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This datasheet on Gymnandrosoma aurantianum covers Identity, Overview, Distribution, Dispersal, Hosts/Species Affected, Diagnosis, Biology & Ecology, Environmental Requirements, Natural Enemies, Impacts, Uses, Prevention/Control, Further Information.

Extreme ultraviolet (EUV) lithography is expected to succeed in 193-nm immersion multi-patterning technology for sub-10-nm critical layer patterning. In order to be successful, EUV lithography has to demonstrate that it can satisfy the industry requirements in the following critical areas: power, dose stability, etendue, spectral content, and lifetime. Currently, development of second-generation laser-produced plasma (LPP) light sources for the ASML’s NXE:3300B EUV scanner is complete, and first units are installed and operational at chipmaker customers. We describe different aspects and performance characteristics of the sources, dose stability results, power scaling, and availability data for EUV sources and also report new development results.

In this paper, we provide an overview of various challenges and their solutions for scaling laser-produced-plasma (LPP) extreme-ultraviolet (EUV) source performance to enable high volume manufacturing. We will discuss improvements to source architecture that facilitated the increase of EUV power from 100W to >200W, and the technical challenges for power scaling of key source parameters and subsystems. Finally, we will describe current power-scaling research activities and provide a forward looking perspective for LPP EUV sources towards 500W.

We present highlights from plasma simulations performed in collaboration with Lawrence Livermore National Labs. This modeling is performed to advance the rate of learning about optimal EUV generation for laser produced plasmas and to provide insights where experimental results are not currently available. The goal is to identify key physical processes necessary for an accurate and predictive model capable of simulating a wide range of conditions. This modeling will help to drive source performance scaling in support of the EUV Lithography roadmap. The model simulates pre-pulse laser interaction with the tin droplet and follows the droplet expansion into the main pulse target zone. Next, the interaction of the expanded droplet with the main laser pulse is simulated. We demonstrate the predictive nature of the code and provide comparison with experimental results.

BACKGROUND: South Africa has the greatest burden of HIV-infection in the world with about 5.2 million HIV-infected adults. In 2003, the South African Government launched a comprehensive HIV and AIDS care treatment program supported by the United States in 2004 through the President's Emergency Plan for AIDS Relief (PEPFAR). METHODS: To describe the scale-up and continuation of antiretroviral therapy in South African Government and PEPFAR-supported sites in South Africa, we conducted a retrospective analysis of routinely collected program reporting data, 2005-2009. RESULTS: From 2005 through 2009, the average rate of persons initiated on antiretroviral therapy in PEPFAR-supported South African Government treatment programs increased nearly four-fold from 6,327 a month in 2005-2006 to 24,622 a month in 2008-2009 resulting in an increase from 33,543 patients on continued treatment in April-June 2005 to 631,985 patients in July-September 2009. Of those 631,985 patients receiving treatment, 65% were women. Men were more likely to be lost to follow-up (9.2% vs. 7.8%, PR 1.18, 95% CI 1.17-1.19) and more likely to die (5.6% vs. 4.1%, PR 1.36, 95% CI 1.35-1.37) than women. CONCLUSIONS: Scale-up and continuation of antiretroviral therapy in South Africa has been a remarkable medical accomplishment. Because more women receive and continue treatment, more efforts are needed to treat and retain men.

Platynota rostrana is recorded for the first time as citrus pests in Mexico, on Citrus sinensis and Citrus limon.

Moore's Law, which predicts thecontinued increase in device density onintegrated circuits, has been driven by advancesin lithography. Both resolutionand productivity of the exposure toolhave been enabled by the light sourcetechnology. The transition to shorterwavelength, first by introducing excimerlasers and more recently by developmentof EUV Laser Produced Plasma sources hasdriven resolution. In addition, the continuedcost effectiveness of lithography isdependent on the scaling of the power output for both types of source.

Previous studies have shown that high dose 17beta-estradiol (10 (-5) M) has a G2/M blocking effect in SW-13 human adrenal carcinoma cultures and strongly enhances apoptosis. To examine the differential effects of estrogen alpha and beta-receptors in this system, we incubated SW-13 cells with specific alpha- and beta-estrogen receptor agonists, PPT [4,4',4''-(propyl-[ (1)H]-pyrazole-1,3,5-triyl) trisphenol] and DPN [2,3-bis (4-hydroxyphenyl) propionitrile], respectively (each at 10 (-5) M). Flow cytometry was used to analyze the percentages of cells in various phases of the cell cycle [sub-G1 (apoptosis), G1, S, and G2/M] in each experimental condition. Exposure to 17 beta-estradiol for 48 hours increased apoptosis more than 5-fold (from 3.6+/-0.5 to 20+/-2.2% of cells; p

During the mid 18th century, the standard British Army issue weapon was the Brown Bess Musket. There are various accounts of the performance of this early form of firearm and its tactical deployment (e.g. Hanger 1816). Using a technical replica of the Brown Bess, range trials and computer modelling have been used to asses the weapon's capabilities and likely performance. The research found the Brown Bess musket to be a lethal weapon at the ranges at which enemy was commonly engaged, so long as it was accurate enough to hit the target. A single shot fired at 150 yards could penetrate at least two soldiers, even if bone were hit. The armour of the day (shields of wood, leather and sometimes steel, and the layers of woollen clothing) was easily pierced by the shot. The shot was found to readily deform on impact with metal targets. The maximum range could extend to around 1200m, with 202m reached when fired horizontally.

This paper describes the development and evolution of the critical architecture for a laser-produced-plasma (LPP) extreme-ultraviolet (EUV) source for advanced lithography applications in high volume manufacturing (HVM). In this paper we discuss the most recent results from high power sources in the field and testing on our laboratory based development systems, and describe the requirements and technical challenges related to successful implementation of those technologies on production sources. System performance is shown, focusing on pre-pulse operation with high conversion efficiency (CE) and with dose control to ensure high die yield. Finally, experimental results evaluating technologies for generating stable EUV power output for a high volume manufacturing (HVM) LPP source will be reviewed.

Multiple NXE:3300 are operational at customer sites. These systems, equipped with a Numerical Aperture (NA) of 0.33, are being used by semiconductor manufacturers to support device development. Full Wafer Critical Dimension Uniformity (CDU) of 1.0 nm for 16nm dense lines and 1.1 nm for 20nm isolated space and stable matched overlay performance with ArF immersion scanner of less than 4nm provide the required lithographic performance for these device development activities. Steady progresses in source power have been achieved in the last 12 months, with 100Watts (W) EUV power capability demonstrated on multiple machines. Power levels up to 90W have been achieved on a customer machine, while 110W capability has been demonstrated in the ASML factory. Most NXE:3300 installed at customers have demonstrated the capability to expose 500 wafers per day, and one field system upgraded to the 80W configuration has proven capable of exposing 1,000 wafers per day. Scanner defectivity keeps being reduced by a 10x factor each year, while the first exposures obtained with full size EUV pellicles show no appreciable difference in CDU when compared to exposures done without pellicle. The 4th generation EUV system, the NXE: 3350, is being qualified in the ASML factory.

Since their invention in 1966 copper vapour lasers (CVLs) have developed into a mature technology with applications including high-speed imaging, micro-machining, non-linear frequency conversion to the ultraviolet, and pumping of solid-state laser materials. However, the performance characteristics of conventional CVLs are fundamentally limited by kinetic processes at play within the gain medium and hence, these devices largely failed to keep pace with advances in visible solid state lasers during the late 1980s and early 1990s. In 1996 a new subclass of CVL, termed a kinetically enhanced or KE-CVL, was developed that used a ternary gas mixture (HCl–H2–Ne) to tailor the kinetic processes that limit laser performance. These devices offer dramatic improvements in power (both average and high beam quality) and repetition rate scalability. Indeed, 100 W of visible, high beam quality power is now readily available from relatively small copper laser systems. In this paper the underlying principles and performance characteristics of KE-CVLs will be reviewed.

This paper describes the development of a laser-produced-plasma (LPP) extreme-ultraviolet (EUV) source for advanced lithography applications in high volume manufacturing. EUV lithography is expected to succeed 193nm immersion double patterning technology for sub- 20nm critical layer patterning. In this paper we discuss the most recent results from high power testing on our development systems targeted at the 250W configuration, and describe the requirements and technical challenges related to successful implementation of these technologies. Subsystem performance will be shown including Conversion Efficiency (CE), dose control, collector protection and out-of-band (OOB) radiation measurements. This presentation reviews the experimental results obtained on systems with a focus on the topics most critical for a 250W HVM LPP source.

Laser produced plasma (LPP) light sources have been developed as the primary approach for EUV scanner imaging of circuit features in sub-20nm devices in high volume manufacturing (HVM). This paper provides a review of development progress and readiness status for the LPP extreme-ultra-violet (EUV) source. We present the latest performance results from second generation sources, including Prepulse operation for high power, collector protection for long lifetime and low cost of ownership, and dose stability for high yield. Increased EUV power is provided by a more powerful drive laser and the use of Prepulse operation for higher conversion efficiciency. Advanced automation and controls have been developed to provide the power and energy stability performance required during production fab operation. We will also discuss lifetesting of the collector in Prepulse mode and show the ability of the debris mitigation systems to keep the collector multi-layer coating free from damage and maintain high reflectivity.

We report the performance characteristics of a copper laser master-oscillator power-amplifier system incorporating kinetically enhanced active elements. The advantages provided by kinetic enhancement lead to record brightness levels.

A detailed computer model has been used to simulate the plasma kinetics and lasing characteristics in a kinetically enhanced copper vapor laser (KE-CVL) which utilizes Ne-H/sub 2/-HCl buffer gas mixtures. The model reproduces key features of the observed operating characteristics of the KE-CVL-in particular, relating to the electrical characteristics of the plasma tube, time evolution of Cu 4s/sup 2/S/sub 1/2/ ground state density, and formation of the laser output. It is shown that the principal role of the HCl additive is to increase the electron loss rate during the interpulse period via dissociative attachment reactions between free electrons and vibrationally excited HCl (/spl nu/=1,2) molecules. This leads to a reduction of the prepulse electron density establishing more favorable prepulse conditions for laser action during the subsequent excitation phase. In the KE-CVL, the plasma skin effect governing the development of the radial electric field is greatly reduced compared to conventional CVL's, altering the spatio-temporal evolution of the optical gain and laser field intensities to substantially enhance high-beam-quality output. Comparisons between model results and experimental data for the decay rate of the Cu 4s/sup 2/ /sup 2/D/sub 3/2/ metastable lower laser level in the early afterglow suggest that there may be an additional de-excitation mechanism for the /sup 2/D/sub 3/2,5/2/ levels in the KE-CVL plasma which has yet to be identified.

We report dramatic improvements (up to four times) in the generation of high-beam-quality (HBQ) output power from copper vapor lasers (CVLs) by using tailored HCl-H/sub 2/-Ne buffer gas mixtures. Up to 60 W of HBQ power was obtained from a 38-mm bore-diameter CVL at a pulse repetition frequency of 12 kHz and 50 W at 22 kHz. This improvement in power capability is attributable to the modification of the spatio-temporal gain characteristics of the laser when using the new buffer gas mixture.

Etch rates (/spl mu/m/pulse) for glycol-modified polyethylene terephthalate (PETG) under pulsed UV (255 nm) laser processing are measured as a function of pulse repetition frequency in the range 0.7-15 kHz. Materials removal rates (/spl mu/m/s) scale approximately linearly with pulse repetition frequency at a fluence of 0.59 J/cm/sup 2/, and there appears to be no attenuation of the ablating laser beam by the ejected material plume for pulse rates up to 15 kHz. The instantaneous etch rate for pulses in a sequence increases markedly (/spl sim/40%) for long pulse sequences (>100 pulses) at high PRF (15 kHz), an effect which can be used to increase machining rates while operating at a moderate laser fluence.

A detailed computer model for the kinetics in an elemental copper vapour laser (Cu–Ne–H 2 ) has been used to investigate the importance of the pre-pulse electron density on the performance and lasing characteristics of such a device. The results show that the laser output power and operating efficiency are increased by 65% and 100%, respectively, at a pulse repetition frequency of 17 kHz, if the pre-pulse electron density is reduced by a factor of 5–10. Modelling of the plasma kinetics during the afterglow period suggests that such a reduction is brought about when trace quantities (∼0.3%) of HCl are introduced into the plasma to increase the electron density decay rates via dissociative attachment reactions. The predicted improvements in laser performance which occur as a result of a reduced pre-pulse electron density are consistent with the observed operating characteristics of Kinetically Enhanced copper vapour lasers which use HCl–H 2 –Ne buffer gas mixtures.

Potential–density pair basis sets can be used for highly efficient N-body simulation codes, but they suffer from a lack of versatility, i.e. a basis set has to be constructed for each different class of stellar system. We present numerical techniques for generating a biorthonormal potential–density pair basis set that has a general specified pair as its lowest-order member. We go on to demonstrate how the set can be used to construct N-body equilibria, which we then evolve using an N-body code that calculates forces using the basis set.

We report on the operation of a 6 cm bore copper HyBrID laser which incorporates a high-magnification (M = 280) negative-branch confocal optical resonator and utilizes a magnetic pulse compression excitation circuit. 125 W total output was obtained at a pulse repetition frequency of 12.5 kHz, of which 101 W (i.e. 80% of the total) was high beam quality output. `Power in the bucket' measurements revealed that of the high beam quality output was within the diffraction limit (62 rad), and within the diffraction limit.

The output powers from 25 mm (volume 0.49 l) and 40 mm (volume 1.9 l) diameter copper vapour lasers (nominally 20 and 55 W devices) are approximately doubled to >50 and >100 W respectively by adding small partial pressures of both H2 and HCl to the neon buffer gas. Our studies show that this gas mixture performs better than a H2–HBr admix, a result we attribute to more efficient reassociation of HCl in the plasma region.

The interferometric "Hook" method has been used to measure the copper ground-state density during the interpulse period for a 38 mm bore diameter copper vapor laser (CVL) operated in kinetically enhanced (KE) mode (Ne-HCl-H/sub 2/ gas mixture) and in conventional mode (pure neon and Ne-H/sub 2/ gas mixtures). It was found that the rate of regrowth of the axial copper density during the afterglow of the KE-CVL is 3-4 times faster, and the axial prepulse ground-state copper density is 2-3 times higher, than that observed for pure Ne or Ne-HI buffer gases. We conclude that the primary action of the HCl+H/sub 2/ additives is to increase the interpulse plasma relaxation rate and to increase the threshold copper density beyond which thermal runaway occurs. These effects are primarily responsible for the elevated pulse rates and increased pulse energies giving improved power scaling characteristics of KE-CVLs.

A synthesis of 2-amino-1-hydroxyethylene-1,1-bisphosphonic acid 3 has been developed from N -phthaloylglycine via dimethyl 2-( N -phthaloylamino)acetylphosphonate 1 . The preparation of the N -methylated and N , N -dimethylated derivatives 4 and 5 has been achieved by the reaction of 3 with formic acid and formaldehyde. The synthesis of 1-amino-2-hydroxyethylene-1,1-bisphosphonic acid 9 (RR′H) and its N -methylated and N , N -dimethylated analogues has been achieved by the reaction of phosphorus trichloride and phosphorous acid with the appropriate O -benzyl protected hydroxyacetamide, followed by catalytic hydrogenolysis of the protecting group.

Acute lung allograft rejection is believed to be initiated by passenger leukocytes, such as alveolar macrophages (AM), in the donor organ, which release TNF-alpha, and present alloantigens to host lymphocytes, to up-regulated Th1 cellular and humoral immunity. However, the role of donor AM in local TNF-alpha synthesis, and their ability to induce local Th1 cellular and humoral immunity have not been evaluated. By depleting Brown Norway (BN, RT1n) rat lung allografts of AM before transplantation into Lewis rat (LEW, RT1(1)) recipients, the current study determined the role of donor AM in including the production of TNF-alpha, IFN-gamma (Th1 cytokine), IL-4 (Th2 cytokine), IgG subtypes, and rejection pathology in the allograft. The data show that compared with untreated BN allografts, pretransplant depletion of donor lung AM resulted in significantly less TNF-alpha, and IFN-gamma production in allograft bronchoalveolar lavage fluid with variable effects on local IL-4 production. Depletion of AM in the donor lung before transplantation affected the local production of several IgG subclasses. However, pretransplant depletion of donor AM had no effect on the development of the pathology of severe acute rejection. These data show that donor AM have a central role in the local synthesis of TNF-alpha and induce the production of IFN-gamma and IgG subtypes, locally, during acute lung allograft rejection. However, depletion of AM before transplantation does not prevent the development of severe acute rejection in BN rat lungs, transplanted into LEW recipients.

Depletion of the metal vapor density from the central region of metal vapor laser tubes has recently been identified as an important factor limiting laser output. We have studied the mechanisms that deplete the ground-state metal density profile by measuring radially resolved population histories of neutral and ionic species during a “burst” (i.e., a pulse train of 20–30 excitation pulses) in a barium vapor laser (BVL). The observed spatiotemporal density behavior during the afterglow of the first shot in the burst agrees well with a simple model for diffusion and recombination, which we have used to show that the primary depletion mechanism during the establishment of steady-state conditions arises from the ambipolar diffusion of ions to the tube wall, and that gas-heating effects are secondary. Analysis of the steady-state (i.e., late-burst) afterglow behavior further reveals that the depletion is significantly greater than that expected from the measured barium ionization, particularly when operating a...

We have studied the factors limiting the performance of a barium vapour laser (BVL) as the pulse repetition frequency (PRF) is elevated. By measuring the population densities of key barium species, we have found that increasing the PRF leads to progressively larger depletion of the axial pre-pulse Ba ground-state density (up to 85% at 15 kHz PRF), due to the combined effects of ion pumping and gas heating. A direct consequence of this Ba density depletion is a proportional decrease in the peak upper laser-level density of the 1.50 μm and 1.13 μm laser transitions (i.e. Ba 1 P 1 ) during the excitation pulse. The results suggest that ground-state depletion is the dominant factor limiting laser output at high PRFs, and that the effects of the pre-pulse lower laser-level and electron densities play a secondary role. The implications to the PRF scaling of BVLs and other metal vapour lasers are discussed.

Observations of amplitude modulation in laser pulses emitted by a discharge-excited Sr + recombination laser are presented. The mechanism of mode-beating is proposed to account for such behaviour. Comparisons are made with previous reports of similar behaviour in a number of metal vapour laser systems, and suggestions that this phenomenon is the result of self mode-locking are examined.

We report an injection-seeded oscillator system based on Cu HyBrID laser active elements producing 120 W of output power with pulse-average divergence

We report on a detailed study of the effects of bromine and hydrogen bromide buffer-gas additive on the electrical and lasing characteristics of a conventional, high-temperature copper vapour laser. At standard buffer gas flow rates HBrNe mixtures produced relatively small improvements in output power, however, larger increases in output power were observed at elevated HBrNe flow rates. Added HBr also significantly modifies the spatio-temporal characteristics of laser output, increasing the pulse duration by a factor of 2 while also improving the radial intensity profile. This result has important implications for improving the extraction of high beam quality output from devices employing high magnification unstable resonators.

We have studied the development of steady-state prepulse conditions in the barium vapor laser (BVL) and the factors that influence steady-state laser output using the "hook" method. The ground-state and excited-state Ba and Ba/sup +/ species were measured during the afterglow, and the Ba/sup 1/P/sub 1/ upper laser level during the excitation phase, of selected pulses in a burst of excitation pulses at 8 kHz. Results show that large depletion of the prepulse Ba/sup 1/S/sub 0/ ground-state density from the axial region of the tube occurs during the burst, and proportional decreases in the peak upper-laser-level density occur during the excitation phase. The prepulse electron density (inferred from the total Ba/sup +/ density) and lower-laser-level densities do not accumulate during the burst, and it is concluded that ground-state depletion is primarily responsible for the decrease in laser pulse energy that occurs during a burst as reported by Pask and Piper (1994). We observe significantly greater depletion of the ground-state density on-axis in the presence of neon buffer gas than helium, which we attribute primarily to the high ionization observed in neon and the corresponding increase in the effects of ambipolar diffusion. The results highlight the influence of buffer-gas composition on the establishment of steady-state prepulse conditions (and therefore the steady-state laser pulse characteristics). The results have implications to metal vapor lasers in general, including those operating with buffer-gas additives.

Background The prevalence of hypertension is rising worldwide with an estimated one billion people now affected globally and is of near epidemic proportions in many parts of South Asia. Recent turmoil has until recently precluded estimates in Afghanistan so we sought, therefore, to establish both prevalence predictors in our population. Methods We conducted a cross-sectional study of adults ≥40 years of age in Kabul from December 2011-March 2012 using a multistage sampling method. Additional data on socioeconomic and lifestyle factors were collected as well as an estimate of glycaemic control. Bivariate and multivariable analyses were undertaken to explore the association between hypertension and potential predictors. Results A total of 1183 adults (men 396, women 787) of ≥ 40years of age were assessed. The prevalence of hypertension was 46.2% (95% CI 43.5 – 49.3). Independent predictors of hypertension were found to be: age ≥50 (OR = 3.86, 95% CI: 2.86 – 5.21); illiteracy (OR = 1.90, 1.05 – 1.90); the consumption of rice >3 times per week (OR = 1.43, 1.07 – 1.91); family history of diabetes (OR = 2.20, 1.30 – 3.75); central obesity (OR = 1.67, 1.23 – 2.27); BMI ≥ 30 Kg/meter squared (OR = 2.08, 1.50 – 2.89). The consumption of chicken and fruit more than three times per week were protective with ORs respectively of 0.73 (0.55-0.97) and 0.64 (0.47 – 0.86). Conclusions Hypertension is a major public health problem in Afghan adults. We have identified a number of predictors which have potential for guiding interventions.

Laser produced plasma (LPP) systems have been developed as the primary approach for use in EUV scanner light sources for optical imaging of circuit features at 20nm nodes and beyond. This paper provides a review of development progress and productization status for LPP extreme-ultra-violet (EUV) sources with performance goals targeted to meet specific requirements from ASML. We present the latest results on power generation and collector protection for sources in the field operating at 10W nominal power and in San Diego operating in MOPA (Master Oscillator Power Amplifier) Prepulse mode at higher powers. Semiconductor industry standards for reliability and source availability data are provided. In these proceedings we show results demonstrating validation of MOPA Prepulse operation at high dose-controlled power: 40 W average power with closed-loop active dose control meeting the requirement for dose stability, 55 W average power with closed-loop active dose control, and early collector protection tests to 4 billion pulses without loss of reflectivity.

This paper describes the development of a laser-produced-plasma (LPP) extreme-ultraviolet (EUV) source for advanced lithography applications in high volume manufacturing. EUV lithography is expected to succeed 193nm immersion double patterning technology for sub-20nm critical layer patterning. In this paper we discuss the most recent results from high power testing on our development systems in San Diego, and describe the requirements and technical challenges related to successful implementation of these technologies. Subsystem performance will be shown including the CO2 drive laser, droplet generation, laser-to-droplet targeting control, intermediate-focus (IF) metrology, out-of-band (OOB) radiation measurements and system use and experience. In addition, a multitude of smaller lab-scale experimental systems have also been constructed and tested..

Laser produced plasma (LPP) systems are the leading approach for extreme-ultra-violet (EUV) lithography of circuit features at sub-20nm nodes. This paper reviews technology and development progress for high-power sources optimized for EUV lithography. Article not available.

Dans un effort continu pour eradiquer ou au moins, reduire, la presence deLantana camara L., advantice bien repandue a Guam, un suivi bi-mensuel a ete effectue, sur une periode de 4 ans et demi, pour etudier l’efficacite des ennemis naturels a affaiblir la plante et a diminuer le nombre de graines viables. Au total, huit agents de lutte biologique ont ete recenses. Les insectes s’attaquant aux feuilles sont :Uroplata girardi Pic. (Col. : Chrysomelidae),Teleonemia scrupulosa Stal (Hem. : Tingidae),Calycomyza lantanae Frick (Dip. : Agromyzidae) etHypena strigata (F.) (Lep. : Noctuidae). Les papillons de nuitLantanophaga pusillidactyla (Walker, (Lep. : Pterophoridae),Epinotia lantana (Busck) (Lep. : Tortricidae) etAdoxopheyes melia Clarke (Lep. : Tortricidae) s’attaquent aux fleurs ainsi queT. scrupulosa. E. lantana etOphomyia lantanae (Froggatt) (Dip. : Agromyzidae) font des degâts aux fruits. Un modele empirique de lutte biologique a ete etabli a partir des donnees observees. Le modele a mis en evidence que les 8 auxiliaires empechent la production ou detruisent 225,9 baies par metre carre sur une periode d’observation de deux semaines. Sur cette meme periode, la production de fruits non abimes observee au metre carre n’est que de 96,1. Ainsi, les auxiliaires reduisent la production potentielle de fruits de 70,1 %. Le modele a aussi permis d’estimer le role tenu par chaque auxiliaire dans la lutte biologique globale contreL. camara a Guam

We have identified numerous molecular and atomic impurities evolving from the alumina ceramics used in the construction of copper vapour laser (CVL) plasma tubes during the high temperatures associated with typical operating conditions. The majority of these molecular impurities fragments under discharge conditions, with most of the by-products of dissociation contributing to the formation of solid deposits within the plasma tube while hydrogen-bearing molecules produce free or H which can improve CVL output power. Implications for plasma tube design and processing are discussed.

We present results of a detailed study comparing the effects of H/sub 2/ buffer gas additive on the output power and the spatio-temporal evolution of laser output produced by copper vapor lasers of varying aperture-size. We show that while the optimum H/sub 2/ concentration is relatively insensitive to the laser diameter, it is influenced by the type of resonator employed and the total neon buffer gas pressure.

We report results of a detailed study investigating the effects of hydrogen additive on the generation of high-beam quality output from a copper vapor laser. Increases up to 390% were observed for the power extracted in the high-beam quality component of laser output, however, the power of the low beam quality output remained relatively unchanged. We attribute these results to modification of the spatio-temporal characteristics of the laser gain with added H/sub 2/. >

We report significant improvements in ultraviolet (UV) power generation at elevated pulse-repetition frequencies (10/spl ges/kHz) from a frequency-doubled copper-vapor laser (CVL), employing a Ne-H/sub 2/ buffer gas. In particular, UV powers of 1.3 W and 0.6 W at 255 nm (SHG green) were generated at 10 kHz and 20 kHz, respectively, when using H/sub 2/ additive in a medium scale (nominally 20 W) CVL oscillator. These results represent improvements of 6.5/spl times/ and /spl sim/100/spl times/, respectively, over the UV powers obtained for pure neon-buffer gas. The enhanced UV powers are directly related to the improvement in high-beam quality extraction from the CVL due to the beneficial effects of the H/sub 2/ add-gas on CVL gain characteristics. >