A DFT and direct MO dynamics study on the structures and electronic states of phenyl-capped terthiophene

The structures and electronic states of phenyl-capped terthiophene (denoted by P3T) and the ionic species of P3T have been investigated by means of density functional theory (DFT) and direct MO dynamics calculations. P3T is one of the high-performance molecular devices, which has been utilized as a semi-conductor. The calculations indicated that the neutral P3T has a non-planar structure whose the phenyl rings in both ends of thiophene chain are largely deviated from the molecular plane. The cation and anion radicals, dication and dianion were considered as its ionic states. The structure for cation radical of P3T is close to more planar than that of neutral P3T. The structures for anion radical, dication and dianion take a pure planar structure. The first excitation energy of neutral P3T is calculated to be 2.90 eV at the TD-B3LYP/6-31G(d)//B3LYP/6-311+G(d) level, while the P3T cation and anion radicals have lower excitation energies (1.22 and 1.10 eV, respectively). The direct MO dynamics calculation showed that neutral, cation and anion hold near planar structure at 300 K. On the other hand, oligothiophene (n = 5) and its ionic species are strongly deformed from the planar structure, and thiophene rings in both ends of chain rotate rapidly by thermal activation. The mechanism of the electron conductivity in P3T was discussed on the basis of theoretical results.     

Preparation and Characterisation of Nano-Structured WO<Subscript>3</Subscript>-TiO<Subscript>2</Subscript> Layers for Photoelectrochromic Devices

Nano-structured WO₃-TiO₂ layers were prepared by the sol-gel route. To obtain transparent, porous and crack free layers up to 0.8 μ m with a single dipping cycle a templating strategy was used. As a template three-dimensionally network based on organically modified silane was introduced to the WO₃ and TiO₂ sols. The WO₃ layers were dip-coated onto the conductive glass substrate (TCO) and the TiO₂ layers on the top of the WO₃ layer. The morphology and the structure of the layers were determined by Scanning Electron Microscopy (SEM), High Resolution Transmission Electron Microscopy (HR-TEM), Energy Dispersive X-Ray Spectroscopy (EDXS), Auger and Infrared spectroscopy. SEM image of the WO₃-TiO₂ layer confirmed the nano-porosity of the layers and give the size of the particles of about 10 nm for TiO₂ and 30 nm for WO₃ layer. Further analysis indicated that the titanium sol penetrates the WO₃ layer. Particles in the WO₃ layer consist of a crystalline monoclinic WO₃ core surrounded by a 5–10 nm amorphous phase consisting of WO₃, TiO₂ and SiO₂. The WO₃-TiO₂ layers were used to assemble all solid state photoelectrochromic (PE) devices. Under 1 sun irradiation (1000 W/m²) the visible transmittance of the PE device changes from 62% to 1.6%. The colouring and bleaching processes last about 10 minutes.     

回旋速调管放大器输出腔的特性研究

 利用变截面波导的耦合模理论，根据输出腔中电场幅值分布函数所满足的微分方程组，编写了具有自动优化功能的计算程序，分析研究了不同渐变角度、考虑腔体损耗前后和输出腔与外电路失配时，谐振频率、腔体品质因数和高频场幅值沿轴分布的变化情况，为进一步研究高频场与电子注的互作用和输出腔奠定了基础。     

A novel non-invasive electrochemical biosensing device for in situ determination of the alcohol content in blood by monitoring ethanol in sweat

A non-invasive, passive and simple to use skin surface based sensing device for determining the blood's ethanol content (BAC) by monitoring transdermal alcohol concentration (TAC) is designed and developed. The proposed prototype is based on bienzyme amperometric composite biosensors that are sensitive to the variation of ethanol concentration. The prototype correlates, through previous calibration set-up, the amperometric signal generated from ethanol in sweat with its content in blood in a short period of time. The characteristics of this sensor device permit determination of the ethanol concentration in isolated and in continuous form, giving information of the BAC of a subject either in a given moment or its evolution during long periods of time (8 h). Moreover, as the measurements are performed in a biological fluid, the evaluated individual is not able to alter the result of the analysis. The maximum limit of ethanol in blood allowed by legislation is included within the linear range of the device (0.0005–0.6 g L⁻¹). Moreover, the device shows higher sensitivity than the breathalyzers marketed at the moment, allowing the monitoring of the ethanol content in blood to be obtained just 5 min after ingestion of the alcoholic drink. The comparison of the obtained results using the proposed device in the analysis of 40 volunteers with those provided by the gas chromatographic reference method for determination of BAC pointed out that there were no significant differences between both methods.     

Development and evaluation of microfluidic device for the determination of organophosphorus pesticide incorporating monolith based immobilized AChE with spectrophotometric detection

A spectrophotometric microfluidic bioreactor system is described for the determination of organophosphorus pesticides. The glass chip was designed and fabricated for in situ monolithic preparation and subsequently acetlycholineserase (AChE) immobilization via a covalent bonding method. The porous polymer monolith was prepared using glycidyl methacrylate, ethylenedimethacrylate and 2,2-dimethoxy-1,2-diphenylethan-1-one in binary porogenic solvents of cyclohexanol and dodecanol. The epoxide groups of monolith were reacted with ethylenediamine and gluteraldehyde to allow immobilization of the enzyme using their amine groups. Organophosphorus pesticides can be determined by measuring their inhibition effect on the enzyme AChE using Ellman's reaction. A linear relationship between the absorbance and percentage inhibitions was obtained over the concentration range of 0.25 to 2.50?mg?L^?1 paraoxon with a correlation coefficient (r ²) of 0.9974. The limit of detection (LOD) defined as 10% inhibition (I ₁₀) was 0.17?mg?L^?1 for paraoxon. The relative standard deviations (RSD) of 1.0?mg?L^?1 paraoxon was 3.73% (n?=?5). The proposed µFI system incorporates efficient enzyme immobilization and reduces reagent consumption and waste production and could thus be considered to be more environmentally friendly.     

Reversible solubilisation through hydrogen-bond-mediated assembly

A novel approach was developed to improve the solubility of non-soluble compounds by introducing solubilising molecules peripherally through hydrogen-bond-mediated assembly. The solubilisation process can be reversed by adding competing hydrogen bonding moieties and removing the solubilising molecules. This method may potentially facilitate device fabrication.     

What can statistical process control show us about ionization chamber stability?

PurposeStatistical process control (SPC) has been shown to be a suitable tool for medical physicists to monitor quality and keep variability low and within specifications. We report our findings regarding ionisation chamber stability in our department when using a radioactive stability check device (RSCD) and we compare them with similar previously published records, including calibration results.MethodsWe retrospectively studied the stability of a PPC 40 parallel-plate chamber, and two Farmer chambers (FC65-G and FC65-P) by checking them with dedicated RSCDs. We analysed the data following SPC methodology which includes plotting I-MR control charts, monitoring out-of-control observations, calculating process capability ratios (C_p), and estimating conformance to specifications. We also estimated the C_p and adherence to specifications of previously published data.ResultsThe PPC40 chamber hardly went out of the control limits over the whole six-year period assessed. However, Farmer chamber verifications drifted in opposite directions in phase II, and the deviations observed did not agree with their calibration records, which only increased by a maximum of 0.5%. In phase I the most unstable chamber was the FC65-P with a C_p equal to 0.9 at a specification level of ±1%. The PPC40 chamber was stable to within a maximum C_p of 1.3. Several sets of analysed data, including ours and those from other authors, fitted well within these limits: within ±1.9% and ±1.5% for a C_p of 1.5 and 1.33 respectively.ConclusionsSPC with constant long-term RSCD checking gave us a meaningful plot of the instability of our ionisation chambers. Although a period of two years between calibrations should not be surpassed, in the interim this check can conform to specifications of ±1.5%.     

Improved device reliability in organic light emitting devices by controlling the etching of indium zinc oxide anode

A controllable etching process for indium zinc oxide （IZO） films was developed by using a weak etchant of oxalic acid with a slow etching ratio. With controllable etching time and temperature, a patterned IZO electrode with smoothed surface morphology and slope edge was achieved. For the practical application in organic light emitting devices （OLEDs）, a sup- pression of the leak current in the current-voltage characteristics of OLEDs was observed. It resulted in a 1.6 times longer half lifetime in the IZO-based OLEDs compared to that using an indium tin oxide （ITO） anode etched by a conventional strong etchant of aqua regia.     

DNA purification using dynamic solid-phase extraction on a rotationally-driven polyethylene-terephthalate microdevice

We report the development of a disposable polyester toner centrifugal device for semi-automated, dynamic solid phase DNA extraction (dSPE) from whole blood samples. The integration of a novel adhesive and hydrophobic valving with a simple and low cost microfabrication method allowed for sequential addition of reagents without the need for external equipment for fluid flow control. The spin-dSPE method yielded an average extraction efficiency of ∼45% from 0.6 μL of whole blood. The device performed single sample extractions or accommodate up to four samples for simultaneous DNA extraction, with PCR-readiness DNA confirmed by effective amplification of a β-globin gene. The purity of the DNA was challenged by a multiplex amplification with 16 targeted amplification sites. Successful multiplexed amplification could routinely be obtained using the purified DNA collected post an on-chip extraction, with the results comparable to those obtained with commercial DNA extraction methods. This proof-of-principle work represents a significant step towards a fully-automated low cost DNA extraction device.