When biological samples are first exposed to electrons in cryo-electron microcopy (cryo-EM), proteins exhibit a rapid ‘burst’ phase of beam-induced motion that cannot be corrected with software. This lowers the quality of the initial frames, which are the least damaged by the electrons. Hence, they are commonly excluded or down-weighted during data processing, reducing the undamaged signal and the resolution in the reconstruction. By decreasing the cooling rate during sample preparation, either with a cooling-rate gradient or by increasing the freezing temperature, we show that the quality of the initial frames for various protein and virus samples can be recovered. Incorporation of the initial frames in the reconstruction increases the resolution by an amount equivalent to using ~60% more data. Moreover, these frames preserve the high-quality cryo-EM densities of radiation-sensitive residues, which is often damaged or very weak in canonical three-dimensional reconstruction. The improved freezing conditions can be easily achieved using existing devices and enhance the overall quality of cryo-EM structures.

The migration and accumulation of immiscible silicate liquids may play a significant role in the differentiation of crustal magma bodies and the formation of some economic mineral deposits. However, our understanding of the processes that control the segregation of these liquids is currently limited by the short timescales of petrological experiments. Detailed microstructural investigations of Palaeogene basaltic dykes from Northeast England, coupled with simple 1D thermal models, constrain the effects of cooling rate on the microstructure of unmixed immiscible silicate liquids under natural conditions. The size of unmixed Fe-rich droplets within a continuous silicic phase is related to the cooling rate by a power law, with droplet diameter increasing with decreasing cooling rate, accompanied by an increase in the number of droplets. Fe-rich droplet coarsening is a result of diffusion-controlled growth. The average apparent aspect ratio and grain size of matrix plagioclase crystals indicate that nucleation and growth of these grains probably occurred in a static (or only weakly convecting) fluid dynamical regime.

Under conventional solidification conditions, immiscible alloy melt would undergo large-scale composition segregation after liquid–liquid phase separation, resulting in the loss of properties and application value. In the present study, the ternary immiscible Al70Bi10Sn20 alloy was chosen to study the effect of cooling rate on its resultant microstructure by casting the melt under different cooling conditions. The results indicated that the Al–Bi–Sn alloy with a slow cooling rate exhibits a strong spatial phase separation trend during solidification. However, as the cooling rate increases, the decreasing volume fraction of the segregated Bi–Sn-rich regions indicates the efficient suppression of spatial phase separation. The relatively dispersed distribution of Bi–Sn phase in the Al-rich matrix can be obtained by quenching the melt into water. The influence mechanism of cooling rate on the microstructure of the alloy is also discussed. The present study is beneficial to further tailoring the microstructure of immiscible alloys.

The effect of cooling rate on the microstructure evolution and the mechanical properties of ingots and rods of 2–5 mm diameter of (Ni0.92Zr0.08)100−xAlx (0 ≤ x ≤ 4 at.%) ultrafine eutectic composites have been investigated. The microstructure of the composites is comprised of micrometer size γ-Ni dendrites embedded in a nano/-ultrafine lamellar fcc γ-Ni and Ni5Zr matrix. The evolution of the microstructure at a wide range of cooling rates (10–104 K/s) has been analyzed in respect of volume fraction of the phases, lamellar spacing, and secondary dendritic arm spacing. All these composites exhibit high hardness up to 4.6 GPa and yield strength up to 1.6 GPa with large compressive plasticity up to 22% at room temperature. The effect of cooling rates on the strength and hardness, and the plasticity of the nanolamellar composites with wide range of alloy composition have been correlated.

The crystal chemistry of clinopyroxene, orthopyroxene and olivine from a crushed fragment of the H5 Zaoyang chondrite has been investigated by X-ray structure refinement and detailed microprobe analysis. The meteoritic pyroxenes have cell and polyhedral volumes which compare well with such data from terrestrial pyroxenes that typically crystallize at low-pressure. Fe2+ and Mg are rather disordered in M1 and M2 sites of clino- and orthopyroxenes; the closure temperatures of the exchange reaction are 600 and 512°C respectively, which is consistent with a reasonably fast cooling rate, estimated to be of the order of 1°C/day.

The closure temperature for the intercrystalline Ca-Mg exchange reaction for clino- and orthopyroxenes is 900°C as calculated from clino- and orthopyroxene intergrowth.

The cooling rates obtained from Fe2+-Mg intracrystalline partitioning suggest a cooling of the order of degrees per day at temperatures of 600–500°C due to a strong loss of heat by irradiation.

Monosized spherical Cu–20% Sn (wt%) alloy particles with diameter ranging from 70.6 to 334.0 μm were prepared by the pulsated orifice ejection method (termed “POEM”). Fully dense without pores and bulk inclusions, the cross-sectional micrographs of the spherical alloy particles indicate an even distribution of Cu and Sn. These spherical Cu–Sn alloy particles exhibit a good spherical shape and a narrow size distribution, suggesting that the liquid Cu–Sn alloy can completely break the balance between the surface tension and the liquid static pressure in the crucible micropores and accurately control the volume of the droplets. Furthermore, the cooling rate of spherical Cu–20% Sn alloy particles is estimated by a Newton’s cooling model. The cooling rate of the Cu–20% Sn alloy particle decreases gradually with the particle diameter increasing. Smaller particles have higher cooling rates and when the particle diameter is less than 70 μm, the cooling rate of particles can reach more than 3.3 × 104 K/s. The secondary dendrite arm spacing has strong dependence on particle diameter which increases gradually with the increase of particle diameter. The results demonstrate that POEM is an effective route for fabrication of high-quality monosized Cu–20% Sn alloy particles.

Compositional zoning is observed rarely in chrome-spinel grains from slowly-cooled layered intrusions because diffusion of cations continues within the spinel to low temperatures. However, in certain circumstances, such gradational zoning of both divalent and trivalent cations is observed and may be useful in deciphering the thermal history of the host intrusions. The accessory chrome-spinels of the Kabanga mafic-ultramafic chonolith intrusions of the Kibaran igneous event in north western Tanzania are notable because they have preserved gradational compositional zoning. This zoning is demonstrated to predate and be independent of later hydrous alteration of the silicate assemblage. At Kabanga, most chrome-spinel grains within olivine-rich cumulate rocks are gradationally and cryptically zoned from Fe2+-Cr3+ rich cores to more Mg2+-Al3+ rich rims (normal zoning). A few grains are zoned from Mg2+-Al3+ rich cores to more Fe2+-Cr3+ rich rims (reverse zoned). The zoning of divalent cations is proportional to that of trivalent cations with Mg2+ following Al3+ and Fe2+ following Cr3+ from core to rim. The zoning of trivalent and tetravalent cations is interpreted to be caused by either new growth from an evolving melt or peritectic reactions between evolved or contaminated melt and adjacent Al-Cr-bearing ferromagnesian minerals, which is preserved by relatively rapid initial cooling in the small chonolith intrusions. Divalent cation zoning is controlled by sub-solidus exchange of Fe2+ and Mg with adjacent ferromagnesian minerals and continues to lower temperatures, indicated to be 580 to 630°C by the spinel-olivine geothermometer. Preservation of such zoning is more likely in the smaller chonolith intrusions that typically host magmatic nickel-copper sulfide deposits and can be used as an exploration indicator when interpreting chromite compositions in regional heavy indicator mineral surveys.

The influence of cooling rates on the solidification and microstructure of rapidly solidified quasicrystal alloys with a nominal compositions of Mg57Zn37Y6 (at.%) prepared by melt spinning method was investigated. The microstructure, phase constitution, phase transition, and phase structure of the alloys were examined by means of scanning electron microscopy, x-ray diffraction, energy dispersive spectrometer, differential scanning calorimetry, and transmission electron microscopy. The results show that rapid solidification refines and homogenizes the microstructure of Mg57Zn37Y6 alloys, compared to the conventionally-cast master alloy. With the increasing cooling rate of rapid solidification, the thickness of the ribbon decreases greatly and a larger amount of I-phase can be formed. α-Mg, MgZn, and icosahedral phases are found in the as-cast alloy, but the MgZn phase is absent from rapidly solidified alloys. The I-phase in both as-cast and rapidly solidified alloys can precipitate directly from the melt during the solidification process. A higher cooling rate can lead to a large degree of supercooling, resulting in a decreased phase transition temperature and a large number of icosahedral short-range orders (ISROs). ISROs can act as templates in liquid and promote the nucleation of I-phase.

The one-dimensional behavior of a thin plasma foil heated by laser is studied, emphasizing on the fully kinetic effects associated with initial energetic electrons using a relativistic kinetic 1D3V Particle-In-Cell code. For this purpose, the generalized Lorentzian (Kappa) function inclusive the high energy tail is employed for initial electron distribution. The presence of the initially high-energy electrons leads to a different ion energy spectrum than the initially Maxwellian distribution. It is shown for the smaller Kappa parameter k where the high energy tail of the electron distribution function becomes more significant, the electron cooling rate increases. Moreover, the spatiotemporal evolution of electric field is strongly affected by the initial super-thermal electrons.

Cholesterol-loaded cyclodextrins (CLC) added to the sperm before cryopreservation enhance sperm quality after freeze-thawing in several cold shock-sensitive species, including cattle and goats. However, all studies conducted to date have used conventional protocols, in which sperm are cooled slowly to 5°C before freezing. As cholesterol plays a significant role in sperm cold shock resistance, it is possible that CLC-treated sperm can withstand cooling damage when the sperm are not cooled slowly to 5°C before freezing. In this study, we determined whether CLC-treated goat (1 mg CLC/120×106 sperm) and bull (2 mg CLC/120×106 sperm) sperm quality, after thawing, was different for sperm frozen using conventional protocols (including a slow cooling phase to 5ºC) and protocols in which the sperm were frozen from room temperature, without cooling the sperm slowly to 5°C before freezing. CLC-treated sperm exhibited higher percentages of plasma membrane-intact sperm than control sperm when cryopreserved using conventional protocols. In addition, CLC treatment enhanced both sperm motility and plasma membrane integrity when sperm were frozen directly from room temperature. However, this treatment did not fully prevent the damage of the sperm after cooling rapidly and subsequent freezing, as the sperm quality was lower than that presented by the samples frozen using the conventional protocol. The results are promising, but studies to optimize the protocols for freezing sperm directly from room temperature need to be conducted, as well as studies to determine how cryopreserving sperm in this manner affects other sperm functions.

The magnetic Fe–6.5 wt% Si powder was produced by gas atomization and its microstructure was also investigated. The secondary dendritic arm spacing (SDAS) is related to the droplet size, ${\rm{\lambda }} = 0.29 \cdot {D^{0.5}}$, and the numerical solidification model was applied to the system, giving rise to the correlation of microstructure to the solidification process of the droplet. It is found that the solid fraction at the end of recalescence is strongly dependent on the undercooling achieved before nucleation; the chances for the smaller droplets to form the grain-refined microstructures are less than the larger ones. Furthermore, the SDAS is strongly influenced by the cooling rate of post-recalescence solidification, and the relationship can be expressed as follows, ${\rm{\lambda }} = 74.2 \cdot {\left( {\dot T} \right)^{ - 0.347}}$. Then, the growth of the SDAS is driven by the solute diffusion of the interdendritic liquids, leading to a coarsening phenomenon, shown in a cubic root law of local solidification time, ${\rm{\lambda }} = 10.73 \cdot {\left( {{t_f}} \right)^{0.296}}$.

The finite difference method of the low-alloy wear-resistant steel quenching process wasstudied. The temperature field and cooling rate variation of thickness of 45-mmwear-resistant steel (NM450) were calculated for different quenching practices. Themicrostructure and hardness of quenched plates were examined. The results indicate thatwhen quenching started, the cooling rate was highest on the subsurface and decreasedgradually until the center of the plate. However, as the quenching progressed, the coolingrate distribution along the plate thickness was reversed. The cooling rate increasedlinearly when the heat transfer coefficient (HTC) increased from 0–10 000W/m2 K, and then the speed gradually slowed down until achieving the maximumcooling rate. Close to the plate mid-thickness, the maximum cooling rate was easilyreached. Compared with high-pressure (HP) quenching and low-pressure (LP) quenching, underthe HP + LP continuous quenching mode, it is possible to obtain a high critical coolingrate in the temperature range of 900 °C–400 °C and small temperature difference betweenthe surface and center below 400 °C. The microstructure and hardness distribution on theplate surface for the HP + LP quenching mode indicated 100% martensite on the surface andmartensite with a little granular bainite in the plate center, while the hardnessdifference in the entire steel plate was less than 7%. This study provided guidance forthe formulation and optimization of wear-resistant steel.

The glass-forming ability of chalcogenide glasses from the GeSe2-Sb2Te3-PbSb2Te4 system is investigated at different cooling rates. The samples are synthesized by direct synthesis in evacuated quartz ampoules from the initial compounds and quenched in air, water, water+ice+NaCl and liquid nitrogen with cooling rates of 3, 9, 34 and 400 K/s, respectively. The obtained bulks are characterized by visual and X-ray diffraction analyses. The critical cooling rate for obtaining chalcogenide glasses from the investigated system is 34 K/s. Above this rate the border between the glassy and crystalline phases shows a tendency towards narrowing of the glass-forming region.

Various cooling (01–5.100 Cmin−1) and warming (2O–6,8OO½Cmin−1) rates, stepped cooling schedules and four cryoprotective additives (dimethyl sulphoxide, methanol, ethanediol and glycerol) were investigated in cryopreservation studies with Dictyocaulus viviparus third-stage larvae. Exsheathment with sodium hypochlorite was essential to achieve significant survival. With uninterrupted cooling, highest survival (30% normally motile) was achieved with rates of 10–70½C min−1. Survival was higher (50–75%) using 1 ½C min−1 to — 10½C followed by plunging into liquid nitrogen. The optimum warming rate was 6,8OO½C min−1. The use of cryoprotectants led to marginally lower survival while varying the suspending media had no significant effect on survival. X-irradiated, exsheathed third-stage larvae cryopreserved by the optimum protocol yielded 38–3 ±4–2% survival. Two calves each infected with 45,000 (15,000 viable) exsheathed, unirradiated, C“ryopreserved third-stage larvae harboured 494 worms (11% infectivity) and 355 worms (0-8%) at necropsy. Numbers of first-stage larvae in the faeces reached 420/G and 105/G respectively 27 days after infection.

In the range of water contents studied (0.1–0.4 g H2O g dw−1), Coffea arabica seeds were less sensitive to desiccation than C. costatifructa, C. racemosa and C. sessiliflora seeds. At 0.20 g H2O g dw−1, 53% of C. arabica seeds germinated after direct immersion in LN (rapid cooling, 200°C min−1), but none of them developed into normal seedlings. By contrast, in C. costatifructa, C. racemosa and C. sessiliflora, when seeds were dehydrated to the optimal water content (0.19, 0.28 and 0.31 g H2O g dw−1, respectively), the percentages of seeds which developed into normal seedlings after LN exposure were 26, 78 and 31% of the desiccation control, respectively. Normal seedlings could be recovered from cryopreserved C. arabica seeds only if they were desiccated to 0.20 g H2O g dw−1 and precooled slowly to −50°C prior to immersion in LN. Precooling seeds at 2°C min−1 allowed 25% of seeds to develop into normal seedlings. The thawing rate had no effect on the survival of cryopreserved C. arabica seeds. In all cryopreservation experiments, the total germination did not reflect the percentage of seeds which developed into normal seedlings. Examination of excised embryos indicated a partial explanation of this difference since only the shoot apex was destroyed in abnormal embryos, whereas the hypocotyl and radicle were normal.

The influence of surface structure and chemistry on high-temperature dewetting of silicate liquids on ceramic surfaces has been investigated. Model systems based on well-defined crystallography and known chemistry have been used to illustrate the effect of surface roughness and chemistry on the dewetting process. Reconstructed ceramic surfaces provide ideal substrates to study effects of surface roughness. It has been shown that the morphology of dewet droplets depend on the length scale and the crystallography of the facets on the surface. Complex pattern formation due to solute redistribution during dewetting is illustrated in the case of SiO2 dewetting on (001) rutile substrates. The role of kinetics on the dewetting process has also been clarified.