A Vibrational Investigation of Crystal Nucleation and Growth from a Physically Confined and Supercooled Liquid

1994 ◽  
Vol 366 ◽  
Author(s):  
R. Mu ◽  
D. O. Henderson ◽  
Z. Pan ◽  
Y. Xue
Keyword(s):  
Solid Phase ◽  
Porous Silica ◽  
Supercooled Liquid ◽  
Nucleation And Growth ◽  
Crystal Nucleation ◽  
Melting Transition ◽  
Temperature Dependent ◽  
Freezing Transition ◽  
20 Nm

ABSTRACTTemperature dependent Raman measurements were conducted on bulk and the confined 2,4,6-trinitrotoluene (TNT) in 2.5, 5, 10, and 20 nm porous silica. Two bands at 23 and 190 cm−1 were chosen to evaluate the structure and the melting and freezing transitions of the confined TNT in pores. The results show that the solid phase TNT confined in larger pores (dp > 5 nm) forms conventional solid TNT structure, while the TNT restricted in small pores has no freezing and melting transition characteristics. The results also suggest that the freezing transition of the confined TNT starts at the pore center and the confined TNT maintains its interconnectivity during the freezing transition.

Using priority growth orientation of crystallite of the Monte Carlo method to study the process of crystal nucleation and growth in liquid phase

2016 ◽  
Vol 30 (05) ◽  
pp. 1650014 ◽  
Author(s):  
Yu Shi ◽  
Manjiao Chen ◽  
Jiankang Huang ◽  
Yufen Gu ◽  
Ding Fan
Keyword(s):  
Monte Carlo ◽  
Liquid Phase ◽  
Crystallite Size ◽  
Solid Fraction ◽  
Solid Phase ◽  
Growth Index ◽  
Nucleation And Growth ◽  
Crystal Nucleation ◽  
Crystallite Growth ◽  
Tracking Method

The technique of “crystallite growth preferred orientation” was presented based on the Monte Carlo (MC) simulations of grain growth, and its factor was used to establish a lattice coordinate tracking method. The nucleation and growth of crystal from the liquid phase throughout the whole simulation were examined. Changes in solid fraction and crystallite size were counted via simulation by lattice tracking. Results showed that the established model could properly reflect crystallite nucleation and growth. The model was also determined capable of accurately estimating the number of solid phase fraction and achieving change in crystallite size by the lattice tracking method. The change in solid fraction and MC step (MCS) satisfied the [Formula: see text] curve during simulation. The crystallite growth index was 0.477, which was relatively close to the theoretical value of 0.5.

Freezing/Melting Transition of Physically Restricted n-Decane

1994 ◽  
Vol 366 ◽  
Author(s):  
P. M. Hoffmann ◽  
V. M. Malhotra
Keyword(s):  
Large Fraction ◽  
Porous Silica ◽  
Melting Transition ◽  
Scanning Calorimetry ◽  
Freezing Transition ◽  
Dsc Measurements ◽  
Linear Behavior ◽  
Alkane Chain ◽  
Two Peaks ◽  
Interesting Behavior

ABSTRACTWe undertook differential scanning calorimetry (DSC) measurements at 170 K < T < 300 K on n-decane, physically confined in 8 nm (= diameter D) porous silica derivatized with various functional groups, to understand how surface structure of the confining media affects the freezing or melting transition of the n-decane. Though we observed a typical depression (ΔT) in the freezing or melting transition temperature of the physically confined decane, our results failed to manifest usual linear dependence of ΔT on D−1 when the expected contraction in D, due to the presence of aminopropyl-, hexyl-, phenyl- or trimethyl-groups on the silica surface, was taken into account. However, it is worth noting that a linear behavior was observed between ΔT and D−1 if only alkane-chain derivatized hosts were considered. Our results also indicate that a large fraction of physically confined n-decane (35 to 70 %), depending on the host silica, does not participate either in the melting or freezing transition. The most interesting behavior observed in the present study is the occurrence of the unusual two peaks associated with the freezing transition of physically confined decane. This bimodal behavior is strongly dependent on the chemistry of the confining silica host's surface.

scholarly journals Solid-Phase “Self-Hydrolysis” of [Zn(NH3)4MoO4@2H2O] Involving Enclathrated Water—An Easy Route to a Layered Basic Ammonium Zinc Molybdate Coordination Polymer

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4022
Author(s):  
Kende Attila Béres ◽  
István E. Sajó ◽  
György Lendvay ◽  
László Trif ◽  
Vladimir M. Petruševski ◽  
...  
Keyword(s):  
Coordination Polymer ◽  
Solid Phase ◽  
Water Molecules ◽  
Temperature Dependent ◽  
Dynamic Interactions ◽  
Ammonia Release ◽  
Successive Substitution ◽  
Red Dye ◽  
Hydrolysis Of ◽  
Zinc Molybdate

An aerial humidity-induced solid-phase hydrolytic transformation of the [Zn(NH3)4]MoO4@2H2O (compound 1@2H2O) with the formation of [(NH4)xH(1−x)Zn(OH)(MoO4)]n (x = 0.92–0.94) coordination polymer (formally NH4Zn(OH)MoO4, compound 2) is described. Based on the isostructural relationship, the powder XRD indicates that the crystal lattice of compound 1@2H2O contains a hydrogen-bonded network of tetraamminezinc (2+) and molybdate (2−) ions, and there are cavities (O4N4(μ-H12) cube) occupied by the two water molecules, which stabilize the crystal structure. Several observations indicate that the water molecules have no fixed positions in the lattice voids; instead, the cavity provides a neighborhood similar to those in clathrates. The @ symbol in the notation is intended to emphasize that the H2O in this compound is enclathrated rather than being water of crystallization. Yet, signs of temperature-dependent dynamic interactions with the wall of the cages can be detected, and 1@2H2O easily releases its water content even on standing and yields compound 2. Surprisingly, hydrolysis products of 1 were observed even in the absence of aerial humidity, which suggests a unique solid-phase quasi-intramolecular hydrolysis. A mechanism involving successive substitution of the ammonia ligands by water molecules and ammonia release is proposed. An ESR study of the Cu-doped compound 2 (2#dotCu) showed that this complex consists of two different Cu2+(Zn2+) environments in the polymeric structure. Thermal decomposition of compounds 1 and 2 results in ZnMoO4 with similar specific surface area and morphology. The ZnMoO4 samples prepared from compounds 1 and 2 and compound 2 in itself are active photocatalysts in the degradation of Congo Red dye. IR, Raman, and UV studies on compounds 1@2H2O and 2 are discussed in detail.

scholarly journals Molecular Dynamics Simulations of Crystal Nucleation near Interfaces in Incompatible Polymer Blends

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 347
Author(s):  
Wenlin Zhang ◽  
Lingyi Zou
Keyword(s):  
Molecular Dynamics ◽  
Polymer Blends ◽  
Md Simulations ◽  
Nucleation And Growth ◽  
Crystal Nucleation ◽  
Crystalline Order ◽  
Mobile Species ◽  
Deep Supercooling ◽  
Crystallizable Polymer ◽  
Dynamics Simulations

We apply molecular dynamics (MD) simulations to investigate crystal nucleation in incompatible polymer blends under deep supercooling conditions. Simulations of isothermal nucleation are performed for phase-separated blends with different degrees of incompatibility. In weakly segregated blends, slow and incompatible chains in crystallizable polymer domains can significantly hinder the crystal nucleation and growth. When a crystallizable polymer is blended with a more mobile species in interfacial regions, enhanced molecular mobility leads to the fast growth of crystalline order. However, the incubation time remains the same as that in pure samples. By inducing anisotropic alignment near the interfaces of strongly segregated blends, phase separation also promotes crystalline order to grow near interfaces between different polymer domains.

Temperature Dependent Photoluminescence of ZnSe/Alq3 Hybrid Heterostructure

2008 ◽  
Vol 55-57 ◽  
pp. 493-496
Author(s):  
Wisanu Pecharapa ◽  
P. Potirak ◽  
W. Yindeesuk
Keyword(s):  
Electron Beam ◽  
Quantum Efficiency ◽  
Exciton State ◽  
Temperature Dependent ◽  
Pl Spectra ◽  
20 Nm ◽  
Temperature Dependent Photoluminescence

II-VI inorganic/organic heterostructures consisting of ZnSe and tris(8-hydroxyquinoline) aluminum (Alq3) were prepared by electron beam evaporator. Alq3 layer with 20 nm was grown between 200-nm ZnSe layers. Photoluminescence measurement was conducted at various temperatures in order to investigate the important temperature-dependent parameters of this structure. PL spectra revealed thermal population of exciton state and the change in PL quantum efficiency of the film.

scholarly journals Crystal nucleation and growth kinetics of NaF in photo-thermo-refractive glass

2013 ◽  
Vol 378 ◽  
pp. 115-120 ◽  
Author(s):  
I. Dyamant ◽  
A.S. Abyzov ◽  
V.M. Fokin ◽  
E.D. Zanotto ◽  
J. Lumeau ◽  
...  
Keyword(s):  
Growth Kinetics ◽  
Nucleation And Growth ◽  
Crystal Nucleation ◽  
Kinetics Of

Solid-phase crystallization of ultra-thin amorphous Ge layers on insulators

2021 ◽  
Author(s):  
Ryo Oishi ◽  
Koji ASAKA ◽  
Bolotov Leonid ◽  
Noriyuki Uchida ◽  
Masashi Kurosawa ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Barrier Height ◽  
Carrier Mobility ◽  
Solid Phase ◽  
Hole Mobility ◽  
Solid Phase Crystallization ◽  
Simple Method ◽  
20 Nm ◽  
Grain Boundary Barrier

Abstract A simple method to form ultra-thin (< 20 nm) semiconductor layers with a higher mobility on a 3D-structured insulating surface is required for next-generation nanoelectronics. We have investigated the solid-phase crystallization of amorphous Ge layers with thicknesses of 10−80 nm on insulators of SiO2 and Si3N4. We found that decreasing the Ge thickness reduces the grain size and increases the grain boundary barrier height, causing the carrier mobility degradation. We examined two methods, known effective to enhance the grain size in the thicker Ge (>100 nm). As a result, a relatively high Hall hole mobility (59 cm2/Vs) has been achieved with a 20-nm-thick polycrystalline Ge layer on Si3N4, which is the highest value among the previously reported works.

Analysis and Characterization of Solid and Liquid Organic Fertilizer from Hydrothermal Carbonization (HTC) of Chicken Feather and Blood Waste

2021 ◽  
Vol 21 (3) ◽  
pp. 651
Author(s):  
Agus Kuncaka ◽  
Rizky Ibnufaatih Arvianto ◽  
Almas Shafira Ramadhanty Bunga Latifa ◽  
Munawir Ramadhan Rambe ◽  
Adhitasari Suratman ◽  
...  
Keyword(s):  
Iron Content ◽  
Solid Phase ◽  
Organic Fertilizer ◽  
Liquid Product ◽  
Hydrothermal Carbonization ◽  
Mass Ratio ◽  
Solid Product ◽  
Chicken Waste ◽  
20 Nm

Conversion of feather and blood from chicken slaughterhouse waste for producing solid and liquid organic fertilizer excluding composting process with a variation of the mass ratio of feather and blood of a chicken has been conducted. The nitrogen, sulfur, and iron content in the solid and liquid product of the hydrothermal carbonization process were analyzed to identify and characterize the possibility of hydrolysate as a source of nitrogen, sulfur, and iron in soil fertilizer. Feather and blood of chicken waste were introduced to a hydrothermal carbonization reactor with the addition of limestone at a temperature range of 160–170 °C for the preparation of solid and liquid organic fertilizer. According to the FTIR interpretation, the solid product had functional groups such as NH, OH, CH sp3, SH, C=O, C=C, C–O–C, and C–H aromatic. The nitrogen, sulfur, and iron content of the optimal ratio in the solid phase were 4.67%, 1.63%, and 3694.56 ppm, while their contents in the liquid fertilizer were 3.76%, 1.80%, and 221.56 ppm, respectively. The vibration of 478 cm–1 is attributed to Fe–O paramagnetic (Fe2O3) confirmed by TEM images showed the diameter size less than 20 nm indicating the presence of superparamagnetic material.

Transport Properties of B-, P-Doped and Undoped 50 kHz PECVD Microcrystalline Silicon

1989 ◽  
Vol 164 ◽  
Author(s):  
M.A. Hachicha ◽  
Etienne Bustarret
Keyword(s):  
Grain Size ◽  
Hall Mobility ◽  
Solid Phase ◽  
Grazing Angle ◽  
Dc Conductivity ◽  
X Ray Diffraction ◽  
Crystalline Fraction ◽  
Average Grain Size ◽  
20 Nm ◽  
Solid Phase Density

AbstractUndoped 500 nm-thick silicon layers with a crystalline fraction around 95% and an average grain size of 20 nm have been deposited at 350°C by 50 kHz triode PECVD in a H2/SiH4 mixture, in the presence of a magnetic field. Their room temperature (rt) dc conductivity μrt is 0.03 Δ−1cm−1 for a Hall mobility of 0.8 cm 2V−1s−1.The study by SIMS, infrared absorption, grazing angle x-ray diffraction and Raman scattering spectroscopies of the doped samples shows how the crystalline fraction and the grain size drop as the B2H6/SiH4 and PH3/SiH4 volumic ratios increase from 10 ppm to 1%.The rt dc conductivity reaches 2 Δ−1 cm−1 (Hall mobility: 15 cm2V−ls−1) for a solid phase density of 1019 cm−3 boron atoms, and 30 Δ−1cm−1 (Hall mobility: 55 cm2V−ls−1) at the maximum P incorporation of 8 × 1020cm−3.

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