Synthetic diamond crystal strength enhancement through annealing at 50 kbar and 1500 °C

1995 ◽  
Vol 10 (7) ◽  
pp. 1700-1709 ◽  
Author(s):  
Steven W. Webb ◽  
W.E. Jackson
Keyword(s):  
Diamond Crystal ◽  
Synthetic Diamond ◽  
Diamond Lattice ◽  
Type I ◽  
Strength Enhancement ◽  
High Metal Content ◽  
Diamond Crystals ◽  
High Pressure High Temperature ◽  
High Metal ◽  
Low Levels

High-pressure, high temperature (HPHT) annealing of synthetic type I diamond crystals at 1200–1700 °C and 50–60 kbar was found to induce aggregate-nitrogen dissociation and metal coalescence as well as heal diamond lattice dislocations. For crystals with low levels of metal inclusions, HPHT annealing was observed to increase the average compressive fracture strength of the crystals by apparently strengthening the strongest crystals of the population. Crystals with high metal-content, or otherwise of low quality, are weakened by anncaling. Strengthening is believed to occur by locally stabilizing the diamond lattice by healing lattice dislocations as well as dispersing nitrogen within the lattice. A general model is presented that ties together these results with those of other researchers.

TEM and DSC Studies on the Synthetic Diamond Grown from Fe-Ni-C-B System under HPHT

2011 ◽  
Vol 320 ◽  
pp. 3-7
Author(s):  
Jian Hong Gong ◽  
Shu Xia Lin ◽  
Jun Gao
Keyword(s):  
Thermal Stability ◽  
Boron Content ◽  
Synthetic Diamond ◽  
Scanning Calorimetry ◽  
Dsc Studies ◽  
Diamond Crystals ◽  
Transmission Electron ◽  
High Pressure High Temperature ◽  
Alloy Catalysts ◽  
Thermal Stability Of

Transmission Electron Microscope (TEM) and Different Scanning Calorimetry (DSC) Methods Were Used to Investigate the Diamonds Grown with Different Boron Content Alloy Catalysts under High-Pressure High-Temperature (HPHT). Experimental Results Demonstrated the Microstructure and Composition of Boride Compounds in Synthetic Diamond, such as (FeNi)23(CB)6 ,(Fe, Ni)3(C,B), (Fe,Ni)B and B4C, Whose Formation Process Was Analyzed. the Thermal Stability of Diamond Depends on Boron Concentration in Catalyst According to DSC Studies. we Analyzed the Reason of Diamond Oxidation.The Work Offers Valuable Information for Improving the Thermal Stability of Synthetic Diamond Crystals by Adjusting Boron Content in the Fe-Ni Based Catalyst.

Strain and Impurity Content of Synthetic Diamond Crystals

1994 ◽  
Vol 349 ◽  
Author(s):  
T. L. Mccormick ◽  
W. E. Jackson ◽  
R.J. Nemanich
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Synthetic Diamond ◽  
Impurity Content ◽  
Nitrogen Forms ◽  
Inclusion Content ◽  
Diamond Crystals ◽  
High Pressure High Temperature ◽  
Photoluminescence Studies ◽  
Integrated Intensities

ABSTRACTSamples of diamond crystals produced under various high pressure, high temperature conditions were studied using both micro photoluminescence and Raman spectroscopy. The 0.3 - 0.6 mm sized samples exhibited various levels of inclusion content, impurity content and strain. Photoluminescence studies revealed the presence of nitrogen in three forms. The 1.945 eV, 2.15 eV and 2.46 eV zero phonon lines and their associated sidebands were detected. The ratios between forms of impurities and their integrated intensities varied between samples. Variations in the distribution of the nitrogen forms were seen between regions of high and low strain birefringence patterns.

The characterization of strain, impurity content, and crush strength of synthetic diamond crystals

1997 ◽  
Vol 12 (1) ◽  
pp. 253-263 ◽  
Author(s):  
Terri L. McCormick ◽  
W. E. Jackson ◽  
R. J. Nemanich
Keyword(s):  
High Pressure ◽  
High Strain ◽  
Synthetic Diamond ◽  
Impurity Content ◽  
Inclusion Content ◽  
Diamond Crystals ◽  
High Pressure High Temperature ◽  
Two Samples ◽  
Crush Strength

This study addresses the correlation of the macroscopic and microscopic characteristics of synthetic diamond crystals produced by high pressure, high temperature conditions. Microscopic properties were characterized using Raman spectroscopy, birefringence, and photoluminescence (PL). Macroscopic properties characterized included inclusion content and crush force. Raman measurements detected measurable stress shifts in only two samples. The PL measurements indicated an increased presence of the H3 center in areas of high strain. The absence of the H3 center and the presence of the N-V PL center was correlated to lower average crush force. A hierarchy has been developed that relates microscopic properties to average crush force.

scholarly journals Small Bragg-plane slope errors revealed in synthetic diamond crystals

2020 ◽  
Vol 27 (6) ◽  
pp. 1553-1563
Author(s):  
Paresh Pradhan ◽  
Michael Wojcik ◽  
Xianrong Huang ◽  
Elina Kasman ◽  
Lahsen Assoufid ◽  
...  
Keyword(s):  
High Temperature ◽  
Diamond Crystal ◽  
Synthetic Diamond ◽  
Bragg Diffraction ◽  
High Temperature Annealing ◽  
Rocking Curve ◽  
X Ray ◽  
Silicon Crystals ◽  
Crystal Imperfections ◽  
Diamond Crystals

Wavefront-preserving X-ray diamond crystal optics are essential for numerous applications in X-ray science. Perfect crystals with flat Bragg planes are a prerequisite for wavefront preservation in Bragg diffraction. However, this condition is difficult to realize in practice because of inevitable crystal imperfections. Here, X-ray rocking curve imaging is used to study the smallest achievable Bragg-plane slope errors in the best presently available synthetic diamond crystals and how they compare with those of perfect silicon crystals. It is shown that the smallest specific slope errors in the best diamond crystals are about 0.08 (3) µrad mm−2. These errors are only 50% larger than the 0.05 (2) µrad mm−2 specific slope errors measured in perfect silicon crystals. High-temperature annealing at 1450°C of almost flawless diamond crystals reduces the slope errors very close to those of silicon. Further investigations are in progress to establish the wavefront-preservation properties of these crystals.

The Genetic Defect of Type I von Willebrand Disease “Vicenza” Is Linked to the von Willebrand Factor Gene

1993 ◽  
Vol 69 (02) ◽  
pp. 173-176 ◽  
Author(s):  
Anna M Randi ◽  
Elisabetta Sacchi ◽  
Gian Carlo Castaman ◽  
Francesco Rodeghiero ◽  
Pier Mannuccio Mannucci
Keyword(s):  
Von Willebrand Factor ◽  
Autosomal Dominant ◽  
Genetic Defect ◽  
Von Willebrand Disease ◽  
Type I ◽  
Bleeding Tendency ◽  
Factor Gene ◽  
Low Levels ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryType I von Willebrand disease (vWD) Vicenza is a rare variant with autosomal dominant transmission, characterized by the presence of supranormal von Willebrand factor (vWF) multimers in plasma, similar to those normally found in endothelial cells and megakaryocytes. The patients have very low levels of plasma vWF contrasting with a mild bleeding tendency. The pathophysiology of this subtype is still unknown. The presence of supranormal multimers in the patients’ plasma could be due to a mutation in the vWF molecule which affects post-translational processing, or to a defect in the cells’ processing machinery, independent of the vWF molecule. In order to determne if type I vWD Vicenza is linked to the vWF gene, we studied six polymorphic systems identified within the vWF gene in two apparently unrelated families with type I vWD Vicenza. The results of this study indicate a linkage between vWF gene and the type I vWD Vicenza trait. This strongly suggests that type I vWD Vicenza is due to a mutation in one of the vWF alleles, which results in an abnormal vWF molecule that is processed to a lesser extent than normal vWF.

Effect of pressure on synthetic diamond crystals at high temperatures and pressures in Fe/Ni catalyst system

CrystEngComm ◽  
2021 ◽  
Author(s):  
Shuai Fang ◽  
Yongkui Wang ◽  
Liangchao Chen ◽  
Zhiyun Lu ◽  
Zhenghao Cai ◽  
...  
Keyword(s):  
Nitrogen Content ◽  
Growth Mechanism ◽  
Synthetic Diamond ◽  
Natural Diamond ◽  
Catalyst System ◽  
Necessary Condition ◽  
Ni Catalyst ◽  
Effect Of Pressure ◽  
Diamond Crystals ◽  
System P

Pressure is a necessary condition for the growth of natural diamond. Studying the effect of pressure on the nitrogen content of diamond is important for exploring the growth mechanism of...

Anteroposterior patterning in the zebrafish, Danio rerio: an explant assay reveals inductive and suppressive cell interactions

Development ◽  
1996 ◽  
Vol 122 (6) ◽  
pp. 1873-1883 ◽  
Author(s):  
C.G. Sagerstrom ◽  
Y. Grinblat ◽  
H. Sive
Keyword(s):  
Danio Rerio ◽  
Neural Induction ◽  
Active Role ◽  
Cell Number ◽  
Type I ◽  
Animal Pole ◽  
Anteroposterior Patterning ◽  
Embryonic Shield ◽  
Low Levels ◽  
Neural Markers

We report the first extended culture system for analysing zebrafish (Danio rerio) embryogenesis with which we demonstrate neural induction and anteroposterior patterning. Explants from the animal pole region of blastula embryos ('animal caps') survived for at least two days and increased in cell number. Mesodermal and neural-specific genes were not expressed in cultured animal caps, although low levels of the dorsoanterior marker otx2 were seen. In contrast, we observed strong expression of gta3, a ventral marker and cyt1, a novel type I cytokeratin expressed in the outer enveloping layer. Isolated ‘embryonic shield’, that corresponds to the amphibian organizer and amniote node, went on to express the mesodermal genes gsc and ntl, otx2, the anterior neural marker pax6, and posterior neural markers eng3 and krx20. The expression of these genes defined a precise anteroposterior axis in shield explants. When conjugated to animal caps, the shield frequently induced expression of anterior neural markers. More posterior markers were rarely induced, suggesting that anterior and posterior neural induction are separable events. Mesodermal genes were also seldom activated in animal caps by the shield, demonstrating that neural induction did not require co-induction of mesoderm in the caps. Strikingly, ventral marginal zone explants suppressed the low levels of otx2 in animal caps, indicating that ventral tissues may play an active role in axial patterning. These data suggest that anteroposterior patterning in the zebrafish is a multi-step process.

scholarly journals Green remediation of tailings from the mine using inorganic agents

2017 ◽  
Vol 71 (2) ◽  
pp. 155-165 ◽  
Author(s):  
Aleksandar Dosic ◽  
Dragana Tomasevic-Pilipovic ◽  
Miladin Gligoric ◽  
Bozo Dalmacija ◽  
Djurdja Kerkez ◽  
...  
Keyword(s):  
Mine Tailings ◽  
Treatment Process ◽  
Mine Tailing ◽  
High Metal Content ◽  
Green Remediation ◽  
High Metal ◽  
Environmentally Sound ◽  
Sound Management ◽  
The Impact

Increasing amounts of residues and waste materials coming from industrial activities in different processes have become an increasingly urgent problem for the future. The paper presents the problem of mine tailings generated in mine ?Sase? (Republic of Srpska, Bosnia and Herzegovina) with high metal content (Pb, Cu and Zn). Dumpsite of this tailing represents potential risk for water bodies in the vicinity of this location. Chosen treatment process was stabilization/solidification (S/S). Inorganic agents used in this study were fly ash and red mud that represent secondary industrial waste generated on locations relatively near the mine. Therefore, their application can be used as an example of a sustainable solution of regional environmental problem. Further investigations are related to the impact of various factors on metals leaching from mine tailings solidified/stabilized material using the above mentioned immobilization agents. The performance of the immobilizing procedures was examined using several leaching tests: ANS 16.1, TCLP, DIN, MWLP. The results indicated that all S/S samples can be considered as non-hazardous waste, as all leached metal concentrations met the set criteria. These results will further enable the modelling of metals behaviour during long-term leaching from treated mine tailing. The data are invaluable in terms of economically and environmentally sound management of mine tailing.

Abstract 628: Hepatic Insulin Signaling Regulates ApoA-I Gene Expression Through the Type I Deiodinase.

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Jing Liu ◽  
Antonio Hernandez-Ono ◽  
Valerie Galton ◽  
Henry Ginsberg
Keyword(s):  
Insulin Signaling ◽  
Knockout Mice ◽  
Hepg2 Cells ◽  
Density Lipoprotein ◽  
Type I ◽  
Mrna Levels ◽  
Reverse T3 ◽  
Hepatic Insulin Signaling ◽  
Low Levels

People with low levels of high density lipoprotein cholesterol (HDLC) and apolipoprotein A-I (ApoA-I) have a higher risk of cardiovascular disease. Low levels of HDLC are common in individuals who are insulin resistant (IR), e.g., with metabolic syndrome and type 2 diabetes mellitus (T2DM). Despite the high prevalence of these two disorders, very little work has been reported regarding the molecular pathways linking insulin signaling or action and the levels of either HDLC or ApoA-1. We reported previously that liver specific insulin receptor (InsR) knockout mice (LIRKO) have markedly reduced plasma HDLC levels that increase after restoration of hepatic Akt signaling. In the present study, we created acute LIRKO mice by injecting an albumin-Cre adenovirus (Ad) into InsR floxed mice and observed marked reductions in HDLC, the expression of ApoA-I, and the expression of the gene coding Type1 iodothyronine deiodinase1, a selenoenzyme expressed highly in the liver that converts thyroxine to 3,5,3’-triiodothyronine (T3) or reverse T3. Deiodinase 1 knockout mice also had significantly reduced hepatic ApoA-I mRNA levels. Overexpression of Dio1 in LIRKO restored HDLC and significantly increased the expression of ApoA-I mRNA. In vitro studies showed that the expression of ApoA-I was significantly reduced after knockdown of either InsR or Dio1 expression in HepG2 cells. Moreover, overexpression of Dio1 restored ApoA-I promoter activity that had been decreased by knockdown of InsR. Deletion analysis of ApoAI promoter regions showed that insulin signaling regulated ApoA-I expression by acting on a region which does not contain any thyroid response elements. Pulse-chase experiments in HepG2 cells showed that deficiency of insulin signaling resulted in decreased synthesis and secretion of ApoAI. Our results indicates that defective hepatic insulin signaling results in reduced expression of Dio1 which, in turn, leads to reduced expression of ApoA-I and decreased synthesis and secretion of ApoA-I from hepatocytes. We believe our studies have defined a novel pathway from insulin signaling to ApoA-I synthesis that may lead to new approaches for increasing HDL levels in people with defective insulin signaling.

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