Preparation and optical properties of an all‐polymer light modulator using colored N‐isopropylacrylamide gel particles in a gel‐in‐gel system

A novel all‐polymer light modulator with a gel‐in‐gel system was developed. The gel‐in‐gel system was constructed with colored gel particles responsive to stimuli held independently in another stimuli‐nonresponsive gel matrix. Well‐known thermoresponsive N‐isopropylacrylamide (NIPAM) gel particles containing a pigment were dispersed and fixed in an outer stimuli‐nonresponsive gel matrix. When poly(vinyl alcohol)–styrylpyridinium (PVA–SbQ) was used for the outer gel matrix, the light modulator showed excellent color‐changing properties because the PVA–SbQ matrix was selectively formed around the NIPAM gel particles and the particles exhibited a large volume change in the matrix. The temperature when the outer gel matrix was formed affected the haze of the light modulator. When the outer gel matrix was formed in the swollen state of the NIPAM gels, the haze of a light modulator increased with heating. On the contrary, the haze of a light modulator prepared in the shrunken state of the NIPAM gels decreased with heating. The response time of the color change was less than 1 s. The gel‐in‐gel system made a very fast macroscopic color change, taking advantage of the fast response of the micrometer‐sized gel particles. We believe that a light modulator with a gel‐in‐gel system may find various applications in optical devices. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2295–2303, 2007     

铽-聚N-乙烯基乙酰胺-1,10-菲罗啉三元配合物的光学性能

以N乙烯基乙酰胺(NVA)为原料通过自由基聚合反应合成了N乙烯基乙酰胺(PNVA),在乙醇溶液中合成了铽聚N乙烯基乙酰胺1,10菲罗啉(TbPNVAphen)的三元稀土高分子配合物。利用FTIR、UV-vis和荧光光谱对三元配合物进行了结构表征。荧光光谱表明,配合物的最佳激发波长为304nm;在此波长激发下,配合物在490nm和546nm处发出较强铽的特征荧光,荧光强度分别为846.853和2086.798,分别比TbPNVA配合物增强了1310%和1290%。     

Effect of regeneration temperatures in the exergetic performances of the developed desiccant-evaporative air-conditioning system

The developed desiccant-evaporative air-conditioning system was evaluated using the exergetic method under controlled environmental conditions to determine the performances of the whole system and its components.Percentage contributions of exergy destruction of system components at different regeneration temperatures and reference temperatures were determined. Exergy destruction coefficient of different components at different regeneration and reference temperatures were presented. It was shown that exergetic performances varied with respect to the regeneration and reference temperatures. The exergetic performances based on thermal, electric, total exergy input, first definition and second definition efficiencies were shown.Based on the results, reference and regeneration temperatures affected the determination of the system performances and its components. It was shown that air-heating coil, air fans and desiccant wheel contributed to large percentage of exergy destruction. Hence, the mentioned components should be given attention for further improvement of the system performances.     

Alternate drop coating for forming dual biointerfaces composed of polyelectrolyte multilayers

Two types of polyelectrolyte multilayers were formed on both sides of a quartz crystal microbalance (QCM) substrate by a novel alternate drop coating process. In this study, poly(diallyldimethylammonium chloride) (PDDA) and poly(sodium 4-styrene sulfonate) (PSS) were used as strong-strong polyelectrolytes. On the other hand, PDDA and poly(acrylic acid) (PAA) were used as strong-weak polyelectrolytes. The novel alternate drop coating process can separately fabricate each polyelectrolyte multilayer on both sides of the substrate. The substrate provides dual biointerfaces, both sides of which comprise different multilayers, by employing a combination of polymers. The formation of the multilayer by alternate drop coating was evaluated in terms of changes in the frequency of the QCM and model protein adsorption for proteins such as bovine serum albumin, and their characteristics were investigated with those of the conventional alternate adsorption process by performing dip coating. There was no significant difference between the surface properties resulting from the two formation conditions. This result strongly supported the fact that the multilayers fabricated by alternate drop coating were similar in quality to those fabricated by conventional dip coating. The resulting dual biointerfaces with polyelectrolyte multilayers provide alternative biofunctions in terms of individual protein loading. In summary, the novel alternate drop coating process for substrates is a good candidate for the preparation of dual biointerfaces in the biomedical field.     

Study on shock wave and turbulent boundary layer interactions in a square duct at Mach 2 and 4

In this paper, the outline of the Mach 4 supersonic wind tunnel for the investigation of the supersonic internal flows in ducts was firstly described. Secondly, the location, structure and characteristics of the Mach 2 and Mach 4 pseudo-shock waves in a square duct were investigated by color schlieren photographs and duct wall pressure fluctuation measurements. Finally, the wall shear stress distributions on the side, top and bottom walls of the square duct with the Mach 4 pseudo-shock wave were investigated qualitatively by the shear stress-sensitive liquid crystal visualization method. The side wall boundary layer separation region under the first shock is narrow near the top wall, while the side wall boundary layer separation region under the first shock is very wide near the bottom wall.     

Acute aortic dissection complicated with acute myocardial infarction--a case report of successful operation for the case of DOA

A 61-year-old woman who suddenly manifested chest and back pain was admitted after the diagnosis of acute type A dissection complicated with acute inferior myocardial infarction at another hospital. While being transported to our hospital by ambulance, her ECG repeatedly demonstrated ventricular fibrillation of cardiac arrest. She was in the state of dead on arrival (DOA) when arrived at our hospital. ECG demonstrated complete A-V block and cardiac arrest alternately. However, soon after right ventricular pacing was done, her blood pressure increased and she recovered consciousness. We therefore performed an emergency operation. We performed reconstruction of the ascending aorta and right coronary bypass grafting, since she had aortic dissection and conus brach avulsion. The postoperative course was uneventful.     

Formation of giant liposomes promoted by divalent cations: critical role of electrostatic repulsion

Spontaneous formation of giant unilamellar liposomes in a gentle hydration process, as well as the adhesion energy between liposomal membranes, has been found to be dependent on the concentration of divalent alkali cations, Ca2+ or Mg2+, in the medium. With electrically neutral phosphatidylcholine (PC), Ca2+ or Mg2+ at 1-30 mM greatly promoted liposome formation compared to low yields in nonelectrolyte or potassium chloride solutions. When negatively charged phosphatidylglycerol (PG) was mixed at 10%, the yield was high in nonelectrolytes but liposomes did not form at 3-10 mM CaCl2. In the adhesion test with micropipette manipulation, liposomal membranes adhered to each other only in a certain range of CaCl2 concentrations, which agreed with the range where liposome did not form. The adhesion range shifted to higher Ca2+ concentrations as the amount of PG was increased. These results indicate that the divalent cations bind to and add positive charges to the lipids, and that membranes are separated and stabilized in the form of unilamellar liposomes when net charges on the membranes produce large enough electrostatic repulsion. Under the assumption that the maximum of adhesion energy within an adhesive range corresponds to exact charge neutralization by added Ca2+, association constants of PC and PG for Ca2+ were estimated at 7.3 M(-1) and 86 M(-1), respectively, in good agreement with literature values.     

Genetic variation of envelope gp90 gene of equine infectious anemia virus isolated from an experimentally infected horse

Six strains of equine infectious anemia virus (EIAV) were recovered from febrile and non-febrile stages of a horse experimentally infected with the P337-V70 strain given once to a horse. The env gp90 genes of the isolates, the P337-V70 and P337-V26, avirulent virus derived from the P337-V70 strain, were sequenced. A comparison of the gp90 gene sequences revealed that amino acid variations among the viruses tested showed as high as 8.2 to 11.5%. In addition, the comparison also indicated that the isolates that recovered from the non-febrile stage were contained in nucleotide insertions in the principal neutralizing domain (PND) region. The insertions were arranged regularly with smaller segments. The nucleotide sequence of the P337-V26 gp90 gene was found to contain a six-nucleotides insertion and seven nucleotide substitutions outside the PND region, when compared with that of the P337-V70 strain.