Minimizing Process‐Induced Slip in Silicon Wafers by Slow Heating and Cooling

1976 ◽  
Vol 123 (3) ◽  
pp. 434-435 ◽  
Author(s):  
A. Wayne Fisher ◽  
G. L. Schnable
Keyword(s):  
Silicon Wafers ◽  
Slow Heating ◽  
Heating And Cooling

Control of thermochromic behaviour in crystal violet lactone (CVL)/alkyl gallate/alcohol ternary mixtures

2015 ◽  
Vol 93 (1) ◽  
pp. 22-31 ◽  
Author(s):  
Alexander N. Bourque ◽  
Mary Anne White
Keyword(s):  
Solid State ◽  
Crystal Violet ◽  
Alkyl Chain ◽  
Ternary Mixtures ◽  
Slow Heating ◽  
Solvent Interaction ◽  
Alkyl Gallates ◽  
Heating And Cooling ◽  
Thermochromic Properties ◽  
Chain Lengths

Three-component thermochromic mixtures generally consist of a leuco dye, a phenolic colour developer, and a high-melting organic solvent (listed in order of increasing mass). Their colouring behaviour is controlled by competing binary interactions, with the dye–developer interaction responsible for colour formation and the developer–solvent interaction responsible for solid-state colour erasure. In the present study, the reversible thermochromic properties of twelve systems of three-component mixtures comprising crystal violet lactone (CVL, dye), one of four alkyl gallates (developer), and one of three long-chain alkyl alcohols (solvent) were examined, as bulk samples, with slow heating and cooling rates. The thermochromic behaviour (i.e., melt-lightened vs melt-darkened thermochromism) of these mixtures was examined as a function of the difference in length of the alkyl chains attached to the developer and solvent. When the alkyl chain lengths were well-matched, the developer–solvent interaction dominated in the solid state and melt-darkened thermochromism was observed. When the alkyl chain lengths were poorly matched, the dye–developer interaction dominated in the solid state, and melt-lightened thermochromism was observed. Ternary thermochromic phase diagrams define compositional regions of optimal thermochromic behaviour (i.e., demonstrating high colour contrast), showing the intricate balance between developer–dye and developer–solvent interactions, and component concentration, in determining thermochromic behaviour.

EFFECT OF SLOW HEATING AND COOLING ON THE INTERDIFFUSION OF THIN FILMS

2007 ◽  
Vol 14 (04) ◽  
pp. 703-707 ◽  
Author(s):  
H. D. JOUBERT ◽  
J. J. TERBLANS ◽  
H. C. SWART
Keyword(s):  
Thin Films ◽  
Annealing Time ◽  
Slow Heating ◽  
Heating Period ◽  
Depth Profiles ◽  
Heating And Cooling ◽  
Diffusion Parameters ◽  
Exact Moment ◽  
The Moment ◽  
Heating Profiles

Interdiffusion parameters are often extracted from depth profiles of the interface of annealed thin films by measuring the annealing time of the sample as well as the distance over which interdiffusion took place. The annealing time is usually taken as the time from the moment the sample enters the oven to the exact moment the sample is removed from the oven. However, diffusion does not start and stop at these points, as the temperature of the sample does not change instantaneously. Any calculation performed with the instantaneous and therefore erroneous time will result in incorrect diffusion parameters extracted from the depth profiles. The influence of the extended heating period is studied by solving Fick's second law numerically and employing three distinct heating profiles in the calculations, namely instantaneous, actual, and linear. The results indicate a clear difference between the first two calculated depth profiles. Using these calculations and some experimental results, a method that employs linear heating and cooling of a sample is proposed for studying the interdiffusion of fast diffusing elements (with low activation energies).

Microstructure and Strength of Alumina-Metal Joint Brazed by Activated Molybdenum–Manganese Method

2007 ◽  
Vol 353-358 ◽  
pp. 2049-2052 ◽  
Author(s):  
Gui Wu Liu ◽  
Guan Jun Qiao ◽  
Hong Jie Wang ◽  
Zhi Hao Jin
Keyword(s):  
Cooling Rate ◽  
Joint Strength ◽  
Shear Loading ◽  
Holding Time ◽  
Slow Heating ◽  
Heating And Cooling ◽  
Migration Direction ◽  
Process Factors ◽  
Seal Strength ◽  
Steel Joints

High purity alumina/stainless steel joints were produced via activated molybdenummanganese (Mo-Mn) route using 72Ag-28Cu solder. Microstructures of the metallized ceramic and joint sections were observed by scanning electron microscopy. Joint strength was tested by shear-loading method. Some process factors were characterized and analyzed, which include temperature, holding time and heating and cooling rate in ceramic metallization process. The effects of Ni plating and succedent annealing were also investigated. Experimental results show that, migration of glassy phases is the main mechanism of the ceramic metallization. Glass migration direction is from metallizing layer to ceramic side. In the ranges of temperature and holding time of metallization, joint strength firstly increases and then falls with temperature raising and time extending. More fully sintered metallizing layer can be obtained while the temperature increases from 1200oC to 1500oC, and the time prolongs from 30min to 60min. Over-sintering of the metallizing layer will take place with metallizing temperature of 1600 oC and overlong holding time of 70min, which reduces the joint strength. The slower heating and cooling rate, and the annealing after Ni plating both help enhance the seal strength, due to relieving or eliminating interlayer residual thermal stress. However, too slow heating and cooling rate, such as 5 oC /min, is equivalent to overlong holding time and finally also decline the strength. A thin Ni coating helps solder wet metallizing surface, and stops solder erode metallizing layer.

EFFECT OF COPPER ADDITIVES ON IRREVERSIBLE MELTING IN [{(Fe0.5Co0.5)0.75B0.2Si0.05}96Nb4]100-xCux, x ≤ 3, ALLOYS

2011 ◽  
Vol 10 (04n05) ◽  
pp. 1013-1017
Author(s):  
T. KARAN ◽  
S. RAM ◽  
M. STOICA ◽  
J. ECKERT
Keyword(s):  
Melting Point ◽  
Amorphous Alloys ◽  
Amorphous Structure ◽  
Slow Heating ◽  
Differential Scanning Calorimetric ◽  
Bulk Amorphous Alloys ◽  
Heating And Cooling ◽  
Effect Of Copper ◽  
Ferromagnetic Bulk ◽  
Mould Casting

Iron and cobalt based ferromagnetic bulk amorphous alloys have received considerable interest nowadays in view of their useful properties for wide spread applications in magnet technology, shape memory alloys, high frequency communications at low power loss, and other devices. In this purview, here we report synthesis and thermal properties of bulk amorphous alloys [{( Fe 0.5 Co 0.5)0.75 B 0.2 Si 0.05}96 Nb 4]100-x Cu x (x = 0, 1, 2, and 3). A copper mould casting of molten alloy was used to obtain a vitrified alloy in form of thin rods (1–2 mm diameter). Amorphous structure retains at a cooling rate as low as 100 K/s in argon atmosphere. Heat out-put measured in terms of a differential scanning calorimetric signal during heating and cooling cycles of these alloys demonstrate irreversibility in a compositional dependent melting point, which follows the glass transition temperature and successive crystallization. The irreversibility persists in this specific example of the bulk amorphous alloys even on sufficiently slow heating or cooling rates such as 0.33 K/s in argon. The copper inclusion tailors the melting point, the enthalpy of the fusion, and other thermodynamic parameters. Results are analyzed in corroboration to the magnetic properties.

scholarly journals Temperature-induced conformational changes in prosomatostatin-II: implications for processing

1998 ◽  
Vol 334 (1) ◽  
pp. 275-282 ◽  
Author(s):  
Joydeep MITRA ◽  
Xue-jun TANG ◽  
Steven C. ALMO ◽  
Dennis SHIELDS
Keyword(s):  
Conformational Changes ◽  
Peptide Hormone ◽  
Structural Features ◽  
Proteolytic Processing ◽  
Helical Conformation ◽  
Slow Heating ◽  
Heating And Cooling ◽  
Dimeric Form ◽  
Intracellular Sorting ◽  
Single Set

Somatostatin (SRIF) is a 14-residue peptide hormone synthesized in the hypothalamus and pancreatic islets. SRIF-14 and an N-terminally extended form, SRIF-28, are generated by the proteolytic processing of an approx. 102-residue precursor prosomatostatin (proSRIF) at a single set of paired basic residues (Arg-Lys) and at a monobasic (Arg) site respectively. Previous work in our laboratory demonstrated that the propeptide of SRIF mediates intracellular sorting; we suggested that this information resides in the prohormone structure. To identify putative sorting domains we have investigated structural features of recombinant anglerfish proSRIF-II purified from Escherichia coli. Two species of proSRIF-II were obtained: a monomeric form and a disulphide-linked dimer. CD analyses revealed that monomeric proSRIF-II lacks appreciable periodic secondary structure; however, on slow heating (2 °C/min) and cooling, it assumed a predominantly α-helical conformation. When subjected to a second heating-and-cooling cycle, the α-helical conformation was maintained. In contrast, the dimeric form of proSRIF-II was predominantly α-helical and its helicity did not increase in response to heating and recooling. Our results suggest that proSRIF-II might exist in several different folding intermediate states.

scholarly journals Design of Ag-Ge-Zn braze/solder alloys: Experimental thermodynamics and surface properties

2017 ◽  
Vol 53 (3) ◽  
pp. 295-302 ◽  
Author(s):  
S. Delsante ◽  
D. Li ◽  
R. Novakovic ◽  
G. Borzone
Keyword(s):  
Cooling Rate ◽  
Room Temperature ◽  
Slow Heating ◽  
Experimental Investigations ◽  
Spectroscopy Analysis ◽  
Heating And Cooling ◽  
Experimental Thermodynamics ◽  
Liquid Phases ◽  
Dsc Analyses ◽  
S Model

The experimental investigation of the Ag-Ge-Zn phase diagram was performed by using combined microstructural and Differential Scanning Calorimeter (DSC) analyses. The samples were subjected to thermal cycles by a heat-flux DSC apparatus with heating and cooling rate of 0.5 or 0.3?C/min. The microstructure of the samples, both after annealing and after DSC analysis, was studied by optical and scanning electron microscopy coupled with EDS (Energy Dispersive Spectroscopy) analysis. Considering the slow heating and cooling rate adopted, the isothermal section at room temperature was established. No ternary compounds were observed. On the basis of the experimental investigations the invariant reactions were identified. Combining the thermodynamic data on the Ag-Ge, Ag-Zn and Ge-Zn liquid phases by means of Butler?s model the surface tension of Ag-Ge-Zn alloys was calculated.

An Analysis of the Effect of Laser Beam Geometry on Laser Transformation Hardening

2005 ◽  
Vol 128 (3) ◽  
pp. 659-667 ◽  
Author(s):  
Shakeel Safdar ◽  
Lin Li ◽  
M. A. Sheikh ◽  
Zhu Liu
Keyword(s):  
Laser Beam ◽  
Laser Scanning ◽  
Rapid Heating ◽  
Homogenization Temperature ◽  
Slow Heating ◽  
Transient Effects ◽  
Full Transformation ◽  
Heating And Cooling ◽  
Beam Geometry ◽  
Laser Transformation Hardening

The effect of transformation hardening depends upon both heating and cooling rates. It is desirable to have a slow heating rate and a rapid cooling rate to achieve full transformation. To date laser transformation hardening has been carried out using circular or rectangular beams which result in rapid heating and cooling. Although the use of different beam intensity distributions within the circular or rectangular laser beams has been studied to improve the process, no other beam geometries have been investigated so far for transformation hardening. This paper presents an investigation into the effects of different laser beam geometries in transformation hardening. Finite element modeling technique has been used to simulate the steady state and transient effects of moving beams in transformation hardening of EN 43A steel. The results are compared with experimental data. The work shows that neither of the two commonly used beams, circular and rectangular, are optimum beam shapes for transformation hardening. The homogenization temperature exceeds the melting point for these beam shapes for the usual laser scanning speeds and power density. Triangular beam geometry has been shown to produce the best thermal history to achieve better transformation and highest hardness due to slower heating without sacrificing the processing rate and hardening depths.

High-resolution synchrotron radiation studies on natural and thermally annealed scleractinian coral biominerals

2007 ◽  
Vol 40 (1) ◽  
pp. 2-9 ◽  
Author(s):  
J. Stolarski ◽  
R. Przeniosło ◽  
M. Mazur ◽  
M. Brunelli
Keyword(s):  
High Resolution ◽  
Synchrotron Radiation ◽  
Scleractinian Coral ◽  
Structural Phase ◽  
Lattice Parameter ◽  
Precise Determination ◽  
Slow Heating ◽  
En Bloc ◽  
Heating And Cooling ◽  
Synchrotron Radiation Diffraction

The structural phase transition from aragonite to calcite in biogenic samples extracted from the skeletons of selected scleractinian corals has been studied by synchrotron radiation diffraction. Biogenic aragonite samples were extracteden blocwithout pulverization from two ecologically different scleractinian taxa:Desmophyllum(deep-water, solitary and azooxanthellate) andFavia(shallow-water, colonial, zooxanthellate). It was found that natural (not pulverized) samples contribute to narrow Bragg peaks with Δd/dvalues as low as 1 × 10−3, which allows the exploitation of the high resolution of synchrotron radiation diffraction. A precise determination of the lattice parameters of biogenic scleractinian coral aragonite shows the same type of changes of thea,b,clattice parameter ratios as that reported for aragonite extracted from other invertebrates [Pokroy, Quintana, Caspi, Berner & Zolotoyabko (2004).Nat. Mater.3, 900–902]. It is believed that the crystal structure of biogenic samples is influenced by interactions with organic molecules that are initially present in the biomineralization hydrogel. The calcite phase obtained by annealing the coral samples has a considerably different unit-cell volume and lattice parameter ratioc/aas compared with reference geological calcite and annealed synthetic aragonite. The internal strain in the calcite structure obtained by thermal annealing of the biomineral samples is about two times larger than that found in the natural aragonite structure. This effect is observed despite slow heating and cooling of the sample.

On the formation of dislocations in aluminium during slow heating and cooling

1967 ◽  
Vol 1 (3) ◽  
pp. 149-159 ◽  
Author(s):  
B. N∅st ◽  
G. S∅rensen ◽  
E. Nes
Keyword(s):  
Slow Heating ◽  
Heating And Cooling
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