surfaces, respectively. We have studied the influence of hydrophobicity on the surface-catalyzed assembly of IAPP on ultrasmooth hydrocarbon films grown on ion-beam-modified mica surfaces by atomic force microscopy. The contact angle θ of these surfaces can be tuned continuously in the range from ≤20° to ∼90° by aging the samples without significant changes of the chemical composition or the topography of the surface. On hydrophilic surfaces with a θ of ∼20°, electrostatic interactions induce the assembly of IAPP nanofibrils, whereas aggregation of large (∼2.6 nm) oligomers is observed at hydrophobic surfaces with a θ of ∼90°. At intermediate contact angles, the interplay between electrostatic and hydrophobic substrate interactions dictates the pathway of aggregation with fibrillation getting continuously delayed when the contact angle is increased. In addition, the morphology of the formed protofibrils and mature fibrils at intermediate contact angles differs from those observed at more hydrophilic surfaces. These results might contribute to the understanding of the surface-catalyzed assembly of different amyloid aggregates and may also have implications for the technologically relevant controlled synthesis of amyloid nanofibrils of desired morphology.

Amorphous Photodiode with an Intermediate Contact for Improved Color Separation

ABSTRACTMost of actual photonic devices being sensitive in the visible (VIS) spectrum are based on crystalline silicon (x-Si). The production of x-Si requires an expensive high temperature process. The color reproduction with x-Si diodes additionally requires an integration of color filters [1] to realize a shift in spectral sensitivity. This work presents an amorphous silicon (a-Si:H) photodiode with an intermediate contact for color separation without color filters. Such detectors can be produced in a low cost and low temperature PECVD process, which allows their direct deposition on a custom specific ASIC [2]. Another advantage of a-Si:H is the up to 10 times higher light absorption compared to that of x-Si in the VIS spectrum [3]. The device consists of a metal (Cr) cathode, an amorphous NIP diode structure and a TCO (Al doped ZnO) anode. The I-layer includes an interior TCO contact buried between two P-layers. The thickness of this TCO layer is about 200 nm; the P-layers have a thickness of about 10 nm. The chromium cathode is sputtered on a glass substrate in a PVD process. The amorphous layers are deposited in a multi-chamber PECVD line; the buried and top TCO contacts are sputtered in the same line continuously under high-vacuum conditions. In a first photolithography step the top anode is patterned while the buried anode is uncovered. Afterwards, the diode must be patterned again, resulting in a final Cr, NIP-a-Si:H, TCO, PIP-a-Si:H and TCO multi-layer stack.The spectral sensitivity of a common NIP diode can be shifted by external bias voltages. The spectral sensitivity at higher negative voltages overlays those of that at lower voltages and additionally shifts to longer wavelengths. The color reproduction is difficult; it can be improved by reducing the overlap of the spectral sensitivity [4]. The spectral response of the diodes presented in this work also can be shifted by the bias voltage. Furthermore, it can be split by substituting the disclosed anodes. The spectral response, using the cathode and top anode has a maximum at short wavelengths. If the diode between the interior anode and the cathode is used, the spectral sensitivity for longer wavelengths increases. Shorter wavelengths are blocked by the top part of the diode; it works like a filter. The presented device structure offers good prospects to improve color separation compared to currently existing detectors by using an additional intermediate contact.

Retracting and seeking movements during laparoscopic goal-oriented movements. Is the shortest path length optimal?

AimsMinimally invasive surgery (MIS) requires a high degree of eye–hand coordination from the surgeon. To facilitate the learning process, objective assessment systems based on analysis of the instruments’ motion are being developed. To investigate the influence of performance on motion characteristics, we examined goal-oriented movements in a box trainer. In general, goal-oriented movements consist of a retracting and a seeking phase, and are, however, not performed via the shortest path length. Therefore, we hypothesized that the shortest path is not an optimal concept in MIS.MethodsParticipants were divided into three groups (experts, residents, and novices). Each participant performed a number of one-hand positioning tasks in a box trainer. Movements of the instrument were recorded with the TrEndo tracking system. The movement from point A to B was divided into two phases: A-M (retracting) and M-B (seeking). Normalized path lengths (given in %) of the two phases were compared.ResultsThirty eight participants contributed. For the retracting phase, we found no significant difference between experts [median (range) %: 152 (129–178)], residents [164 (126–250)], and novices [168 (136–268)]. In the seeking phase, we find a significant difference (<0.001) between experts [180 (172–247)], residents [201 (163–287)], and novices [290 (244–469)]. Moreover, within each group, a significant difference between retracting and seeking phases was observed.ConclusionsGoal-oriented movements in MIS can be split into two phases: retracting and seeking. Novices are less effective than experts and residents in the seeking phase. Therefore, the seeking phase is characteristic of performance differences. Furthermore, the retracting phase is essential, because it improves safety by avoiding intermediate tissue contact. Therefore, the shortest path length, as presently used during the assessment of basic MIS skills, may be not a proper concept for analyzing optimal movements and, therefore, needs to be revised.

Thermal and spectroscopic analysis of worn polyoxymethylene surfaces and wear debris explaining degradation and polymerisation mechanisms

Degradation and polymerization of polyoxymethylene homopolymer (POM-H) surfaces after sliding at 8 to 150 MPa and 0.005 m/s over a total sliding distance of 3000 m is investigated by using thermal analysis (DSC, TGA, DTA) and Raman spectroscopy of worn surfaces or wear debris. There is mainly mechanical interaction and slight softening at 8 MPa (relatively high friction, low wear), softening at 16 to 55 MPa (decreasing friction and high wear) and finally melting at 150 MPa (very low friction, overload wear). At low contact pressures, wear debris remains amorphous and degradation of noncrystallised material during sliding manifests in broadening of the melting peak below the melting temperature. Degradation of C–O–C due to chain scission and radical reactions into CH3 end groups are illustrated by Raman spectra. It is confirmed that the debris has long resident times and the maximum polymer surface temperature (T* = 93°C) is below the crystallisation temperature. At intermediate contact pressures, crystallisation results in a polymer fraction with higher thermal resistance. From the calculated temperatures T* = 120 to 150°C, crystallisation is beneficial for coherent transfer with larger particle sizes. At high contact pressures, the wear debris is immediately removed from the contact interface due to melting (T* = 200°C) and has thermal properties similar to the bulk material. There is no reaction between the debris in the interface, resulting in a thick polymer transfer film.

Developing technology for production of combined fibres for protective articles

The possibility of fabricating inhomogeneous conducting fibres for preparation of special clothing on the winding machine bench was demonstrated. The structure of a combined conducting fibre in which the necessary contact between the current-conducting intermediate product and contact conductor is attained was developed; it ensured electrical resistance of gloves of less than 30 Ω and a high breaking load.

Molecular modeling of the complex between Torpedo acetylcholine receptor and anti-MIR Fab198

Myasthenia gravis is a neuromuscular disorder caused by an antibody-mediated autoimmune response to the muscle-type nicotinic acetylcholine receptor (AChR). The majority of monoclonal antibodies (mAbs) produced in rats immunized with intact AChR compete with each other for binding to an area of the α-subunit called the main immunogenic region (MIR). The availability of a complex between the AChR and Fab198 (Fab fragment of the anti-MIR mAb198) would help understand how the antigen and antibody interact and in designing improved antibody fragments that protect against the destructive activity of myasthenic antibodies. In the present study, we modeled the Torpedo AChR/Fab198 complex, based primarily on the recent 4 Å resolution structure of the Torpedo AChR. In order to computationally dock the two structures, we used the ZDOCK software. The total accessible surface area change of the complex compared to those of experimentally determined antigen–antibody complexes indicates an intermediate size contact surface. CDRs H3 and L3 seem to contribute most to the binding, while L2 seems to contribute least. These data suggest mutagenesis experiments aimed at validating the model and improving the binding affinity of Fab198 for the AChR.

Low-resistive metal/n+-InAsSb/n-GaSb contacts

We present low-resistive electrical contacts to n-type GaSb with Te doping of 5 × 1017 cm−3 using a Ti/Pt/Au (1/35/275 nm) metalization sequence and an intermediate InAsSb contact layer with n-doping of 1 × 1020 cm−3 (also Te). The high doping level is achieved during growth, so in-diffusion of dopants is not required. To reduce the impact of the native oxide layer we remove it in a sputter-etching process using Ar ions and afterwards deposit the metalization in the same chamber. No annealing is necessary to achieve ohmic IV-characteristics with a resistivity as low as 5.1 × 10−6 Ω cm2. It improves to 3.3 × 10−6 Ω cm2 after annealing at 350 °C for 90 s. The resistivity slightly increases for deeper etching of the native oxide, which is probably due to surface damage induced during the sputter-etching process.

Surface functionalized titanium thin films: Zeta-potential, protein adsorption and cell proliferation

The relationship between electric charge at a material surface and protein adsorption is essential to understand the mechanism of biological integration of materials with tissues. This study investigated the influence of titanium thin films’ surface chemistry and surface electric charge (zeta-potential) properties on protein adsorption and cell proliferation. Titanium thin films were surface functionalized with different functional end groups, such as CH CH 2, NH 2 and COOH groups in order to produce surfaces with a variety of electric charge properties. The chemical compositions, electric charges and wettability were investigated by using X-ray photoelectron spectroscopy (XPS), zeta-potential measurements and water contact angle measurements, respectively. XPS revealed the surface functionalization of titanium films with CH CH 2, NH 2, and COOH groups, which were converted from CH CH 2 groups. Ti COOH samples showed the lowest water contact angles and zeta-potential compared to all other samples investigated in this study. NH 2-terminated titanium films displayed intermediate contact angles of 70.3 ± 2.5°. Fibrinogen adsorption on titanium films and surface functionalized titanium films were investigated in this study. Ti–COOH samples displayed a lower protein adsorption than all other groups, such as NH 2 , CH CH 2-terminated titanium thin films. A tendency that the lower zeta-potential of the samples, the lower the protein adsorption at their surfaces was observed. In vitro cell proliferation tests were also performed on the different surface functionalized titanium films. NH 2-terminated titanium films displayed good cell proliferation and cell viability tendency. However, a lower cell proliferation on COOH-terminated titanium films was observed compared with NH 2-terminated titanium films. This effect was attributed to the difference in protein adsorption of these samples.

Testing the Three Step Excited State Proton Transfer Model by the Effect of an Excess Proton

In a previous work, we proposed an extended model for intermolecular excited-state proton transfer to the solvent. The model invoked an intermediate species, the contact ion-pair RO(-)...H(3)O(+), where a proton is strongly hydrogen bonded to the conjugated photabase RO(-). In this study we tested the extended model by measuring the transient absorption and emission of 8-hydroxypyrene-1,3,6-trisulfonate (HPTS) in an aqueous solution in the presence of a large concentration of mineral acids. In a neutral pH solution, the pump-probe signal consists of three time components, <1, 4, and 100 ps. The 4 ps time component, with a relative amplitude of about 0.3, was attributed to the formation of the contact ion-pair and the long 100 ps component to the dissociation of the ion-pair to a free proton and RO(-). In the presence of acid, the recombination of an excess proton competes with the geminate recombination. At a high acid concentration, the recombination process alters the time-dependent concentrations of the reactant, product and intermediate contact ion-pair. We observed that when the acid concentration increases, the amplitude of both the long and intermediate time components decreases. At about 3 M of acid, both components almost disappear. Model calculations of the acid effect on the transient HPTS signal indeed showed that the amplitude of the intermediate time component decreases as the excess proton concentration increases.

Distance perception from motion parallax and ground contact

Meng and Sedgwick (2001, 2002) found that the perceived distance of an object in a stationary scene was determined by the position at which it contacted the ground in the image, or by nested contact relations among intermediate surfaces. Three experiments investigated whether motion parallax would allow observers to determine the distance of a floating object without intermediate contact relations. The displays consisted of one or more computer-generated textured cylinders inserted into a motion picture or still image of an actual 3-D scene. In the motion displays, both the cylinders and the scene translated horizontally. Judged distance for a single cylinder floating above the ground was determined primarily by the location at which the object contacted the ground in the projected image (“optical contact”), but was altered in the direction indicated by motion parallax. When more than one cylinder was present and observers were asked to judge the distance of the top cylinder, judged distance moved closer to that indicated by motion parallax, almost matching that value with three cylinders. These results indicate that judged distance in a dynamic scene is affected both by optical contact and motion parallax, with motion parallax more effective when multiple objects are present.

Some Observations on the Contraction Behavior of a Water-in-Oil Drop with Attached Solids

One of the factors responsible for the high stability of water-in-bitumen or water-in-crude oil emulsions is the presence of a complex adsorbed layer of material at the water−oil interface. However, except for its role as a steric barrier, little is known about the nature and activity of this layer. Studying a macroscopic drop, on which interfacial adsorbed particles can be controlled and directly observed, will provide useful information that can be linked to the behavior of real emulsion systems. A macroscopic drop prepared using silicone oil, water, and silica particles was studied in this work. The results of this study indicate that the presence of slightly hydrophobic particles at the water−oil interface is sufficient to cause the interface crumpling that has been observed with water drops in crude oil or bitumen subjected to interfacial area reduction. For crumpling to occur, the particles need to remain strongly attached to the interface (i.e., have intermediate contact angles) as the drop interfa...

Transition from split streamlines to dip-coating during Langmuir–Blodgett film deposition

Mono-molecular films of arachidic acid were deposited on glass slides using the Langmuir–Blodgett (LB) technique. The liquid subphases were dilute solutions of ZnSO 4 at different pH. Glass slides were treated to create contact angles ( θ) ranging from approximately 15° for clean glass slides, to contact angles greater than 120° for slides treated with ferric stearate. Intermediate contact angles were created by immersing slides in solutions of Sigmacote ® of varying concentration. Very small contact angles, θ≈0° were obtained with clean glass slides at high pH values. LB deposition data and transfer ratios (TR) were recorded for up-stroke and down-stroke operation. During upstroke, TR increase with decreasing contact angles reaching a maximum TR close to 100% when the receding contact angle is approximately 15–20°. This is typical of the split-ejection flow pattern found during up-stroke. For very small contact angles, i.e. less than 10°, TR suddenly become zero indicating a transition to a dip-coating flow pattern. During down-stroke operation, TR is zero or negative for small contact angles, reaching a maximum TR approximately 100% for contact angles larger than 120°.

Addition of lithiated 5-hydroxymethyl-1,3-dithiane to benzaldehyde: HMPA-controlled trans stereoselectivity.

Addition of 5-substituted dithianyl anions to carbonyl compounds normally produces trans adducts. The presence of a nucleophilic hydroxymethyl group in position 5 dramatically decreases the trans stereoselectivity of the reaction in THF. The trans/cis ratio shows a bell curve dependence on HMPA, fitted to a quantitative model involving a series of equilibrated ion pairs, of which an intermediate contact ion pair possessing three (effective) HMPA molecules yields the trans adduct with much higher stereoselectivity. [structure: see text]