Applications of ultrashort pulse propagation in Bragg gratings forwavelength-division multiplexing and code-division multiple access

We discuss theoretical and experimental studies on the propagation of ultrashort pulses through fiber Bragg gratings. We also consider several applications in optical communications to be found by combining ultrashort pulses and fiber Bragg gratings: a multiwavelength source for wavelength-division-multiplexed systems and a means for implementing optical code-division multiple access     

Specific sequence modifications of a cry3B endotoxin gene result in high levels of expression and insect resistance

Solanum melongena (eggplant) cv. Picentia and the wild species Solanum integrifolium were transformed with both a wild type (wt) and four mutagenized versions of Bacillus thuringiensis (Bt) gene Bt43 belonging to the cry3 class. The Bt gene was partly modified in its nucleotide sequence by replacing four target regions (W: +1 to +170; X: +592 to +1057; Y: +1203 to +1376; Z: +1376 to +1984) with synthetic fragments obtained by polymerase chain reaction amplification of crude oligonucleotides. The synthetic Bt genes were designed to avoid, in their modified regions, sequences such as ATTTA sequence, polyadenylation sequences and splicing sites, which might destabilize the messenger RNA. Furthermore, the codon usage was improved for a better expression in the plant system. The amino acid composition was not altered. Four versions of the modified Bt gene were obtained, BtE, BtF, BtH and BtI, with a nucleotide subtitution percentage of 8.2, 8.6, 14, and 16%, respectively, in comparison to the wt gene Bt43. Modified versions contained different subsets of substituted regions: BtE-W + Z, BtF - Y + Z, BtH-X + Y + Z, BtI - W + X + Y + Z. In the final modified version (BtI), overall guanine+cytosine was increased from the 34.1% of the wt gene to 45.5%, and most of the destabilizing sequences were eliminated. Transgenic plants obtained with the more modified versions, BtH and BtI, were fully resistant to Leptinotarsa decemlineata Say first- and third-instar larvae, while Bt43 wt, BtE and BtF genotypes did not cause mortality and did not affect larval development.     

Optical dot gain on newsprint determined with the Lund nuclear microprobe

A technique for measuring optical dot gain, i.e. the relative difference between the actual screen dot and the optically perceived one, is presented. By combining measurements from the non-optical nuclear microprobe with data from image analyzing technique the optical dot gain can be determined. The procedure to reach pixel by pixel correlation on a micrometer scale is discussed. In the newsprint sample studied in this investigation a typical optical dot gain between 15 and 20% was deduced. The variation in the optical dot gain was correlated with other characteristic parameters of the print and newsprint and especially a positive correlation to the mass density of the newsprint was observed.     

Interaction of powder microparticles with the steel matrix under dynamic action

Conclusions In dynamic interaction of powder particles and the steel matrix at the points of their retarding and stoppage, significant high-velocity plastic deformation occurs according to shear, rotational, and twinning mechanisms, which, together with local microalloying of the matrix with elements of the particles, promotes additional hardening of the steel. Processes of complete restoration of the structure in these areas are undesirable since they reduce the effect of hardening of the steel with dispersed particles.Dnepropetrovsk Metallurgical Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 44–45, February, 1991.     

A new SPICE model of power P-I-N diode based on asymptotic waveformevaluation

A new SPICE subcircuit model for power p-i-n diodes is proposed in this paper. The model is based on a moment-matching approximation of the ambipolar diffusion equation. It is shown that both the quasistatic model and the lumped charge model can be obtained as ion-order moment-matching approximations while new and more accurate models can be obtained from higher-order solutions. The proposed model takes into account emitter recombination in the highly doped end regions, conductivity modulation in the base and the moving-boundaries effect during reverse-recovery, showing good convergence properties and fast simulation times. Comparisons between the results of the SPICE model and both numerical device simulations and experimental results are presented     

Qualitativ-quantitative Simulation, ein Instrument zur Analyse nichtlinearer Regelkreise

Qualitative-quantitative simulation is one of the most productive and promising research areas in Artificial Intelligence to emerge in recent years. This method provides an elegant way for an exhaustive analysis of uncertain dynamic systems. The application of the qualitative-quantitative simulation is shown in this paper. The important question about the stability of a quanlitatively described dynamical system is solved by a novel analytic method.     

From categorial to dimensional diagnosis

The concepts of categorical and dimensional assessment approaches and their specific advantages--and disadvantages are described. A combination of both concepts within the framework of Multiple Assessment of Psychiatric Disturbances is proposed. This includes the different levels of behavioural and emotional disturbances, different assessment methods, the situational specificity of behavioural and emotional disturbances and individually tailored and treatment related assessment procedures. Thereby two phases are distinguished. In the first phase basic procedures of the Multiple Assessment of Psychiatric Disturbances are accomplished, which cover a broad spectrum of behavioural and emotional problems. In the second phase a differentiated picture of the-specific disturbance is assessed by using symptom-specific instruments of the Multiple Assessment of Psychiatric Disturbances. In a case report the diagnostic procedure is explained.     

Shaping axisymmetric shells

Assuming constant strains in thickness, the author examines the problem of shaping axisymmetric shells of elastoplastic materials. The results of computer calculations are presented.On the basis of the data obtained in [1] and assuming constant strain through the thickness, we examine the problem of shaping axisymmetric shells made of an elastoplatic material.Translated from Problemy Prochnosti, No. 4, pp. 18–24, April, 1992.