Numerical investigation of nitriding of refractory metals (with account of the phase constitution diagrams for metal-gas systems)

A mathematical model of dissolution of gas in a metal is suggested with account of phase formation in accordance with the phase constitution diagram (PCD). The stage-by-stage saturation process to the final product formation is shown for an individual particle, through which a reaction wave passes, depending on the diffusion permeability of the metal and solubility conditions that obey Sieverts's law. The effect of the filtration supply of the oxidant to the reaction zone and the process exothermicity on the course of the process is shown.Institute of Structural Macrokinetics, Russian Academy of Sciences, Chernogolovka, Russia. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 65, No. 4, pp. 447–450, October, 1993.     

Hematopoietic and lymphopoietic responses in human granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor transgenic mice injected with human GM-CSF

Using a clonal assay of bone marrow (BM) cells from transgenic mice (Tg-mice) expressing the human granulocyte-macrophage colony-stimulating factor receptor (hGM-CSFR), we found in earlier studies that hGM-CSF alone supported the development not only of granulocyte-macrophage colonies, but also of erythrocytes, megakaryocytes, mast cells, blast cells, and mixed hematopoietic colonies. In this report, we evaluated the in vivo effects of hGM-CSF on hematopoietic and lymphopoietic responses in the hGM-CSFR Tg-mice. Administration of this factor to Tg-mice resulted in dose-dependent increases in numbers of reticulocytes and white blood cells (WBCs) in the peripheral blood. Morphological analysis of WBCs showed that the numbers of all types of the cell, including neutrophils, eosinophils, monocytes, and lymphocytes increased; the most remarkable being in lymphocytes that contained a number of large granular lymphocytes (LGLs) in addition to mature T and B cells. However, total cellularity of the BM of the Tg-mice decreased in a dose-dependent manner when hGM-CSF was injected. In sharp contrast to the BM, spleens of the Tg-mice were grossly enlarged. Although all types of blood cells and hematopoietic progenitors increased in the spleen, erythroid cells and their progenitors showed the most significant increase. Increased numbers of megakaryocytes and LGLs were also observed in spleen and liver of the treated Tg-mice. Flow cytometric analysis showed that LGLs expanded in Tg-mice expressed Mac-1+ CD3- NK1.1+. The thymus of Tg-mice treated with hGM-CSF exhibited a dose-dependent shrinkage and a remarkable decrease in CD4+ CD8+ cells. Thus, hGM-CSF stimulated not only myelopoiesis but also erythropoiesis and megakaryopoiesis of hGM-CSFR Tg-mice in vivo, in accordance with our reported in vitro findings. In addition, hGM-CSF affected the development of lymphoid cells, including natural killer cells of these Tg-mice.     

Photolithographic packaging with selectively occupied repeatedtransfer (PL-Pack with SORT) for scalable film optical linkmultichip-module (S-FOLM)

"Photolithographic packaging (PL-pack) with selectively occupied repeated transfer (SORT)" is proposed for optoelectronic microsystem integration. PL-pack with SORT integrates different types of thin-film device pieces into one substrate with desired configurations using an all-photolithographic process. A process design example is presented for a scalable film optical link multichip-module (S-FOLM). A preliminary estimation reveals that PL-Pack with SORT will achieve III-V epitaxial material saving of <1/100 and module cost reduction of <1/10, compared with flip-chip-bonding-based packaging. The result indicates that the process will save on cost and resources simultaneously. A critical issue is how to simplify the procedure for distributing thin-film device pieces onto a substrate. SORT is found to reduce the distribution step count typically by factor of <1/10-1/10000 compared with the conventional one-by-one method. PL-pack with SORT will be extended to the 3R process (reduce, reuse, recycle), which is generally applied to a variety of device/module fabrications     

An eight‐node hybrid‐stress solid‐shell element for geometric non‐linear analysis of elastic shells

This paper presents eight‐node solid‐shell elements for geometric non‐linear analysis of elastic shells. To subdue shear, trapezoidal and thickness locking, the assumed natural strain method and an ad hoc modified generalized laminate stiffness matrix are employed. A selectively reduced integrated element is formulated with its membrane and bending shear strain components taken to be constant and equal to the ones evaluated at the element centroid. With the generalized stresses arising from the modified generalized laminate stiffness matrix assumed to be independent from the ones obtained from the displacement, an extended Hellinger–Reissner functional can be derived. By choosing the assumed generalized stresses similar to the assumed stresses of a previous solid element, a hybrid‐stress solid‐shell element is formulated. Commonly employed geometric non‐linear homogeneous and laminated shell problems are attempted and our results are close to those of other state‐of‐the‐art elements. Moreover, the hybrid‐stress element converges more readily than the selectively reduced integrated element in all benchmark problems. Copyright © 2002 John Wiley & Sons, Ltd.     

INFLUENCE OF DESIGN AND OPERATIONAL PARAMETERS ON YIELD OF FULLERENES

Fullerene production by arc-discharge method using graphite electrodes has been studied with respect to influence of different design and operational parameters on fullerene yield in a constant arc fullerene reactor. The design parameters like reactor length, diameter, heat transfer area and operational parameters like voltage, current, pressure, coolant flow rate, graphite evaporation rate and electrode diameter etc. have been experimentally studied in detail to establish a relationship between these parameters and fullerene yield. All the parameters affecting the yield have been correlated by dimensional analysis and an equation to calculate the fullerene yield is derived. It was observed experimentally as well as by dimensional analysis that many favorable parameters for getting good yield are linked with other parameters which also get changed if the favorable parameters are changed and thus it is difficult to make a substantial change in the yield of fullerenes.  The relationship established between the yield and parameters is however useful in optimising fullerene yield in a reactor and also helpful in designing a futuristic fullerene reactor of improved yield and productivity. The fullerene yield from different designs of reactors is obtained in the range of 4% to 20%.     

Simple concepts for ion source improvement

We report on improvements in the overall intensity of a sputter ion source that evolved originally from an NEC MCSNICS. Beam output increases benefit both AMS measurements and nuclear physics experiments using low natural abundance beams. In particular, minor changes in source geometry suggested by a combination of electrostatic calculations and simple design principles have yielded increases in extracted negative ion intensity of nearly a factor of 4.