Cu/Sb/Sn/Mo/W对新国标09CrCuSb钢组织及力学性能的影响

采用金相显微镜、扫描电镜、电子探针、拉伸力学性能测试、夏比冲击测试,研究了新国标NB/T47019-2021的09CrCuSb钢合金元素Cu、Sb、Sn、Mo和W对其微观组织和力学性能的影响。研究表明,新标准中增加的合金元素将促进钢中δ-铁素体的析出,同时也会增加材料强度但会降低其塑性;δ-铁素体将显著降低材料冲击力学性能[其中,Rp0.2=365.64 MPa,夏比冲击功KV2为243 J(室温)和192 J(-40℃)],使得冲击断口由塑性断口向脆性断口特征转变,特别是对-40℃的冲击功降低作用尤为显著。在新国标成分框架下,须通过合理的热加工工艺调整,降低钢中δ-铁素体的析出,从而提高材料力学性能。

Improved Removal Efficiency of Submicron Inclusions in Non-oriented Silicon Steel during RH Process

To improve the removal efficiency of such submicron inclusions,we designed an argon blowing method for an RH facility based on mathematical simulations.The effect of the argon blowing on the liquid steel flow and the movement of submicron inclusions was studied using the k-ε flow model coupled with the DPM model for inclusion movement based on fluid computational dynamics in FLUENT.It was found that a more uniform argon flow can be achieved in the up-leg snorkel with a new nozzle position and inner diameter,which resulted in a favorable up-lifting and mixing movement.The new design also increased the circulation rate of molten steel in the RH chamber.The increased turbulent kinetic energy and turbulent dispersing rate enhanced the collision probability of submicron inclusions,which results in an improved removal for 0.5-1 μm inclusions.The proposed RH facility could increase the removal rate of submicron inclusions from the original 57.1% to 66.4%,which improves the magnetic properties of non-oriented silicon steel.

冷却速度对6.5%Si高硅钢再结晶织构及磁感的影响

将6.5%Si高硅钢薄板在1000℃下保温1 h后,以不同冷却方式冷却,通过XRD测试分析试样的宏观织构和残余应力,采用EBSD测量试样的微观织构,并通过磁性测量仪测量磁感B8,研究冷却速度对6.5%Si高硅钢再结晶织构、残余应力以及磁感的影响。结果表明,再结晶退火后的冷却速度对6.5%Si高硅钢薄板再结晶织构的类型、含量以及分布无显著影响,但是随着冷却速度的降低,{100}和{110}面织构与理想取向的偏离程度减小,对提高磁感B8有利。(100)和(110)面的残余应力远大于(111)面的残余应力,且随着冷却速度的降低,试样中的残余应力逐渐减小,这是织构偏离程度发生变化的主要原因。随着冷却速度的降低,残余应力引起的晶格畸变减小,则磁化过程中磁畴壁的位移阻力减小,磁感B8逐渐增加。

冷拔应变对304H钢丝扭转性能的影响

研究了304H不锈钢丝Φ2.6 mm至Φ0.89 mm冷拔过程中组织演变和缺陷对不锈钢丝扭转性能的影响。结果表明:当钢丝冷拔真应变介于0~1.39时,扭转性能急剧下降、扭转次数减少;当冷拔真应变介于1.39~2.14时,扭转性能逐步回升,扭转次数增加。随着应变的施加,加工硬化导致位错塞积致使塑韧性变差,是扭转性能下降的主要因素,且此阶段{111}//ND织构含量增加也不利于扭转性能;随着冷拔真应变进一步增大,钢丝内部晶粒细化为超细晶粒导致强度进一步提升,塑韧性回复,是扭转性能回升的主要因素,且{111}//ND织构含量下降也有利于扭转性能。但冷拔真应变超过1.39之后,夹杂物平均面密度也同时增加,阻碍了钢丝扭转性能的进一步恢复。

Antenna selection based on large-scale fading for distributed MIMO systems

An antenna selection algorithm based on large-scale fading between the transmitter and receiver is proposed for the uplink receive antenna selection in distributed multiple-input multiple-output(D-MIMO) systems. By utilizing the radio access units(RAU) selection based on large-scale fading,the proposed algorithm decreases enormously the computational complexity. Based on the characteristics of distributed systems,an improved particle swarm optimization(PSO) has been proposed for the antenna selection after the RAU selection. In order to apply the improved PSO algorithm better in antenna selection,a general form of channel capacity was transformed into a binary expression by analyzing the formula of channel capacity. The proposed algorithm can make full use of the advantages of D-MIMO systems,and achieve near-optimal performance in terms of channel capacity with low computational complexity.

基于蘑菇状的金/聚苯胺纳米复合材料的亚硝酸根传感器

通过原位聚合法制备了金纳米颗粒(Au NPs)掺杂的聚苯胺(PANI)纳米复合材料,该复合材料修饰的电极(Au/PANI/GCE)对亚硝酸根(NO_(2)^(-))的氧化具有明显的电催化活性,其独特且均匀分散的蘑菇状结构可以掺杂更多的Au NPs,提供较多的活性位点和较大的比表面积,有助于提高电化学催化NO_(2)^(-)的效果。导电聚合物PANI中可质子化的苯胺(PhNH^(3+))与溶液中带负电荷的NO_(2)^(-)产生静电吸附可促进电子的传递。Au/PANI/GCE对NO_(2)^(-)的检出限为0.6876μmol/L,线性范围为10~2400μmol/L,线性相关系数R^(2)=0.9957,该传感器为实际湖水样品中亚硝酸盐检测提供了新方法。