Practical application of pulsed “eye-safe” microchip laser to laser rangefinders

The paper describes practical application of pulsed microchip laser generating at 1535-nm wavelength to a laser rangefinder. The complete prototype of a laser rangefinder was built and investigated in real environmental conditions. The measured performance of the device is discussed. To build the prototype of a laser rangefinder at a reasonable price and shape a number of basic considerations had to be done. These include the mechanical and optical design of a microchip laser and the opto-mechanical construction of the rangefinder.     

Application of solid-phase microextraction to monitoring indoor air quality

Practical application of Solid-Phase Microextraction (SPME) for the assessment of the quality of indoor air is presented. SPME was used to sample selected organic pollutants (carbon tetrachloride, benzene, toluene, chlorobenzene, p-xylene and n-decane). An SPME fiber was coated with a 100 μm film of polydimethylsiloxane. The analytes extracted were analysed with a gas chromatograph directly coupled with a mass spectrometer (GC-MS). The method was used to assess the indoor air quality in a few selected flats. The concentrations ranged from below detection limits to 6.9 mg/m³ for benzene depending on the flat; they were relatively high for newly built or freshly renovated flats. Received: 14 July 1998 / Revised: 17 November 1998 / Accepted: 21 November 1998     

RKKY interaction in metallic overlayers of fractional dimensionality

Within an analytical approach we study the RKKY interaction mediated by the electron gas, which shows fractional spectral dimensionality. We derive formula for the RKKY exchange integral in a system of nonintegral dimensionality. Also the modifications of magnetic interaction and magnetic moments in metallic overlayers due to the surface/interface effects are considered. Presented at the VIII-th Symposium on Surface Physics, Třešt’ Castle, Czech Republic, June 28 – July 2, 1999.     

Preparation of new quinolinecarbohydroxamic acids

A series of new quinolinecarbohydroxamic acids has been prepared by treatment of corresponding methyl quinolinecarboxylates with hydroxylamine.     

Phosphate Assisted Proton Transfer in Water and Sugar Glasses: A Study Using Fluorescence of Pyrene-1-carboxylate and IR Spectroscopy

The role of water’s H-bond percolation network in acid-assisted proton transfer was studied in water and glycerol solutions and in sugar glasses. Proton transfer rates were determined by the fluorescence of pyrene-1-carboxylate, a compound with a higher pK in its excited state relative to the ground state. Excitation of pyrene-1-COO⁻ produces fluorescence from pyrene-1-COOH when a proton is accepted during the excited singlet state lifetime of pyrene-1-COO⁻. The presence of glycerol as an aqueous cosolvent decreases proton transfer rates from phosphoric and acetic acid in a manner that does not follow the Stokes relationship on viscosity. In sugar glass composed of trehalose and sucrose, proton transfer occurs when phosphate is incorporated in the glass. Sugar glass containing phosphate retains water and it is suggested that proton transfer requires this water. The infrared (IR) frequency of water bending mode in sugar glass and in aqueous solution is affected by the presence of phosphate and the IR spectral bands of all phosphate species in water are temperature dependent; both results are consistent with H-bonding between water and phosphate. The fluorescence results, which studied the effect of cosolvent, highlight the role of water in assisting proton transfer in reactions involving biological acids, and the IR results, which give spectroscopic evidence for H-bonding between water and phosphate, are consistent with a mechanism of proton transfer involving H-bonding. The possibility that the phosphate-rich surface of membranes assists in proton equilibration in cells is discussed.     

Analysis of data transmission technique based on pulsed laser

Pulsed lasers are used mainly in lidar systems as sources of short and highly energetic light pulses. In data transmission systems continuous wave lasers are typically applied, however it is also possible to use pulsed lasers in such systems. Such approach seems to be especially reasonable for devices where a pulsed laser is applied anyway and executes another function (rangefinding). The article discusses a data transmission concept based on a pulsed laser technology. Advantages and limits of such a transmission method are described. Influence of individual transmission elements on the effective data transmission speed is analysed.     

Sensitive spectrophotometric determination of gallium with eriochrome Cyanine R and cetyltrimethylammonium ions

Summary A new sensitive, spectrophotometric determination of gallium, based on the ternary gallium-Eriochrome Cyanine R-cetyltrimethylammonium system has been developed. At _max=588 nm the molar absorptivity is 1.20×10⁵l·mole^–1·cm^–1. The maximum absorbance is attained in 5 min in the presence of a 10-fold molar ratio of Eriochrome Cyanine R and an approx. 50-fold ratio of cetyltrimethylammonium bromide (to Ga). Citrate, EDTA and to a lesser extent tartrate, interfere. Interference by metals can be eliminated by a preliminary extraction of gallium with di-isopropyl ether from 7 M hydrochloric acid in the presence of ascorbic acid as reductant. The results for gallium (at a concentration level of 1×10^–4%) in aluminium metal and chloride indicate good precision and accuracy.

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Empfindliche spektrophotometrische Bestimmung von Gallium mit Eriochromcyanin-R- und Cetyltrimethylammonium-Ionen

Zusammenfassung Ein neues, empfindliches spektrophotometrisches Verfahren zur Galliumbestimmung wurde ausgearbeitet. Es beruht auf der Verwendung des ternären Systems Gallium — EriochromcyaninR — Cetyltrimethylammonium. Bei _max=588 nm beträgt die molare Extinktion 1,20·10⁵ 1·Mol^–1·cm^–1. Die maximale Absorption wird innerhalb von 5 min bei Gegenwart der 10fachen molaren Menge EriochromcyaninR und der etwa 50fachen Menge Cetyltrimethylammoniumbromid erreicht. Citrat, ÄDTA und in geringerem Maß Tartrat stören. Störende Wirkung durch Metalle kann durch vorhergehende Extraktion des Galliums mit Diisopropyläther aus 7 M Salzsäure in Gegenwart von Askorbinsäure als Reduktionsmittel vermieden werden. Die Ergebnisse (im Konzentrationsbereich von 10^–4% Ga) in metallischem Aluminium und AICI₃ sind genau.

     

微载荷含油轴承摩擦性能研究Ⅰ.摩擦试验机设计

研制了1种针对径向轴承的微载荷摩擦试验机,介绍了其工作原理及结构,即利用外加载荷抵消浮动测试架重量以施加微小载荷,并利用激光位置传感器(PSD传感器)实现无接触位移测量;同时测量了摩擦副的转动角度并计算出摩擦系数;采用摩擦转角测量法和外加力矩平衡摩擦法测量微载荷下的摩擦性能,以测量时间末端位置作为位置基准,通过极限偏载平衡进行载荷标定.结果表明:微载荷摩擦试验机可应用于径向轴承在微小载荷下的摩擦力测量;可以通过在较大范围内设置结构参数来研究径向轴承的摩擦特性;并可利用数据采集技术研究速度和载荷连续变化条件下的摩擦性能.     

Slice modules over minimal 2-fundamental algebras

We consider a class of algebras whose Auslander-Reiten quivers have starting components that are not generalized standard. For these components we introduce a generalization of a slice and show that only in finitely many cases (up to isomorphism) a slice module is a tilting module. The first named author was supported by the Polish Scientific Grant KBN No 1 P03A 018 27     

Possibility of Helical Interlayer Coupling in the Magnetic Superlattices and Overlayers

We consider interlayer magnetic coupling in a superlattice and/or overlayer in the case when spacer layer has the tendency towards formation of the helical spin density wave. Within phenomenological Landau-Ginzburg approach we show that the mutual interplay of the SDW and interlayer coupling spin polarization can lead to the helical interlayer coupling. When surface anisotropy is accounted for the effective interaction mimics interlayer biquadratic coupling.