System for time-resolved laser absorption spectroscopy and its application to high-power impulse magnetron sputtering.

This paper deals with the development and construction of an apparatus for time-resolved tunable diode laser absorption spectroscopy (LAS) for the diagnostics of pulsed plasma. A detailed description of the extension of a progressive method of laser absorption spectroscopy in continuous regime to a direct triggering method of the time-resolved laser absorption spectroscopy (TR-LAS) is presented. The main advantage of the developed method is its capability to measure the time evolution of the whole absorption profile with a preset time resolution, which can be less than 1 µs. Therefore, the presented method of repetitive sampling applied on LAS in plasma processes is capable of simultaneous measurement of the density and kinetic temperature of selected particles. Its appropriate applications are to periodical processes in technological plasma, namely pulsed plasma discharges. The developed method of TR-LAS was applied to measurements of the temporal evolution of density and kinetic temperature of argon metastable species during high-power impulse magnetron sputtering of titanium and titanium dioxide thin films.

A modified Katsumata probe--Ion sensitive probe for measurement in non-magnetized plasmas.

A modified Katsumata probe has been developed for measurement of ion velocity distribution function (IVDF) in technological non-magnetized plasmas. A simple construction of the modified Katsumata probe consists of adding a pair of permanent Sm-Co magnets in front of Katsumata probe. A comparative study regarding IVDF measurement in a high power impulse magnetron sputtering system operating in pure argon atmosphere by means of developed modified Katsumata probe and commercially available gridded retarding field analyzer (RFA) has been carried out. A time-resolved measurement of IVDF for two different pressures whilst other plasma conditions have been kept unchanged has revealed that the main advantage of the modified Katsumata probe compared to the RFA consists in significantly smaller angular aperture of entrance orifice of modified Katsumata probe being approximately 15° in comparison with a commercial RFA having angular aperture more than 160°. It leads in much better velocity resolution in measured IVDF since the transversal part of velocity vector is much more suppressed compared to RFA. Furthermore, the modified Katsumata probe less suffers from collisions of ions in the space charge sheath in front or inside of the probe compared to the RFA.

Time-resolved tunable diode laser absorption spectroscopy of pulsed plasma.

A method for time-resolved tunable diode laser absorption spectroscopy (LAS) has been developed. In this Letter, we describe in detail a developed electronic module that controls the time resolution of the LAS system. The transistor-transistor logic signal triggering the plasma pulse is used for generation of two signals: the first one triggers fine tuning of the laser wavelength and the second one controls time-defined signal sampling from the absorption detector. The described method and electronic system enable investigation of the temporal evolution of the density and temperature of selected particles in technological plasma systems. The high-power impulse magnetron sputtering system with a period of 10 ms and a duty cycle of 1% has been used to verify this method. The temporal evolution of argon metastable density was measured in the active part of the pulse and in the afterglow. The resulting density of Ar* displays a double-peak structure with a first peak in the plasma "ON" phase and a second peak in the afterglow approximately 1 ms after the end of the pulse.

Autogeny in Culex pipiens quinquefasciatus say.

Autogeny was observed in a laboratory colony of Culex pipiens quinquefasciatus Say originating from Hyderabad, India. In a strain selected for an autogeny for 15 generations, all females, both mated and unmated, were able to mature eggs although the unmated females were unable to oviposit them. Ingesting glucose had little effect on the expression of autogeny and on the number of eggs in rafts in the laboratory experiments. Most autogenous females can ingest blood during first gonotrophic cycle, if the host is available. The blood feeding that occurred during the first cycle to initiate the second cycle was not confirmed, however, we cannot exclude this possibility.

Differences in response to temperature and density between two strains of the mosquito, Culex pipiens molestus forskal.

Two strains of Culex pipiens molestus of different geographical origin were reared for more than five years under the same laboratory conditions in order to study to what extent the reactions of these strains to constant temperature and density become similar. Lower temperature and higher densities caused not only the prolongation of developmental time of preimaginal stages and increasing mortality of larvae and pupae in both strains but also the extension of the rate between the first and last emerging imago in both sexes of both strains. Absolute time spent in the preimaginal stage was also influenced by genetic factors. Both strains displayed different values, although both strains were for reared in the laboratory under identical conditions.

Differences in haemagglutination activity in autogenous and anautogenous members of the Culex pipiens mosquito complex.

Hemagglutination activity was studied in whole body extracts of seven laboratory strains of Culex pipiens s.l. (Culex pipiens molestus and Culex pipiens quinquefasciatus). No significant differences in titer between females were observed, but hemagglutination activity in males differed depending on the feeding regime of the mothers of the males.

The effect of age on the fertility of males of Culex molestus (Diptera, Culicidae).

Older males of C. molestus have a markedly lowered fertility (even by 50%) and the image productivity of their progeny is much lower than that of freshly hatched males (more than 6X). This fact may hinder the population explosion particularly in those species whose individual generations coincide in the course of a year or are much diffused.

The effect of tolypin in Tolypocladium niveum crude extract against mosquito and blackfly larvae in the laboratory.

The efficacy of tolypin against mosquito and blackfly larvae was studied under laboratory conditions. It was tested against Culex molestus, Aedes aegypti, Anopheles maculipennis, Simulium noelleri and Odagmia ornata. A concentration 0.1 mg/ml caused 100% mortality in all species tested and a concentration 0.001 mg/ml caused 100% mortality only in the two species of blackflies used within 24 hours.

[The activity of Bacillus thuringiensis var. israelensis against black fly larvae under field conditions in South Bohemia]. / Ucinnost Bacillus thuringiensis var. israelensis proti larvám muchnicek v terénních podmínkách jizních Cech.

The effectiveness of Bacillus thuringiensis var. israelensis spore suspension against black fly larvae was tested in two regulated brooks in the Ceské Budejovice district, South Bohemia. The sites under study were small, regulated, paved brooks of trapezoidal profile, with vegetation of different density, and with stream flow rates ranging from 40 to 90 cm/sec. Lyophilized spores (produced by Roger Belon) at a final concentration of 1 X 10(5) spores per ml were used. The spore efficacy was determined in both natural and artificial substrates in the field and under laboratory conditions, on the larvae collected at the control sites. A 90-100% mortality of the larvae was recorded in all parts of the brooks examined both in the natural samples studied in laboratory and in those kept on artificial substrates. In the area of fading spore suspension action, a higher percentage of the last-instar larvae was found in larval population which may be ascribed, in agreement with other authors, to an increased susceptibility of younger larvae to the preparation. The results of the tests demonstrated that Bacillus thuringiensis var. israelensis is an effective agent to control the black fly species occurring in Central Europe and may be of value mainly in the control of some species of veterinary importance overpopulated in regulated brooks.

The efficacy of Bacillus thuringiensis var. israelensis against larvae of the blackfly Odagmia ornata (Meig.) (Simuliidae) at low temperatures.

The effect of the suspension of Bacillus thuringiensis var. israelensis spores on larvae of the blackfly Odagmia ornata was studied in the laboratory and under field conditions of a natural biotope in southern Bohemia. The preparation Moskitur was used and its effect was tested in laboratory at temperatures 0.1-2.9 degrees C and 17-19 degrees C. Although O. ornata larvae were able to filter feed on a lethal dose of the preparation even at a lower temperature than 2.9 degrees C, no marked manifestation of mortality was observed at low temperatures in comparison with a control sample.

A comparison of developmental dynamics of Dermacentor reticulatus (Fabr.) of different geographic origins and their affection by different microclimate.

Developmental dynamics of D. reticulatus ticks of different geographic origins (NE Poland and SW Slovakia) were investigated and compared. A long-term field experiment was conducted in South Moravia in the zone of thermophilic oak forest. Ticks were studied in two different biotopes: in an open grassy area and in deciduous forest. Differences between the tick populations collected in Poland and Slovakia were observed in the duration of developmental cycle and in the outcome of metamorphosis, depending on biotope. The tick development in the open grassy area was more rapid, but with greater losses. The total production of adults was higher in the population originating from Slovakia.

Virological examination of mosquito larvae from southern Moravia.

254 pools of 4,115 mosquito larvae belonging to nine species were examined by isolation experiments. The larvae were collected in breeding places in an inundated forest--a natural focus of Tahyna virus, in April, June and July 1974 and 1975. Tahyna virus was isolated from one pool of 10 Culiseta annulata larvae collected in July 1974. Ecological questions concerning this finding are discussed.

Influence of microclimate on the life cycle of the common tick Ixodes ricinus (L.) in an open area in comparison with forest habitats.

Under conditions of the South-Moravian region of Pannonian climate (Valtice near Breclav), the life cycle of the common tick Ixodes ricinus (L.) was studied and a continous recording of main elements of microclimate (temperature and humidity) was carried out in an open grassy area. Simultaneously the process of hibernation was studied in four soil layers (surface, depths of 10, 20 and 30 cm). Observations were assessed by mathematiccal-statistical tests and compared with the results obtained by the same methods in the forest biotope (tipe of thermophilic oak forest)and in the ecotone of forest margin (Daniel et al. 1976). The ticks are able to complete the developmental cycle also in the open grassy areas, where during the vegetation period the development proceeds more quickly than in the forest but with considerably higher losses. In the discussion the conclusions are compared with literary data from other parts of Czechoslovakia.

Possibilities of persistence in new biotopes of ticks imported by birds.

Survival and development of 6 tick species (Hyalomma anatolicum, Rhipicephalus sanguineus, Haemaphysalis punctata, Dermacentor marginatus, D. reticulatus and Ixodes ricinus) were studied in 3 groups differing in the range of distribution with respect to the place of importation, as a model for the knowledge of their possible inclusion in the new local biocenosis during transportation by natural hosts.

To the knowledge of ticks of domestic animals in Afghanistan.

Thirteen species and subspecies of ixodid ticks were found on cattle, zebu, buffaloes, goats, sheep and camels examined mainly at the abattoir of Kabul between September 21 and October 1, 1974. All of them are already known from the territory of Afghanistan.

Influence of microclimate on the life cycle of the common tick Ixodes ricinus (L.) in thermophilic oak forest.

Under conditions of the South Moravian thermophilic oak forest (Valtice near Breclav), the life cycle of the common tick Ixodes ricinus was studied by continuous recording of main elements of microclimate (temperature and humidity) in three different biotopes: forest, margin of the forest and meadow. Simultaneously conditions and the process of tick hibernation were studied in four soil layers (surface, depths of 10, 20 and 30 cm). Observations made in the winter and vegetation periods were assessed by mathematical-statistical tests. Results obtained in the forest biotope and at its margin are presented in this paper; results from the meadow biotope will be published separately.