High-entropy alloys(HEAs)possess outstanding features such as corrosion resistance,irradiation resistance,and good mechan-ical properties.A few HEAs have found applications in the fields of aerospace and defense.Exten...High-entropy alloys(HEAs)possess outstanding features such as corrosion resistance,irradiation resistance,and good mechan-ical properties.A few HEAs have found applications in the fields of aerospace and defense.Extensive studies on the deformation mech-anisms of HEAs can guide microstructure control and toughness design,which is vital for understanding and studying state-of-the-art structural materials.Synchrotron X-ray and neutron diffraction are necessary techniques for materials science research,especially for in situ coupling of physical/chemical fields and for resolving macro/microcrystallographic information on materials.Recently,several re-searchers have applied synchrotron X-ray and neutron diffraction methods to study the deformation mechanisms,phase transformations,stress behaviors,and in situ processes of HEAs,such as variable-temperature,high-pressure,and hydrogenation processes.In this review,the principles and development of synchrotron X-ray and neutron diffraction are presented,and their applications in the deformation mechanisms of HEAs are discussed.The factors that influence the deformation mechanisms of HEAs are also outlined.This review fo-cuses on the microstructures and micromechanical behaviors during tension/compression or creep/fatigue deformation and the application of synchrotron X-ray and neutron diffraction methods to the characterization of dislocations,stacking faults,twins,phases,and intergrain/interphase stress changes.Perspectives on future developments of synchrotron X-ray and neutron diffraction and on research directions on the deformation mechanisms of novel metals are discussed.展开更多
Purpose: To compare the repeatability and consistency of anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM) in measuring iris parameters in patients with primary angle closure gl...Purpose: To compare the repeatability and consistency of anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM) in measuring iris parameters in patients with primary angle closure glaucoma. Methods: Twenty-two patients (38 eyes) with primary angle closure glaucoma,including 5 eyes with acute angle closure glaucoma,10 fellow eyes of acute angle closure glaucoma, and 23 eyes with chronic angle closure glaucoma, were recruited consecutively in our hospital. All subjects underwent anterior scanning by AS-OCT and UBM. Peripheral iris thickness (PIT) and iris curvature (IC) in the anterior segment image obtained by AS-OCT and UBM were measured twice. The reproducibility of these two scans was evaluated by the intraclass correlation coefficient (ICC). A paired t-test was used to compare the difference between the two scans and the 95% limits of agreement (LoA) were calculated. Results:The ICCs of PIT and IC measured by UBM were 0.892 and 0.936 respectively, while for AS-OCT these values were 0.629 and 0.859, respectively. UBM had a higher reproducibility in both PIT and IC measurements as compared with AS-OCT.Differences in PIT measurement between AS-OCT and UBM(P=0.331).were not statistically significant, the 95% LoA (-0.178~0.156) mm was 36.1~41.2% of the mean. The IC was 0.053 mm smaller when measured by UBM than by AS-OCT (P=0.017), with the 95% LoA (-0.100~0.206) mm, or 36.2~74.6% of the mean.Conclusion:UBM had a higher reproducibility in measuring iris parameters than AS-OCT. The consistency between AS- OCT and UBM in measuring iris parameters was low in primary angle closure glaucoma patients. (Eye Science 2013; 28:1-6)展开更多
Fe62Cos-xCrxZr6Nb4B20 (x=0-4 at. pct) metallic glasses show high thermal stability with a maximum supercooled liquid region of about 84.8 K. The addition of 2 at. pct Cr causes the extension of the supercooled liqui...Fe62Cos-xCrxZr6Nb4B20 (x=0-4 at. pct) metallic glasses show high thermal stability with a maximum supercooled liquid region of about 84.8 K. The addition of 2 at. pct Cr causes the extension of the supercooled liquid region remarkably, leading to the enhancement of thermal stability and glass-forming ability. The crystallization of the Fe-based glassy alloys takes place through a single exothermic reaction, accompanying the precipitation of more than three kinds of crystallized phases such as α-Fe, Fe2Zr and ZrB2. The long-range atomic rearrangements required for the precipitation of the multiple crystalline phases seem to play an important role in the appearance of the large supercooled liquid region through the retardation of the crystallization reactions. The Fe-based alloys exhibit soft ferromagnetic properties. The saturation magnetization decreases with increasing Cr content while the saturated magnetostriction increases as a function of Cr content. There is no distinct change in the saturation magnetization and coercive force with annealing temperature below the crystallization temperature. The devitrification gives rise to a considerable enhancement in both as and He.展开更多
The recrystallization texture evolution in heavily cold-rolled (93%) FeCo-2V alloy with annealing temperature and time was investigated by X-ray diffraction and electron backscatter diffraction. It was found that th...The recrystallization texture evolution in heavily cold-rolled (93%) FeCo-2V alloy with annealing temperature and time was investigated by X-ray diffraction and electron backscatter diffraction. It was found that the orientation density of α-fiber texture component fluctuates with increasing annealing temperature and time. The transmission electron microscopy images show that abundant precipitates appear inside the recrystallized grains and around the grain boundaries. The amount and size of the precipitates also vary with annealing temperature and time. The enhancement of the α-fiber coincides well with the increase of number density of fine precipitates, indicating that the fine precipitates facilitate the development of α-fiber. The annealing texture evolution observed in the FeCo alloy could be attributed to the facilitating effect of the precipitates on the development of α-fiber and the ordering process.展开更多
A novel silicon carbide(SiC) on silicon(Si) heterojunction lateral double-diffused metal-oxide semiconductor fieldeffect transistor with p-type buried layer(PBL Si/SiC LDMOS) is proposed in this paper for the first ti...A novel silicon carbide(SiC) on silicon(Si) heterojunction lateral double-diffused metal-oxide semiconductor fieldeffect transistor with p-type buried layer(PBL Si/SiC LDMOS) is proposed in this paper for the first time.The heterojunction has breakdown point transfer(BPT) characteristics,and the BPT terminal technology is used to increase the breakdown voltage(BV) of Si/SiC LDMOS with the deep drain region.In order to further optimize the surface lateral electric field distribution of Si/SiC LDMOS with the deep drain region,the p-type buried layer is introduced in PBL Si/SiC LDMOS.The vertical electric field is optimized by Si/SiC heterojunction and the surface lateral electric field is optimized by the p-type buried layer,which greatly improves the BV of device and alleviates the relationship between BV and specific on-resistance(R_(on,sp)).Through TCAD simulation,when the drift region length is 20 μm,the BV is significantly improved from 249 V for the conventional Si LDMOS to 440 V for PBL Si/SiC LDMOS,increased by 77%;And the BV is improved from 384 V for Si/SiC LDMOS with the deep drain region to 440 V for the proposed structure,increased by 15%.The figure-of-merit(FOM) of the Si/SiC LDMOS with the deep drain region and PBL Si/SiC LDMOS are 4.26 MW/cm^(2) and 6.37 MW/cm^(2),respectively.For the PBL Si/SiC LDMOS with the drift length of 20 μm,the maximum FOM is 6.86 MW/cm^(2).The PBL Si/SiC LDMOS breaks conventional silicon limit.展开更多
Background:The usage of the light emitting diode(LED)has been increasingly applied in the illumination setting and electronic equipment.However,the effect of LED lights on the retina remains unclear.In this study,we o...Background:The usage of the light emitting diode(LED)has been increasingly applied in the illumination setting and electronic equipment.However,the effect of LED lights on the retina remains unclear.In this study,we observed and analyzed the impact of white LED lights at different intensities on the function and morphology of rat retinas.Methods:Thirty-six Sprague-Dawley rats weighing 150-180 g were randomly divided into six groups(n=6 in each group)including a normal control(NC)group,4 white LED groups at different light intensities(4,000,6,000,7,000,and 10,000 lux),and an ultraviolet B(UVB)lighting group(302 nm,1,000μw/cm2).After 24 hours of continuous illumination,full-field flash electroretinogram(FERG)and pathological examination were performed in each group.Results:As revealed by FERG,the impairment of retinal function gradually worsened with the increase of LED light intensity.In contrast,the UVB group had the most severe retinal function impairment.Particularly,the functional damage of rod cells and inner nuclear layer cells was the main FERG finding in each group.In the NC group,the retina had typical morphologies featured by well-defined structures,clearly visible border between the inner and outer segments,and neatly arranged inner and outer nuclear layer cells.After 24 hours of illumination,the inner and outer parts of the retina in the 4,000 lux group were still neatly arranged,along with a clear border;however,the inner and outer nuclear layers were randomly arranged,and some irregular nuclei and cells were lost.The damage of the internal and external retinal segments and the internal and external nuclear layers became more evident in the 6,000 lux group,7,000 lux group,and 10,000 lux group.The UVB group had a more obviously disordered arrangement of inner and outer nuclear layers and loss of cells.Conclusions:Continuous exposure to white LED light can cause structural and functional damage to rat retinas,and such damage is related to the intensity of illumination.Therefore,the risk of retinal damage should be considered during LED illumination,and proper LED illumination intensity may help to maintain eye health.展开更多
Background:To investigate the effect of sirolimus(SRL)eye drops on acute alkali-burn-induced corneal neovascularization(CNV)and explore its possible mechanism.Methods:A total of 57 male Sprague-Dawley rats weighing 16...Background:To investigate the effect of sirolimus(SRL)eye drops on acute alkali-burn-induced corneal neovascularization(CNV)and explore its possible mechanism.Methods:A total of 57 male Sprague-Dawley rats weighing 160-180 g were randomly divided into four groups including a normal control group(NC group,n=12),an untreated alkali-burned model control group(MC group,n=15),a blank eye drop treatment group(BT group,n=15),and an SRL eye drop treatment group(ST group,n=15).Corneal inflammation and CNV were observed and scored under a slit-lamp microscope 3,7,and 14 days after alkali exposure.Three rats were randomly sacrificed in each group before modeling and 3,7,14 days after modeling,and the corneas of right eyes were harvested for Western blotting to compare the expression levels of VEGFR2 and caspase-3.Results:Corneal inflammation scoring showed that the corneal edema and conjunctival congestion were severe in the MC,BT,and ST groups 1 day after alkali exposure but were alleviated at day 3.The corneal transparency was significantly higher in the ST group than in the MC and BT groups at days 7(F=9.77,P<0.05)and 14(F=5.81,P<0.05).At day 1,the corneal limbal vascular network was markedly filled.SNV was obvious at days 3,7,and 14.The new blood vessels were shorter and sparser in the ST group than in the MC and BT groups,and the CNV scores showed significant differences among these groups(day 3:F=8.60,P<0.05;day 7:F=11.40,P<0.05;and day 14:F=41.59,P<0.01).Western blotting showed that the expressions of VEGFR2 and caspase-3 were low before modeling and showed no significant difference among the different groups(F=0.52,P>0.05;F=0.98,P>0.05).The corneal expression of VEGFR2 became significantly higher in the MC and BT groups than in the ST group 3,7,and 14 days after alkali exposure,and there were significant differences in relative gray-scale values among these groups(day 3:F=32.16,P<0.01;day 7:F=85.96,P<0.01;day 14:F=57.68,P<0.01).The increase in the corneal expression of caspase-3 was significantly larger in the ST group than in the MC and BT groups at days 3,7,and 14,and there were significant differences in relative gray-scale values among groups(day 3:F=32.16,P<0.01;day 7:F=53.02,P<0.01;day 14:F=38.67,P<0.01).Conclusions:SRL eye drops can alleviate acute alkali-burn-induced corneal inflammation and inhibit alkali-burn-induced CNV in rat models.It can reduce VEGFR2 expression and increase caspase-3 expression in the corneal tissue,which may contribute to the inhibition of alkali-burn-induced CNV.展开更多
We develop a new ultrastrong medium Mn steel with a density reduced to 7.39 g cm^(-3).It has a novel tri-phase microstructure comprising a hierarchical martensitic matrix(α’),dispersed ultra-fine-retained austenite ...We develop a new ultrastrong medium Mn steel with a density reduced to 7.39 g cm^(-3).It has a novel tri-phase microstructure comprising a hierarchical martensitic matrix(α’),dispersed ultra-fine-retained austenite grains(γ),and both compressed and{200}orientedδ-ferrite lamellas,the latter’s formation is due to the alloying of high Al and Si contents for reducing density.As a result,both ultrahigh ultimate tensile strength of 2.1 GPa and good ductility of 16%are achieved after an extraordinary plastic strain hardening increment of about 1.4 GPa.The in-situ synchrotron-based high-energy(HE)X-ray diffraction(XRD)examinations during the tensile deformation revealed that the initial presence of residual com-pressive stress inδ-ferrite could increase the stress required to initiate the plastic tensile deformation of the specimen,leading to the isolatedδ-ferrite lamellas mostly deformed elastically to coordinate the plastic deformation of the martensitic matrix during yielding.During the plastic deformation,the gradual release of residual compressive stress inδandα’,the dislocation multiplication in all the three phases and the successiveγ-to-α’transformation all contribute to such a prominent work hardening increment.This study facilitates the development of novel strategies for fabricating ultrastrong but light steels.展开更多
A series of new nanobiotechnology-based methods have been developed toward achieving safe and efficient cancer treatment.Gold nanorods(AuNRs)have attracted increasing attention owing to their unique optical char-acter...A series of new nanobiotechnology-based methods have been developed toward achieving safe and efficient cancer treatment.Gold nanorods(AuNRs)have attracted increasing attention owing to their unique optical char-acteristics,good biocompatibility,and low toxicity,and they have thus been widely used in tumor treatment.In this study,an AuNR-based system was designed by attaching microRNA-192(miR-192)to polydopamine-coated AuNRs(AuNR@PDA)to explore the possibility of combining genetic and photothermal therapies.RNA/AuNR@PDA exhibited an excellent thermal conversion efficiency under near-infrared(NIR)laser irradi-ation and excellent biocompatibility.Thus,photothermal therapy(PTT)was combined with gene therapy,which was effected by miR-192,a genetic drug that inhibits cancer cell growth.The combinatory treatment approach entailing the AuNRs-based drug carrier system exhibited encouraging antitumor efficacy.展开更多
Corrugated silicon nanocone(SiNC)arrays have been fabricated on a silicon wafer by two polystyrene-sphere-monolayer-masked etching steps in order to create high-performance antireflective coatings.The reflectance was ...Corrugated silicon nanocone(SiNC)arrays have been fabricated on a silicon wafer by two polystyrene-sphere-monolayer-masked etching steps in order to create high-performance antireflective coatings.The reflectance was reduced from above 35%to less than 0.7%in the range 400-1050 nm,and it remained below 0.5%at incidence angles up to 70°at 632.8 nm for both s-and p-polarized light.The fluorinated corrugated SiNC array surface exhibits superhydrophobic properties with a water contact angle of 164°.展开更多
Rapid estimates of impact areas following large earthquakes constitute the cornerstone of emergency response scenarios.However,collecting information through traditional practices usually requires a large amount of ma...Rapid estimates of impact areas following large earthquakes constitute the cornerstone of emergency response scenarios.However,collecting information through traditional practices usually requires a large amount of manpower and material resources,slowing the response time.Social media has emerged as a source of real-time‘citizen-sensor data’for disasters and can thus contribute to the rapid acquisition of disaster information.This paper proposes an approach to quickly estimate the impact area following a large earthquake via social media.Specifically,a spatial logistic growth model(SLGM)is proposed to describe the spatial growth of citizen-sensor data influenced by the earthquake impact strength after an earthquake;a framework is then developed to estimate the earthquake impact area by combining social media data and other auxiliary data based on the SLGM.The reliability of our approach is demonstrated in two earthquake cases by comparing the detected areas with official intensity maps,and the time sensitivity of the social media data in the SLGM is discussed.The results illustrate that our approach can effectively estimate the earthquake impact area.We verify the external validity of our model across other earthquake events and provide further insights into extracting more valuable earthquake information using social media.展开更多
The phase evolution and thermal expansion behavior in superalloy during heating play an essential role in controlling the size and distribution of precipitates,as well as optimizing thermomechanical properties.Synchro...The phase evolution and thermal expansion behavior in superalloy during heating play an essential role in controlling the size and distribution of precipitates,as well as optimizing thermomechanical properties.Synchrotron X-ray diffraction is able to go through the interior of sample and can be carried out with in situ environment,and thus,it can obtain more statistics information in real time comparing with traditional methods,such as electron and optical microscopies.In this study,in situ heating synchrotron X-ray diffraction was carried out to study the phase evolution in a typicalγ′phase precipitation strengthened Ni-based superalloy,Waspaloy,from 29 to 1050°C.Theγ′,γ,M_(23)C_(6)and M C phases,including their lattice parameters,misfits,dissolution behavior and thermal expansion coefficients,were mainly investigated.Theγ′phase and M_(23)C_(6)carbides appeared obvious dissolution during heating and re-precipitated when the temperature dropped to room temperature.Combining with the microscopy results,we can indicate that the dissolution of M_(23)C_(6)leads to the growth of grain andγ′phase cannot be completely dissolved for the short holding time above the solution temperature.Besides,the coefficients of thermal expansions of all the phases are calculated and fitted as polynomials.展开更多
Water dissociation process is generally regarded as the rate-limiting step for alkaline hydrogen evolution reaction(HER),and severely inhibits the catalytic efficiency of Pt based catalysts.To overcome this problem,th...Water dissociation process is generally regarded as the rate-limiting step for alkaline hydrogen evolution reaction(HER),and severely inhibits the catalytic efficiency of Pt based catalysts.To overcome this problem,the in-situ constructed interfaces of PtCo alloy and amorphous cobalt oxide(CoO_(x))on the carbon powder are designed.The amorphous CoO_(x)at Pt-Co/CoO_(x)interfaces not only provide active sites for water dissociation to facilitate Volmer step,but also produce the strong electronic transfer with Pt-Co.Accordingly,the obtained interfacial catalysts exhibit outstanding alkaline HER performance with a Tafel slope of 29.3 mV·dec^(−1)and an ultralow overpotential of only 28 mV at 10 mA·cm^(−2).Density functional theory(DFT)reveals that the electronic accumulation on the interfacial Co atom in Pt-Co/CoO_(x)constructing the novel active site for water dissociation.Compared to the Pt-Co,all of the energy barriers for water adsorption,water dissociation and hydrogen adsorption/desorption are reduced in Pt-Co/CoO_(x)interfaces,suggesting a boosted HER kinetics for alkaline HER.展开更多
The fabrication of surface enhanced Raman spectroscopy(SERS)substrates with controlled high density hot spots still remains challenging.Herein,we report highly effective SERS substrates containing the self-generating(...The fabrication of surface enhanced Raman spectroscopy(SERS)substrates with controlled high density hot spots still remains challenging.Herein,we report highly effective SERS substrates containing the self-generating(SG)nanogaps from polystyrene nanosphere monolayer through isotropic plasma etching.The emergence of multimode hot spots,i.e.,metal film over nanosphere(MFON)-like hot spots(closed gaps,0 nm),individual self-aligned hot spots(discrete gaps,>20 nm)and threedimensional(3D)hot spots(nanogaps,1-10 nm),makes the SG SERS substrates superior as compared to the traditional MFON or the well-ordered self-aligned SERS substrates in terms of enhancement,uniformity,and reproducibility.The SG SERS substrates can function as the excellent SERS platforms for trace molecule detection in the practical application fields.展开更多
A simulation method for investigating the vibration behavior of hoisting rope with time-varying length is improved.By previously creating markers in the MSC.ADAMS software package,the parametric model of the rope woun...A simulation method for investigating the vibration behavior of hoisting rope with time-varying length is improved.By previously creating markers in the MSC.ADAMS software package,the parametric model of the rope wound along helix is established based on the concentrated-mass theory with multi-degree of freedom(multi-DOF).A novel driving strategy,cooperating fixed joints with angle sensors under the control of driving script,is proposed to substitute conventional contact force.Researching on the hoisting rope in the sinking winch mechanism,an equivalent discretization model is obtained with complicated boundary conditions considered.The differential equations of motion of the hoisting system are formulated employing Lagrange’s equation and numerically solved using Runge–Kutta method.The simulation indicates that the horizontal swing is decreased in principle and the simulation with 800 discrete ropes is not performed more than 61 min.Therefore,this feasible strategy could not only guarantee the accuracy but also promote simulation efficiency and stability.The motion curves exported from ADAMS simulation coincide with one in numerical simulation,which validates both the numerical model and the driving strategy.展开更多
The addition of a small amount of oxygen improves the mechanical properties,especially plasticity,of Ti_(45.7)Zr_(33)Ni_(3)Cu_(5.8)Be_(12.5) amorphous alloy composites(AACs)at room temperature(298 K).Compared to the p...The addition of a small amount of oxygen improves the mechanical properties,especially plasticity,of Ti_(45.7)Zr_(33)Ni_(3)Cu_(5.8)Be_(12.5) amorphous alloy composites(AACs)at room temperature(298 K).Compared to the plasticity of AACs without added O(5%),the plasticity of the composites with 0.73 at.%O(nominal composition)was much higher(11%).Even at O content higher than 0.73 at.%,the AACs exhibited good plasticity.The highest plasticity of∼12.3%was observed with 2.87 at.%O.Two distinct mechanisms are proposed to explain the enhanced plasticity of the AACs.At low O content,although deformation-induced phase transformation was suppressed,a substantial amount of α" martensite was formed.The microstructural features of α" martensite,such as thinner laths and homogeneous distribution,induced the formation of multiple shear bands in the amorphous matrix.At high O content,deformation-induced phase transformation was seriously suppressed.A dispersed nanoωphase was formed during rapid solidification in AACs with O content higher than 1.45 at.%.This resulted in a weakening in the anisotropy ofβdendrites and led to their homogenous deformation.Furthermore,multiple shear bands were formed in the amorphous matrix.Apart from plasticity,the strength of the AACs also increased with an increase in the O content.This phenomenon was explained in terms of three mechanisms,viz.the solid-solution-strengthening effect of O,fine-grain strengthening of β dendrites,and secondary phase strengthening by the nano ω phase.展开更多
Residual stress is an important factor for evaluating the deformation and failure of engineering materials. Diffraction-based measurement assumes that the full measured lattice strain tensor contributes to residual st...Residual stress is an important factor for evaluating the deformation and failure of engineering materials. Diffraction-based measurement assumes that the full measured lattice strain tensor contributes to residual stress according to Hookers Law. The present work focuses on the lattice strain determination of individual grains in a dual-phase stainless steel (DPSS) by means of differential-aperture X-ray micro-diffraction (DAXM). The results show that the residual stress only takes part of the responsibility of the total measured lattice strain. In fact, the compositional variation inside the material was found to cause greater strain gradient in both ferrite (c~) and austenite (~) phases in DPSS. Therefore, quantification of compositional and residual stress effects on lattice strain was conducted in order to evaluate the true residual stress inside engineering materials.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52171098 and 51921001)the State Key Laboratory for Advanced Metals and Materials(No.2022Z-02)+1 种基金the National High-level Personnel of Special Support Program(No.ZYZZ2021001)the Fundamental Research Funds for the Central Universities(Nos.FRF-TP-20-03C2 and FRF-BD-20-02B).
文摘High-entropy alloys(HEAs)possess outstanding features such as corrosion resistance,irradiation resistance,and good mechan-ical properties.A few HEAs have found applications in the fields of aerospace and defense.Extensive studies on the deformation mech-anisms of HEAs can guide microstructure control and toughness design,which is vital for understanding and studying state-of-the-art structural materials.Synchrotron X-ray and neutron diffraction are necessary techniques for materials science research,especially for in situ coupling of physical/chemical fields and for resolving macro/microcrystallographic information on materials.Recently,several re-searchers have applied synchrotron X-ray and neutron diffraction methods to study the deformation mechanisms,phase transformations,stress behaviors,and in situ processes of HEAs,such as variable-temperature,high-pressure,and hydrogenation processes.In this review,the principles and development of synchrotron X-ray and neutron diffraction are presented,and their applications in the deformation mechanisms of HEAs are discussed.The factors that influence the deformation mechanisms of HEAs are also outlined.This review fo-cuses on the microstructures and micromechanical behaviors during tension/compression or creep/fatigue deformation and the application of synchrotron X-ray and neutron diffraction methods to the characterization of dislocations,stacking faults,twins,phases,and intergrain/interphase stress changes.Perspectives on future developments of synchrotron X-ray and neutron diffraction and on research directions on the deformation mechanisms of novel metals are discussed.
基金Science and Technology Plan Program of Guangdong Province (2012A0802040022012B0318002942011B080701033)
文摘Purpose: To compare the repeatability and consistency of anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM) in measuring iris parameters in patients with primary angle closure glaucoma. Methods: Twenty-two patients (38 eyes) with primary angle closure glaucoma,including 5 eyes with acute angle closure glaucoma,10 fellow eyes of acute angle closure glaucoma, and 23 eyes with chronic angle closure glaucoma, were recruited consecutively in our hospital. All subjects underwent anterior scanning by AS-OCT and UBM. Peripheral iris thickness (PIT) and iris curvature (IC) in the anterior segment image obtained by AS-OCT and UBM were measured twice. The reproducibility of these two scans was evaluated by the intraclass correlation coefficient (ICC). A paired t-test was used to compare the difference between the two scans and the 95% limits of agreement (LoA) were calculated. Results:The ICCs of PIT and IC measured by UBM were 0.892 and 0.936 respectively, while for AS-OCT these values were 0.629 and 0.859, respectively. UBM had a higher reproducibility in both PIT and IC measurements as compared with AS-OCT.Differences in PIT measurement between AS-OCT and UBM(P=0.331).were not statistically significant, the 95% LoA (-0.178~0.156) mm was 36.1~41.2% of the mean. The IC was 0.053 mm smaller when measured by UBM than by AS-OCT (P=0.017), with the 95% LoA (-0.100~0.206) mm, or 36.2~74.6% of the mean.Conclusion:UBM had a higher reproducibility in measuring iris parameters than AS-OCT. The consistency between AS- OCT and UBM in measuring iris parameters was low in primary angle closure glaucoma patients. (Eye Science 2013; 28:1-6)
基金the National Natural Science Foundation of China under Grant No. 50471075.
文摘Fe62Cos-xCrxZr6Nb4B20 (x=0-4 at. pct) metallic glasses show high thermal stability with a maximum supercooled liquid region of about 84.8 K. The addition of 2 at. pct Cr causes the extension of the supercooled liquid region remarkably, leading to the enhancement of thermal stability and glass-forming ability. The crystallization of the Fe-based glassy alloys takes place through a single exothermic reaction, accompanying the precipitation of more than three kinds of crystallized phases such as α-Fe, Fe2Zr and ZrB2. The long-range atomic rearrangements required for the precipitation of the multiple crystalline phases seem to play an important role in the appearance of the large supercooled liquid region through the retardation of the crystallization reactions. The Fe-based alloys exhibit soft ferromagnetic properties. The saturation magnetization decreases with increasing Cr content while the saturated magnetostriction increases as a function of Cr content. There is no distinct change in the saturation magnetization and coercive force with annealing temperature below the crystallization temperature. The devitrification gives rise to a considerable enhancement in both as and He.
基金support by the Na-tional Natural Science Foundation of China (Grant Nos.50471026 and 50725102) the Swedish Research Coun-cil in the frame of the SIDA project (Grant No. 348-2004-3475).
文摘The recrystallization texture evolution in heavily cold-rolled (93%) FeCo-2V alloy with annealing temperature and time was investigated by X-ray diffraction and electron backscatter diffraction. It was found that the orientation density of α-fiber texture component fluctuates with increasing annealing temperature and time. The transmission electron microscopy images show that abundant precipitates appear inside the recrystallized grains and around the grain boundaries. The amount and size of the precipitates also vary with annealing temperature and time. The enhancement of the α-fiber coincides well with the increase of number density of fine precipitates, indicating that the fine precipitates facilitate the development of α-fiber. The annealing texture evolution observed in the FeCo alloy could be attributed to the facilitating effect of the precipitates on the development of α-fiber and the ordering process.
基金Project supported in part by the Science Foundation for Distinguished Young Scholars of Shaanxi Province,China(Grant No.2018JC-017)the 111 Project(Grant No.B12026)。
文摘A novel silicon carbide(SiC) on silicon(Si) heterojunction lateral double-diffused metal-oxide semiconductor fieldeffect transistor with p-type buried layer(PBL Si/SiC LDMOS) is proposed in this paper for the first time.The heterojunction has breakdown point transfer(BPT) characteristics,and the BPT terminal technology is used to increase the breakdown voltage(BV) of Si/SiC LDMOS with the deep drain region.In order to further optimize the surface lateral electric field distribution of Si/SiC LDMOS with the deep drain region,the p-type buried layer is introduced in PBL Si/SiC LDMOS.The vertical electric field is optimized by Si/SiC heterojunction and the surface lateral electric field is optimized by the p-type buried layer,which greatly improves the BV of device and alleviates the relationship between BV and specific on-resistance(R_(on,sp)).Through TCAD simulation,when the drift region length is 20 μm,the BV is significantly improved from 249 V for the conventional Si LDMOS to 440 V for PBL Si/SiC LDMOS,increased by 77%;And the BV is improved from 384 V for Si/SiC LDMOS with the deep drain region to 440 V for the proposed structure,increased by 15%.The figure-of-merit(FOM) of the Si/SiC LDMOS with the deep drain region and PBL Si/SiC LDMOS are 4.26 MW/cm^(2) and 6.37 MW/cm^(2),respectively.For the PBL Si/SiC LDMOS with the drift length of 20 μm,the maximum FOM is 6.86 MW/cm^(2).The PBL Si/SiC LDMOS breaks conventional silicon limit.
基金Supported by the Guangdong Natural Science Foundation(2016A030313294).
文摘Background:The usage of the light emitting diode(LED)has been increasingly applied in the illumination setting and electronic equipment.However,the effect of LED lights on the retina remains unclear.In this study,we observed and analyzed the impact of white LED lights at different intensities on the function and morphology of rat retinas.Methods:Thirty-six Sprague-Dawley rats weighing 150-180 g were randomly divided into six groups(n=6 in each group)including a normal control(NC)group,4 white LED groups at different light intensities(4,000,6,000,7,000,and 10,000 lux),and an ultraviolet B(UVB)lighting group(302 nm,1,000μw/cm2).After 24 hours of continuous illumination,full-field flash electroretinogram(FERG)and pathological examination were performed in each group.Results:As revealed by FERG,the impairment of retinal function gradually worsened with the increase of LED light intensity.In contrast,the UVB group had the most severe retinal function impairment.Particularly,the functional damage of rod cells and inner nuclear layer cells was the main FERG finding in each group.In the NC group,the retina had typical morphologies featured by well-defined structures,clearly visible border between the inner and outer segments,and neatly arranged inner and outer nuclear layer cells.After 24 hours of illumination,the inner and outer parts of the retina in the 4,000 lux group were still neatly arranged,along with a clear border;however,the inner and outer nuclear layers were randomly arranged,and some irregular nuclei and cells were lost.The damage of the internal and external retinal segments and the internal and external nuclear layers became more evident in the 6,000 lux group,7,000 lux group,and 10,000 lux group.The UVB group had a more obviously disordered arrangement of inner and outer nuclear layers and loss of cells.Conclusions:Continuous exposure to white LED light can cause structural and functional damage to rat retinas,and such damage is related to the intensity of illumination.Therefore,the risk of retinal damage should be considered during LED illumination,and proper LED illumination intensity may help to maintain eye health.
基金Supported by the Guangdong Natural Science Foundation(2016A030313294).
文摘Background:To investigate the effect of sirolimus(SRL)eye drops on acute alkali-burn-induced corneal neovascularization(CNV)and explore its possible mechanism.Methods:A total of 57 male Sprague-Dawley rats weighing 160-180 g were randomly divided into four groups including a normal control group(NC group,n=12),an untreated alkali-burned model control group(MC group,n=15),a blank eye drop treatment group(BT group,n=15),and an SRL eye drop treatment group(ST group,n=15).Corneal inflammation and CNV were observed and scored under a slit-lamp microscope 3,7,and 14 days after alkali exposure.Three rats were randomly sacrificed in each group before modeling and 3,7,14 days after modeling,and the corneas of right eyes were harvested for Western blotting to compare the expression levels of VEGFR2 and caspase-3.Results:Corneal inflammation scoring showed that the corneal edema and conjunctival congestion were severe in the MC,BT,and ST groups 1 day after alkali exposure but were alleviated at day 3.The corneal transparency was significantly higher in the ST group than in the MC and BT groups at days 7(F=9.77,P<0.05)and 14(F=5.81,P<0.05).At day 1,the corneal limbal vascular network was markedly filled.SNV was obvious at days 3,7,and 14.The new blood vessels were shorter and sparser in the ST group than in the MC and BT groups,and the CNV scores showed significant differences among these groups(day 3:F=8.60,P<0.05;day 7:F=11.40,P<0.05;and day 14:F=41.59,P<0.01).Western blotting showed that the expressions of VEGFR2 and caspase-3 were low before modeling and showed no significant difference among the different groups(F=0.52,P>0.05;F=0.98,P>0.05).The corneal expression of VEGFR2 became significantly higher in the MC and BT groups than in the ST group 3,7,and 14 days after alkali exposure,and there were significant differences in relative gray-scale values among these groups(day 3:F=32.16,P<0.01;day 7:F=85.96,P<0.01;day 14:F=57.68,P<0.01).The increase in the corneal expression of caspase-3 was significantly larger in the ST group than in the MC and BT groups at days 3,7,and 14,and there were significant differences in relative gray-scale values among groups(day 3:F=32.16,P<0.01;day 7:F=53.02,P<0.01;day 14:F=38.67,P<0.01).Conclusions:SRL eye drops can alleviate acute alkali-burn-induced corneal inflammation and inhibit alkali-burn-induced CNV in rat models.It can reduce VEGFR2 expression and increase caspase-3 expression in the corneal tissue,which may contribute to the inhibition of alkali-burn-induced CNV.
基金Haiwen Luo and Bin Hu acknowledge financial support from the National Natural Science Foundation of China(Nos.51831002,51904028 and 52233018)Fundamental Research Funds for the Central Universities(No.06500151)The present work is re-lated to awarded patents(No.201910244716.9 in China and No.US 10793932 in the USA).
文摘We develop a new ultrastrong medium Mn steel with a density reduced to 7.39 g cm^(-3).It has a novel tri-phase microstructure comprising a hierarchical martensitic matrix(α’),dispersed ultra-fine-retained austenite grains(γ),and both compressed and{200}orientedδ-ferrite lamellas,the latter’s formation is due to the alloying of high Al and Si contents for reducing density.As a result,both ultrahigh ultimate tensile strength of 2.1 GPa and good ductility of 16%are achieved after an extraordinary plastic strain hardening increment of about 1.4 GPa.The in-situ synchrotron-based high-energy(HE)X-ray diffraction(XRD)examinations during the tensile deformation revealed that the initial presence of residual com-pressive stress inδ-ferrite could increase the stress required to initiate the plastic tensile deformation of the specimen,leading to the isolatedδ-ferrite lamellas mostly deformed elastically to coordinate the plastic deformation of the martensitic matrix during yielding.During the plastic deformation,the gradual release of residual compressive stress inδandα’,the dislocation multiplication in all the three phases and the successiveγ-to-α’transformation all contribute to such a prominent work hardening increment.This study facilitates the development of novel strategies for fabricating ultrastrong but light steels.
基金the National Natural Science Foundation of China(Grant Nos.52101287 and U1806219)the Shenzhen Fundamental Research Program(JCYJ20190807092803583)the Natural Science Foundation of Jiangsu Province(Grant No.BK20190205).
文摘A series of new nanobiotechnology-based methods have been developed toward achieving safe and efficient cancer treatment.Gold nanorods(AuNRs)have attracted increasing attention owing to their unique optical char-acteristics,good biocompatibility,and low toxicity,and they have thus been widely used in tumor treatment.In this study,an AuNR-based system was designed by attaching microRNA-192(miR-192)to polydopamine-coated AuNRs(AuNR@PDA)to explore the possibility of combining genetic and photothermal therapies.RNA/AuNR@PDA exhibited an excellent thermal conversion efficiency under near-infrared(NIR)laser irradi-ation and excellent biocompatibility.Thus,photothermal therapy(PTT)was combined with gene therapy,which was effected by miR-192,a genetic drug that inhibits cancer cell growth.The combinatory treatment approach entailing the AuNRs-based drug carrier system exhibited encouraging antitumor efficacy.
基金This work was supported by the National Natural Science Foundation of China(No.20373019)the Program for New Century Excellent Talents in University,and the National Basic Research Program(Nos.2007CB808003 and 2009CB939701).
文摘Corrugated silicon nanocone(SiNC)arrays have been fabricated on a silicon wafer by two polystyrene-sphere-monolayer-masked etching steps in order to create high-performance antireflective coatings.The reflectance was reduced from above 35%to less than 0.7%in the range 400-1050 nm,and it remained below 0.5%at incidence angles up to 70°at 632.8 nm for both s-and p-polarized light.The fluorinated corrugated SiNC array surface exhibits superhydrophobic properties with a water contact angle of 164°.
基金supported by National Natural Science Foundation of China[grant number 41271399].
文摘Rapid estimates of impact areas following large earthquakes constitute the cornerstone of emergency response scenarios.However,collecting information through traditional practices usually requires a large amount of manpower and material resources,slowing the response time.Social media has emerged as a source of real-time‘citizen-sensor data’for disasters and can thus contribute to the rapid acquisition of disaster information.This paper proposes an approach to quickly estimate the impact area following a large earthquake via social media.Specifically,a spatial logistic growth model(SLGM)is proposed to describe the spatial growth of citizen-sensor data influenced by the earthquake impact strength after an earthquake;a framework is then developed to estimate the earthquake impact area by combining social media data and other auxiliary data based on the SLGM.The reliability of our approach is demonstrated in two earthquake cases by comparing the detected areas with official intensity maps,and the time sensitivity of the social media data in the SLGM is discussed.The results illustrate that our approach can effectively estimate the earthquake impact area.We verify the external validity of our model across other earthquake events and provide further insights into extracting more valuable earthquake information using social media.
基金supported by the Ministry of Science and Technology, China (2017YFA0204402)NSFC Basic Science Center Program for “Multiscale Problems in Nonlinear Mechanics” (11988102)+1 种基金the National Natural Science Foundation of China (11972350 and 11890680)the Chinese Academy of Sciences (XDB22040503)
基金supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.11805009 and 51921001)the Fundamental Research Funds for the Central Universities(Grant No.06111020)。
文摘The phase evolution and thermal expansion behavior in superalloy during heating play an essential role in controlling the size and distribution of precipitates,as well as optimizing thermomechanical properties.Synchrotron X-ray diffraction is able to go through the interior of sample and can be carried out with in situ environment,and thus,it can obtain more statistics information in real time comparing with traditional methods,such as electron and optical microscopies.In this study,in situ heating synchrotron X-ray diffraction was carried out to study the phase evolution in a typicalγ′phase precipitation strengthened Ni-based superalloy,Waspaloy,from 29 to 1050°C.Theγ′,γ,M_(23)C_(6)and M C phases,including their lattice parameters,misfits,dissolution behavior and thermal expansion coefficients,were mainly investigated.Theγ′phase and M_(23)C_(6)carbides appeared obvious dissolution during heating and re-precipitated when the temperature dropped to room temperature.Combining with the microscopy results,we can indicate that the dissolution of M_(23)C_(6)leads to the growth of grain andγ′phase cannot be completely dissolved for the short holding time above the solution temperature.Besides,the coefficients of thermal expansions of all the phases are calculated and fitted as polynomials.
基金supported by the National Natural Science Foundation of China(No.21875039)the Project on the Integration of Industry-Education-Research of Fujian Province(No.2021H6020)Fujian province’s high level innovative and entrepreneurial talents(No.50012709).
文摘Water dissociation process is generally regarded as the rate-limiting step for alkaline hydrogen evolution reaction(HER),and severely inhibits the catalytic efficiency of Pt based catalysts.To overcome this problem,the in-situ constructed interfaces of PtCo alloy and amorphous cobalt oxide(CoO_(x))on the carbon powder are designed.The amorphous CoO_(x)at Pt-Co/CoO_(x)interfaces not only provide active sites for water dissociation to facilitate Volmer step,but also produce the strong electronic transfer with Pt-Co.Accordingly,the obtained interfacial catalysts exhibit outstanding alkaline HER performance with a Tafel slope of 29.3 mV·dec^(−1)and an ultralow overpotential of only 28 mV at 10 mA·cm^(−2).Density functional theory(DFT)reveals that the electronic accumulation on the interfacial Co atom in Pt-Co/CoO_(x)constructing the novel active site for water dissociation.Compared to the Pt-Co,all of the energy barriers for water adsorption,water dissociation and hydrogen adsorption/desorption are reduced in Pt-Co/CoO_(x)interfaces,suggesting a boosted HER kinetics for alkaline HER.
基金This work was supported by the National Natural Science Foundation of China(Nos.51821002 and 21790053)the China Postdoctoral Science Foundation(No.2016M591908).
文摘The fabrication of surface enhanced Raman spectroscopy(SERS)substrates with controlled high density hot spots still remains challenging.Herein,we report highly effective SERS substrates containing the self-generating(SG)nanogaps from polystyrene nanosphere monolayer through isotropic plasma etching.The emergence of multimode hot spots,i.e.,metal film over nanosphere(MFON)-like hot spots(closed gaps,0 nm),individual self-aligned hot spots(discrete gaps,>20 nm)and threedimensional(3D)hot spots(nanogaps,1-10 nm),makes the SG SERS substrates superior as compared to the traditional MFON or the well-ordered self-aligned SERS substrates in terms of enhancement,uniformity,and reproducibility.The SG SERS substrates can function as the excellent SERS platforms for trace molecule detection in the practical application fields.
基金sponsored by National Science Foundation for Young Scientists of China(Grant No.51005233)Special Financial Grant from the China Postdoctoral Science Foundation(Grant No.201104582)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘A simulation method for investigating the vibration behavior of hoisting rope with time-varying length is improved.By previously creating markers in the MSC.ADAMS software package,the parametric model of the rope wound along helix is established based on the concentrated-mass theory with multi-degree of freedom(multi-DOF).A novel driving strategy,cooperating fixed joints with angle sensors under the control of driving script,is proposed to substitute conventional contact force.Researching on the hoisting rope in the sinking winch mechanism,an equivalent discretization model is obtained with complicated boundary conditions considered.The differential equations of motion of the hoisting system are formulated employing Lagrange’s equation and numerically solved using Runge–Kutta method.The simulation indicates that the horizontal swing is decreased in principle and the simulation with 800 discrete ropes is not performed more than 61 min.Therefore,this feasible strategy could not only guarantee the accuracy but also promote simulation efficiency and stability.The motion curves exported from ADAMS simulation coincide with one in numerical simulation,which validates both the numerical model and the driving strategy.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51771049 and 51790484)。
文摘The addition of a small amount of oxygen improves the mechanical properties,especially plasticity,of Ti_(45.7)Zr_(33)Ni_(3)Cu_(5.8)Be_(12.5) amorphous alloy composites(AACs)at room temperature(298 K).Compared to the plasticity of AACs without added O(5%),the plasticity of the composites with 0.73 at.%O(nominal composition)was much higher(11%).Even at O content higher than 0.73 at.%,the AACs exhibited good plasticity.The highest plasticity of∼12.3%was observed with 2.87 at.%O.Two distinct mechanisms are proposed to explain the enhanced plasticity of the AACs.At low O content,although deformation-induced phase transformation was suppressed,a substantial amount of α" martensite was formed.The microstructural features of α" martensite,such as thinner laths and homogeneous distribution,induced the formation of multiple shear bands in the amorphous matrix.At high O content,deformation-induced phase transformation was seriously suppressed.A dispersed nanoωphase was formed during rapid solidification in AACs with O content higher than 1.45 at.%.This resulted in a weakening in the anisotropy ofβdendrites and led to their homogenous deformation.Furthermore,multiple shear bands were formed in the amorphous matrix.Apart from plasticity,the strength of the AACs also increased with an increase in the O content.This phenomenon was explained in terms of three mechanisms,viz.the solid-solution-strengthening effect of O,fine-grain strengthening of β dendrites,and secondary phase strengthening by the nano ω phase.
基金financial supported by the National Science Foundation of China(No.51231002)supported by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,under Contract No.DE-AC02-06CH11357
文摘Residual stress is an important factor for evaluating the deformation and failure of engineering materials. Diffraction-based measurement assumes that the full measured lattice strain tensor contributes to residual stress according to Hookers Law. The present work focuses on the lattice strain determination of individual grains in a dual-phase stainless steel (DPSS) by means of differential-aperture X-ray micro-diffraction (DAXM). The results show that the residual stress only takes part of the responsibility of the total measured lattice strain. In fact, the compositional variation inside the material was found to cause greater strain gradient in both ferrite (c~) and austenite (~) phases in DPSS. Therefore, quantification of compositional and residual stress effects on lattice strain was conducted in order to evaluate the true residual stress inside engineering materials.