A Leukocyte image fast scanning based on max–min distance clustering

A leukocyte image fast scanning method based on max min distance clustering is proposed.Because of the lower proportion and uneven distribution of leukocytes in human peripheral blood,there will not be any leukocyte in lager quantity of the captured images if we directly scan the blood smear along an ordinary zigzag scanning routine with high power(100^(x))objective.Due to the larger field of view of low power(10^(x))objective,the captured low power blood smear images can be used to locate leukocytes.All of the located positions make up a specific routine,if we scan the blood smear along this routine with high power objective,there will be definitely leukocytes in almost all of the captured images.Considering the number of captured images is still large and some leukocytes may be redundantly captured twice or more,a leukocyte clustering method based on max-min distance clustering is developed to reduce the total number of captured images as well as the number of redundantly captured leukocytes.This method can improve the scanning eficiency obviously.The experimental results show that the proposed method can shorten scanning time from 8.0-14.0min to 2.54.0 min while extracting 110 nonredundant individual high power leukocyte images.

A fast scanning strategy based on trajectory shaping for atomic force microscopy

To improve the scanning speed of an atomic force microscopy(AFM),a smooth scanning pattern is elaborately devised via trajectory shaping in this paper,so as to achieve fast imaging without hardware modification.Specifically,in the proposed scanning method,the piezoelectric actuator tracks a well-designed smooth periodic signal in x-direction,and simultaneously tracks a step signal in y-direction.The advantage of the proposed method is that it does not require additional data reprocessing to construct the morphology of the sample surface,while significantly increasing the scanning bandwidth restricted by the raster scanning method.Particularly,to directly utilize the height data collected by scanning to produce the sample morphology,the forward process in the common raster scanning mode is retained in the proposed method,the tracking signal in the forward process is thus set to a ramp function in x-direction.In addition,to ensure the continuity and smoothness of the entire tracking signal in x-direction,a segment of a sine curve is uniquely determined as the backward tracking signal by position and acceleration constraints,so as to ensure that the forward and backward curves are continuous and acceleration-continuous at the intersection point.Moreover,the frequency spectrum analysis of the designed smooth signal is carried out to exhibit the depressed amplitudes of high-frequency components,which demonstrates that the proposed method is able to reduce the resonance in AFM high-speed scanning,so as to improve the capacity of rapidly generating high-quality images.Finally,convincing comparison experiments are implemented to verify the imaging performance of the designed scanning algorithm.

Continuous cooling precipitation diagram of high alloyed Al-Zn-Mg-Cu 7049A alloy

The precipitation behaviour during cooling from solution annealing of high alloyed 7049A aluminium alloy was investigated, covering the complete cooling-rate-range of technical interest. This ranges from slow cooling rates close to equilibrium up to rates above complete supersaturation and is covering seven orders of magnitude in cooling rate （0.0005 to 5000 K/s）. The continuous cooling precipitation behaviour of 7049A alloy was recorded by combining different differential scanning calorimetry （DSC） techniques and microstructure analysis by SEM and Vickers hardness testing. The high alloyed, high strength and quench sensitive wrought aluminium alloy 7049A was investigated during quenching from solution annealing by conventional DSC in the cooling rate range of 0.0005 to 4 K/s. In this range at least two exothermal precipitation reactions were observed： a high temperature reaction in a narrow temperature interval of 450-430℃, and a low temperature reaction in a broad temperature interval down to about 200 ℃. Intensities of both reactions decreased with increasing cooling rate. Quenching from solution annealing with rates up to 1000 K/s was investigated by differential fast scanning calorimetry （DFSC） and the differential reheating method （DRM）. A critical quenching rate to suppress all precipitation reactions of 100-300 K/s was been determined.

Preparation and nucleation of spherical metallic droplet

The preparation and solidification of metallic droplets attract more and more attention for their signiifcance in both engineering and scientiifc ifelds. In this paper, the preparation and characterization of Sn-based al oy droplets using different methods such as atomization and consumable electrode direct current arc （CDCA） technique are reviewed. The morphology and structure of these droplets were determined by optical microscopy, X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The solidiifcation behavior of single droplet was systematical y studied by means of scanning calorimetry （DSC）, and the nucleation kinetics was also calculated. In particular, the development of fast scanning calorimetry （FSC） made it possible to investigate the evolution of undercooling under ultrafast but control able heating and cooling conditions. The combination of CDCA technique and FSC measurements opens up a new door for quantitative studies on droplet solidiifcation, which is accessible to demonstrate some theories by experiments.

Fragility crossover mediated by covalent-like electronic interactions in metallic liquids

Fragility is one of the central concepts in glass and liquid sciences,as it characterizes the extent of deviation of viscosity from Arrhenius behavior and is linked to a range of glass properties.However,the intervention of crystallization often prevents the assessment of fragility in poor glass-formers,such as supercooled metallic liquids.Hence experimental data on their compositional dependence are scarce,let alone fundamentally understood.In this work,we use fast scanning calorimetry to overcome this obstacle and systematically study the fragility in a ternary La–Ni–Al system,over previously inaccessible composition space.We observe fragility dropped in a small range with the Al alloying,indicating an alloying-induced fragility crossover.We use x-ray photoelectron spectroscopy,resistance measurements,electronic structure calculations,and DFT-based deep-learning atomic simulations to investigate the cause of this fragility drop.These results show that the fragility crossover can be fundamentally ascribed to the electronic covalency associated with the unique Al–Al interactions.Our findings provide insight into the origin of fragility in metallic liquids from an electronic structure perspective and pave a new way for the design of metallic glasses.

Impact of shadow glass transition on crystallization in metallic glass

The stability of glass against crystallization is of importance in practical applications and theoretical understanding of the nature of glass materials.Annealing has complicated influences on glass stability.It induces either delayed or early crystallization,depending on detailed protocols and specific materials.By interrogating the thermal behaviors of twelve metallic glasses(MGs),we find that enhanced stability is correlated to another process:the so-called shadow glass transition and its evolution.Delayed crystallization can be observed when the shadow glass transition is shifted to cross the temperature of crystallization.Concurrently,the shadow glass transition evolves to an enthalpy overshoot.Molecular dynamics simulations support these findings and suggest that the suppressed string-like motion,relating to the shadow glass transition and the enthalpy overshoot,is likely the origin of the postponed nucleation ordering and enhanced glass stability.