Calculation of Mass Concrete Temperature and Creep Stress under the Influence of Local Air Heat Transfer

Temperature-induced cracking during the construction of mass concrete is a significant concern.Numerical simulations of concrete temperature have primarily assumed that the concrete is placed in an open environment.The problem of heat transfer between the air and concrete has been simplified to the concrete’s heat dissipation boundary.However,in the case of tubular concrete structures,where air inlet and outlet are relatively limited,the internal air temperature does not dissipate promptly to the external environment as it rises.To accurately simulate the temperature and creep stress in tubular concrete structures with enclosed air spaces during construction,we establish an air–concrete coupled heat transfer model according to the principles of conjugate heat transfer,and the accuracy of the model is verified through experiments.Furthermore,we conduct a case study to analyze the impact of airflow within the ship lock corridor on concrete temperature and creep stress.The results demonstrate that enhancing airflow within the corridor can significantly reduce the maximum concrete temperature.Compared with cases in which airflow within the corridor is neglected,the maximum concrete temperature and maximum tensile stress can be reduced by 12.5℃ and 0.7 MPa,respectively,under a wind speed of 4 m/s.The results of the traditional calculation method are relatively close to those obtained at a wind speed of 1 m/s.However,the temperature reduction process in the traditional method is faster,and the method yields greater tensile stress values for the corridor location.

High-throughput sorting of two-color fluorescent-labeled zebrafish embryos

The zebrafish embryos were widely employed in genetics,development and drug discovery studies as miniatured animal models.Sorting of two-color fluorescent embryos is often required in large-scale experiments but it is challenging to manually sort with high efficiency.Here,we reported a high-throughput sorting system for two-color fluorescent zebraflsh embryos.The embryos can be automatically loaded from a sample pool and sorted based on the average fluorescent intensity.The two-color fluorescent signals were split into two lines and detected by an area array camera.The system achieves the sorting of 100 embryos in less than 10 min with an accuracy of greater than 95%.

Characterizing the luminescent properties of upconversion nanoparticles in single and densely packed state

Luminescent properties of Er^(3+)-and Yb^(3+)-co-doped CaF_(2)upconversion nanoparticles(UCNPs)were investigated in single particle and densely-packed states with a custom-built microscope.The single UCNPs exhibit linear dependency of luminescent intensity on excitation power while the densely-packed UCNPs exhibit a 2-order power law-dependency indicating a two-photon absorption process.Time-domain luminescence intensity measurements were performed and the curves were fitted to excitationnemission rate functions based on a simplified three-state model.The results indicate that the intermediates in single particles are much less and saturated in a short time,and there are strong couplings of the ground states and intermediate states between neighboring UCNPs in densely packed UCNPs.

0.5%托吡卡胺与1%盐酸环喷托酯对近视患者晶状体影响的比较

目的:比较0.5%托吡卡胺与1%盐酸环喷托酯对近视患者晶状体形态及屈光力的影响差异。方法:前瞻性临床研究。于2023年8—12月从绵阳市中心医院随机招募近视患者20例(40眼)。分别使用0.5%托吡卡胺滴眼液与1%盐酸环喷托酯滴眼液进行睫状肌麻痹,2次睫状肌麻痹时间间隔1周以上。分别在睫状肌麻痹前,麻痹后10、20、30 min测量受试者在无调节刺激和-5.00 D调节刺激下的晶状体厚度(LT)、晶状体前表面曲率半径(LAC)、晶状体后表面曲率半径(LPC)、晶状体直径(LD)及晶状体屈光力(LP)。采用两因素重复测量方差分析、配对t检验比较受试者使用2种睫状肌麻痹剂后晶状体各参数变化。结果:受试者使用2种睫状肌麻痹剂后LT、LAC、LPC、LD、LP的药物主效应和交互效应差异均无统计学意义(均P>0.05);时间主效应中LT、LAC、LP差异均有统计学意义(F=12.47,P<0.001;F=36.14,P<0.001;F=14.15,P<0.001),多重比较显示LT在麻痹后10、20、30 min与麻痹前,麻痹后20、30 min与麻痹后10 min比较差异均有统计学意义(均P<0.05),麻痹后20 min与30 min差异无统计学意义(P=0.950);LAC在所有时间点差异均有统计学意义(均P<0.05);LP在麻痹后10、20、30 min与麻痹前比较差异均有统计学意义(均P<0.05),其余时间点之间差异均无统计学意义(均P>0.05)。相比无调节刺激,使用0.5%托吡卡胺10 min后,在调节刺激下LT、LAC变化差异有统计学意义(t=-2.68,P=0.015;t=2.19,P=0.041);20 min后,在调节刺激下LAC变化差异有统计学意义(t=2.36,P=0.029);30 min后,在调节刺激下LT、LAC、LPC、LD、LP变化差异均无统计学意义(均P>0.05)。相比无调节刺激,使用1%盐酸环喷托酯10 min后,在调节刺激下LAC变化差异有统计学意义(t=2.10,P=0.049);20 min后,在调节刺激下LT、LAC、LPC、LD、LP变化差异均无统计学意义(均P>0.05)。结论:0.5%托吡卡胺与1%盐酸环喷托酯主要使LT减小、LAC增大、LP降低;相比0.5%托吡卡胺,1%盐酸环喷托酯降低晶状体调节功能作用更迅速,但0.5%托吡卡胺与1%盐酸环喷托酯对晶状体的放松效果相似。

High-fidelity structured illumination microscopy by point-spread-function engineering

Structured illumination microscopy(SIM)has become a widely used tool for insight into biomedical challenges due to its rapid,long-term,and super-resolution(SR)imaging.However,artifacts that often appear in SIM images have long brought into question its fidelity,and might cause misinterpretation of biological structures.We present HiFi-SIM,a high-fidelity SIM reconstruction algorithm,by engineering the effective point spread function(PSF)into an ideal form.HiFi-SIM can effectively reduce commonly seen artifacts without loss of fine structures and improve the axial sectioning for samples with strong background.In particular,HiFi-SIM is not sensitive to the commonly used PSF and reconstruction parameters;hence,it lowers the requirements for dedicated PSF calibration and complicated parameter adjustment,thus promoting SIM as a daily imaging tool.

Biocompatible Poly(ε-caprolactone)-based Shape-memory Polyurethane Composite Scaffold with Bone-induced Activity

3D porous scaffold could provide suitable bone-like structure for cell adhesion and proliferation;however,surgical suffering from large volume implantation is a great challenge for patients.In this study,a shape programmable porous poly(ε-caprolactone)(PCL)-based polyurethane scaffold with memory effect was synthesized via gas foaming method,using Citrate modified Amorphous calcium Phosphate(CAP)as bioactive factor.The bending experiments indicated that the scaffolds achieved excellent shape-memory effect,which could be influenced by particle weight content.In vitro mineralization results suggested that the deposition of hydroxyapatite was promoted by scaffolds.Additionally,cell assay showed that composite scaffolds presented good cell toxicity and osteogenicity by the differentiation of rat Mesenchymal Stem Cells(rMSCs)into the osteogenic lineage.In the model of rat cranial implantation,the reparative tissue covered the defect site and bone-like structure deposited on the scaffold due to the formation of new bones.In summary,the porous smart shape-memory composite scaffolds could be a potential candidate in future distinctive bone repair applications.

Big Disaster from Small Watershed:Insights into the Failure and Disaster‑Causing Mechanism of a Debris Flow on 25 September 2021 in Tianquan,China

The occurrence of debris flow events in small-scale watersheds with dense vegetation in mountainous areas that result in significant loss of life and missing individuals challenges our understanding and expertise in investigating and preventing these disasters. This has raised concerns about the occurrence of large debris flow disasters from small watersheds. This study focused on a catastrophic debris flow that took place in Longtou Gully(0.45 km^(2)) in Tianquan County, Ya'an City on 25 September 2021, which resulted in 14 deaths and missing individuals. Through comprehensive field investigations, highprecision remote sensing data analyses, and numerical simulations, we analyzed the triggering mechanisms and dynamic processes of this event. Our results indicate that the convergence hollow at the channel head exhibited higher hydraulic conditions during rainfall compared to gentle slopes and convex terrains, leading to the instability of colluvial soil due to the expansion of the saturated zone near the soil–bedrock interface. The entrainment of material eroded from the channel resulted in an approximately 4.7 times increase in volume, and the channel scarp with a height of about 200 m amplified the destructive power of the debris flow. We emphasize the need to take seriously the possibility of catastrophic debris flows in small-scale watersheds, with colluvial deposits in hollows at the channel head under vegetation cover that serve as precursor material sources, and the presence of channel scarps formed by changes in the incision rate of the main river, which is common in the small watershed on both sides. This study provides insights for risk assessment of debris flows in small-scale catchments with dense vegetation cover in mountainous areas, highlighting the importance of vigilance in addressing disasters in small-scale catchments, particularly in regions with increasing human–environment conflicts.