A Mechanism for Supercooling in Organic Liquids

1995 ◽  
Vol 398 ◽  
Author(s):  
Paul E. Thoma
Keyword(s):  
Melting Temperature ◽  
Chemical Structure ◽  
Three Dimensional ◽  
Freezing Temperature ◽  
Organic Liquids ◽  
Molecular Characteristics ◽  
A Charge

ABSTRACTIn this investigation, a mechanism for supercooling in organic liquids is formulated. By comparing the melting temperature and spontaneous freezing temperature of the chemicals evaluated with their molecular characteristics, the factors promoting supercooling are developed. The results obtained indicate that the following molecular characteristics promote supercooling in organic liquids:sharing of electrons between the atoms of a molecule;A three-dimensional chemical structure;A permanent, three-dimensional, and partially charged pocket within the chemical structure;A partially charged projection having a charge opposite that of the pocket and located on the side of the molecule opposite that of the pocket.

Electron Holographic Nano-Characterization of Gold Catalyst at Interface

2002 ◽  
Vol 727 ◽  
Author(s):  
S. Ichikawa ◽  
T. Akita ◽  
M. Okumura ◽  
M. Haruta ◽  
K. Tanaka
Keyword(s):  
Contact Angle ◽  
Titanium Oxide ◽  
Gold Catalyst ◽  
Three Dimensional ◽  
High Resolution Electron Microscopy ◽  
Electron Holography ◽  
Gold Particles ◽  
Oxide Support ◽  
The Mean ◽  
A Charge

AbstractThe catalytic properties of nanostructured gold catalyst are known to depend on the size of the gold particles and to be activated when the size decreases to a few nanometers. We investigated the size dependence of the three-dimensional nanostructure on the mean inner potential of gold catalysts supported on titanium oxide using electron holography and high-resolution electron microscopy (HREM). The contact angle of the gold particles on the titanium oxide tended to be over 90° for gold particles with a size of over 5 nm, and below 90° for a size of below 2 nm. This decreasing change in the contact angle (morphology) acts to increase the perimeter and hence the area of the interface between the gold and titanium oxide support, which is considered to be an active site for CO oxidation. The mean inner potential of the gold particles also changed as their size decreased. The value of the inner potential of gold, which is approximately 25 V in bulk state, rose to over 40 V when the size of the gold particles was less than 2 nm. This phenomenon indicates the existence of a charge transfer at the interface between gold and titanium oxide. The 3-D structure change and the inner potential change should be attributed to the specific electronic structure at the interface, owing to both the “nano size effect” and the “hetero-interface effect.”

3D simulations of warm and hot Jupiter atmospheres: the role of 3D mixing in shaping CH4-to-CO conversion pathways

2021 ◽  
Author(s):  
Maria Zamyatina ◽  
Eric Hebrard ◽  
Nathan Mayne ◽  
Benjamin Drummond
Keyword(s):  
Chemical Structure ◽  
Three Dimensional ◽  
Chemical Species ◽  
Radiation Chemistry ◽  
3D Simulations ◽  
Horizontal Advection ◽  
Co Conversion ◽  
Area Of Influence ◽  
Different Parts

<p>We present results from a set of cloud-free simulations of exoplanet atmospheres using a coupled three-dimensional (3D) hydrodynamics-radiation-chemistry model. We report in particular our investigation of the thermodynamic and chemical structure of the atmospheres of HAT-P-11b and WASP-17b and their comparison with the results for the atmospheres of HD 189733b and HD 209458b presented in Drummond et al. (2020). We found that the abundances of chemical species from simulations with interactive chemistry depart from their respective abundances computed at local chemical equilibrium, especially at higher latitudes. To understand this departure, we analysed the CH<sub>4</sub>-to-CO conversion pathways within the Venot et al. (2019) reduced chemical network used in our model using a chemical network analysis. We found that at steady state nine CH<sub>4</sub>-to-CO conversion pathways manifest in our 3D simulations with interactive chemistry, with different pathways dominating different parts of the atmosphere and their area of influence being determined by the vertical and horizontal advection and shifting between planets.</p>

scholarly journals 2-Methyl-3-(3-methylisoxazol-5-yl)-4-oxo-4H-pyrido[1,2-a]pyrimidin-1-ium chloride

IUCrData ◽  
2016 ◽  
Vol 1 (12) ◽  
Author(s):  
Sanae Lahmidi ◽  
Latifa El Ouasif ◽  
Alae Eddine Jilalat ◽  
Wedad Al-Garadi ◽  
El Mokhtar Essassi ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Three Dimensional ◽  
Extended Structure ◽  
Dimensional Network ◽  
A Charge ◽  
Molecular Salt

In the title molecular salt, C13H12N3O2+·Cl−, the oxazolyl ring is disordered over two orientations in a 0.536 (15):0.464 (15) ratio, both of which approximate to envelopes with the N atom as the flap in each case. The cation and anion are linked by a charge-assisted N—H...Cl hydrogen bond. In the extended structure, C—H...N, C—H...O and C—H...Cl interactions link the components into a three-dimensional network.

The Effect of Acidity Coefficient on Crystallization Behavior of Blast Furnace Slag Fibers

2018 ◽  
Vol 37 (1) ◽  
pp. 33-37
Author(s):  
Tie-Lei Tian ◽  
Yu-Zhu Zhang ◽  
Hong-wei Xing ◽  
Jie Li ◽  
Zun-Qian Zhang
Keyword(s):  
Thermal Stability ◽  
Crystallization Kinetics ◽  
Blast Furnace Slag ◽  
Chemical Structure ◽  
Crystallization Behavior ◽  
Three Dimensional ◽  
Mineral Wool ◽  
Mineral Wool Fiber ◽  
Kinetics Of ◽  
Furnace Slag

AbstractThe chemical structure of mineral wool fiber was investigated by using Fourier Transform Infrared Spectroscopy (FTIR). Next, the glass transition temperature and the crystallization temperature of the fibers were studied. Finally, the crystallization kinetics of fiber was studied. The results show that the chemical bond structure of fibers gets more random with the increase of acidity coefficient. The crystallization phases of the fibers are mainly melilites, and also a few anorthites and diopsides. The growth mechanism of the crystals is three dimensional. The fibers with acidity coefficient of 1.2 exhibit the best thermal stability and is hard to crystallize as it has the maximum aviation energy of crystallization kinetics.

scholarly journals Biological Significance of Tumor Heterogeneity in Esophageal Squamous Cell Carcinoma

Cancers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1156 ◽  
Author(s):  
Lehang Lin ◽  
De-Chen Lin
Keyword(s):  
Squamous Cell Carcinoma ◽  
Esophageal Squamous Cell Carcinoma ◽  
Cell Carcinoma ◽  
Squamous Cell ◽  
Tumor Heterogeneity ◽  
Three Dimensional ◽  
Biological Significance ◽  
Molecular Characteristics ◽  
Tumor Evolution ◽  
Evolutionary Trajectories

Esophageal squamous cell carcinoma (ESCC) is a common and aggressive malignancy, with hitherto dismal clinical outcome. Genomic analyses of patient samples reveal a complex heterogeneous landscape for ESCC, which presents in both intertumor and intratumor forms, manifests at both genomic and epigenomic levels, and contributes significantly to tumor evolution, drug resistance, and metastasis. Here, we review the important molecular characteristics underlying ESCC heterogeneity, with an emphasis on genomic aberrations and their functional contribution to cancer evolutionary trajectories. We further discuss how novel experimental tools, including single-cell sequencing and three-dimensional organoids, may advance our understanding of tumor heterogeneity. Lastly, we suggest that deciphering the mechanisms governing tumor heterogeneity holds the potential to developing precision therapeutics for ESCC patients.

Development of a Fused Deposition Modeling System for Low Melting Temperature Metal Alloys

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Jorge Mireles ◽  
Ho-Chan Kim ◽  
In Hwan Lee ◽  
David Espalin ◽  
Francisco Medina ◽  
...  
Keyword(s):  
Melting Temperature ◽  
Fused Deposition Modeling ◽  
Printed Circuit Board ◽  
Three Dimensional ◽  
Single Layer ◽  
Metal Alloys ◽  
Circuit Board ◽  
Fused Deposition ◽  
Extrusion Head ◽  
Deposition Modeling

This research focused on extending the applications of fused deposition modeling (FDM) by extrusion and deposition of low melting temperature metal alloys to create three-dimensional metal structures and single-layer contacts which may prove useful for electronic interconnects. Six commercially available low melting temperature solder alloys (Bi36Pb32Sn31Ag1, Bi58Sn42, Sn63Pb37, Sn50Pb50, Sn60Bi40, Sn96.5Ag3.5) were tested for the creation of a fused deposition modeling for metals (FDMm) system with special attention given to Sn–Bi solders. An existing FDM 3000 was used and two alloys were successfully extruded through the system's extrusion head. Deposition was achieved through specific modifications to system toolpath commands and a comparison of solders with eutectic and non-eutectic compositions is discussed. The modifications demonstrate the ability to extrude simple single-layer solder lines with varying thicknesses, including sharp 90 deg angles and smooth curved lines and showing the possibility of using this system for printed circuit board applications in which various connections need to be processed. Deposition parameters altered for extrusion and the deposition results of low melting temperature metal alloys are introduced.

High Precision in Raman Frequency Achieved Using Real-Time Calibration with a Neon Emission Line: Application to Three-Dimensional Stress Mapping Observations

2008 ◽  
Vol 62 (10) ◽  
pp. 1084-1087 ◽  
Author(s):  
Shoko Odake ◽  
Satoshi Fukura ◽  
Hiroyuki Kagi
Keyword(s):  
Emission Line ◽  
Real Time ◽  
Natural Diamond ◽  
Three Dimensional ◽  
Atomic Emission ◽  
Residual Pressure ◽  
Present System ◽  
Time Calibration ◽  
Stress Mapping ◽  
A Charge

A three-dimensional (3D) Raman mapping system with a real-time calibration function was developed for detecting stress distributions in solid materials from subtle frequency shifts in Raman spectra. An atomic emission line of neon at 918.3 cm−1 when excited at 514.5 nm was used as a wavenumber standard. An emission spectrum of neon and a Raman spectrum from a sample were introduced into a single polychromator using a bifurcated optical fiber. These two spectra were recorded simultaneously on a charge-coupled device (CCD) detector using double-track mode. Energy deviation induced by the fluctuation of laboratory temperature, etc., was removed effectively using the neon emission line. High stability during long measurements was achieved. By applying curve fitting, positions of the Raman line were determined with precision of about 0.05 cm−1. The present system was applied to measurements of residual pressure around mineral inclusions in a natural diamond: 3D stress mapping was achieved.

scholarly journals Research on the Temperature Field and Frost Heaving Law of Massive Freezing Engineering in Coastal Strata

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Chaochao Zhang ◽  
Dongwei Li ◽  
Junhao Chen ◽  
Guanren Chen ◽  
Chang Yuan ◽  
...  
Keyword(s):  
Temperature Field ◽  
Three Dimensional ◽  
Element Model ◽  
Freezing Temperature ◽  
Frozen Soil ◽  
Physical Parameters ◽  
Frost Heaving ◽  
Soil Frost ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

In this study, based on the background of massive freezing engineering in coastal strata, the thermal physical parameters and some freezing laws of soil were obtained through soil thermal physical tests and frozen soil frost heaving tests. When the freezing temperatures were −5°C, −10°C, −15°C, and −20°C, the frost heaving rates of the soil were 0.53%, 0.95%, 1.28%, and 1.41%, and the frost heaving forces of the soil were 0.37 MPa, 0.46 MPa, 0.59 MPa, and 0.74 MPa, respectively. In the range of test conditions, the frost heaving rate and the frost heaving force of the soil increased with the decrease of the freezing temperature, and the relationship was roughly linear with the temperature. The entire cooling process could be roughly divided into three stages: active freezing stage, attenuation cooling stage, and stability stage. The range of the frozen soil expansion did not increase linearly with the decrease of the freezing temperature, and there was a limit radius for the frozen soil expansion. A three-dimensional finite element model was established to simulate the temperature field and frost heaving of the soil under the on-site working conditions. The entire frost heaving process could be roughly divided into two stages. The calculated temperature values and the frost heaving force values were compared with the on-site measured values, and the results verified that the numerical calculation could accurately reflect the temperature field and frost heaving law of the formation.

scholarly journals Heterochromatin rewiring and domain disruption-mediated chromatin compaction during erythropoiesis

2021 ◽  
Author(s):  
Dong Li ◽  
Fan Wu ◽  
Shuo Zhou ◽  
Xiaojun Huang ◽  
Hsiang-Ying Sherry Lee
Keyword(s):  
Molecular Mechanisms ◽  
Chromatin Condensation ◽  
Nuclear Periphery ◽  
Chromatin Modification ◽  
Three Dimensional ◽  
Molecular Characteristics ◽  
Structural Factors ◽  
Erythroid Progenitors ◽  
Chromatin Compaction ◽  
Active Transcription

Development of mammalian red blood cells involves progressive chromatin compaction and subsequent enucleation in terminal stages of differentiation, but the molecular mechanisms underlying the three-dimensional chromatin reorganization and compaction remains obscure. Here, we systematically analyze the distinct features of higher-order chromatin in purified populations of primary human erythroblasts. Our results reveal that while heterochromatin regions undergo substantial compression, select transcription competent regions with active transcription signature are preferentially maintained to achieve a highly-compacted yet functional chromatin state in terminal erythropoiesis, which is about 20-30% of the nuclear volume compared to that of erythroid progenitors. While the partition of euchromatic and heterochromatic regions (compartment A and B) remain mostly unchanged, H3K9me3 marks relocalize to the nuclear periphery and a significant number of H3K9me3 long-range interactions are formed in the three-dimensional rewiring during terminal erythroid chromatin condensation. Moreover, ~63% of the topologically associating domain (TAD) boundaries are disrupted, while certain TADs with active chromatin modification are selectively maintained during terminal erythropoiesis. The most well-maintained TADs are enriched for chromatin structural factors CTCF and SMC3, as well as factors and marks of the active transcription state. Finally, we demonstrate that the erythroid master regulator GATA1 involves in safeguarding select essential chromatin domains during terminal erythropoiesis. Our study therefore delineate the molecular characteristics of a development-driven chromatin compaction process, which reveals transcription competence as a key determinant of the select domain maintenance to ensure appropriate gene expression during immense chromatin compaction.

Sign in / Sign up

Export Citation Format

Share Document