A novel kind of multi-core magnetic composite particles, the surfaces of which were respectively mo- dified with goat-anti-mouse IgG and antitransferrin receptor（anti-CD71）, was prepared. The fetal nucleated red blo...A novel kind of multi-core magnetic composite particles, the surfaces of which were respectively mo- dified with goat-anti-mouse IgG and antitransferrin receptor（anti-CD71）, was prepared. The fetal nucleated red blood cells（FNRBCs） in the peripheral blood of a gravida were rapidly and effectively enriched and separated by the mo- dified multi-core magnetic composite particles in an external magnetic field. The obtained FNRBCs were used for the identification of the fetal sex by means of fluorescence in situ hybridization（FISH） technique. The results demonstrate that the multi-core magnetic composite particles meet the requirements for the enrichment and speration of FNRBCs with a low concentration and the accuracy of detetion for the diagnosis of fetal sex reached to 95%. Moreover, the obtained FNRBCs were applied to the non-invasive diagnosis of Down syndrome and chromosome 3p21 was de- tected. The above facts indicate that the novel multi-core magnetic composite particles-based method is simple, relia- ble and cost-effective and has opened up vast vistas for the potential application in clinic non-invasive prenatal diag- nosis.展开更多
To find a simple, effective method of isolating fetal cells from maternal peripheral blood for prenatal diagnosis, 45 women were studied with their gestation being 6-14 weeks and age 21- 30 years. The fetal cells wer...To find a simple, effective method of isolating fetal cells from maternal peripheral blood for prenatal diagnosis, 45 women were studied with their gestation being 6-14 weeks and age 21- 30 years. The fetal cells were isolated from maternal blood by using discontinuous density gradient centrifugation. Some of the isolated cells were made smear and counted under the microscope; others were used for predicting fetal sex by PCR amplification of Y chromosome specific DYZ1 gene. The major cells in the upper separation interface were lymphocytes and monocytes, with occasionally seen nucleated red blood cells (NRBC); while those in the middle separation interface were neutrocytes, with NRBC scattering. The ratio of NRBC/nucleated cells was 1. 98±0. 28× 10-5. There was no significant difference between the first and second trimester (P>0. 05). The amount of isolated fetal cells was sufficient for prenatal genetic diagnosis. Male pregnancy was correctly predicted in 10 out of 13 cases. It is concluded that the method of discontinuous density gradient centrifugation was of considerable importance in the development of non-invasive prenatal genetic diagnosis.展开更多
The effect of clay on the nucleating behavior of 1,3：2,4-bis（3,4-dimethylbenzylidene） sorbitol （DMDBS） in cryatallization of isotactic polypropylene （iPP） was investigated by means of differential scanning calo...The effect of clay on the nucleating behavior of 1,3：2,4-bis（3,4-dimethylbenzylidene） sorbitol （DMDBS） in cryatallization of isotactic polypropylene （iPP） was investigated by means of differential scanning calorimetry （DSC）, dynamic rheology and polarized light microscopy （PLM）. It is interesting to note that the incorporation of layered clay nanoparticles into DMDBS-nucleated iPP may induce a synergetic nucleation effect while the DMDBS content is below 0.1 wt%, otherwise it restricts the crystallization rate prominently as the DMDBS content increases up to 0.3 wt%, which has exceeded the content threshold to yield a nucleating agent （NA） network. As shown by dynamic rheological investigations, the clay nanoparticles demonstrate an obstructive effect of disturbing the consistency of DMDBS fibrils network. Moreover, to further demonstrate the importance of NA network formation in the crystallization of iPP, we used another NA named HPN-20e, which can not form network structure at all over the concentration studied, for comparison. In this case, the nucleated-crystallization rate is independent on the addition of clay nanoparticles, as the nucleating mechanism is an individual nuclei manner without NA network forming.展开更多
The single cell isolation technique was used to detect fetal nucleated erythroblasts at a single cell level from the peripheral blood of pregnant women in order to investigate the feasibility of this method for nonin...The single cell isolation technique was used to detect fetal nucleated erythroblasts at a single cell level from the peripheral blood of pregnant women in order to investigate the feasibility of this method for noninvasive prenatal diagnosis. Single fetal nucleated erythroblasts were isolated from the peripheral blood samples from 51 pregnant women by micromanipulation techniques after density gradient centrifugation. Nested polymerase chain reaction method was used to amplify the SRY gene. It was found that the concordance rate of amplification results with real fetal sex was 82.61 %. The sensitivity and specificity were 80 % and 87.50 % respectively. It was suggested that it is feasible and promising in non invasive prenatal diagnosis to detect fetal nucleated erythroblasts at a single cell level by using micromanipulation techniques.展开更多
In order to search for a more reliable method of sorting fetal nucleated red blood cells (NRBCs) and DNA from maternal peripheral blood and to identify origin of NRBCs and DNA, NRBCs were isolated from peripheral bloo...In order to search for a more reliable method of sorting fetal nucleated red blood cells (NRBCs) and DNA from maternal peripheral blood and to identify origin of NRBCs and DNA, NRBCs were isolated from peripheral blood of 88 pregnant women by density gradient centrifugation and fluorescence activated cell sorter (FACS) respectively. Nested polymerase chain reaction was used to detect normal male SRY gene from blood plasma DNA of 65 pregnant women. The results revealed that fetal NRBCs were found in 14 of 27 maternal samples by density gradient centrifugation. The number of cells was from 1 to 10. Using FACS, CD71 + cells were identified among all 61 samples. The frequency was (0.35±0.25)×10 -2; The detectable rate of the SRY gene of blood plasma DNA from 46 women carrying male fetuses was 65.22 % (30/46). Non-detectable rate for 19 women carrying female fetuses was 94.74 % (18/19). It was concluded that the methods of sorting fetal NRBCs and DNA have already made great progress. The methods for fetal NRBCs and plasma DNA from maternal peripheral blood to diagnose genetic diseases seem to be the best methods of noninvasive prenatal diagnosis.展开更多
An aryl dicarboxylic acid amide compound TMB-5 is an efficient β-form nucleating agent for isotactic polypropylene （iPP）. Because of the solubility of TMB-5, superstructure and morphology of iPP crystals changed wi...An aryl dicarboxylic acid amide compound TMB-5 is an efficient β-form nucleating agent for isotactic polypropylene （iPP）. Because of the solubility of TMB-5, superstructure and morphology of iPP crystals changed with melting conditions. Effects of final heating temperature （Tf） on heterogeneous nucleation of iPP/TMB-5 were investigated. It was discovered that the crystallization temperature increased with decreasing Tf value. The optical microscopic images indicated that when TMB-5 partially dissolved in iPP melt, the remaining （non-dissolved） TMB-5 facilitated the recrystallization of dissolved nucleating agent from the melt, which promoted crystallization. Complete solubility of nucleating agent caused the decreasing efficiency. TMB-5 recrystallized in the form of tiny needles, whose aggregates induced dendritic iPP crystals.展开更多
It is difficult to generate coherent twin boundaries in bulk Al alloys due to their high intrinsic stacking fault energy. Here, we report a strategy to induce high-density growth twins in aluminum alloys through the h...It is difficult to generate coherent twin boundaries in bulk Al alloys due to their high intrinsic stacking fault energy. Here, we report a strategy to induce high-density growth twins in aluminum alloys through the heterogeneous nucleation of twinned Al grains on twin-structured TiC nucleants and the preferred growth of twinned dendrites by laser surface remelting of bulk metals. The solidification structure at the surface shows a mixture of lamellar twinned dendrites with ultra-fine twin boundary spacing (∼2 µm), isolated twinned dendrites, and regular dendrites. EBSD analysis and finite element method (FEM) simulations have been used to understand the competitive growth between twinned and regular dendrites, and the solidification conditions for the preferred growth of twinned dendrites during laser remelting and subsequent rapid solidification are established. It is shown that the reduction in the ratio of temperature gradient G to solidification rate V promotes the formation of lamellar twinned dendrites. The primary trunk spacing of lamellar twinned dendrites is refined by the high thermal gradient and solidification rate. The present work paves a new way to generate high-density growth twins in additive-manufactured Al alloys.展开更多
Due to the low content of alloying elements and the lack of effective nucleation sites,the fusion zone(FZ)of tungsten inert gas(TIG)welded AZ31 alloy typically exhibits undesirable coarse columnar grains,which can res...Due to the low content of alloying elements and the lack of effective nucleation sites,the fusion zone(FZ)of tungsten inert gas(TIG)welded AZ31 alloy typically exhibits undesirable coarse columnar grains,which can result in solidification defects and reduced mechanical properties.In this work,a novel welding wire containing MgO particles has been developed to promote columnar-to-equiaxed transition(CET)in the FZ of TIG-welded AZ31 alloy.The results show the achievement of a fully equiaxed grain structure in the FZ,with a significant 71.9%reduction in grain size to 41 μm from the original coarse columnar dendrites.Furthermore,the combination of using MgO-containing welding wire and pulse current can further refine the grain size to 25.6 μm.Microstructural analyses reveal the homogeneous distribution of MgO particles in the FZ.The application of pulse current results in an increase in the number density of MgO(1-2 μm)from 5.16 × 10^(4) m^(-3) to 6.18 × 10^(4) m^(-3).The good crystallographic matching relationship between MgO and α-Mg matrix,characterized by the orientation relationship of[11(2)0]α-Mg//[0(1)1]MgO and(0002)_(α-Mg)//(111)_(MgO),indicates that the MgO particles can act as effective nucleation sites for α-Mg to reduce nucleation undercooling.According to the Hunt criteria,the critical temperature gradient for CET is greatly enhanced due to the significantly increased number density of MgO nucleation sites.In addition,the correlation with the thermal simulation results reveals a transition in the solidification conditions within the welding pool from the columnar grain zone to the equiaxed grain zone in the CET map,leading to the realization of CET.The exceptional grain refinement has contributed to a simultaneous improvement in the strength and plasticity of welded joints.This study presents a novel strategy for controlling equiaxed microstructure and optimizing mechanical properties in fusion welding or wire and arc additive manufacturing of Mg alloy components.展开更多
Memristive crossbar arrays(MCAs)offer parallel data storage and processing for energy-efficient neuromorphic computing.However,most wafer-scale MCAs that are compatible with complementary metal-oxide-semiconductor(CMO...Memristive crossbar arrays(MCAs)offer parallel data storage and processing for energy-efficient neuromorphic computing.However,most wafer-scale MCAs that are compatible with complementary metal-oxide-semiconductor(CMOS)technology still suffer from substantially larger energy consumption than biological synapses,due to the slow kinetics of forming conductive paths inside the memristive units.Here we report wafer-scale Ag_(2)S-based MCAs realized using CMOS-compatible processes at temperatures below 160℃.Ag_(2)S electrolytes supply highly mobile Ag+ions,and provide the Ag/Ag_(2)S interface with low silver nucleation barrier to form silver filaments at low energy costs.By further enhancing Ag+migration in Ag_(2)S electrolytes via microstructure modulation,the integrated memristors exhibit a record low threshold of approximately−0.1 V,and demonstrate ultra-low switching-energies reaching femtojoule values as observed in biological synapses.The low-temperature process also enables MCA integration on polyimide substrates for applications in flexible electronics.Moreover,the intrinsic nonidealities of the memristive units for deep learning can be compensated by employing an advanced training algorithm.An impressive accuracy of 92.6%in image recognition simulations is demonstrated with the MCAs after the compensation.The demonstrated MCAs provide a promising device option for neuromorphic computing with ultra-high energy-efficiency.展开更多
The unique structure and exceptional properties of two-dimensional(2D)materials offer significant potential for transformative advancements in semiconductor industry.Similar to the reliance on wafer-scale single-cryst...The unique structure and exceptional properties of two-dimensional(2D)materials offer significant potential for transformative advancements in semiconductor industry.Similar to the reliance on wafer-scale single-crystal ingots for silicon-based chips,practical applications of 2D materials at the chip level need large-scale,high-quality production of 2D single crystals.Over the past two decades,the size of 2D single-crystals has been improved to wafer or meter scale,where the nucleation control during the growth process is particularly important.Therefore,it is essential to conduct a comprehensive review of nucleation control to gain fundamental insights into the growth of 2D single-crystal materials.This review mainly focuses on two aspects:controlling nucleation density to enable the growth from a single nucleus,and controlling nucleation position to achieve the unidirectionally aligned islands and subsequent seamless stitching.Finally,we provide an overview and forecast of the strategic pathways for emerging 2D materials.展开更多
pH-dependent multiple equilibria in cobalt sulfate-gluconate baths were calculated using stability constants adopted from literature.Changes of the bath speciation were then discussed in terms of spectrophotometric ex...pH-dependent multiple equilibria in cobalt sulfate-gluconate baths were calculated using stability constants adopted from literature.Changes of the bath speciation were then discussed in terms of spectrophotometric experiments and buffering properties of the solutions(pH 3-10).Cyclic voltammetry indicated changes in electrochemical behavior of cobalt species caused by different ionic compositions of the electrolytes.Tafel slopes were calculated and discussed in relation to electroreduction of cobalt species.Chronoamperometric studies showed 3D instantaneous nucleation of cobalt followed by diffusion-controlled growth,but it was disturbed at higher pH due to the release of cation from gluconate complexes as a limiting step.Diffusion coefficients of cobalt species were found.Changes in the pH were also reflected by modifications of morphology(SEM),development of preferred orientation planes(XRD,texture coefficients)and current efficiency,but not the thickness of the coatings deposited at constant potential of-1.0 V(vs Ag/AgCl).Anodic stripping analysis showed changes in anodic responses originated from the existence of preferentially oriented planes in cobalt layers.展开更多
Four typical admixtures,polycarboxylate superplasticiser(PCE),tartaric acid(TA),sorbitol and polyacrylamide(PAM),were selected to systematically investigate their regulatory mechanisms on the formation of ettringite t...Four typical admixtures,polycarboxylate superplasticiser(PCE),tartaric acid(TA),sorbitol and polyacrylamide(PAM),were selected to systematically investigate their regulatory mechanisms on the formation of ettringite through Fourier transform infrared spectroscopy,X-ray diffraction,particle size analysis and nucleation kinetic model.The experimental results indicate that the admixtures alter the formation of ettringite through physical adsorption,complexation and solution viscosity modulation without changing its chemical structure.Low concentrations of PCE inhibit size growth by forming an adsorption layer on the surface of ettringite,whereas high concentrations of PCE alter the size change of ettringite by modulating the distribution of ionic concentrations.TA significantly reduces the size of ettringite by complexing Ca^(2+).Sorbitol and PAM promote the local growth of ettringite at low concentrations,leading to larger sizes.But at high concentrations,the size growth of ettringite is inhibited due to the increase in viscosity or the enhancement of complexation.Matlab nucleation kinetic modelling further shows that the addition of admixtures enhances the initial nucleation during ettringite synthesis,with values ranging from 14.45%to 114.25%.However,the subsequent nucleation rate of ettringite is significantly affected,decreasing by 12.79%to 71.74%.The results provide a theoretical basis for the design of ettringite materials and the optimisation of the application of admixtures.展开更多
To investigate the nucleation behavior during the single-phased metallic solidification process,the commercial ultrapure ferritic stainless steels with no(Initial steel)and various melt treatments(R1,MR1,Y2,MY1,and M1...To investigate the nucleation behavior during the single-phased metallic solidification process,the commercial ultrapure ferritic stainless steels with no(Initial steel)and various melt treatments(R1,MR1,Y2,MY1,and M1 steels)were used to carry out the differential scanning colorimetry(DSC)and high-temperature confocal laser scanning microscope(HT-CLSM)experiments.Based on the results of DSC experiments,the equilibrium solidification process as well as the relationship among the critical undercooling degree(△T_(c)^(DSC)),latent heat of fusion/crystallization(△H_(f)/△H_(c)),equiaxed grain ratio(ER),and average grain size(△_(ave)^(ingot))was revealed.ER is increased with the decreasing△T_(c)^(DSC)and increasing△H_(f)/△H_(c);however,△_(ave)^(ingot)is decreased with them.Referring to the results of HT-CLSM experiments,the average sizes of micro-/macrostructures(d_(ave)/D_(ave)/)are decreased with the increasing cooling rate,as well as the difference between and apparent critical undercooling degree(△T_(c)^(CLSM))was revealed.The heterogeneous nucleation of the crystal nuclei occurs only if△T_(c)^(CLSM)>△T_(c)^(DSC).Combining with the interfacial wetting-lattice mismatch heterogeneous nucleation model,the dynamic mechanism of the metallic solidification was revealed.The as-cast grains of the melt-treated samples were obviously refined,owing to the much higher actual heterogeneous nucleation rates(I_(heter.,i))obtained through melt treatments,and the heterogeneous nucleation rates(I_(heter.,ij))for all samples are increased with the cooling rates,firmly confirming that the as-cast grains of each sample could be refined by the increasing cooling rates.展开更多
The unveiling of temperature effects on the deformation behaviors of wrought magnesium(Mg)alloys is beneficial for optimizing the hot forming parameters of these alloys with limited room temperature(RT)formability.In ...The unveiling of temperature effects on the deformation behaviors of wrought magnesium(Mg)alloys is beneficial for optimizing the hot forming parameters of these alloys with limited room temperature(RT)formability.In the present work,we performed nanoindentations on individual grains of textured wrought AZ31 alloy along the normal direction(ND)from RT to 300℃to investigate the intrinsic non-basal dislocation behaviors at various temperatures.Interestingly,we observed abnormally enhanced nanoindentation displacement bursts(pop-ins)at elevated temperatures ranging from 150 to 250℃,which is beyond the general scenario that higher temperatures typically result in smoother plastic flow.The bursts exhibited Gaussian-like statistics,which differ from the well-reported bursts with power-law size distributions resulting from the destruction of jammed dislocation configurations.Through transmission electron microscopy(TEM)examination of the microstructure beneath the indentation just after the burst,we found that the abnormal displacement bursts originated from the heterogeneous nucleation of prismatic screw(a)dislocations due to the exhaustion of dislocation sources within the specified temperature range.展开更多
The amalgamation of herbal medicine and nanoformulation technology presents a compelling avenue for the advancement of pharmaceutical and health food products.This synergy capitalizes on the inherent therapeutic prope...The amalgamation of herbal medicine and nanoformulation technology presents a compelling avenue for the advancement of pharmaceutical and health food products.This synergy capitalizes on the inherent therapeutic properties of herbal extracts while harnessing the innovative capabilities of nano-scale formulation.Nano-technology has revolutionized drug delivery systems,offering enhanced bioavailability and targeted delivery of active compounds.The global research landscape reflects a burgeoning interest in nano-based pharmaceuticals,driven by their potential to overcome traditional limitations and optimize therapeutic outcomes.Vietnam,with its rich biodiversity and burgeoning nano-industry,stands at the forefront of this convergence.Vietlife,a prominent player in health product research and manufacturing,is poised to capitalize on this convergence.By leveraging indigenous herbal knowledge and cutting-edge nanoformulation techniques,Vietlife can pioneer the development of novel pharmaceutical and health food solutions.In conclusion,the integration of herbal medicine and nanoformulation technology opens up promising opportunities for the development of pharmaceuticals and healthcare products.Vietnam and Vietlife can capitalize on this trend to drive sustainable development and establish their presence in the international market.展开更多
The early stages of crystallization and occurrence of surface wrinkling were investigated using poly(butadiene)-block-poly(ε-caprolactone)with an ordered lamellar structure.Direct evidence has demonstrated that surfa...The early stages of crystallization and occurrence of surface wrinkling were investigated using poly(butadiene)-block-poly(ε-caprolactone)with an ordered lamellar structure.Direct evidence has demonstrated that surface wrinkling precedes nucleation and crystal growth.This study examined the relationship between surface wrinkling,nucleation,and the formation of crystalline supramolecular structures using atomic force microscopy(AFM)and X-ray scattering measurements.Surface wrinkling is attributed to curving induced by accumulated stresses,including residual stress from the sample preparation and thermal stress during cooling.These stresses cause large-scale material flow and corresponding changes in the molecular conformations,potentially reducing the nucleation barrier.This hypothesis is supported by the rapid crystal growth observed following the spread of surface wrinkles.Additionally,the surface curving of the polymer thin film creates local minima of the free energy,facilitating nucleation.The nuclei subsequently grow into crystalline supramolecular structures by incorporating polymer molecules from the melt.This mechanism highlights the role of localized structural inhomogeneity in the early stages of crystallization and provides new insights into structure formation processes.展开更多
The nanoindentation pop-in behaviors of 13 grains with diverse crystallographic orientations were analysed using a coarse-grained Mg-2 wt.% Gd alloy.Within nanoscale stressed volumes within all grains,the converted sh...The nanoindentation pop-in behaviors of 13 grains with diverse crystallographic orientations were analysed using a coarse-grained Mg-2 wt.% Gd alloy.Within nanoscale stressed volumes within all grains,the converted shear stresses for the first pop-in,calculated using the indentation Schmid factor,ranged from 1 to 1.3 GPa,consistent with theoretical predictions for dislocation nucleation in Mg.The estimated activation volume of the first pop-in was approximately 27–40 A3(involving about ~2 atoms),aligning with reported atomistic simulations of the surface dislocation semi-loop nucleation.While indented near the -axis,grains exhibit higher first pop-in loads and successive pop-ins,implying the possibility of a cross-slip nucleation mechanism to accommodate -axis deformation.展开更多
Earthquakes are caused by the rapid slip along seismogenic faults.Whether large or small,there is inevitably a certain nucleation process involved before the dynamic rupture.At the same time,significant foreshock acti...Earthquakes are caused by the rapid slip along seismogenic faults.Whether large or small,there is inevitably a certain nucleation process involved before the dynamic rupture.At the same time,significant foreshock activity has been observed before some but not all large earthquakes.Understanding the nucleation process and foreshocks of earthquakes,especially large damaging ones,is crucial for accurate earthquake prediction and seismic hazard mitigation.The physical mechanism of earthquake nucleation and foreshock generation is still in debate.While the earthquake nucleation process is present in laboratory experiments and numerical simulations,it is difficult to observe such a process directly in the field.In addition,it is currently impossible to effectively distinguish foreshocks from ordinary earthquake sequences.In this article,we first summarize foreshock observations in the last decades and attempt to classify them into different types based on their temporal behaviors.Next,we present different mechanisms for earthquake nucleation and foreshocks that have been proposed so far.These physical models can be largely grouped into the following three categories:elastic stress triggering,aseismic slip,and fluid flows.We also review several recent studies of foreshock sequences before moderate to large earthquakes around the world,focusing on how different results/conclusions can be made by different datasets/methods.Finally,we offer some suggestions on how to move forward on the research topic of earthquake nucleation and foreshock mechanisms and their governing factors.展开更多
Growth of high-quality Nb_(3)Sn thin films for superconducting radiofrequency(SRF)applications using the vapor diffusion method requires a uniform distribution of tin nuclei on the niobium(Nb)surface.This study examin...Growth of high-quality Nb_(3)Sn thin films for superconducting radiofrequency(SRF)applications using the vapor diffusion method requires a uniform distribution of tin nuclei on the niobium(Nb)surface.This study examines the mechanism underlying the observed non-uniform distribution of tin nuclei with tin chloride SnCl_(2).Electron backscatter diffraction(EBSD)analysis was used to examine the correlation between the nucleation behavior and orientation of niobium grains in the substrate.The findings of the density functional theory(DFT)simulation are in good agreement with the experimental results,showing that the non-uniform distribution of tin nuclei is the result of the adsorption energy of SnCl_(2)molecules by varied niobium grain orientations.Further analysis indicated that the surface roughness and grain size of niobium also played significant roles in the nucleation behavior.This study provides valuable insights into enhancing the surface pretreatment of niobium substrates during the growth of Nb_(3)Sn thin films using the vapor diffusion method.展开更多
Sequential processing(SqP)of the active layer offers independent optimization of the donor and acceptor with more targeted solvent design,which is considered the most promising strategy for achieving efficient organic...Sequential processing(SqP)of the active layer offers independent optimization of the donor and acceptor with more targeted solvent design,which is considered the most promising strategy for achieving efficient organic solar cells(OSCs).In the SqP method,the favorable interpenetrating network seriously depends on the fine control of the bottom layer swelling.However,the choice of solvent(s)for both the donor and acceptor have been mostly based on a trial-and-error manner.A single solvent often cannot achieve sufficient yet not excessive swelling,which has long been a difficulty in the high efficient SqP OSCs.Herein,two new isomeric molecules are introduced to fine-tune the nucleation and crystallization dynamics that allows judicious control over the swelling of the bottom layer.The strong non-covalent interaction between the isomeric molecule and active materials provides an excellent driving force for optimize the swelling-process.Among them,the molecule with high dipole moment promotes earlier nucleation of the PM6 and provides extended time for crystallization during SqP,improving bulk morphology and vertical phase segregation.As a result,champion efficiencies of 17.38%and 20.00%(certified 19.70%)are achieved based on PM6/PYF-T-o(all-polymer)and PM6/BTP-eC9 devices casted by toluene solvent.展开更多
文摘A novel kind of multi-core magnetic composite particles, the surfaces of which were respectively mo- dified with goat-anti-mouse IgG and antitransferrin receptor（anti-CD71）, was prepared. The fetal nucleated red blood cells（FNRBCs） in the peripheral blood of a gravida were rapidly and effectively enriched and separated by the mo- dified multi-core magnetic composite particles in an external magnetic field. The obtained FNRBCs were used for the identification of the fetal sex by means of fluorescence in situ hybridization（FISH） technique. The results demonstrate that the multi-core magnetic composite particles meet the requirements for the enrichment and speration of FNRBCs with a low concentration and the accuracy of detetion for the diagnosis of fetal sex reached to 95%. Moreover, the obtained FNRBCs were applied to the non-invasive diagnosis of Down syndrome and chromosome 3p21 was de- tected. The above facts indicate that the novel multi-core magnetic composite particles-based method is simple, relia- ble and cost-effective and has opened up vast vistas for the potential application in clinic non-invasive prenatal diag- nosis.
文摘To find a simple, effective method of isolating fetal cells from maternal peripheral blood for prenatal diagnosis, 45 women were studied with their gestation being 6-14 weeks and age 21- 30 years. The fetal cells were isolated from maternal blood by using discontinuous density gradient centrifugation. Some of the isolated cells were made smear and counted under the microscope; others were used for predicting fetal sex by PCR amplification of Y chromosome specific DYZ1 gene. The major cells in the upper separation interface were lymphocytes and monocytes, with occasionally seen nucleated red blood cells (NRBC); while those in the middle separation interface were neutrocytes, with NRBC scattering. The ratio of NRBC/nucleated cells was 1. 98±0. 28× 10-5. There was no significant difference between the first and second trimester (P>0. 05). The amount of isolated fetal cells was sufficient for prenatal genetic diagnosis. Male pregnancy was correctly predicted in 10 out of 13 cases. It is concluded that the method of discontinuous density gradient centrifugation was of considerable importance in the development of non-invasive prenatal genetic diagnosis.
基金financially supported by the National Natural Science Foundation of China(Nos.21034005,50903048)
文摘The effect of clay on the nucleating behavior of 1,3：2,4-bis（3,4-dimethylbenzylidene） sorbitol （DMDBS） in cryatallization of isotactic polypropylene （iPP） was investigated by means of differential scanning calorimetry （DSC）, dynamic rheology and polarized light microscopy （PLM）. It is interesting to note that the incorporation of layered clay nanoparticles into DMDBS-nucleated iPP may induce a synergetic nucleation effect while the DMDBS content is below 0.1 wt%, otherwise it restricts the crystallization rate prominently as the DMDBS content increases up to 0.3 wt%, which has exceeded the content threshold to yield a nucleating agent （NA） network. As shown by dynamic rheological investigations, the clay nanoparticles demonstrate an obstructive effect of disturbing the consistency of DMDBS fibrils network. Moreover, to further demonstrate the importance of NA network formation in the crystallization of iPP, we used another NA named HPN-20e, which can not form network structure at all over the concentration studied, for comparison. In this case, the nucleated-crystallization rate is independent on the addition of clay nanoparticles, as the nucleating mechanism is an individual nuclei manner without NA network forming.
基金This project was supported by a grant from Science Foun-dation of Ministry of Public Heath of China (No. 96 .2 - 112 )and a grant from Hubei Provincial National Natural ScienceFoundation(96 J0 6 8)
文摘The single cell isolation technique was used to detect fetal nucleated erythroblasts at a single cell level from the peripheral blood of pregnant women in order to investigate the feasibility of this method for noninvasive prenatal diagnosis. Single fetal nucleated erythroblasts were isolated from the peripheral blood samples from 51 pregnant women by micromanipulation techniques after density gradient centrifugation. Nested polymerase chain reaction method was used to amplify the SRY gene. It was found that the concordance rate of amplification results with real fetal sex was 82.61 %. The sensitivity and specificity were 80 % and 87.50 % respectively. It was suggested that it is feasible and promising in non invasive prenatal diagnosis to detect fetal nucleated erythroblasts at a single cell level by using micromanipulation techniques.
文摘In order to search for a more reliable method of sorting fetal nucleated red blood cells (NRBCs) and DNA from maternal peripheral blood and to identify origin of NRBCs and DNA, NRBCs were isolated from peripheral blood of 88 pregnant women by density gradient centrifugation and fluorescence activated cell sorter (FACS) respectively. Nested polymerase chain reaction was used to detect normal male SRY gene from blood plasma DNA of 65 pregnant women. The results revealed that fetal NRBCs were found in 14 of 27 maternal samples by density gradient centrifugation. The number of cells was from 1 to 10. Using FACS, CD71 + cells were identified among all 61 samples. The frequency was (0.35±0.25)×10 -2; The detectable rate of the SRY gene of blood plasma DNA from 46 women carrying male fetuses was 65.22 % (30/46). Non-detectable rate for 19 women carrying female fetuses was 94.74 % (18/19). It was concluded that the methods of sorting fetal NRBCs and DNA have already made great progress. The methods for fetal NRBCs and plasma DNA from maternal peripheral blood to diagnose genetic diseases seem to be the best methods of noninvasive prenatal diagnosis.
文摘An aryl dicarboxylic acid amide compound TMB-5 is an efficient β-form nucleating agent for isotactic polypropylene （iPP）. Because of the solubility of TMB-5, superstructure and morphology of iPP crystals changed with melting conditions. Effects of final heating temperature （Tf） on heterogeneous nucleation of iPP/TMB-5 were investigated. It was discovered that the crystallization temperature increased with decreasing Tf value. The optical microscopic images indicated that when TMB-5 partially dissolved in iPP melt, the remaining （non-dissolved） TMB-5 facilitated the recrystallization of dissolved nucleating agent from the melt, which promoted crystallization. Complete solubility of nucleating agent caused the decreasing efficiency. TMB-5 recrystallized in the form of tiny needles, whose aggregates induced dendritic iPP crystals.
基金supported by the National Natural Science Foundation of China(grant no.52371029)the Science and Technology Development Program of Jilin Province,China(grant no.20210402083GH).
文摘It is difficult to generate coherent twin boundaries in bulk Al alloys due to their high intrinsic stacking fault energy. Here, we report a strategy to induce high-density growth twins in aluminum alloys through the heterogeneous nucleation of twinned Al grains on twin-structured TiC nucleants and the preferred growth of twinned dendrites by laser surface remelting of bulk metals. The solidification structure at the surface shows a mixture of lamellar twinned dendrites with ultra-fine twin boundary spacing (∼2 µm), isolated twinned dendrites, and regular dendrites. EBSD analysis and finite element method (FEM) simulations have been used to understand the competitive growth between twinned and regular dendrites, and the solidification conditions for the preferred growth of twinned dendrites during laser remelting and subsequent rapid solidification are established. It is shown that the reduction in the ratio of temperature gradient G to solidification rate V promotes the formation of lamellar twinned dendrites. The primary trunk spacing of lamellar twinned dendrites is refined by the high thermal gradient and solidification rate. The present work paves a new way to generate high-density growth twins in additive-manufactured Al alloys.
基金supported by the National Natural Science Foundation of China(No.51871155).
文摘Due to the low content of alloying elements and the lack of effective nucleation sites,the fusion zone(FZ)of tungsten inert gas(TIG)welded AZ31 alloy typically exhibits undesirable coarse columnar grains,which can result in solidification defects and reduced mechanical properties.In this work,a novel welding wire containing MgO particles has been developed to promote columnar-to-equiaxed transition(CET)in the FZ of TIG-welded AZ31 alloy.The results show the achievement of a fully equiaxed grain structure in the FZ,with a significant 71.9%reduction in grain size to 41 μm from the original coarse columnar dendrites.Furthermore,the combination of using MgO-containing welding wire and pulse current can further refine the grain size to 25.6 μm.Microstructural analyses reveal the homogeneous distribution of MgO particles in the FZ.The application of pulse current results in an increase in the number density of MgO(1-2 μm)from 5.16 × 10^(4) m^(-3) to 6.18 × 10^(4) m^(-3).The good crystallographic matching relationship between MgO and α-Mg matrix,characterized by the orientation relationship of[11(2)0]α-Mg//[0(1)1]MgO and(0002)_(α-Mg)//(111)_(MgO),indicates that the MgO particles can act as effective nucleation sites for α-Mg to reduce nucleation undercooling.According to the Hunt criteria,the critical temperature gradient for CET is greatly enhanced due to the significantly increased number density of MgO nucleation sites.In addition,the correlation with the thermal simulation results reveals a transition in the solidification conditions within the welding pool from the columnar grain zone to the equiaxed grain zone in the CET map,leading to the realization of CET.The exceptional grain refinement has contributed to a simultaneous improvement in the strength and plasticity of welded joints.This study presents a novel strategy for controlling equiaxed microstructure and optimizing mechanical properties in fusion welding or wire and arc additive manufacturing of Mg alloy components.
基金supported by the Swedish Strategic Research Foundation(SSF FFL15-0174 to Zhen Zhang)the Swedish Research Council(VR 2018-06030 and 2019-04690 to Zhen Zhang)+1 种基金the Wallenberg Academy Fellow Extension Program(KAW 2020-0190 to Zhen Zhang)the Olle Engkvist Foundation(Postdoc grant 214-0322 to Zhen Zhang).
文摘Memristive crossbar arrays(MCAs)offer parallel data storage and processing for energy-efficient neuromorphic computing.However,most wafer-scale MCAs that are compatible with complementary metal-oxide-semiconductor(CMOS)technology still suffer from substantially larger energy consumption than biological synapses,due to the slow kinetics of forming conductive paths inside the memristive units.Here we report wafer-scale Ag_(2)S-based MCAs realized using CMOS-compatible processes at temperatures below 160℃.Ag_(2)S electrolytes supply highly mobile Ag+ions,and provide the Ag/Ag_(2)S interface with low silver nucleation barrier to form silver filaments at low energy costs.By further enhancing Ag+migration in Ag_(2)S electrolytes via microstructure modulation,the integrated memristors exhibit a record low threshold of approximately−0.1 V,and demonstrate ultra-low switching-energies reaching femtojoule values as observed in biological synapses.The low-temperature process also enables MCA integration on polyimide substrates for applications in flexible electronics.Moreover,the intrinsic nonidealities of the memristive units for deep learning can be compensated by employing an advanced training algorithm.An impressive accuracy of 92.6%in image recognition simulations is demonstrated with the MCAs after the compensation.The demonstrated MCAs provide a promising device option for neuromorphic computing with ultra-high energy-efficiency.
基金supported by the National Natural Science Foundation of China(12322406,12404208)the National Key R&D Program of China(2022YFA1403503)+2 种基金China Postdoctoral Science Foundation(2024M750970)the Science and Technology Program of Guangzhou(SL2024A04J00033)the Scientific Research lnnovation Project of Graduate School of South China Normal University.
文摘The unique structure and exceptional properties of two-dimensional(2D)materials offer significant potential for transformative advancements in semiconductor industry.Similar to the reliance on wafer-scale single-crystal ingots for silicon-based chips,practical applications of 2D materials at the chip level need large-scale,high-quality production of 2D single crystals.Over the past two decades,the size of 2D single-crystals has been improved to wafer or meter scale,where the nucleation control during the growth process is particularly important.Therefore,it is essential to conduct a comprehensive review of nucleation control to gain fundamental insights into the growth of 2D single-crystal materials.This review mainly focuses on two aspects:controlling nucleation density to enable the growth from a single nucleus,and controlling nucleation position to achieve the unidirectionally aligned islands and subsequent seamless stitching.Finally,we provide an overview and forecast of the strategic pathways for emerging 2D materials.
文摘pH-dependent multiple equilibria in cobalt sulfate-gluconate baths were calculated using stability constants adopted from literature.Changes of the bath speciation were then discussed in terms of spectrophotometric experiments and buffering properties of the solutions(pH 3-10).Cyclic voltammetry indicated changes in electrochemical behavior of cobalt species caused by different ionic compositions of the electrolytes.Tafel slopes were calculated and discussed in relation to electroreduction of cobalt species.Chronoamperometric studies showed 3D instantaneous nucleation of cobalt followed by diffusion-controlled growth,but it was disturbed at higher pH due to the release of cation from gluconate complexes as a limiting step.Diffusion coefficients of cobalt species were found.Changes in the pH were also reflected by modifications of morphology(SEM),development of preferred orientation planes(XRD,texture coefficients)and current efficiency,but not the thickness of the coatings deposited at constant potential of-1.0 V(vs Ag/AgCl).Anodic stripping analysis showed changes in anodic responses originated from the existence of preferentially oriented planes in cobalt layers.
基金Funded by the National Natural Science Foundation of China(Nos.51578412,51878479,52078372,and 52478272)the International Science and Technology Cooperation Project of the Key R&D Program of Science and Technology Innovation Yongjiang 2035(No.2024H023)。
文摘Four typical admixtures,polycarboxylate superplasticiser(PCE),tartaric acid(TA),sorbitol and polyacrylamide(PAM),were selected to systematically investigate their regulatory mechanisms on the formation of ettringite through Fourier transform infrared spectroscopy,X-ray diffraction,particle size analysis and nucleation kinetic model.The experimental results indicate that the admixtures alter the formation of ettringite through physical adsorption,complexation and solution viscosity modulation without changing its chemical structure.Low concentrations of PCE inhibit size growth by forming an adsorption layer on the surface of ettringite,whereas high concentrations of PCE alter the size change of ettringite by modulating the distribution of ionic concentrations.TA significantly reduces the size of ettringite by complexing Ca^(2+).Sorbitol and PAM promote the local growth of ettringite at low concentrations,leading to larger sizes.But at high concentrations,the size growth of ettringite is inhibited due to the increase in viscosity or the enhancement of complexation.Matlab nucleation kinetic modelling further shows that the addition of admixtures enhances the initial nucleation during ettringite synthesis,with values ranging from 14.45%to 114.25%.However,the subsequent nucleation rate of ettringite is significantly affected,decreasing by 12.79%to 71.74%.The results provide a theoretical basis for the design of ettringite materials and the optimisation of the application of admixtures.
基金supported by the National Natural Science Foundation of China(Grant Nos.52274339,52174321,52074186,and 52104337)Natural Science Foundation of Jiangsu Province(Grant No.BK20231317)China Baowu Low-Carbon Metallurgy Innovation Fund(Grant No.BWLCF202108).
文摘To investigate the nucleation behavior during the single-phased metallic solidification process,the commercial ultrapure ferritic stainless steels with no(Initial steel)and various melt treatments(R1,MR1,Y2,MY1,and M1 steels)were used to carry out the differential scanning colorimetry(DSC)and high-temperature confocal laser scanning microscope(HT-CLSM)experiments.Based on the results of DSC experiments,the equilibrium solidification process as well as the relationship among the critical undercooling degree(△T_(c)^(DSC)),latent heat of fusion/crystallization(△H_(f)/△H_(c)),equiaxed grain ratio(ER),and average grain size(△_(ave)^(ingot))was revealed.ER is increased with the decreasing△T_(c)^(DSC)and increasing△H_(f)/△H_(c);however,△_(ave)^(ingot)is decreased with them.Referring to the results of HT-CLSM experiments,the average sizes of micro-/macrostructures(d_(ave)/D_(ave)/)are decreased with the increasing cooling rate,as well as the difference between and apparent critical undercooling degree(△T_(c)^(CLSM))was revealed.The heterogeneous nucleation of the crystal nuclei occurs only if△T_(c)^(CLSM)>△T_(c)^(DSC).Combining with the interfacial wetting-lattice mismatch heterogeneous nucleation model,the dynamic mechanism of the metallic solidification was revealed.The as-cast grains of the melt-treated samples were obviously refined,owing to the much higher actual heterogeneous nucleation rates(I_(heter.,i))obtained through melt treatments,and the heterogeneous nucleation rates(I_(heter.,ij))for all samples are increased with the cooling rates,firmly confirming that the as-cast grains of each sample could be refined by the increasing cooling rates.
基金supported by the Natural Science Foundation of China(Nos.52031011 and 51971167).
文摘The unveiling of temperature effects on the deformation behaviors of wrought magnesium(Mg)alloys is beneficial for optimizing the hot forming parameters of these alloys with limited room temperature(RT)formability.In the present work,we performed nanoindentations on individual grains of textured wrought AZ31 alloy along the normal direction(ND)from RT to 300℃to investigate the intrinsic non-basal dislocation behaviors at various temperatures.Interestingly,we observed abnormally enhanced nanoindentation displacement bursts(pop-ins)at elevated temperatures ranging from 150 to 250℃,which is beyond the general scenario that higher temperatures typically result in smoother plastic flow.The bursts exhibited Gaussian-like statistics,which differ from the well-reported bursts with power-law size distributions resulting from the destruction of jammed dislocation configurations.Through transmission electron microscopy(TEM)examination of the microstructure beneath the indentation just after the burst,we found that the abnormal displacement bursts originated from the heterogeneous nucleation of prismatic screw(a)dislocations due to the exhaustion of dislocation sources within the specified temperature range.
文摘The amalgamation of herbal medicine and nanoformulation technology presents a compelling avenue for the advancement of pharmaceutical and health food products.This synergy capitalizes on the inherent therapeutic properties of herbal extracts while harnessing the innovative capabilities of nano-scale formulation.Nano-technology has revolutionized drug delivery systems,offering enhanced bioavailability and targeted delivery of active compounds.The global research landscape reflects a burgeoning interest in nano-based pharmaceuticals,driven by their potential to overcome traditional limitations and optimize therapeutic outcomes.Vietnam,with its rich biodiversity and burgeoning nano-industry,stands at the forefront of this convergence.Vietlife,a prominent player in health product research and manufacturing,is poised to capitalize on this convergence.By leveraging indigenous herbal knowledge and cutting-edge nanoformulation techniques,Vietlife can pioneer the development of novel pharmaceutical and health food solutions.In conclusion,the integration of herbal medicine and nanoformulation technology opens up promising opportunities for the development of pharmaceuticals and healthcare products.Vietnam and Vietlife can capitalize on this trend to drive sustainable development and establish their presence in the international market.
基金the National Natural Science Foundation of China(Nos.U2032101 and 11905306)the National Key Research and Development Project of China(No.2022YFB2402602).
文摘The early stages of crystallization and occurrence of surface wrinkling were investigated using poly(butadiene)-block-poly(ε-caprolactone)with an ordered lamellar structure.Direct evidence has demonstrated that surface wrinkling precedes nucleation and crystal growth.This study examined the relationship between surface wrinkling,nucleation,and the formation of crystalline supramolecular structures using atomic force microscopy(AFM)and X-ray scattering measurements.Surface wrinkling is attributed to curving induced by accumulated stresses,including residual stress from the sample preparation and thermal stress during cooling.These stresses cause large-scale material flow and corresponding changes in the molecular conformations,potentially reducing the nucleation barrier.This hypothesis is supported by the rapid crystal growth observed following the spread of surface wrinkles.Additionally,the surface curving of the polymer thin film creates local minima of the free energy,facilitating nucleation.The nuclei subsequently grow into crystalline supramolecular structures by incorporating polymer molecules from the melt.This mechanism highlights the role of localized structural inhomogeneity in the early stages of crystallization and provides new insights into structure formation processes.
基金financial support of NSERC Discovery Grant (RGPIN-2019–05882) and Canada Research Chair program (CRC-2021–00512)。
文摘The nanoindentation pop-in behaviors of 13 grains with diverse crystallographic orientations were analysed using a coarse-grained Mg-2 wt.% Gd alloy.Within nanoscale stressed volumes within all grains,the converted shear stresses for the first pop-in,calculated using the indentation Schmid factor,ranged from 1 to 1.3 GPa,consistent with theoretical predictions for dislocation nucleation in Mg.The estimated activation volume of the first pop-in was approximately 27–40 A3(involving about ~2 atoms),aligning with reported atomistic simulations of the surface dislocation semi-loop nucleation.While indented near the -axis,grains exhibit higher first pop-in loads and successive pop-ins,implying the possibility of a cross-slip nucleation mechanism to accommodate -axis deformation.
基金supported by U.S.National Science Foundation grant RISE-2425889.
文摘Earthquakes are caused by the rapid slip along seismogenic faults.Whether large or small,there is inevitably a certain nucleation process involved before the dynamic rupture.At the same time,significant foreshock activity has been observed before some but not all large earthquakes.Understanding the nucleation process and foreshocks of earthquakes,especially large damaging ones,is crucial for accurate earthquake prediction and seismic hazard mitigation.The physical mechanism of earthquake nucleation and foreshock generation is still in debate.While the earthquake nucleation process is present in laboratory experiments and numerical simulations,it is difficult to observe such a process directly in the field.In addition,it is currently impossible to effectively distinguish foreshocks from ordinary earthquake sequences.In this article,we first summarize foreshock observations in the last decades and attempt to classify them into different types based on their temporal behaviors.Next,we present different mechanisms for earthquake nucleation and foreshocks that have been proposed so far.These physical models can be largely grouped into the following three categories:elastic stress triggering,aseismic slip,and fluid flows.We also review several recent studies of foreshock sequences before moderate to large earthquakes around the world,focusing on how different results/conclusions can be made by different datasets/methods.Finally,we offer some suggestions on how to move forward on the research topic of earthquake nucleation and foreshock mechanisms and their governing factors.
基金supported by the National Natural Science Foundation of China(No.12175283)Youth Innovation Promotion Association of Chinese Academy of Sciences(2020410)Advanced Energy Science and Technology Guangdong Laboratory(HND20TDSPCD,HND22PTDZD).
文摘Growth of high-quality Nb_(3)Sn thin films for superconducting radiofrequency(SRF)applications using the vapor diffusion method requires a uniform distribution of tin nuclei on the niobium(Nb)surface.This study examines the mechanism underlying the observed non-uniform distribution of tin nuclei with tin chloride SnCl_(2).Electron backscatter diffraction(EBSD)analysis was used to examine the correlation between the nucleation behavior and orientation of niobium grains in the substrate.The findings of the density functional theory(DFT)simulation are in good agreement with the experimental results,showing that the non-uniform distribution of tin nuclei is the result of the adsorption energy of SnCl_(2)molecules by varied niobium grain orientations.Further analysis indicated that the surface roughness and grain size of niobium also played significant roles in the nucleation behavior.This study provides valuable insights into enhancing the surface pretreatment of niobium substrates during the growth of Nb_(3)Sn thin films using the vapor diffusion method.
基金supported by the Guangdong Basic and Applied Basic Research Foundation (2022A1515010875)National Natural Science Foundation of China (12404480)+4 种基金Shenzhen Science and Technology Program (JCYJ20240813113238050, JCYJ20240813113306008)Education Department of Guangdong Province (2021KCXTD045)National Natural Science Foundation of China (12274303)the Shenzhen Key Laboratory of Applied Technologies of Super-Diamond and Functional Crystals (ZDSYS20230626091303007)Characteristic Innovation Foundation of Higher Education Institutions of Guangdong Province (2022KTSCX116)
文摘Sequential processing(SqP)of the active layer offers independent optimization of the donor and acceptor with more targeted solvent design,which is considered the most promising strategy for achieving efficient organic solar cells(OSCs).In the SqP method,the favorable interpenetrating network seriously depends on the fine control of the bottom layer swelling.However,the choice of solvent(s)for both the donor and acceptor have been mostly based on a trial-and-error manner.A single solvent often cannot achieve sufficient yet not excessive swelling,which has long been a difficulty in the high efficient SqP OSCs.Herein,two new isomeric molecules are introduced to fine-tune the nucleation and crystallization dynamics that allows judicious control over the swelling of the bottom layer.The strong non-covalent interaction between the isomeric molecule and active materials provides an excellent driving force for optimize the swelling-process.Among them,the molecule with high dipole moment promotes earlier nucleation of the PM6 and provides extended time for crystallization during SqP,improving bulk morphology and vertical phase segregation.As a result,champion efficiencies of 17.38%and 20.00%(certified 19.70%)are achieved based on PM6/PYF-T-o(all-polymer)and PM6/BTP-eC9 devices casted by toluene solvent.
