热冷组合铸型水平连铸Cu-0.36Be-0.46Co合金带材冷轧过程中显微组织和力学性能变化

采用热冷组合铸型(HCCM)水平连铸工艺制备300 mm(宽)×10 mm(厚) Cu-0.36%Be-0.46%Co(质量分数)合金带材,对连铸带材进行冷轧,研究轧制过程中合金显微组织和力学性能的变化规律与变形机理。结果表明:连铸带材具有沿长度方向的柱状晶组织,表面质量好,断后伸长率达到35%,无需表面处理可直接进行大变形冷轧加工,无中间退火的累积冷轧变形量达98%。当变形量较小时(20%),变形机理为位错滑移,形成大量弥散分布的位错和位错胞;当变形量为40%时,合金中出现形变孪晶,且孪晶与位错胞相互作用形成长条状位错胞;当变形量超过60%时,形成切变带,发生明显的微区晶体转动;随着变形量的进一步增大,切变带数量增多且相互作用,使晶粒明显细化。抗拉强度和硬度由铸态的353 MPa和HV 119分别升高至冷轧变形量95%时的625 MPa和HV 208,断后伸长率则由35%降低至7.6%。该结果可为发展铍铜合金带材HCCM水平连铸-冷轧短流程高效加工方法提供实验依据。

Ni含量对Cu−0.4Be合金时效组织和性能的影响

研究Ni含量(0~2.10%,质量分数)对Cu−0.4Be(质量分数,%)合金常规时效析出相、强度和导电率的影响,并分析影响机理。结果表明:添加Ni元素可促进强化相的析出,显著提高时效强化作用。当Ni含量由0增大到2.10%时,合金时效后的强度呈先增大后减小的变化趋势,在Ni含量为1.50%时达到最大;含1.50%Ni合金的峰值时效参数为400℃保温60 min,时效后合金的抗拉强度和屈服强度分别为611 MPa和565 MPa,分别是不含Ni合金的2.8倍和6.1倍;含Ni合金的导电率随着时效时间的延长而增加,但随着Ni含量的增大而下降。在400℃,随着时效时间的延长,Cu−0.4Be−1.5Ni合金发生γ″相→γ′相→γ相转变;当时效时间为60 min时,合金中出现大量弥散分布的纳米级共格γ″相和γ′相,析出强化作用显著,是合金具有较高强度的主要原因。

两焦点与三焦点人工晶状体植入术后视觉质量的比较

目的:比较两焦点(AT LISA 809MP)和三焦点(AT LISA tri 839MP)IOL植入术后的视觉质量。方法:回顾性研究。共收集2018-03/2019-02行超声乳化吸除术联合多焦点IOL植入术的白内障患者28例49眼。两焦点组18例30眼,年龄40~85(平均67.08±10.80)岁。三焦点组10例19眼,年龄38~79(平均62.21±14.50)岁。所有患者均行视觉质量分析系统(OQAS)、离焦曲线等检查。结果:两焦点组近BCVA优于三焦点,三焦点组中UCVA和远BCVA均优于两焦点组(P<0.05)。三焦点组+1.5、-1.0、-1.5、-2.0、-2.5、-3.0D视力显著优于两焦点组。两组间OQAS视觉质量参数两焦点组OV 20%、OV 9%、SR均优于三焦点组(P<0.05)。结论:两焦点和三焦点IOL植入术后均可获得良好的裸眼远和近视力,视觉质量均较高,而三焦点IOL可获得更佳的中间视力。

Microstructure and mechanical properties of BFe10 cupronickel alloy tubes fabricated by a horizontal continuous casting with heating-cooling combined mold technology

A new horizontal continuous casting method with heating-cooling combined mold （HCCM） technology was explored for fabri- cating high-quality thin-wall cupronickel alloy tubes used for heat exchange pipes. The microstructure and mechanical properties of BFe 10 cupronickel alloy tubes fabricated by HCCM and traditional continuous casting （cooling mold casting） were comparatively investigated. The results show that the tube fabricated by HCCM has smooth internal and external surfaces without any defects, and its internal and external surface roughnesses are 0.64 μm and 0.85 μm, respectively. The tube could be used for subsequent cold processing without other treatments such as surface planning, milling and acid-washing. This indicates that HCCM can effectively reduce the process flow and improve the pro- duction efficiency of a BFel0 cupronickel alloy tube. The tube has columnar grains along its axial direction with a major casting texture of {012}〈 621 〉. Compared with cooling mold casting （6 = 36.5%）, HCCM can improve elongation （3 = 46.3%） by 10% with a slight loss of strength, which indicates that HCCM remarkably improves the cold extension performance of a BFe 10 cupronickel alloy tube.

Liquid-solid interface control of BFe10-1-1 cupronickel alloy tubes during HCCM horizontal continuous casting and its effect on the microstructure and properties

Based on horizontal continuous casting with a heating-cooling combined mold （HCCM） technology, this article investigated the effects of processing parameters on the liquid-solid interface （LSI） position and the influence of LSI position on the surface quality, microstructure, texture, and mechanical properties of a BFe10-1-1 tube （φ50 mm × 5 mm）. HCCM efficiently improves the temperature gradient in front of the LSI. Through controlling the LSI position, the radial columnar-grained microstructure that is commonly generated by cooling mold casting can be eliminated, and the axial columnar-grained microstructure can be obtained. Under the condition of 1250℃ melting and holding temperature, 1200-1250℃ mold heating temperature, 50-80 mm/min mean drawing speed, and 500-700 L/h cooling water flow rate, the LSI position is located at the middle of the transition zone or near the entrance of the cooling section, and the as-cast tube not only has a strong axial columnar-grained microstructure （{hkl}〈621〉, {hkl}〈221〉） due to strong axial heating conduction during solidification but also has smooth internal and external surfaces without cracks, scratches, and other macroscopic defects due to short solidified shell length and short contact length between the tube and the mold at high temperature. The elongation and tensile strength of the tube are 46.0%-47.2% and 210-221 MPa, respectively, which can be directly used for the subsequent cold-large-strain processing.

Numerical simulation of temperature field in horizontal core-filling continuous casting for copper cladding aluminum rods

The steady-state temperature field of horizontal core-filling continuous casting （HCFC） for producing copper cladding aluminum rods was simulated by finite element method to investigate the effects of key processing parameters on the positions of solid-liquid interfaces （SLIs） of copper and aluminum. It is found that mandrel tube length and mean withdrawing speed have significant effects on the SLI positions of both copper and aluminum. Aluminum casting temperature （TAI） （1003-1123 K） and secondary cooling water flux （600-900 L.h-1） have little effect on the SLI of copper but cause the SLI of aluminum to move 2-4 mm. When TA1 is in a range of 1043-1123 K, the liquid aluminum can fill continuously into the pre-solidified copper tube. Based on the numerical simulation, reasonable processing parameters were determined.

白内障日间手术患者术后当天检查和随访研究

目的:探究白内障日间手术患者在术后当天进行视力、眼压和裂隙灯显微镜检查的必要性,探索安全有效的术后观察方法。方法:收集我院2018-10/11的白内障日间手术的患者149例149眼,完成白内障超声乳化摘除联合人工晶状体植入术,观察患者术眼术前、术后2h,1d,1wk的BCVA和眼压并进行术前术后的对比,在裂隙灯下观察其角膜水肿情况、是否有人工晶状体脱位和其他并发症,对术前和术后高眼压率、低眼压率进行比较。结果:术眼术前与术后2h BCVA,术后2h与术后1d BCVA,术后1d与术后1wk的BCVA均有差异(P<0.05),呈逐渐改善的趋势。患者术眼术前与术后2h,1d眼压均无差异(P>0.05),但术后1wk的眼压均低于术前、术后2h,1d的眼压(P<0.05)。术后2h出现高眼压的比例高于术前、术后1d,1wk。术后1wk未发现患者出现眼部并发症。结论:白内障日间手术患者术后1wk视力、眼压和角膜水肿均恢复良好,在术后2h容易出现高眼压,进行视力、眼压和裂隙灯显微镜检查,较为安全,可对出现高眼压的患者作对症处理。

Effect of strain rate on the compressive deformation behaviors of lotus-type porous copper

Lotus-type porous copper was fabricated by unidirectional solidification, and compressive experiments were subsequently conducted in the strain rate range of 10-3-2400 s-1 with the compressive direction parallel to the pores. A GLEEBLE-1500 thermal-mechanical simulation system and a split Hopkinson pressure bar （SHPB） were used to investigate the effect of strain rate on the compressive deforma-tion behaviors of lotus-type porous copper. The influence mechanism of strain rate was also analyzed by the strain-controlling method and by high-speed photography. The results indicated that the stress-strain curves of lotus-typed porous copper consist of a linear elastic stage, a plateau stage, and a densification stage at various strain rates. At low strain rate （〈1.0 s^-1）, the strain rate had little influence on the stress-strain curves; but when the strain rate exceeded 1.0 s^-1, it was observed to strongly affect the plateau stage, showing obvious strain-rate-hardening characteristics. Strain rate also influenced the densification initial strain. The densification initial strain at high strain rate was less than that at low strain rate. No visible inhomogeneous deformation caused by shockwaves was observed in lotus-type porous copper during high-strain-rate deformation. However, at high strain rate, the bending deformation characteristics of the pore walls obviously differed from those at low strain rate, which was the main mechanism by which the plateau stress exhibited strain-rate sensitivity when the strain rate exceeded a certain value and exhibited less densification initial strain at high strain rate.

先天性白内障患者眼轴和角膜曲率的研究

目的:探究先天性白内障患者的AL和角膜曲率,为该疾病的发展、治疗和预后提供重要参考。方法:回顾分析2014-01/2018-12在我院确诊为先天性白内障并住院手术,排除其他眼部或全身疾病的20岁以内的患者229例333眼。使用IOL Master500测量患者的眼轴和角膜曲率,角膜曲率使用K1与K2的平均值Km来表示。采用偏相关分析对AL、Km与年龄的关系进行评估,与年龄相关的参数使用逐步多元回归进行曲线拟合。比较双眼患者、单眼患者患眼及健眼的AL和Km差异,并对比男性与女性患者AL和Km的不同。结果:患者的AL与年龄呈正相关(r=0.250,P=0.001),得到AL=20.85+0.96×ln(年龄)的拟合曲线,而患者的Km与年龄无相关性(r=-0.024,P=0.759)。男性和女性患者的AL无明显差异(P=0.495),但女性患者的Km大于男性患者(P=0.018)。双眼患者的AL与单眼患者患眼的AL无差异(P=0.159),但小于单眼患者健眼的AL(P=0.033)。双眼患者的Km与单眼患者患眼、健眼的Km均无差异(P=0.483、0.176)。结论:先天性白内障可影响AL发育,尤其对于双眼患者,其AL小于单眼患者健眼的AL;尚未发现对角膜曲率的影响,但女性患者的角膜曲率大于男性患者。

Effects of Fe content on the microstructure and properties of CuN i10FeM n1 alloy tubes fabricated by HCCM horizontal continuous casting

Heating-cooling combined mold（HCCM） horizontal continuous casting technology developed by our research group was used to produce high axial columnar-grained CuN i10 FeM n1 alloy tubes with different Fe contents. The effects of Fe content（1.08wt%–2.01wt%） on the microstructure, segregation, and flushing corrosion resistance in simulated flowing seawater as well as the mechanical properties of the alloy tubes were investigated. The results show that when the Fe content is increased from 1.08wt% to 2.01wt%, the segregation degree of Ni and Fe elements increases, and the segregation coefficient of Ni and Fe elements falls from 0.92 to 0.70 and from 0.92 to 0.63, respectively. With increasing Fe content, the corrosion rate of the alloy decreases initially and then increases. When the Fe content is 1.83wt%, the corrosion rate approaches the minimum and dense, less-defect corrosion films, which contain rich Ni and Fe elements, form on the surface of the alloy; these films effectively protect the α-matrix and reduce the corrosion rate. When the Fe content is increased from 1.08wt% to 2.01wt%, the tensile strength of the alloy tube increases from 204 MPa to 236 MPa, while the elongation to failure changes slightly about 46%, indicating the excellent workability of the CuNi10FeMn1 alloy tubes.

Effect of continuous induction annealing on the microstructure and mechanical properties of copper-clad aluminum flat bars

Copper-clad aluminum （CCA） flat bars produced by the continuous casting-rolling process were subjected to continuous induction heating annealing （CIHA）, and the effects of induction heating temperature and holding time on the microstructure, interface, and mechanical properties of the fiat bars were investigated. The results showed that complete recrystallization of the copper sheath occurred under CIHA at 460℃ for 5 s, 480℃ for 3 s, or 500℃ for 1 s and that the average grain size in the copper sheath was approximately 10.0 μm. In the case of specimens subjected to CIHA at 460-500℃ for longer than 1 s, complete recrystallization occurred in the aluminum core. In the case of CIHA at 460-500℃ for 1-5 s, a continuous interracial layer with a thickness of 2.5-5.5 μm formed and the thickness mainly increased with increasing annealing temperature. After CIHA, the interracial layer consisted primarily of a Cu9A14 layer and a CuA12 layer; the average interface shear strength of the CCA flat bars treated by CIHA at 460-500℃ for 1-5 s was 45-52 MPa. After full softening annealing, the hardness values of the copper sheath and the aluminum core were HV 65 and HV 24, respectively, and the hardness along the cross section of the CCA flat bar was uniform.

Feasibility Study of the Natural Derived Chitosan Dialdehyde for Chemical Modification of Collagen

The aim of the study is to evaluate the chemical crosslinking effects of the natural derived chitosan dialdehyde(OCS)on collagen.Fourier transform infrared(FTIR)spectroscopy,differential scanning calorimetry(DSC)and circular dichroism(CD)measurements suggest that introducing OCS might not destroy the natural triple helix conformation of collagen but enhance the thermal-stability of collagen.

MicroRNA let-7a： a novel therapeutic candidate in prostate cancer

Dear Editor, It is known that microRNA let-7a can be useful for diagnosis and therapy of cancer, including prostate cancer （PCa）.1 A recent article by Wang et al. 2 comprehensively showed that let-7al could inhibit the expression of insulin-like growth factor- 1 receptor （IGF 1 R） by directly targeting the T1 and T2 sites in the 3＇ untranslated region （3＇UTR） of IGF 1R mRNA. Furthermore, they found that let-7a 1-mediated IGF I R downregulation was accompanied by attenuation of Elk1 activity and c-fos expression, inhibition of PC-3 cell proliferation, cell cycle arrest and induced apoptosis and that inhibition oflet-7al could up-regulate IGF 1R accompanied by an increase of Elk1 activity and c-fos expression,

Electrolyte perspective on stabilizing LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)cathode for lithium-ion batteries

Nickel-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)is regarded as the promising cathode for lithium-ion batteries(LIBs).However,the challenges such as safety issues and poor cycling performance have seriously hindered its commercial applications.In order to overcome these difficulties,there has been extensive research and development of electrolyte modifications for high-energy-density LIBs with Ni-rich cathodes.Herein,this review introduces the research progress based on solvent additives,salt type additives and other electrolytes for LIBs with NCM811cathode materials and discusses how they control the interface stability.In particular,some recommendations for further modification of enhancing electrolyte stability and improving NCM811 electrochemical properties are summarized and proposed,which put forward new design rules for the screening and customizing ideal electrolyte additives for high performance NCM811 cathode-based LIBs.

Perspective on cycling stability of lithium-iron manganese phosphate for lithium-ion batteries

Lithium-iron manganese phosphates(LiFex Mn_(1-x)PO_(4),0.1<x<0.9)have the merits of high safety and high working voltage.However,they also face the challenges of insufficient conductivity and poor cycling stability.Some progress has been achieved to solve these problems.Herein,we firstly summarized the influence of different electrolyte systems on the electrochemical performance of LiFexMn_(1-x)PO_(4),and then discussed the effect of element doping,lastly studied the influences of conductive layer coating and morphology control on the cycling stability.Finally,the prospects and challenges of developing high-cycling LiFexMn_(1-x)PO_(4) were proposed.

Toward a function realization of multi-scale modeling for lithium-ion battery based on CHAIN framework

As the most mature portable power source,lithium-ion battery has become the mainstream of power source for electric vehicles(EVs)by virtue of its high energy density,long cycle life and relatively low cost.However,an excellent battery management system remained to be a problem for the operational states monitoring and safety guarantee for EVs.In this paper,a function realization of multi-scale modeling is proposed based on cyber hierarchy and interactional network framework,realizing basic functions such as multi-scale mapping and cloud-based modeling.Furthermore,to solve the problem of limited computing capability of the conventional vehicle-end battery management system,the novel system consists of hierarchies of side,edge and cloud,which are designed to take on different computing tasks methodically and swap data iteratively,providing specific services for drivers,enterprise users,etc.Due to a series of promising features,this system has a large range of application scenarios as well as some critical bottlenecks,which will be discussed at the end of the article.Please check and confirm D.-B.Shan"is correctly identified in author group.It’s not correct.There is no"D.-B.Shan"in author group,please just remove it.

Shearing-force-driven delamination of waste residue into oxidatively stable MXene composites for high-performance Si anode

The low yield of MXene is normally related to the delaminating step,contributing to the key technical challenges in moving toward industrial applications.Here,a shearing-force-driven strategy is proposed for re-exfoliating waste MXene residue to prepare oxidatively stable MXene composites in a low-cost manner,where the strong shear stress in the assisted solvent,such as carbon nanotubes(CNTs),chitosan(CS),and polyacrylamide(PAM)aqueous solutions,acts on the surface of MXene(Ti_(3)C_(2)T_(x))through coordination between hydroxyl and Ti atoms,resulting in a rapid and efficient exfoliation of waste Ti_(3)C_(2)T_(x)residue under stirring.Furthermore,this formed coordinate bond helps to stabilize the low-valent Ti atoms on the surface of MXene,thereby enhancing the oxidative stability of Ti_(3)C_(2)T_(x).Besides,the CNT@MXene composite is selected to construct a free-standing membrane to encapsulate Si nanoparticles,achieving a high and reversible capacity after 50 cycles.This work supports the concept of valorizing waste and adopts a fluid shear forceassisted method to re-exfoliate waste residues,which greatly reduces the cost of processing and improves the chemical stability of MXene.More importantly,this work has uncovered a new direction for the commercialization of MXene composites and has significantly improved the realworld applications of MXene-based materials.

State of health and remaining useful life prediction for lithiumion batteries based on differential thermal voltammetry and a long and short memory neural network

As the lithium-ion battery is widely applied,the reliability of the battery has become a high-profile content in recent years.Accurate estimation and prediction of state of health(SOH)and remaining useful life(RUL)prediction are crucial for battery management systems.In this paper,the core contribution is the construction of a datadriven model with the long short-term memory(LSTM)network applicable to the time-series regression prediction problem with the integration of two methods,data-driven methods and feature signal analysis.The input features of model are extracted from differential thermal voltammetry(DTV)curves,which could characterize the battery degradation characteristics,so that the accurate prediction of battery capacity fade could be accomplished.Firstly,the DTV curve is smoothed by the Savitzky-Golay filter,and six alternate features are selected based on the connection between DTV curves and battery degradation characteristics.Then,a correlation analysis method is used to further filter the input features and three features that are highly associated with capacity fade are selected as input into the data driven model.The LSTM neural network is trained by using the root mean square propagation(RMSprop)technique and the dropout technique.Finally,the data of four batteries with different health levels are deployed for model construction,verification and comparison.The results show that the proposed method has high accuracy in SOH and RUL prediction and the capacity rebound phenomenon can be accurately estimated.This method can greatly reduce the cost and complexity,and increase the practicability,which provides the basis and guidance for battery data collection and the application of cloud technology and digital twin.

Concept of hydrophobic Li^(+)-solvated structure for high performances lithium metal batteries

The large-scale application of lithium metal batteries remains a challenge due to the hydrolysis of LiPF_(6),which can induce capacity fade and series of safety issues.Prof.Ma and his co-workers have designed a hydrophobic Li^(+)-solvated structure to obtain high performances lithium metal batteries.The specific functional groups of theadditive,hexafluoroisopropyl acrylate.

Ultrasound extraction optimization, structural features, andantioxidant activity of polysaccharides from Tricholoma matsutake

An ultrasonic-assisted technique was employed to extract crude polysaccharide from Tricholomamatsutake fruiting bodies. Single-factor tests and orthogonal experimental design （L9（33）） were used to obtain theoptimal extraction conditions. Results showed that the optimal parameters were as follows： ultrasonic temperature,40℃; ultrasonic time, 50 min; water to raw material ratio, 25 ml/g; ultrasonic frequency, 45 kHz; and ultrasonic power,100 W. Three novel T. matsutake polysacchadde （TMP） fractions （TMP30, TMP60, and TMP80） were isolated andpurified from TMP by stepwise alcohol precipitation. Their preliminary structural features were determined by high-performance anion-exchange chromatography with pulsed-amperometric detection （HPAEC-PAD） and Fouriertransform infrared spectrophotometer （FT-IR） analyses. Furthermore, their in vitro antioxidant activity was investigatedin terms of a reducing power assay and the scavenging rates of 2,2-diphenyl-l-picrylhydrazyl （DPPH） and hydroxylradicals. The order of the various fractions based on their antioxidant activity was TMP80〉TMP〉TMP60〉TMP30.These findings suggested that novel polysaccharide fractions from T. matsutake, especially TMP80, could be prom-ising active macromolecules for biomedical use.