Nucleation Behavior ofd-Threonine on Different Faces ofl-Threonine Crystals

2008 ◽  
Vol 8 (8) ◽  
pp. 2716-2720 ◽  
Author(s):  
Akihiko Ito ◽  
Masakuni Matsuoka
Keyword(s):  
2021 ◽  
pp. 126185
Author(s):  
Conghui Zhao ◽  
Di Cao ◽  
Wenli Zhao ◽  
Shijie Xu ◽  
Yanfei Wang

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2920
Author(s):  
Qin Peng ◽  
Bin Yang ◽  
Benjamin Milkereit ◽  
Dongmei Liu ◽  
Armin Springer ◽  
...  

Understanding the rapid solidification behavior characteristics, nucleation undercooling, and nucleation mechanism is important for modifying the microstructures and properties of metal alloys. In order to investigate the rapid solidification behavior in-situ, accurate measurements of nucleation undercooling and cooling rate are required in most rapid solidification processes, e.g., in additive manufacturing (AM). In this study, differential fast scanning calorimetry (DFSC) was applied to investigate the nucleation kinetics in a single micro-sized Al-20Si (mass%) particle under a controlled cooling rate of 5000 K/s. The nucleation rates of primary Si and secondary α-Al phases were calculated by a statistical analysis of 300 identical melting/solidification experiments. Applying a model based on the classical nucleation theory (CNT) together with available thermodynamic data, two different heterogeneous nucleation mechanisms of primary Si and secondary α-Al were proposed, i.e., surface heterogeneous nucleation for primary Si and interface heterogenous nucleation for secondary α-Al. The present study introduces a practical method for a detailed investigation of rapid solidification behavior of metal particles to distinguish surface and interface nucleation.


2000 ◽  
Vol 644 ◽  
Author(s):  
Nobuyuki Nishiyama ◽  
Mitsuhide Matsushita ◽  
Akihisa Inoue

AbstractGlass-forming ability, thermal stability and nucleation behavior of a Pd40Cu30Ni10P20 alloy prepared using a high purity polycrystalline phosphorus are investigated. The critical cooling rate for glass formation for the high purity alloy is the same as that for the previous result, but the improvement of undercooling reaches about 80 K as compared with the fluxed ordinary alloy. In comparison with the non-fluxed alloy, the solidified structure of the present highly purified alloy is significantly different. The non-fluxed sample shows the characteristic “island-like” structure consisted of acicular fcc-Pd2Ni2P solid solution and Cu3Pd intermetallic compound. These acicular phases appear to be caused by the growth of quenched-in nuclei. In the isothermal experiment, nucleus density exhibits time dependence even at 683 K near the nose temperature. It is assumed that the crystallization behavior for the highly purified alloy is closer to homogeneous nucleation from quenched-in nuclei dominant behavior. In order to investigate the nucleation behavior, in-situ TEM observation was carried out. Spherical Pd15P2 particle with a diameter about 15 nm is observed, and this spherical region repeats generation and annihilation during isothermal annealing. The reason for the high glass-forming ability is discussed on the basis of the obtained results.


Nano Energy ◽  
2021 ◽  
Vol 89 ◽  
pp. 106452
Author(s):  
Da-Qian Cai ◽  
Jin-Lin Yang ◽  
Ting Liu ◽  
Shi-Xi Zhao ◽  
Guozhong Cao

2008 ◽  
Vol 39 (6) ◽  
pp. 1237-1247 ◽  
Author(s):  
M.G. Mecozzi ◽  
M. Militzer ◽  
J. Sietsma ◽  
S. van der Zwaag

2001 ◽  
Vol 49 (7) ◽  
pp. 3223-3229 ◽  
Author(s):  
S. Martini ◽  
M. L. Herrera ◽  
R. W. Hartel

2021 ◽  
Author(s):  
Bernd Kärcher ◽  
Claudia Marcolli

Abstract. The homogeneous nucleation of ice in supercooled liquid water clouds is characterized by time-dependent freezing rates. By contrast, water phase transitions induced heterogeneously by ice nucleating particles (INPs) are described by time-independent ice-active fractions depending on ice supersaturation (s). Laboratory studies report ice-active particle number fractions (AFs) that are cumulative in s. Cloud models budget INP and ice crystal numbers to conserve total particle number during water phase transitions. Here, we show that ice formation from INPs with time-independent nucleation behavior is overpredicted when models budget particle numbers and at the same time derive ice crystal numbers from s-cumulative AFs. This causes a bias towards heterogeneous ice formation in situations where INPs compete with homogeneous droplet freezing during cloud formation. We resolve this issue by introducing differential AFs, moving us one step closer to more robust simulations of aerosol-cloud interactions.


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