125-TW Ti:sapphire/Nd:glass laser system

We have demonstrated a Ti:sapphire/Nd:glass laser system that produces up to 51 J of energy in 395-fs pulses (125TW). Focusing at f/3 to a 2.5-times diffraction-limited spot results in a peak irradiance greater than 10(20) W/cm(2) . Our 40-cm-diameter gold diffraction gratings have a damage threshold of 0.42 J/cm(2) for 320-fs pulses.     

Zum Nachweis von Strychnin

Ohne Zusammenfassung     

Ice-active proteins from New Zealand snow tussocks, Chionochloa macra AND C. rigida

The ice active protein profile of New Zealand snow tussocks Chionochloa macra and C. rigida consisted of ice nucleation activity but no antifreeze or recrystallization inhibition activity. The ice nucleation activity was similar in the two species, despite them being collected at different altitudes and at different times. The activity is intrinsic to the plant and is associated with the surface of the leaves. Snow tussocks collect water from fog. Nucleation sites on the surface of their leaves may aid the efficiency of this process.     

Freezing rate affects the survival of a short-term freezing stress in Panagrolaimus davidi, an Antarctic nematode that survives intracellular freezing

The ability of the Antarctic nematode Panagrolaimus davidi to survive a short-term freezing stress depended upon the rate of freezing of its surroundings, measured as the duration of the sample exotherm. The freezing rate increased as the sample volume and freezing temperature decreased and resulted in fewer nematodes surviving. This appears to be due to the greater risk of physical damage by ice crystal growth at high freezing rates. Once frozen the nematodes will then survive exposure to lower temperatures. The environment of the nematode is likely to produce the slow rate of freezing of its surroundings that is necessary for its survival.     

Correspondence between zero angular momentum transfer cross sections of (6Li, 6He) reactions and the Gamow-Teller strength

The (⁶Li, ⁶He) cross sections on targets between ⁶Li and ⁴⁸Ca have been measured. The cross section due to zero angular momentum transfer appears to be correlated with the known Gamow-Teller strength. The reaction mechanism sometimes is dominated by multistep processes.     

On Estimating Aggregate Inventory Characteristics

It is shown that where usage rates are approximately lognormal in distribution, the aggregate characteristics of simple EOQ/EBQ inventory control systems can be easily and accurately determined from estimates of the mean and median usage rates.     

A simple ice nucleation spectrometer

The construction of a simple ice nucleation spectrometer is described. It uses 10 microliter droplets loaded into glass capillary tubes which are then inserted into an aluminium holder. Each holder takes six capillary tubes surrounding a central thermocouple. Four holders are placed into a cooling block, cooled by fluid from a programmable refrigerated circulator, and the thermocouples interfaced to a computer to record temperatures. Freezing of each sample is detected by an exotherm on the temperature recording, with 24 samples recorded per run. The spectrometer was tested using deionized water, an extract from a New Zealand alpine cockroach and an extract of lawn grass. The cockroach extract is estimated to contain about 10(3) more nucleators, active at -5 degrees C, than the grass extract.     

A Structural Investigation of Ga3−xIn5+xSn2O16

The structure of the recently reported transparent conductor, Ga_3−xIn_5+xSn₂O₁₆(0.3<x<1.6), was established by a combination of high-resolution electron microscopy, convergent-beam electron diffraction, and Rietveld analysis of powder diffraction data (X-ray and time-of-flight neutron methods). This “T-phase” compound has an anion-deficient fluorite-derivative structure whose space group isI4₁/a. Although there are similarities to the parent oxide structures, the T-phase lacks one of the distorted InO₆octahedra observed in In₂O₃, which may account for its inability to be donor-doped by Sn.     

Zur Entdeckung freier Minerals?uren im Essig

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