Interfacial tension of aqueous two-phase systems containing poly(ethylene glycol) and dipotassium hydrogenphosphate

Liquid-liquid equilibrium (LLE) compositions and interfacial tensions of the aqueous two-phase system containing poly(ethylene glycol) (PEG 4000, average Mr=3500; PEG 6000, average Mr=7500; and PEG 20000, average Mr =20000) and dipotassium hydrogenphosphate were experimentally determined by using a shaking flask method and a drop volume method at 288.15, 298.15 and 308.15 K, respectively.     

Search for Superconductivity in the Stress-Induced Ferromagnetic Phase of Sr3Ru2O7

To explore the possibility of the existences of superconductivity and ferromagnetism in Sr₃Ru₂O₇, we have performed resistivity measurements on a single crystalline sample under uniaxial stresses of 0–110 MPa along the c-axis (perpendicular to the conducting RuO₂ plane). In this stress region no superconductivity was so far detected down to at least 160 mK. At the same time an indication of ferromagnetism was not seen clearly in the resistivity, either. Technical difficulties yet to be overcome for further progress are discussed.     

Non-volatile one-transistor-cell multiple-valued CAM with a digit-parallel-access scheme and its applications

A new high-density non-volatile multiple-valued content-addressable memory (CAM) is proposed for highly parallel search operations. Multiple-valued stored data correspond to the threshold voltage of a floating-gate MOS transistor, so that the cell circuit can be designed using only a single transistor. Since a single match line in a one-word circuit is used for performing a multi-input wired AND operation, the magnitude comparison result between multi-digit data can be obtained simultaneously. As a result, a one-word magnitude comparison with n digits can be performed by just n steps in spite of a single-transistor cell circuit and single-match-line architecture, which makes the peripheral circuit of a CAM cell array small. Moreover, typical applications clearly demonstrate that the proposed non-volatile CAM is useful as a hardware accelerator for a high-speed comparison.     

Fine particle removal by a negatively-charged fine particle collector in silane plasma

To suppress inclusion of fine particles in amorphous silicon films, a negatively-charged fine particle (NFP) collector has been successfully installed in a silane plasma. Two modes of operation of the NFP collector biasing were examined: (i) turning on after the appearance of fine particles; and (ii) turning on from the very beginning of the plasma operation. While the former proved the effectiveness of the NFP collector in the removal of fine particles, apparently very small particles (<100 nm) removal in the latter reduced the degradation of the photo conductivity in deposited a-Si:H films by light soaking. This effect is accompanied by the increased density of SiH bonding, which can be related to the possible modification in the silicon networks in the amorphous film.     

Differential contribution of various adhesion molecules to leukocyte kinetics in pulmonary microvessels of hyperoxia-exposed rat lungs

To elucidate the differential role of various adhesion molecules in distorting leukocyte behavior in the microvasculature of hyperoxia-exposed rat lungs, we investigated fluorescein-labeled leukocyte and erythrocyte kinetics in isolated lungs taken from the animals exposed to 90% O2 for 48 h under conditions in which endothelial intercellular adhesion molecule-1 (ICAM-1) and P-selectin were inhibited by appropriate monoclonal antibodies (1A29 for ICAM-1 and ARP2-4 for P-selectin), while leukocyte L-selectin was restrained with fucoidin. Measurements of blood cell kinetics were made by a confocal laser luminescence microscope coupled with a high-speed video camera. In addition, we histologically examined leukocyte accumulation within the alveolar septa and ICAM-1 as well as P-selectin expressions in the lung. We found that P-selectin expression was sparsely enhanced only in arterioles, whereas ICAM-1 was significantly induced in both venules and capillaries. Firm adhesion of leukocytes was not identified in arterioles and venules, whereas leukocyte rolling was evident in both the vessels. Arteriolar rolling was regulated via a P-selectin- and ICAM-1-independent but L-selectin-dependent mechanism, whereas venular rolling was mediated via a P-selectin-independent but ICAM-1- and L-selectin-dependent pathway. Leukocyte sequestration within capillaries was augmented by an ICAM-1-related mechanism. These findings may suggest that, in hyperoxia-exposed lungs, induction of adhesion molecules and their obstacles to leukocyte behavior are qualitatively different among arterioles, venules, and capillaries.     

Controlled dispersion of a porphyrin/fullerene donor‐acceptor complex in semiconducting polymer thin films: Intermolecular interactions of polymers with porphyrin and fullerene

Thin films composed of semiconducting polymers [poly(2‐vinyl naphthalene), poly(4‐diphenyl aminostyrene), poly(1‐vinyl pyrene), and poly(3‐hexyl thiophene‐2,5‐diyl)], zinc(II)?5,10,15,20‐tetra‐(2‐naphthyl)porphyrin, and [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester blends were prepared to investigate the controlled dispersion of porphyrin molecules in semiconducting polymer thin films. Tailoring the intermolecular interactions between the polymer/fullerene, polymer/porphyrin, and porphyrin/fullerene systems was found to be an effective method of controlling the dispersion. When the polymer/porphyrin interactions were enhanced, intermixed porphyrin/fullerene donor–acceptor complex domains were formed, whereas under conditions where the polymer/porphyrin interactions were weakened, the complex assembled at the borders between the polymer and fullerene phases. This concept could potentially be applied to various combinations of porphyrin/fullerene systems in semiconducting polymer thin films to develop polymer solar cells with excellent performance. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41629.     

Investigation and Improvement of the Staggered Labyrinth Seal

Recent studies on staggered labyrinth seals have focused on the effects of different parameters,such as the pressure ratio and rotational speed on the leakage flow rate.However,few investigations pay sufficient attention to flow details and the sealing mechanism,which would be of practical importance in designing seals having higher performance.This paper establishes a theoretical model to study the seal mechanism,thus revealing that leakage is determined by the pressure ratio and geometric structure.Numerical simulation is implemented to illustrate details of the flow field within the seal structure.Viscous dissipation is used to quantitatively investigate the contribution that each location makes to the seal performance,revealing that orifices and stagnation points are the most important positions in the seal structure,generating the most dissipation.The orifice is carefully studied by using the theoretical model.Experiments for different pressure ratios are conducted and the results match well with those of the theoretical model and numerical simulation,verifying the theoretical model and analysis of the seal mechanism.Three new designs,based on a good understanding of the seal mechanism,are presented,with one reducing leakage by 24.5%.     

Modulation of Interparticle Distance in Discrete Gold Nanoparticle Dimers and Trimers by DNA Single‐Base Pairing

Self‐assembled structures of metallic nanoparticles with dynamically changeable interparticle distance hold promise for the regulation of collective physical properties. This paper describes gold nanoparticle dimers and trimers that exhibit spontaneous and reversible changes in interparticle distance. To exploit this property, a gold nanoparticle is modified with precisely one long DNA strand and approximately five short DNA strands. The long DNA serves to align the nanoparticles on a template DNA via hybridization, while the short DNAs function to induce the interparticle distance changes. The obtained dimer and trimer are characterized with gel electrophoresis, dynamic light scattering measurements, and transmission electron microscopy (TEM). When the complementary short DNA is added to form the fully matched duplexes on the particle surface in the presence of MgCl₂, spontaneous reduction of the interparticle distance is observed with TEM and cryo‐electron microscopy. By contrast, when the terminal‐mismatched DNA is added, no structural change occurs under the same conditions. Therefore, the single base pairing/unpairing at the outermost surface of the nanoparticle impacts the interparticle distance. This unique feature could be applied to the regulation of structures and properties of various DNA‐functionalized nanoparticle assemblies.