Electrohydraulic effect in heterodisperse water-plant systems. II. Chemical nature of the suspended particles

On the basis of the results of acid hydrolysis, chromatographic analysis of the hydrolysates, and a study of IR spectra, it has been established that the suspended particles liberated under the action of electrohydraulic shocks on heterodisperse water—plant systems consist of small fragments of the lignocarbohydrate complex of the plant tissue.     

Isolation of phospholipase A2 from the venom of the green toadBufo viridis

Phospholipase A₂ has been isolated fromthe venom of he Central Asian green toad Bufo viridis in the electroophoretically homogeneous state for the first time by biospecific absorption chromatography. The affinity sorbent used was Affi-Gel 10 with covalently bound phosphatidylserine (PDS). The chemical inertness of the bound PDS to the hydrolytic action of phospholipase A2 and its high tendency to form biospecific complexes have been shown. Some biochemical characteristics of the enzyme isolated have been studied: influence of the pH and of the Ca²⁺ concentration and dependence of activity on substrate concentration.A. S. Sadykov Institute of Bioorganic Chemistry, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax 627071. Tashkent State University, fax 462472. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 105–109, January–February, 1994.     

Correlation of the leakage current and charge pumping in silicon oninsulator gate-controlled diodes

The leakage and charge pumping currents were measured in gate-controlled MOS p-i-n diodes fabricated on thin SIMOX substrates. The efficiencies of the techniques as well as their complementary features are analyzed for various experimental conditions. The interface properties of device-grade SIMOX wafers are characterized and shown to be compatible with VLSI requirements. Special interface coupling effects, which occur only in fully depleted SOI devices and modify the conventional signature of charge pumping and leakage current, are thoroughly investigated     

Highly reliable 200 mW AlGaAs laser diode with fundamental transverse mode

A highly reliable 200 mW AlGaAs laser diode with a fundamental transverse mode has been developed, by optimising its structure with a 0.8 mu m thick p-cladding layer, a 1200 mu m long cavity length, and a front facet coating with a low reflectivity of 2%. The maximum output power was 500 mW, and stable fundamental transverse mode operation was obtained up to 350 mW. Stable operation under 200 mW and 50 degrees C was confirmed for more than 1200 h. Optical feedback noise was below 3*10/sup -14/ Hz/sup -1/.<>     

Reduction of noise figure in semiconductor laser amplifiers with Ga1-xInxAs/GaInAsP/InP strained quantum wellstructures

The noise characteristics of semiconductor laser amplifiers (SLAs) in the Ga_1-xIn_xAs/GaInAsP/InP strained quantum well (QW) system are theoretically calculated and analyzed using density-matrix theory and taking into account the effects of band mixing on both the valence subbands and the transition dipole moments. The numerical results show that a reduced noise figure can be obtained in both tensile and compressively strained QW structures due to the increase in differential gain and the decrease in transparent carrier density. From a comparison among compressively strained (x=0.70), unstrained (x=0.53), and tensile strained (x=0.40) QW SLAs at a fixed carrier density and optical confinement factor, it is found that the noise figure of the tensile strained QW reaches its lowest value of 3.4 dB at average input optical power of -20 dB     

Reliability studies on GaAs MESFETs fabricated using spin-onplatinum source

GaAs MESFETs were fabricated using a spin-on platinum source as the gate material. They were subsequently aged at 200°C for up to 1000 h. DC electrical characterisation of the MESFETs was carried out during various stages of annealing. The aging behaviour of these MESFETs was compared with those fabricated using conventionally evaporated platinum sources. The results show that the performance of the MESFETs fabricated using a spin-on platinum source is comparable to those of MESFETs fabricated using a conventionally evaporated platinum source     

10 Gbit/s optical soliton transmission over 7200 km by using amonolithically integrated MQW-DFB-LD/MQW-EA modulator light source

The authors demonstrate 10 Gbit/s optical soliton transmission in a recirculating loop through the use of a monolithically integrated MQW-DFB-LD/MQW-EA modulator light source. The timing jitter due to the Gordon-Haus effect is successfully reduced by the optical bandpass filters conventionally used in the cascaded EDFAs to avoid the accumulation of amplified spontaneous emission. The transmission distance of 7200 km is achieved at a bit error rate of 10^-9