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Considering the fact that large surface areas and fast electron transport properties of photoanodes play an essential role in determining dye sensitized solar cell efficiency. A centrifugation-assisted method was designed to fabricate nanoparticle decorated hierarchical nanowire arrays. The hierarchical nanostructure arrays enable the fast charge transport properties of the photoanode. At the same time, the nanoparticles and the hierarchical nanostructures work together to guarantee the large surface areas of the photoanodes. During the fabrication process, TiO2 hierarchical nanowire arrays were firstly fabricated on fluorine doped tin oxide substrates via a hydrothermal method and then nanoparticles were deposited subsequently in the interval spaces among the neighboring nanostructures. Field-emission scanning electron microscopy and X-ray diffraction were used to characterize the morphology and structure of the obtained products, respectively. The results show that the nanoparticles do deposit in the interval spaces among the hierarchical nanowires forming a hybrid structure composed of anatase and rutile TiO2. The obtained nanoparticle decorated hierarchical nanowire arrays have been successfully applied in dye sensitized solar cells. A power conversion efficiency of 5.52% was achieved with the photoanode film thickness of about 20 µm.

OBJECTIVE To assess the efficacy of septoplasty and the correlation between the subjective evaluations of a visual analogue scale (VAS) and the Nasal Obstruction Symptom Evaluation (NOSE) questionnaire and active anterior rhinomanometry of the nasal airway after septoplasty. DESIGN A retrospective, individual cohort study. SETTING Ear, Nose and Throat Department, Taipei City Hospital, Taipei, Taiwan. PARTICIPANTS Fifty patients with chronic nasal obstruction were enrolled in the study. All 50 patients underwent septoplasty because of nasal septal deviation. Another 28 patients without nasal symptoms served as controls. MAIN OUTCOME MEASURES VAS, NOSE and active anterior rhinomanometry were used to measure the sensation of nasal obstruction. All measurements were performed in both groups preoperatively and then repeated on three postoperative visits (3, 6 and 12 months). RESULTS The mean VAS score, NOSE score and the nasal resistance in the narrow side of the nose in the study group showed reduced symptoms at 3, 6 and 12 months postoperatively compared with the respective preoperative measurements (P < 0.001, all). The VAS and NOSE scores did not significantly correlate with total nasal resistance preoperatively or postoperatively. The VAS and nasal resistance in the obstructed nasal cavity correlated significantly preoperatively (P < 0.05), but not postoperatively. CONCLUSIONS The subjective and objective symptoms of nasal obstruction had improved 1 year after septoplasty. A significant correlation between VAS scores and nasal resistance in the narrow side of the nose was found before surgery. The subjective and objective measurements of nasal obstruction lacked significant correlation postoperatively.

Magnet supports is one of the key components to sustain the ITER superconductor magnet coils, which operate at several K low temperature. Cooling of the supports is needed for maintaining temperature balance. It is suggested to use brazing connection to attach the thermal anchor to the support which made from SS 316LN plates. In this study, several kinds of brazing filler were developed as candidates, including Sn–Pb brazing filler, Ag-based and Cu-based brazing filler. The test result shows that Ag-based brazing filler has the best weldability with 316LN, but Cu-based alloy shows the best mechanical properties at both room temperature and 77 K. Even though the Sn–Pb alloy shows the lowest strength, it can be easily brazed due to the low brazing temperature. Detail of the brazing filler selection is suggested and discussed in this article.

Single crystal ZnO nanowires diffused with europium (Eu) from a solid source at 900 °C for 1 h or doped with Eu during growth have been characterized. The ZnO nanowires were grown by chemical vapor deposition on Si substrates employing Au as a catalyst. The diameter of the resulting nanowires was ∼200 nm with a length of 1 μm. Photoluminescence spectra excited by a He–Cd laser at room temperature showed the green luminescence at 515 nm in Eu-diffused nanowires. A small red shift of near-band-edge emission of ZnO nanowires was observed in the diffused wires, but sharp emission from Eu3 ions was not present. Transmission electron microscopy shows crystalline Eu2O3 formation on the diffused nanowire surface, which forms a coaxial heterostructure system. When Eu was incorporated during the nanowire growth, the sharp 5DO–7F2 transition of the Eu3+ ion at around 615 nm was observed.

Defect formation in ZnO epilayers grown by molecular beam epitaxy (MBE) is studied by employing optical characterization techniques such as photoluminescence (PL) and optically detected magnetic resonance (ODMR). Excess of oxygen during the growth was found to cause an appearance of the PL peak at around 3.338 eV, which indicates that the corresponding defects are predominantly formed in O-rich ZnO. On the other hand, non-stoichiometry during the growth was singled out as the main factor facilitating formation of defects involved in the yellow PL emission band peaking at around 2.17 eV. Several magnetic-resonance active defects are revealed via monitoring this emission and their magnetic-resonance signatures are obtained.

Rapamycin/curcumin co-loaded and rapamycin-loaded poly(lactide-co-glycolide)(PLGA) films were prepared by a casting method. The components of different drug-loaded films were analyzed by Fourier transform infrared spectroscopy (FTIR), and the major peaks of rapacymin and curcumin were both observed in these films. Compared to the rapamycin-loaded film, the results of in vitro platelet adhesion tests show that the number of adhered platelets reduce, and few aggregated and activated platelets are observed. The APTTs (activated partial thromboplastin time) of rapamycin/curcumin co-loaded films is nearly 6 seconds longer than for the rapamycin-loaded PLGA films. All results indicate that curcumin may suppress thrombosis activated by rapamycinloaded film, and improve the anticoagulative property. The results of alamar blue indicate that the rapamycin/curcumin co-loaded film has better antiproliferation effect than 316 stainless steel (SS).

Heteroepitaxial zinc oxide (ZnO) films were grown on GaN templates by plasma-assisted molecular beam epitaxy. The epitaxial GaN templates were deposited by metalorganic chemical vapor deposition on c -plane sapphire substrates. Photoluminescence (PL) spectra of ZnO epilayers excited by a He–Cd laser exhibit only bound-exciton emission at 369 nm with phonon replicas at 10 K. The bound-exciton intensity of the ZnO epilayer grown under O-rich condition is five times greater than that of Zn-rich condition, indicating more non-radiative defects in the latter. High-intensity excitation PL was carried out using a N 2 337-nm laser. The threshold of the emission from inelastic scattering between excitons is higher for Zn-rich-grown ZnO (68 kW/cm 2 ) than for O-rich-grown ZnO (47 kW/cm 2 ), indicating better optical quality for the latter. X-ray diffraction measurements show that there exists a residual compressive strain, e =−0.25%, along the c -axis direction of the ZnO epilayer grown under Zn-rich condition.

Photoluminescence (PL) of homoepitaxial and heteroepitaxial ZnO films grown by plasma-assisted molecular beam epitaxy is studied. Homoepitaxial ZnO layers were grown on an O-face melt-grown ZnO (0 0 0 1) substrate. Heteroepitaxial ZnO layers were grown on an epitaxial GaN template predeposited by metalorganic chemical vapor deposition on a c -plane sapphire substrate. The low-excitation PL spectra of ZnO epilayers excited by a He–Cd laser exhibit only bound-exciton emission with phonon replicas. There are green luminescence from the ZnO substrate but not from the ZnO epilayers. However, under high-excitation by a N 2 pulse laser, the emission due to exciton–exciton scattering dominates the PL spectrum from the heteroepitaxial ZnO layer but is not observed from the homoepitaxial ZnO layer. The difference is probably due to the different quality of the ZnO substrate and GaN template.

Poly(ethlene terephthalate) (PET) used in artificial heart valve sewing rings were treated by argon plasma discharge and grafted by different molecular water-soluble polymer—polyethylene glycols (PEG). The surface properties of the plasma treated and grafted films were determined by contact angle measurement, X-ray photoelectron spectroscopy (XPS), and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The contact angle of water decreased from 83.5° to 38.7° and the interfacial energy diminished from 30.7 to 6.3 mN/m. The ratio of oxygen to carbon increased from 0.15 to 0.25. All the results revealed that PEG chains were successfully grafted onto the surface of the PET films. The interaction between the surface-modified PETs and blood components was investigated to evaluate the blood compatibility of the samples. Activated partial thromboplastin time (APTT) of the PET-PEG was significantly longer than that of the untreated PET. Scanning electron microscopy (SEM) and optical microscopy indicated that adhered, aggregated and morphologically changed platelets were significantly reduced by grafting PEG chains onto the PET films. The in vitro blood compatibility tests suggested that the blood compatibility of PET grafted with PEG was related to the molecular weight of PEG. The best blood compatibility was achieved when the grafted molecular weight of PEG was 6000. The hemocompatibility improvement can be explained by the low interfacial free energy, sterically hindered effects of PEG chains, and maintaining of the normal conformation.

In this paper, polyethylene glycol (PEG) of various different molecular weights was grafted onto PET films using plasma surface grafting modification. The surface structure of PEG-grafted PET films was analyzed by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS), suggesting that the surface structure and composition of PET films changes due to the presence of PEG. Blood compatibility was characterized by in vitro platelet adhesion experiments and coagulation factors. The tests of platelet adhesion and coagulation factors in vitro suggest that PEG grafted onto polymer surfaces can improve the blood compatibility of PET films remarkably. The modified PET films were pre-coated with albumin and fibrinogen respectively; platelet adhesion tests in vitro then indicated that samples pre-coated with albumin have better blood compatibility than with fibrinogen, resulting in the conclusion that the albumin can improve blood compatibility. The contact angle of PEG-grafted films was measured by the sessile drop method and the surface free energy and interface free energy were induced. It is indicated that the PEG-grafted PET films have the characteristic of preferentially adsorbing albumin.

There is an increasing interest in developing new methods to reduce bacterial adhesion onto polymeric materials used in biomedical implants. The antibacterial adsorption behavior on polyethylene terephthalate (PET) treated by plasma immersion ion implantation–deposition (PIII–D) using acetylene (C2H2) at different working pressures is investigated. The surface structure of the treated PET is determined by Rutherford backscattering spectrometry (RBS), laser Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The results show the formation of thin hydrogenated amorphous carbon (a-C:H) films with different structures and chemical bonds on the PET surface. The ability of Staphylococcus aureus (SA) and Staphylococcus epidermidis (SE) to adhere to PET is quantitatively determined by plate counting and Gamma-ray counting of the 125I-labeled bacteria in vitro. The adhesion efficiency of SA on the a-C:H film deposited at 0.5 Pa of working pressure is about 16% of that on the untreated PET surface, and the adhered bacterial concentration of SE on the carbon film deposited at 1.0 Pa is about 1/6 of that of the PET surface. Bacterial adhesion onto a-C:H films is influenced by the structures and chemical bonds of the materials. The reduction in bacterial adhesion can be explained by the free energy of adhesion (ΔFAdh), which predicts whether microbial adhesion is energetically favorable (ΔFAdh 0). Our results show that bacterial adhesion is energetically unfavorable on the a-C:H films deposited at 0.5 and 1.0 Pa, and this study suggests one possible method to repel bacteria from polymeric surfaces.

Photoluminescence (PL) of N-doped epitaxial ZnO and N+-implanted bulk ZnO are studied. The N-doped epitaxial ZnO films were grown on GaN templates by plasma-assisted molecular beam epitaxy with a flux of N2 gas was added to the O2 gas flow in the RF plasma source. The N+-implanted bulk ZnO was fabricated using nitrogen ions implanted into a melt-grown ZnO (0001) substrate with subsequent annealing at 800 °C under oxygen ambient. PL spectra of N-doped epitaxial ZnO and N+-implanted bulk ZnO excited by a He-Cd laser exhibit donor-acceptor pair (DAP) transition emission at 385 nm with a full width at half maximum of 30 nm at 10 K. The DAP emission is associated with the acceptor energy of nitrogen in ZnO, 170 meV. Defect-related red luminescence at about 610 nm observed in N+-implanted ZnO is attributed to the damage due to implantation because it is also observed in P+- or Ar+-implanted bulk ZnO but is not observed in N-doped epitaxial ZnO. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The magnetohydrodynamic (MHD) pressure drop of 22 Na 78 K flow in a circular duct was measured under a quickly changing magnetic field. The MHD pressure drop reduced with time as the magnetic field strength decreased. However, the dimensionless pressure drop gradient varied with the interaction parameter and had a higher value in the middle of the range of values of the interaction parameter. Therefore, a quickly changing magnetic field is harmful to the structural material in a liquid metal self-cooled blanket of a fusion reactor, since the greater pressure drop gradient may cause a larger stress in the blanket. This is even more harmful if the magnetic field strength decreases very quickly or its distribution in space is greatly non-uniform.

Summary form only given. In the ITER magnet system, low voltage insulation coating on the shear pin is required in both CC supports and TF supports. Based on the ITER design, the plasma spray Al 2 O 3 +3% TiO 2 coating with 0.3mm thickness should be developed. Because the coating withstands the strong shear force during operation, high adhesion with the matrix is expected. In this study, an advanced plasma spray system (developed by GTV, Germany) was applied. In order to increase the bonding, a 0.1mm thick NiAl alloy interface was prepared before the plasma spray, which can be clearly seen in the microstructure of the coating. The test result shows that the interface can improve the bonding strength of the coating with a matrix: without interface 33.4 MPa, with NiAl interface about 40MPa. Further thermal shock tests of the coated sample were carried out between 300K and 77 K for more than 50 times, no crack and debonding were found. The electrical resistance test shows that the resistance is 1.06×1010 Ωm after cycling load test, which can satisfy the ITER requirements. In addition, the shear pin with Al 2 O 3 +3% TiO 2 coating can be polished to very good conditions. However, further 120,000 cyclic shear loading test of the coating are still planned, a special test machine is set up in our lab, the result will be present soon.

Si and Zn codoped In/sub x/Ga/sub 1-x/N-GaN multiple-quantum-well (MQW) light-emitting diode (LED) structures were grown by metal-organic vapor phase epitaxy (MOVPE). It was found that we can observe a broad long-wavelength donor-acceptor (D-A) pair related emission at 500 nm/spl sim/560 nm. White light can thus be achieved by the combination of such a long-wavelength D-A pair emission with the InGaN bandedge related blue emission. It was also found that the electroluminescence (EL) spectra of such Si and Zn codoped InGaN-GaN MQW LEDs are very similar to those measured from phosphor-converted white LEDs. That is, we can achieve white light emission without the use of phosphor by properly adjusting the indium composition and the concentrations of the codoped Si and Zn atoms in the active well layers and the amount of injection current.

Thermal anchor is the key components of ITER magnet supports to maintain the low temperature for the normal operation of superconducting coils. During the advanced research of ITER thermal anchor attachment, dozens of brazing filler and several kinds of brazing technique have been developed and investigated. Argon arc brazing with Cu-based filler was chosen as the principal method for the attachment of thermal anchor. The brazing temperature of Cu-based filler is over 1000°C,but heat input is relatively low for shallower heating depth of argon arc brazing. Lower heat input is good for the control of brazing deformation. It is no need to clean after brazing because for argon arc brazing there is no brazing flux used. The test result shows that Cu-based alloy have the best mechanical properties at both room temperature and 77K for high brazing temperature. Detail of argon arc brazing with Cu-based filler have been investigated in this article.

A liquid metal experimental loop for magnetohydrodynamic (MHD) pressure drop and compatibility studies has been built up in China recently. It is operating in two phases: phase I, using 22Na78K, the loop operates at Room Temperature (RT) for MHD experiments; phase II, liquid lithium will be employed and the loop operates at elevated temperatures for compatibility experiments. The gap of the electromagnet is 8 cm and the magnetic strength within it, where the MHD test section is installed, is 1.9 T. The maximum values of the Hartmann number M and interaction parameter N for MHD experiments are 7500 and 25 000, respectively. The minimum value of the pressure drop which can be reliably measured by the pressure transducer is 3000 Pa, and the maximum flow velocity in the present MHD test section is 0.9 m/s. The operation temperature for compatibility experiments is up to 520° C and the maximum flow velocity in the compatibility test section is not less than 1.7 m/s.

The characteristics of GaN films diAused with Mg were studied. The undoped GaN films were grown by metalorganic chemical vapor deposition (MOCVD). The photoluminescence (PL) spectra of Mg diAused GaN showed a broad violet emission. The Mg-diAused GaN was p-type conductivity with a mobility of 13 cm 2 /V-s and a hole concentration of 3 10 15 /cm 3 at a diAusion temperature of 11008C. However, the samples, which were diAused at 11008C, showed a red emission peak after the annealing process. From the diAusion depth profile observed by secondary ion mass spectrometry (SIMS), we obtained the activation energy of 1.3 eV for Mg diAusion in GaN. # 1999 Published by Elsevier Science Ltd. All rights reserved.

A major complication of coronary stenting is in-stent restenosis (ISR) due to thrombus formation. We hypothesized that locally released curcumin from coronary stent surface would inhibit ISR due to thrombus formation because of antithrombosis of curcumin. In the present work, curcumin-eluting polylactic acid-co-glycolic acid (PLGA) films were fabricated and their properties in vitro were investigated. The in vitro platelet adhesion and activation, as well as protein adsorption on curcumin-loading PLGA films were investigated to evaluate the blood compatibility of curcumin-eluting films. The structure of curcumin-eluting PLGA film and control was examined by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy indicating that the peaks of curcumin did not shift in curcumin-eluting films. The results of contact angle and surface free energy indicated that loading curcumin in PLGA would make PLGA become more hydrophilic, which contributed to the increase of polar fraction of surface free energy. With the increase of curcumin in films, platelets adhering to the curcumin-eluting films decreased significantly. The number of activation platelets decreased after incorporating curcumin in PLGA films. Loading curcumin in PLGA film can markedly reduce the fibrinogen adsorption. All results indicated that incorporating curcumin in PLGA film can improve the blood compatibility of PLGA films. It can be used to fabricate drug-eluting stent to prevent thrombosis formation.

In this study, using polylactic acid-co-glycolic acid (PLGA) with a molecular weight of 95,800 Da as drug carrier, three dose (low, moderate, high) rapamycin-eluting stents and the corresponding coating films were prepared. The pre- and post-expansion morphology of the rapamycin-eluting stent was examined by scanning electron microscopy (SEM), indicating that the coating was very smooth and uniform. The coating had the ability to withstand the compressive and tensile strains imparted without cracking from the stent during expansion process. There were many voids on stent coating surface after released for 18 days in release medium. The thermodynamics data of the stent coating film measured by differential scanning calorimetry (DSC) showed a lack of measurable solubility of rapamycin in the PLGA matrix. The release behavior of rapamycin from stent surface had a two phase release profile with a burst release period of about 2 days, followed by a sustained and slow release phase. The mass loss behavior of PLGA appeared linear throughout most of the degradation period, corresponding to an approximately constant mass loss rate. The platelet adhesion tests showed that the rapamycin-eluting films may have a good blood compatibility compared with control samples. Take into these results account, this novel rapamycin-eluting may be a good candidate to resolve in-stent restenosis.

This low-pass filter implements approximate processing for decimation and interpolation in oversampled data converters. Included in an experimental circuit are a pair of decimation filters and two pairs of interpolation filters in a single-chip multimedia audio system. Total power for these filters is 86.4 mW with 5 V power supply when the full order of the filters is used. Power is reduced by 36% for decimation and 17% for interpolation when approximate filtering is enabled.

Photoluminescence (PL) and optically detected magnetic resonance are employed to study effects of nonstoichiometry during the growth on defect formation in ZnO epilayers grown by molecular-beam epitaxy (MBE). Several defects are revealed via monitoring the yellow PL emission (∼2.17eV) and their magnetic resonance signatures are obtained. The defects are concluded to be common for the MBE growth and are facilitated during the off-stoichiometric growth conditions, especially under excess of oxygen.