Effect of thermomechanical processing on microstructure and mechanical properties of CoCrFeNiMn high entropy alloy

The CoCrFeNiMn high entropy alloy was produced by homogenization, cold rolling and recrystallization. The effects of thermomechanical processing on microstructures and tensile properties at different temperatures were investigated using X-ray diffractometry（XRD）, optical microscopy（OM）, scanning electron microscopy（SEM） and multi-functional testing machine. The results show that dendritic structures in cast alloy evolve into equiaxed grains after being recrystallized, with single face-centered cubic（FCC） phase detected. The most refined alloys, stemming from the highest rolling ratio（40%）, exhibit the highest strength due to the grain boundary strengthening, while the variation of elongation with temperature shows a concave feature. For the coarse-grained alloys, both the ductility and work hardening ability decrease monotonically with increasing temperature. Serrated flow observed at intermediate temperatures is attributed to the effective pinning of dislocations, which manifests the occurrence of dynamic strain hardening and results in the deterioration in ductility. Besides, dimples on the fracture surfaces indicate the typical ductile rupture mode.

Microstructures,tensile properties and serrated flow of Al_xCrMnFeCoNi high entropy alloys

Microstructures and mechanical properties of dual-phase AlxCrMnFeCoNi (x=0.4, 0.5, 0.6, at.%) alloys were investigated. Thermomechanical processing leads to a microstructural evolution from cast dendritic structures to equiaxed ones, consisting of face-centered cubic (fcc) and body-centered cubic (bcc) phases in the two states. The volume fraction of bcc phase increases and the size of fcc grain decreases with increasing Al content, resulting in remarkably improved tensile strength. Specifically, the serrated flow occurring at the medium temperatures varies from type A+B to B+C or C as the testing temperature increases. The average serration amplitude of these Al-containing alloys is larger than that of CoCrFeNiMn alloy due to the enhanced pinning effect. The early small strain produces low-density of dislocation arrays and bowed dislocations in fcc grains while the dislocation climb and shearing mechanism dominate inside bcc grains. The cross-slip and kinks of dislocations are frequently observed and high-density-tangled dislocations lead to dislocation cells after plastic deformation with a high strain.

Microstructure and mechanical properties of Al-Fe meshing bonding interfaces manufactured by explosive welding

In order to improve the mechanical properties of Al.Fe transition joints manufactured by explosive welding,meshing bonding interfaces were obtained by prefabricating dovetail grooves in base plates.The microstructure and mechanical properties of the meshing interfaces were systematically investigated.The microstructure observation showed that metallurgical bonding without pores was created in the form of direct bonding and melting zone bonding at the interface.Fractography on tensile specimens showed cleavage fracture on the steel side and ductile fracture on the aluminum side near the interfaces.The tensile shear test results indicated that the shear strength of the meshing interface 0°and 90°was increased by 11%and 14%,respectively,when being compared to that of the ordinary Al.Fe transition joints.The values of microhardness decreased as the distance from the interface increased.After three-point bending,cracks were observed at the bonding interface for some specimens due to the existence of brittle Fe.Al compounds.

Motor Compatibility Effect on the Comprehension of Complex Manual Action Sentences in L2:An ERP Study

Embodiment theories proposed that the comprehension of language involves sensory-motor simulation in the brain.The present study examined the brain response to motor compatibility effect in comprehending action-related linguistic materials for participants learning Chinese as a second language(L2).In this study,participants are required to read action-related sentences describing an agent performing two manual actions simultaneously or sequentially by manipulating temporal conjunctions.The sentences with simultaneous actions are marked by Chinese parallel structure一边……一边……(“while”)showing non-congruent motor condition while the sequential action sentences are marked by先……然后……(“after”)showing congruent motor condition.Event-Related Potentials(ERPs)were recorded with the second verb phrase.A larger fronto-central late positivity was observed for the sentences with simultaneous actions rather than the sentences with sequential actions due to body constraints,revealing that late L2 Chinese learners integrate embodied knowledge while processing action-related complex sentence despite demanding more cognitive resources,and longer processing time.

Effect of yttrium and calcium additions on electrochemical behaviors and discharge performance of AZ80 anodes for Mg-air battery

The effects of yttrium(Y)and yttrium+calcium(Y+Ca)additions on the electrochemical properties and discharge performance of the as-extruded Mg−8Al−0.5Zn−0.2Mn(AZ80)anodes for Mg−air batteries were investigated.The results show that the addition of 0.2 wt.%Y increased the corrosion resistance and discharge activity of AZ80 anode.This was attributed to the fine and sphericalβ-Mg_17)Al_(12) phases dispersing evenly in AZ80+0.2Y alloy,which suppressed the localized corrosion and severe“chunk effect”,and facilitated the rapid activation ofα-Mg.Combinative addition of 0.2 wt.%Y and 0.15 wt.%Ca generated grain refinement and a reduction of theβ-Mg_17)Al_(12) phase,resulting in a further enhancement in discharge voltage.However,the incorporation of Ca in Mg_17)Al_(12) and Al_(2)Y compounds compromised the corrosion resistance and anodic efficiency of AZ80+0.2Y+0.15Ca anode.Consequently,AZ80+0.2Y anode exhibited excellent overall discharge performance,with the peak discharge capacity and anodic efficiency of 1525 mA·h·g^(−1) and 67%at 80 mA/cm^(2),13%and 14%higher than those of AZ80 anode,respectively.

Design and evaluation of cab seat suspension system based on negative stiffness structure

To improve the vibration-isolation performance of cab seats,the optimization model of the seat suspension system of construction machinery cabs is proposed based on the negative stiffness structure.The negative stiffness nonlinear kinetic equation is established by designing the seat negative stiffness suspension structure(NSS).Using MATLAB,the different parameters of the suspension system and their influences on the dynamic stiffness are analyzed.The ideal configuration parameter range of the suspension system is obtained.Meanwhile,the optimization model of NSS is proposed,and the vibration transmissibility characteristics are simulated and analyzed by different methods.The results show that the displacement and acceleration amplitudes of the optimized seat suspension system are evidently reduced,and the four-time power vibration dose value and root mean square calculation values in the vertical vibration direction of the seat decrease by 86%and 87%,respectively.Seat effective amplitude transmissibility(SEAT)and the vibration transmissibility ratio values also decrease.Moreover,the peak frequencies of the vibration transmitted to the driver deviate from the key frequency values,which easily cause human discomfort.Thus,the design of the seat suspension system has no effect on the health condition of the driver after being vibrated.The findings also illustrate that the NSS suspension system has good vibration-isolation performance,and the driver's ride comfort is improved.

Influence of Neighboring Layers on Interfacial Energy of Adjacent Layers

The binding energy and generalized stacking-fault energy (GSFE) are two critical interface properties of two dimensional layered materials, and it is still unclear how neighboring layers affect the interface energy of adjacent layers. Here, we investigate the effect of neighboring layers by comparing the differences of binding energy and GSFE between trilayer heterostructures (graphene/graphene/graphene, graphene/graphene/boron nitride,boron nitride/graphene/boron nitride) and bilayer heterostructures (graphene/graphene,graphene/boron nitride) using density functional theory. The binding energy of the adjacent layers changes from -2.3% to 22.55% due to the effect of neighboring layer, with a very small change of the interlayer distance. Neighboring layers also make a change from -2% to 10% change the GSFE, depending on the property of the interface between adjacent layers. In addition, a new simple expression is proven to describe the GSFE landscape of graphene-like structure with high accuracy.

First description of male Phrynarachne xuxiake(Araneae,Thomisidae)from Anhui Province,China

The male of Phrynarachne xuxiake Lin&Li,2022 is described for the first time,based on a specimen collected from the type locality in Anhui Province,China.A morphological description and illustrations are given.

Effect of combined scalp and body acupuncture on Parkinson’s disease:A randomized clinical trial

Objective:To observe the therapeutic effect of combined scalp and body acupuncture on the motor symptoms in Parkinson’s disease(PD),and on the score of levodopa equivalent dose(LED).Methods:This is a randomized,single blind trial.Sixty-six patients with PD were randomized into an acupuncture+medication group(33 patients)and a medication group(33 patients).The patients were aware of allocation and the assessors were blinded to group assignment and therapeutic regimen.AntiPD drugs were administered in both groups.In the acupuncture+medication group,scalp and body acupuncture therapy was added.Treatments were applied for 8 weeks.In scalp acupuncture,the anterior oblique line of the vertex-temporal(MS6),lateral line 1 of the vertex(MS8),lateral line 2 of the vertex(MS9),and lower-lateral line of the occiput(MS14)were selected.In the body acupuncture,the acupoints included Bǎihuì(百会GV20),Sìshéncōng(四神聪EX-HN1),and Dàzhuī(大椎GV14),as well as the bilateral Fēngchí(风池GB20),Nèiguān(内关PC6),Hégǔ(合谷LI4),Gānshū(肝俞BL18),Shènshū(肾俞BL23),Yánglíngquán(阳陵泉GB34),Zúsānlǐ(足三里ST36),Fēnglóng(丰隆ST40),Sānyīnjiāo(三阴交SP6),Tàixī(太溪KI3),and Tàichōng(太冲LR3).Before and after treatments,the unified Parkinson’s disease rating scale(UPDRS),3section of the UPDRS(UPDRS-Ⅲ),and motor dysfunction rating scale for Parkinson’s disease(MDRSPD)were scored in the patients.The therapeutic effect of traditional Chinese medicine(TCM)and LED score were compared between both groups.Results:Thirty-three cases were included in data analysis in each group.After treatment,UPDRS scores were(28.77±8.85)and(36.58±10.16)points,UPDRS-Ⅲscores were(12.16±1.97)and(17.47±2.93)points and MDRSPD scores were(15.56±3.31)and(19.13±4.87)points in the acupuncture+medication and medication groups respectively.The UPDRS,UPDRS-Ⅲ,and MDRSPD scores all reduced after treatments in both groups(all P<0.05).All three scores were lower in the acupuncture+medication group than in the medication group(all P<0.05).When examining the therapeutic effects of TCM,the total effective rate was 87.88%in the acupuncture+medication group and 75.76%in the medication group(P<0.05).After treatment,the LED scores were(387.55±146.24)points and(437.42±183.16)points in the acupuncture+medication and medication groups,respectively.The LED dose differences before and after treatment for the acupuncture+medication and medication groups were(40.36±16.33)points and(95.88±35.79)points,respectively.The LED scores in both groups were higher than the pre-treatment scores(P<0.05).However,the post-treatment LED score was lower in the acupuncture+medication group than in the medication group(P<0.05),as was the dose difference before and after treatment(P<0.05).No relevant adverse reaction was found in each group.Conclusion:In addition to anti-PD medication,the scalp and body acupuncture may effectively relieve the motor symptoms of PD and improve the control of LED score.

某电厂1000MW火电机组引风机和增压风机优化改造研究与应用

某1000MW火电机组投运以来,发现引风机和增压风机的经济性和安全性均较差,其中,引风机选型偏大,增压风机选型偏小,且在低负荷工况时,引风机失速风险较大,高负荷时增压风机失速风险较大。通过对现有风机系统的热态试验,分析了现有引风机和增压风机的运行情况,提出了最优的技术改造方案,并重点评估了改造对锅炉防爆的影响。经过对引风机和增压风机的优化合并改造,取消了增压风机,采用高效的动叶可调轴流引风机取代原有的低效的静叶可调轴流引风机,同时,对烟道系统进行优化改造,大幅提高了机组运行的经济性和安全性。

量子时代的组织与领导力--专访“量子管理”奠基人丹娜·左哈尔

对于组织而言,量子管理要求组织打破自上而下的层级权力结构;对于领导力而言,量子领导者需要有一种更高的道德使命,他的服务是由价值驱动而不是利润驱动。

杨静书法

杨静楷书初学颜、欧,后习渚遂良,兼习墓志’行草宗二王。作品入展全国职工第二届美术书法展和全国石化职工第二届美术书法展,全国职工美展,获全国石化职工第三届美术书法展三等奖,获全国十大企业美术书法摄影展锏奖,参加中、日、韩美术书法巡展,入展全国第八届中青年书法家书法篆刻展,获中国书法家协会书法培训中心第七届学员结业暨教学成果汇报展一等奖。

Interface Characteristics and Evolution Mechanism of W/CuCrZr in Hot Melt Explosion Welding

Explosion welding was carried out on the basis of vacuum hot melt W/CuCrZr composite plate.Metallurgical microscope,scanning electron microscope and energy dispersive X-ray spectroscope were used to observe the microscopic morphology of the bonding interface.At the same time,combined with finite element calculations,the evolution mechanism of the interface of the hot melt explosion welded W/CuCrZr composite plate was explored.The results show that the interface bonding of the hot melt explosion welded W/CuCrZr composite plate is good and there is a cross-melting zone with 3–8μm in thickness,but cracks are developed on the W side.The numerical simulation reproduces the changes of pressure,stress,strain and internal energy at the bonding interface in the process of hot melt explosion welding.The location of the crack generated in the experiment coincides with the high stress position calculated by numerical simulation.The high pressure and high temperature near the hot melt explosion welding interface further promote the bonding of the interface.