Application of the integral definition of the curl operator tonumerical solutions in electromagnetics

The definition of the curl operator in terms of an integral is shown to lead to a method for numerical solutions that facilitates the use of mixtures of cells having different shapes and different dielectric properties. The derivation is followed by examples for, waveguides, mixtures of different cells, and a method for increasing the accuracy when an equation is known for the field on the outer boundary. Thus, these results suggest that the formal definition of the curl operator has more than pedagogical value. This definition is taught in an undergraduate class at Florida International University     

Enhanced electron emission from phosphorus-doped diamond-cladsilicon field emitter arrays

Undoped and phosphorus (P)-doped diamond-clad Si field emitter arrays have been successfully fabricated using microwave plasma chemical vapor deposition (MPCVD) technology. The electron emission from the blunt diamond-clad microtips are much higher than those for the pure Si tips with sharp curvature due to a lower work function. Furthermore, the characteristics of emission current against applied voltage for the P-doped diamond-clad tips show superior emission at lower field to the undoped ones. After the examination of Auger electron spectroscopy (AES) and electrical characteristics of as-grown diamond, such a significant enhancement of the electron emission from the P-doped diamond-clad tips is attributed to a higher electron conductivity and defect densities     

Determination of the width of the transition layer between the crystalline and amorphous zones in nylon 1010 by SAXS

The width of the transition layer between the crystalline and amorphous zones in nylon 1010 was determined by SAXS with point collimation and long-slit collimation, respectively. The width of the transition layer, E, was found to be 1.7 nm. The results show that the width of the transition layer is independent of crystallinity.     

The natural killer cell receptor specific for HLA-A allotypes: a novel member of the p58/p70 family of inhibitory receptors that is characterized by three immunoglobulin-like domains and is expressed as a 140-kD disulphide-linked dimer

Human natural killer (NK) cells express inhibitory receptors that are specific for different groups of HLA-C or HLA-B alleles. The majority of these receptors belong to the immunoglobulin (Ig) superfamily and are characterized by two or three extracellular Ig-like domains. Here we describe a novel inhibitory NK receptor that is specific for a group of HLA-A alleles. The HLA-A3-specific NK cell clone DP7 has been used for mice immunization. Two mAbs, termed Q66 and Q241, bound to the immunizing clone and stained only a subset of NK cell populations or clones. Among Q66 mAb-reactive clones, we further selected those that did not express any of the previously identified HLA-class I-specific NK receptors. These clones did not lyse HLA-A3+ (or -A11+) target cells, but lysis of these targets could be detected in the presence of Q66 or Q241 mAbs. On the other hand, target cells expressing other HLA-A alleles, including -A1, -A2, and -A24, were efficiently lysed. Moreover, none of the HLA-C or HLA-B alleles that were tested exerted a protective effect. Q66+, but not Q66- NK cell clones, expressed messenger RNA coding for a novel 3 Ig domain protein homologous to the HLA-C (p58) and HLA-B (p70) receptors. The corresponding cDNA (cl.1.1) was used to generate transient and stable transfectants in COS7 and NIH3T3 cell lines, respectively. Both types of transfectants were specifically stained by Q66 and Q241 mAbs. Since the cytoplasmic tail of Q66-reactive molecules was at least 11 amino acid longer than the other known p58/p70 molecules, we could generate an antiserum specific for the COOH-terminus of Q66-reactive molecules, termed PGP-3. PGP-3 immunoprecipitated, only from Q66+ NK cells, molecules displaying a molecular mass of 140 kD, under nonreducing conditions, which resolved, under reducing conditions, in a 70-kD band. Thus, differently from the other p58/p70 receptors, Q66-reactive molecules appear to be expressed as disulphide-linked dimers and were thus termed p140. The comparative analysis of the amino acid sequences of p58, p70, and p140 molecules revealed the existence of two cysteins proximal to the transmembrane region, only in the amino acid sequence of p140 molecules.     

Extinction of dispersed heterogeneous systems

We consider extinction of various dispersed systems. Isolated boron particles and boron particles in gases are studied. Stability analysis of steady-state thermal regimes of reacting heterogeneous systems for the case of two parallel reactions on the reaction surface using the Frank-Kamenetskii method gives extinction conditions in oxygen-containing media. Curves of the extinction particle size versus the ambient temperature, oxidizer concentration, and, for particles in gases, also versus the oxidizer-to-fuel ratio are plotted. Approximate analytical calculations showed that the extinction process can be most actively controlled by varying the combustion temperature: a decrease in the latter increases the extinction particle size and decreases the completeness of fuel combustion. It is shown that at low ambient temperatures the extinction particle size for suspensions is larger than that for isolated particles. This effect is caused by a decrease in the oxidizer concentration during combustion of suspensions. At high temperatures, the role of this factor weakens.Translated from Fizika Goreniya i Vzryva, Vol. 32, No. 6, pp. 12–19, November–December, 1996.     

Cyclobutanones as markers for irradiated samples of Brie and Camembert cheese

The feasibility of applying a chemical method based on the formation of 2-alkylcyclobutanone to samples of irradiated soft cheese (Brie and Camembert) was investigated. Significant quantities of 2-dodecylcyclobutanone (DCB) and 2-tetradecylcyclobutanone (TCB) were detected in both types of irradiated cheese and are proposed as qualitative markers. Other members of the cyclobutanone family (decyl- and tetradecenyl-) are also thought to be present but could not be substantiated due to a lack of authentic standards. These compounds were absent from the unirradiated samples. Results also show a significant linear relationship between the irradiation dose (1 to 8 kGy) and the amount of DCB and TCB detected in the cheese.     

WKB近似下的Fourier衍射成象方法

对于介质目标微波衍射成象，本文引入了ＷＫＢ近似来模拟目标内部总场。基于这种近似，我们导出了Ｆｏｕｒｉｅｒ衍射公式，并采用了广义滤波逆传播方法由目标空间谱实现目标特性的重建。计算机模拟结果表明采用ＷＫＢ近似重建目标特性较Ｂｏｒｎ近似有明显改善。     

Modeling electromigration lifetime under bidirectional currentstress

Electromigration reliability of interconnect under bidirectional current stress has been studied in a wide frequency range (mHz to 200 MHz). Experimental results show that the AC lifetime rises with the stress current frequency. The current density exponent and the activation energy of AC lifetime are found to be twice that of DC lifetime. Pure AC current stress failure at extremely high current density is believed to result from thermal migration of metal at hot/cold transition points