Synthesis,Characterization and Xerographic Performance of the Triazo Pigments from Tris(4-amino)triphenylamine

As the era for digital printer has come since the 1990s,the investigation into a highly photosensitive charge generator materials(CGM) suitable for IR photoreceptor is concerned.^1-2 This research focuses on the triphenylamine triazo pigments, which exhibit a broad spectral response(450-800mn) and an excellent photosensitivity, especially in the near red-infrared region where solid-state diode laser emit(450-800nm). They are particularly potential CGM for laser printer and digital printer.     

Identification of steel by X-ray fluorescence analysis with a pyroelectric X-ray generator

An application of X-ray fluorescence analysis with a pyroelectric X-ray generator is presented. Steel standard samples were identified by X-ray fluorescence analysis with this novel X-ray generator to check its capability for performing qualitative and quantitative analysis as an X-ray source for X-ray fluorescence spectrometers. Cr, Ni, V, Co, and W were detected in steel standard samples. V and Cr can be detected even when the content is below 1%. Although it is difficult to detect minor elements because of the low power of the excitation X-rays, it is possible to identify the analyzed samples on the basis of major elements at the percentage level. The pyroelectric X-ray generator is very suitable for portable X-ray fluorescence spectrometers.     

Prompt-gamma neutron activation analysis system design: Effects of D-T versus D-D neutron generator source selection

Prompt-gamma neutron activation (PGNA) analysis is used for the non-invasive measurement of human body composition. Advancements in portable, compact neutron generator design have made those devices attractive as neutron sources. Two distinct generators are available: D-D with 2.5 MeV and D-T with 14.2 MeV neutrons. To compare the performance of these two units in our present PGNA system, we performed Monte Carlo simulations (MCNP-5; Los Alamos National Laboratory) evaluating the nitrogen reactions produced in tissue-equivalent phantoms and the effects of background interference on the gamma-detectors. Monte Carlo response curves showed increased gamma production per unit dose when using the D-D generator, suggesting that it is the more suitable choice for smaller sized subjects. The increased penetration by higher energy neutrons produced by the D-T generator supports its utility when examining larger, especially obese, subjects. A clinical PGNA analysis design incorporating both neutron generator options may be the best choice for a system required to measure a wide range of subject phenotypes.     

Improvement of spectral resolution in the presence of periodic noise and microphonics for hyper-pure germanium detector gamma-ray spectrometry using a new digital filter

The radiation dose of workers and patients resulting from inhaling radon and through the consumption of spring waters was examined in the hospital near the Héviz lake in Hungary. The radiation dose originating from radon was 2.15–3.95 mSv·y⁻¹ concerning workers at the spa. The radiation dose originating from radon in the case of those regularly taking a bath was an average of 0.75 mSv·y⁻¹. Due to the limited duration of treatments a bound effective dose of maximum 100 μSv·y⁻¹ may originate from radon and inhaling radon, while a maximum of 1.4 μSv·y⁻¹ may originate from ingestion of ²²²Rn, ²²⁶Ra, ²³⁴U and ²³⁸U radionuclides.     

A micro surface tension pump (MISPU) in a glass microchip

A non-membrane micro surface tension pump (MISPU) was fabricated on a glass microchip by one-step glass etching. It needs no material other than glass and is driven by digital gas pressure. The MISPU can be seen working like a piston pump inside the glass microchip under a microscope. The design of the valves (MISVA) and pistons (MISTON) was based on the surface tension theory of the micro surface tension alveolus (MISTA). The digital gas pressure controls the moving gas-liquid interface to open or close the input and output MISVAs to refill or drive the MISTON for pumping a liquid. Without any moving parts, a MISPU is a kind of long-lasting micro pump for micro chips that does not lose its water pumping efficiency over a 20-day period. The volumetric pump output varied from 0 to 10 nl s(-1) when the pump cycle time decreased from 5 min to 15 s. The pump head pressure was 1 kPa.     

Quantitative calibration of vapor levels of TNT, RDX, and PETN using a diffusion generator with gravimetry and ion mobility spectrometry

A prototype generator for creating a continuous stream of explosive vapor was referenced quantitatively both to a standard weight from the National Institute of Standards and Technology (NIST) and to the response of an ion mobility spectrometer. Vapors from solid explosive, in a precision bore glass tube at constant temperature, diffuse into an inert gas flow. Mass output rates were determined by (1) sample temperature, and (2) sample tube dimensions (length and cross-sectional area). A reference to NIST was achieved gravimetrically though a microbalance calibrated with a reference weight; mass output rates were obtained for 2,4,6-trinitrotoluene (TNT), cyclotrimethylenetrinitramine (RDX) and pentaerythritol tetranitrate (PETN) at three or more oven temperatures between 79 degrees C and 150 degrees C. The mass output rate was stable over hundreds of hours of continuous operation and the output was adjustable from a few picograms per second to several nanograms per second through variation of the oven temperature. An independent calibration of the vapor generator for TNT at 79 degrees C using an ion mobility spectrometer matched exactly the gravimetric-based findings. In most instances, measured mass output rates compared favorably with theoretically calculated mass output rates, with discrepancies in a few cases resulting primarily from uncertainties in terms (vapor pressures and diffusion coefficients) used to perform the calculations. Agreement is generally not good for PETN, where molecular decomposition contributed to higher than expected measured mass outputs.     

Étude spectrométrique d'un plasma induit par haute fréquence : Partie I: Performances analytiques

A new design of inductively coupled plasma generator operating at 40 MHz is described. Data are presented to show that the generator gives satisfactory performance when used in both atomic emission and absorption spectrometry, although the former has the advantage of simplicity of operation.     

A simple method for improving control of the time constant in recording transient signals in atomic-absorption spectrometry

Significant improvements can be made in signal:noise ratios of transient signals arising in atomic-absorption spectroscopy by the use of resistor-capacitor damping. A suitable device is described and the effect it has on signals arising from instruments using analogue and digital forms of output is demonstrated.     

A Hollow Stiffening Structure for Low Pressure Sensors

This paper presents a novel process for producing thin-walled hollow stiffening structures on thin silicon diaphragms using an electro-chemical etch stop process. Examples of structures produced using the method are presented together with focused ion beam (FIB) analysis of critical areas within the structure. These demonstrate the integrity the structures and show that the process is it suitable for use in MEMS sensor applications. Using this process a 30mbar full-scale differential pressure sensor has been demonstrated. The process allows for increased sensor performance, with reduced die size. Details of the pressure sensor design and characterization are presented, showing a device with 20mV/V full-scale output with linearity less than 0.4% (terminal base nonlinearity).     

Electrical generators driving microhollow and dielectric barrier discharges applied for analytical chemistry

Scaling down the size of plasma discharges would reduce the amount of gases, liquids, and consumables required, which in turn would decrease the operating costs. Nevertheless, the application of a specialized plasma generator for microhollow cathode discharges (MHCD) and dielectric barrier discharges are driven with commercially available power sources. Those generators are bulky and expensive and their overall efficiency is poor. This work develops and explains several circuit topologies and design hints to excite MHCD and dielectric barrier discharge (DBD) plasmas with respect to its system with as low as possible input power in a very efficient way. Benefits in sensitivity and life expectancy are shown. The generator for the MHCD needs voltages up to 7 V and consumes up to 5 W. The DBD generator has an input power of 3 W and produces a fast rising output pulse up to 9 kV, which has a time duration of 2 µs. These low-power circuits offer the operation with batteries.     

痕量臭氧标准气体发生装置的研制

研制了一种新型的痕量臭氧标准气体发生装置,可输出设定量值的稳定臭氧标准气体,24 h连续运行,输出量值相对标准偏差小于1.2%。发生臭氧浓度范围为25～1 000 nmol/mol。该装置可输出一组按顺序增大或减小的臭氧标准气体,可与被校准仪器连接进行比对试验或检定校准。与美国国家标准局(NIST)臭氧基准测量装置SPR41比对试验研究表明,研制的臭氧标准气体发生装置具有很好的准确性,定值不确定度小于1%(k=2)。     

On the direct determination of metals in lubricating oils by ICP

New equipment and procedures are evaluated for the direct analysis of metals in lubricating oils without the need for sample pretreatment or dilution. A modified Babington principle nebulizer equipped with a sample heater is shown to be capable of producing aerosols from undiluted oils, which are suitable for introduction into an inductively coupled plasma atomic emission spectrophotometer. Heating the samples immediately prior to nebulization greatly increases the output of aerosol and reduces output variations in emission intensity due to differences in oil manufacture and viscosity. The type of organometallic complex used in the preparation of standards is shown to be unimportant if the plasma observation region is properly chosen. Performance of a conventional plasma geometry and an inverted torch geometry on analysis of field collected oil samples is presented.     

A fast event processor for counting loss-corrected gamma-spectrometry

The design of a fast microprogrammed direct memory access processor for a PDP-11/34 is described. The controller is able to address a storage area of 128K-16 bit words, enabling us to record several conventional spectra and loss-corrected spectra of 4096 channels in three byte precision simultaneously and in short temporal succession. Beyond it, the interface contains: a) system timing controller for multisource multiscaling; b) two d/A-converters for general purposes; c) display generator with gray scale control for an external oscilloscope; d) two 16-bit parallel input/output ports, which provide interfacing beetween peripheral devices and the minicumputer.     

On the construction and use of cheap digitalized calorimeter

Summary The physical properties of electrical calorimeter constructed at Mendel University and the corresponding data processing are presented. The calorimeter is used for measurement of the specific heats, namely foods. It is built from widely used equipment, the main parts are frequent digital multimeters and an older computer. Its main advantage is low costs, simplicity, rate of the measurement and digital data output and storage. Lower accuracy of the measurement, ~5%, is its partial disadvantage.     

Binary data acquisition from instrumentation with BCD-coded output: a hardware converter and an example of the relative software control

Simple hardware for conversion from BCD into binary code is described. The device is of low cost, performs a 16-bit conversion in a maximum time of 400 nsec, and is able to output the converted number to either an 8-bit or a 16-bit data bus. An example of the software necessary to perform data acquisition from a digital voltmeter by using this converter is also presented.     

Identification of glass and ceramics by X-ray fluorescence analysis with a pyroelectric X-ray generator.

Applications of X-ray fluorescence (XRF) analysis with a pyroelectric X-ray generator are presented. Glass and ceramics were analyzed with this novel X-ray generator to examine its capability for analyzing nonmetallic inorganic material. Although the power of X-ray output was a few orders of magnitude lower than conventional X-ray tubes, many elements such as Si, K, Ca, Ti, Cr, Fe, Zn, Sr, Ba, and Pb were detected in glass and ceramic samples. Light elements such as Na, Mg, and Al were not detected because of the low fluorescence yield and the absorption of fluorescent X-rays in air. The elements detected or the relative peak intensities of the elements were different from each other, and the samples analyzed were identified by the XRF spectrum, notwithstanding the low power of the X-ray output. This novel device showed the sufficient capability for preliminary screening before strict identification of analytes. The pyroelectric X-ray generator can also be used to analyze large samples that cannot be put into ordinary XRF spectrometers because the device has no dimensional limitation of analytes.     

A Multi-component All-DNA Biosensing System Controlled by a DNAzyme

We report on a programmable all-DNA biosensing system that centers on the use of a 4-way junction (4WJ) to transduce a DNAzyme reaction into an amplified signal output. A target acts as a primary input to activate an RNA-cleaving DNAzyme, which then cleaves an RNA-containing DNA substrate that is designed to be a component of a 4WJ. The formation of the 4WJ controls the release of a DNA output that becomes an input to initiate catalytic hairpin assembly (CHA), which produces a second DNA output that controls assembly of a split G-quadruplex as a fluorescence signal generator. The 4WJ can be configured to produce either a turn-off or turn-on switch to control the degree of CHA, allowing target concentration to be determined in a quantitative manner. We demonstrate this approach by creating a sensor for E. coli that could detect as low as 50 E. coli cells mL⁻¹ within 85 min and offers an amplified bacterial detection method that does not require a protein enzyme.     

Detection of dopamine in the presence of excess ascorbic acid at physiological concentrations through redox cycling at an unmodified microelectrode array

The electrochemical behavior of dopamine was examined under redox cycling conditions in the presence and absence of a high concentration of the interferent ascorbic acid at a coplanar, microelectrode array where the area of the generator electrodes was larger than that of the collector electrodes. Redox cycling converts a redox species between its oxidized and reduced forms by application of suitable potentials on a set of closely located generator and collector electrodes. It allows signal amplification and discrimination between species that undergo reversible and irreversible electron transfer. Microfabrication was used to produce 18 individually addressable, 4-μm-wide gold band electrodes, 2 mm long, contained in an array having an interelectrode spacing of 4 μm. Because the array electrodes are individually addressable, each can be selectively biased to produce an overall optimal electrochemical response. Four adjacent microbands were shorted together to serve as the collector, and were flanked on each side by seven microbands shorted as the generator (a ratio of 1:3.5 of electroactive area, respectively). This configuration achieved a detection limit of 0.454?±?0.026 μM dopamine at the collector in the presence of 100 μM ascorbic acid in artificial cerebrospinal fluid buffer, concentrations that are consistent with physiological levels. Enhancement by surface modification of the microelectrode array to achieve this detection limit was unnecessary. The results suggest that the redox cycling method may be suitable for in vivo quantification of transients and basal levels of dopamine in the brain without background subtraction.