Solidification crack characteristics and sensitivity of peritectic steel

The characteristics and sensitivity of solidification cracks in peritectic steels were investigated using directional solidifi-cation technology.Interdendritic cracks were observed in both hypoperitectic steels(12CrlMoV,15CrMo)and hyper-peritectic steel(20CrMo)during solidification at growth velocities of 15,50,and 80 pm/s.At the dendritic boundaries,sulphide precipitates were found,promoting crack formation.Based on the statistical analysis of interdendritic cracks in peritectic steels,the area ratio(RA)of interdendritic cracks in a directional solidification structure was proposed to evaluate the crack sensitivity of peritectic steels.Furthermore,the crack sensitivities of peritectic steels(12CrlMoV,15CrMo,and 20CrMo)were tested,evaluated,and compared with the surface crack rates of three types of steels produced from a steel plant.The results demonstrated that RA was in good agreement with that of the steel plant,and the crack sensitivity of 12CrlMoV steel was the strongest,followed by that of 15CrMo and 20CrMo steels.Thus,RA can be used to evaluate the crack sensitivity of peritectic steel.

孔雀石绿对金属钴超填充和成核过程的影响

随着芯片制程低于7 nm,互连线后端填充的铜线电阻急剧增加,而平均自由程更低的金属钴(Co)可以用来取代铜,以减少由外表面和晶界处发生的散射导致的线电阻增长。在此选用硫酸钴(CoSO_(4))作为主盐,硼酸为缓冲剂,以孔雀石绿(MG)为抑制剂进行研究。通过电化学伏安法测试,发现随着MG浓度的增加,金属Co的沉积过电势逐渐增加,沉积受到抑制。利用电化学石英晶体微天平(EQCM)测试得出,MG的加入对整个沉积过程产生明显的抑制作用。这是因为MG容易吸附在阴极表面,与Co^(2+)形成配位键,从而抑制了Co^(2+)还原。随着对流过程的增强,阴极电流密度逐渐减小。最终确定镀液配方为0.4 mol·L^(-1)CoSO_(4),0.5 mol·L^(-1)硼酸,少量Cl^(-),20 mg·L^(-1)3-巯基-1-丙磺酸钠盐和10 mg·L^(-1)MG,在-1.27 V,pH=4的条件下,可以实现微米级别PCB盲孔的超填充。由计时电流法测定的曲线分析得出金属Co的成核方式为三维瞬时成核。通过量化计算和分子静电势可知,静电势分布在35~78 kcal·mol^(-1)之间,MG分子中与氮相连的共轭结构吸附在阴极表面,而其中的苯环结构通过离域π键结构与Co^(2+)发生作用,从而抑制了Co^(2+)沉积过程。

Energy saving analysis for CO_(2)–O_(2)mixed injection technology in converter steelmaking

Energy-saving in China's iron and steel industry still relies on the development and improvement of short-term energy saving technologies.Therefore,a special converter smelting technology incorporating energy saving was proposed.To evaluate the energy-saving potential of the CO_(2)–O_(2)mixed injection(COMI)technology,collected production data were used to develop an improved techno-economic model.Calculations reveal that the technology can save energy through auxiliary material consumption,sensible heat of solid by-product,iron loss reduction,and energy recovery.The application of COMI technology in an enterprise is cost effective,involving the energy saving potential of 0.206 GJ/t,the cost of conserved energy of−48.83 yuan/GJ,and a simple payback period of 0.35 year for a 60-million-yuan investment.Sensitivity analysis shows that the investment cost and discount rate primarily influence the cost of conserved energy of the technology.As the discount rate increased,the cost of conserved energy also gradually increased.Overall,the COMI technology is an energy-saving technology with good development prospects.

Xanthogranulomatous Cholecystitis and Misdiagnosis Analysis

INTRODUCTION Gastric sub-epithelial masses （SEMs） are relatively common findings when receiving gastric endoscopy. It is a mass, bulge, or impression visible. Computed tomography （CT） and magnetic resonance imaging can assist in making a diagnosis,