利用高性能模拟器件简化便携式医疗设备设计

目前,医疗电器OEM厂商正在开发技术含量更高的、用于治疗和监控常见疾病的个人保健设备。这些产品价格合理,极大提高了医疗保健质量。MCU在家用血压计、肺活量计、脉搏血氧计及心率监测器等便携式医疗设备中起着重要作用。大多数此类产品中的实际生理信号是模拟信号,在测量、监控或显示前需要进行放大、过滤等处理。     

Performance study on basin type double slope solar still with different wick materials and minimum mass of water

Solar still is one of the best solutions to solve water problem in remote arid areas. This device is not popular because of its lower productivity. One of the methods to increase the productivity is by decrease the volumetric heat capacity of the basin. A layer of water with wick material in the basin will increase the evaporation area and enhance the production.A basin type double slope solar still with mild steel plate was fabricated and tested with minimum mass of water and different wick materials like light cotton cloth, sponge sheet, coir mate and waste cotton pieces in the basin. Still with aluminium rectangular fin arranged in different configurations and covered with different wicks were also tested. It was found that, the still with light black cotton cloth is the effective wick material. The still with rectangular Aluminium fin covered with cotton cloth and arranged in length wise direction was more effective.The still was theoretically modeled. The variation in transmittance of the cover was considered in the proposed model. The total radiation on the covers was taken as input. Theoretical values of water and glass temperatures using proposed model were compared with theoretical values obtained by Dunkle model and actual experimental values. It was found that the theoretical production rate using the proposed model were close to the experimental.     

Experimental Investigation on the Performance of a Solar Still Using SiO2 Nanoparticles /Jatropha curcas L

Silicon - Now, enticing systematic civic since everywhere the world is used in green synthesis and benefit of the simple is eco-friendly with an emergent method of producing nanoparticles (NPs)....     

Variable thermal loading analysis on (111) plane of single crystal gold

The temperature response on the properties of single crystal gold (111) plane at elevated temperatures was considered in this work. The ability to perform nanoindentation experiments at elevated temperatures opens up significant new possibilities in nanotechnology. The experiments are performed at various temperatures of 373 K, 473 K and 573 K with tailor made Berkovitch tip of radius 100 nm to study the behavior of single crystal gold. The new phenomenon of material bouncing back under the indenter at the end of unloading was clearly noted, due to the accumulation of high energy. The results for different temperatures were compared. Our experiments clearly show the onset of the first burst of dislocation glide, which is indicated by a sudden increase of displacement with no increase of loading, the onset of plastic deformation in connection with the periodic bursts, and the strain hardening, softening and release effects. Pile up was also observed. The complete elastic range was found. There was significant drop in the hardness, elastic modulus and the increase in depth with increasing temperature. The elastic recovery was reduced at higher temperatures.     

Thermal behavior of aryl-aliphatic polyamides

Low molecular weight poly(p-phenylene sebacamides) and (m-phenylene sebacamides) were prepared by interfacial polycondensation by varying the concentration of p-and m-phenylenediamine in the initial feed. The polymers were characterized by intrinsic viscosity measurement and IR spectra. The relative thermal stability was evaluated by differential thermal analysis and dynamic thermogravimetry in air and nitrogen atmospheres. A systematic dependence of stability on intrinsic viscosity of poly(m-phenylene sebacamide) was observed indicating an endgroup initiation of degradation. No such dependence was observed in poly(p-phenylene sebacamide). A probable mechanism for the thermal degradation has been proposed.     

Interface Control of Ferroelectricity in an SrRuO3/BaTiO3/SrRuO3 Capacitor and its Critical Thickness

The atomic‐scale synthesis of artificial oxide heterostructures offers new opportunities to create novel states that do not occur in nature. The main challenge related to synthesizing these structures is obtaining atomically sharp interfaces with designed termination sequences. In this study, it is demonstrated that the oxygen pressure during growth plays an important role in controlling the interfacial terminations of SrRuO₃/BaTiO₃/SrRuO₃ (SRO/BTO/SRO) ferroelectric (FE) capacitors. The SRO/BTO/SRO heterostructures are grown by a pulsed laser deposition method. The top SRO/BTO interface, grown at high (around 150 mTorr), usually exhibits a mixture of RuO₂–BaO and SrO–TiO₂ terminations. By reducing , the authors obtain atomically sharp SRO/BTO top interfaces with uniform SrO–TiO₂ termination. Using capacitor devices with symmetric and uniform interfacial termination, it is demonstrated for the first time that the FE critical thickness can reach the theoretical limit of 3.5 unit cells.     

Studies on various divalent metal complexes of poly(2-hydroxy-4-acryloyloxybenzophenone) in aqueous medium

2-Hydroxy-4-acryloyloxybenzophenone (2H4ABP) prepared by reacting acryloyl chloride with 2,4-dihydroxybenzophenone, was polymerized in 2-butanone at 65°C using benzoyl peroxide as initiator. Polychelates were obtained in the alkaline solution of poly(2H4ABP) with aqueous solutions of metal ions such as Ni(II), Mn(II), Co(II), Ca(II), Cd(II) and Zn(II). The polymer and polychelates were characterized by elemental analyses and spectral studies. Elemental analyses of the polychelates suggest that the metal-to-ligand ratio is 1: 2. The IR spectral data of the polychelates indicate that the metals were coordinated through the oxygen of the keto group and oxygen of the phenolic −OH group. The diffuse reflectance spectra, EPR and magnetic moments studies reveal that the polychelates of Cu(II) complex are square planar, and Ni(II), Mn(II) and Co(II) complexes are octahedral, while Ca(II), Cd(II) and Zn(II) complexes are tetrahedral. X-ray diffraction studies revealed that the polychelates are highly crystalline. The thermal and electrical properties of polymer and polymer–metal complexes are discussed. © 1998 SCI.     

Synthesis and spectral,thermal, and photocrosslinking studies of poly(benzylidene phosphoramide ester)s

A new class of poly(benzylidene phosphoramide ester)s containing a photoreactive benzylidene chromophore in the main chain were synthesized from bis(4-hydroxy-3-methoxy benzylidene) acetone with various substituted N-aryl phosphoramidic dichlorides by an interfacial polycondensation technique. The synthesized polymers were characterized by inherent viscosity, IR, and ¹H-, ¹³C-, and ³¹P-NMR spectroscopy. The molecular weights of these polymers were determined by gel permeation chromatography. These polymers were studied for their thermal stability and photochemical properties. Thermal properties were evaluated by thermogravimetric analysis and differential scanning calorimetry. It was found that halogen-containing polymers show a higher thermal stability than that of nonhalogenated polymers. The photocrosslinking property of these polymers was studied by ultraviolet spectroscopy. The photoreactive benzylidene chromophore in the main chain dimerizes via 2π + 2π cycloaddition reaction to form a cyclobutane derivative and leads to crosslinking. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2151–2157, 1997     

Studies on photo-crosslinkable polyphosphoramide esters containing divanillylidene cycloalkanone units

Two series of photo-crosslinkable polyphosphoramide esters were synthesized from 2,5-bis(4-hydroxy-3-methoxy benzylidene)cyclopentanone and 2,6-bis(4-hydroxy-3-methoxy benzylidene)cyclohexanone with various N-arylphosphoramide dichlorides by interfacial polycondensation using hexadecyl trimethylammonium bromide as phase transfer catalyst at ambient temperature. The resulting polymers were characterized by inherent viscosity, Fourier transform infra-red, ¹H and ¹³C nuclear magnetic resonance spectroscopy. The thermal stability of the polymers synthesized was evaluated by thermogravimetric analysis. These polymers were studied for their photo-chemical reactions. The divanillylidene cycloakanone groups in the polymer chain function as photo-active centres. Crosslinking proceeds via 2π + 2π cycloaddition reaction of the divanillylidene cycloalkanone moieties. The rate of crosslinking decreases with increase in the size of the cycloalkanone ring, while the thermal stability increases with increase in the size of the cycloalkanone ring.     

Spectroscopic studies on DLC/TM (Cr,Ag, Ti,Ni) multilayers

The hydrogen-free diamond-like carbon (DLC) films with transition metal (TM = Cr, Ag, Ti, Ni) interlayer (bilayer and multilayer) were deposited on to stainless steel and silicon substrates using pulsed laser deposition technique. Secondary ion mass spectroscopy (SIMS) confirmed that the films were hydrogen free. Incorporation of chromium inter layer reduced the stress value by about 3 GPa as determined by micro Raman spectroscopy. Incorporation of the TM inter layer enhanced the photoluminescence (PL) intensity as compared to the monolithic DLC films. The optical band gap determined by spectroscopic ellipsometry for DLC/TM films was found to be in the range of 1.56–1.67 eV.