区块链技术在工会治理新模式中的应用研究

工会体系数字化、智能化转型过程中需全面提升整体智治、数据赋能、普惠服务和业务上网等内容。针对工会中存在的数据孤岛、跨数据及跨行业协作难、生态圈未有效建立、缺少创新服务供给等问题,文章设计实现了工会治理模式总体架构,构建了基于区块链的基本医疗服务及保障、旅游休闲、消费购物、创新服务等场景应用模型。经上线试运行证明,该系统各项功能完备,这表明区块链技术在赋能数字经济、数字社会及推进智慧工会建设方面具有重要意义。

我国外商直接投资外汇管理方式研究——基于准入前国民待遇加负面清单模式的制度背景

2019年,《中华人民共和国外商投资法》颁布,以法律的形式明确我国对外资实施准入前国民待遇加负面清单管理。为适应这一管理制度改革的要求,近年来,外汇管理部门大力精简优化外商直接投资(FDI)管理流程,初步建立FDI负面清单外汇管理框架。但在实际中,FDI负面清单管理仍存在政策缺乏独立性、负面清单管理理念执行不够到位、配套制度不够完善等问题。为此,本文提出进一步改进负面清单FDI外汇管理方式的相关政策建议,以保障“准入前国民待遇加负面清单”外资管理模式顺利推行。

薄带连铸结晶辊表面毛化工艺的全过程计算模型

提出了一种全新的统一计算方法,该方法建立了高速微粒轰击毛化工艺与结晶辊表面最终形貌参数之间的数学模型,即将整个毛化工艺制备过程划分为三个阶段:第一阶段是应用计算流体力学(Computational Fluid Dynamics,CFD)方法模拟轰击微粒在喷嘴内外的加速过程,并获得微粒到达结晶辊基体表面时的轰击速度;第二阶段是应用非线性分析工具(Lsdyna)和已获得的轰击速度值来模拟微粒与基体之间的碰撞过程,同时获得基体表面轰击坑的深度数值;第三阶段是在大量试验统计的基础上,提出一种简化粗糙度模型,将轰击坑深度与表面粗糙度参数Rz(微观不平度十点高度)等联系起来。综合前述三个阶段的数值模拟结果,给出毛化工艺的全过程计算模型,并且通过试验进行反复验证和校核,最终计算模型在结晶辊表面形貌的设计、制备及生产实践中得到了较好的应用。

Progress in the application of cold gas dynamic spraying to repairing continuous casting molds

A new continuous casting mold repairing method--cold gas dynamic spraying （CGDS） is introduced. The study investigates the advantages of the CGDS process regarding repairing operation, such as convenient, in-situ repairation,little heat delivery, microstructural and dimensional stability and other special applications. Microstructure and mechanical properties of the copper alloy coating, nickel coating, ceramic composite coating, and their interface to the substrates ,which are usually used in repairing operation have been researched by means of optical microscopy （ OM）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and micro-hardness tests. Experimental results have demonstrated the relative density of the copper alloy coating is as high as 98.7%, and that no obvious difference can be observed between the CrZrCu substrate and the Cu alloy coating in terms of microstructures; thus the interface is quite difficult to be identified. The bonding strength and micro-hardness of the Cu alloy coating reach up to 37 MPa and 310 HV0.2 ,respectively. The interface between the copper alloy coating and the nickel coating is either zigzag or wave shaped, and the cohesion is relatively good. As-sprayed nickel coating is dominated by severely deformed particles,and the relative density is up to 98.5%. Complete recrystallization occurred after annealing at 900℃ for one hour,while its micro-hardness remains as high as 124.1 HV02. All these results have indicated that CGDS is a promising technology for repairing the continuous casting mold and that its future development is prosperous as well.

Numerical simulation of the effects of the impact velocity on the particle deposition characteristics in cold gas dynamic spraying

In this study, the effects of the impact velocity on the particle deposition characteristics in cold gas dynamic spraying （CGDS） of 304 stainless steel （SS） on an interstitial free （IF） steel substrate are numerical simulated by means of a finite element analysis （FEA）. The results have illustrated that when the particle impact velocity exceeds a critical value at which adiabatic shear instability of the particle starts to occur. Meanwhile, the fatten ratio and impact crater depth （or the effective contacting area ） increase rapidly. The particle-substrate bonding and deposition mechanism can be attributed to such an adiabatic shear deformation induced by both the compressive force and the slide friction force of particle. The critical velocity can be predicted by numerical simulation, which is useful to optimize the CGDS processing parameters for various materials.

The effect of annealing treatment on the microstructures and mechanical properties of cold-sprayed nickel coating

The effect of annealing treatment on the microstructures and mechanical properties of cold-sprayed Ni coating was investigated by conducting micro-hardness and tensile tests and using a normal optical microscope （OM） ,a scanning electron microscope （ SEM）, a transmission electron microscope （TEM） and an electron probe X-ray microanalyzer （EPMA）. The results show that following the increase of the annealing temperature ,the micro-hardness of cold-sprayed Ni coating decreases and the elongation after fracture increases, while the tensile strength increases before decreasing. The tensile deformation and fracture behavior change from a typical brittle fracture to a hybrid brittle and ductile fracture, then to a typical ductile failure. It is found that when annealed at an elevated temperature （ e. g. 900℃ ） ,the grains tend to grow abnormally with the oxides spheroidizing and the defects agglomerating at the interfaces, causing the tensile strength reduction of the cold-sprayed nickel coating. It is also pointed out that the tensile strength of the cold-sprayed Ni coating can be significantly improved by the appropriate annealing procedures, but the elongation after fracture cannot be clearly increased because it is difficult to eliminate the main defects in the coating by the following heat treatments.

A unified computational model for surface texturing process of strip casting rollers

A new unified computational method is proposed for modeling the relationship between the parameters of the high-speed particle-impact texturing process and the final surface morphology of the casting roller. The whole surface-texturing process is divided into three parts. The first part is the acceleration process of particles inside and outside the nozzle,which can be analyzed using the computational fluid dynamics method to obtain the particle impact velocities. The second part is a simulation of the bombardment process of particles onto the roller surface using the LS-DYNA software as the analysis tool and the results obtained in the first part as input parameters. The last part is the continuously random impact process of particles on the casting roller surface to form a functional surface,which is characterized by a simplified roughness model. Finally,the above three parts are combined to establish a unified computational model,the performance of which is successfully verified in a series of experiments.

Influence of the preheated substrate temperature on the microstructure deposition behavior of the 304 stainless steel coatings deposited by cold gas dynamic spraying

The effects of the substrate temperature on the deposition and microstructure of the 304 stainless steel （SS） cold gas dynamic spraying （CGDS） coatings were investigated. It was found that the higher substrate temperature could increase the deposition rate of the 304 SS particles,even the oxide films existed at the interface. There was a critical oxide film with a thickness of 3 -4 um which could be destroyed by the impacted particles. The micro-hardness and microstructure of the 304 SS coatings under different substrate preheating temperatures were almost the same.

Effect of surface nanocrystallization on the electrochemical hydrogen evolution behavior of IF steel

Cathodic polarization curve and electrochemical impedance spectroscopy in 30% NaOH solution were utilized to investigate the hydrogen evolution （HE） behavior of interstitial free （IF） steel surface nanocrystallized （SNC） via ultrasonic particulate peening （USPP）. The surface morphology and grain size of the steel were analyzed by scanning electronic microscope （SEM） and X-ray diffraction （XRD）. It was found that the IF steel treated by SNC and SNC ＋ 1% roiling got reductions of 200 mV and 300 mV in HE over-potentials ,respectively. Their real surface areas are enlarged by about 20 times and the hydrogen evolution reaction activation flee energies are about 50% of the original IF steels＇ s activation free energy.

埃克替尼相关局灶增生型IgA肾病和急性肾小管损伤

1例68岁男性肺腺癌患者接受埃克替尼125 mg口服、3次/d和康莱特软胶囊2.7 g口服、4次/d治疗。用药前血清肌酐(Scr)91μmol/L。用药29 d后患者出现泡沫尿、乏力、胸闷、食欲下降、颈部及胸前皮肤出现红色皮疹等,未予干预,共用药76 d。实验室检查示Scr 167μmol/L,免疫球蛋白A(IgA)4090 mg/L,尿蛋白2 g/L,24 h尿蛋白2.61 g,尿红细胞6.8个/高倍视野,尿α微球蛋白66.9 mg/L。病理检查结果示局灶增生型IgA肾病和急性肾小管损伤,考虑由埃克替尼引起可能性大。嘱患者低蛋白饮食并予对症治疗,80 d后,患者Scr 189μmol/L、尿蛋白2 g/L。此后患者失访。

基于美国胸科医师学会抗栓指南思考的抗血栓药物围手术期管理

2022年美国胸科医师学会(American College of Chest Physicians,ACCP)发布抗栓治疗的围手术期管理指南。该指南主要针对4种临床情况提出抗栓建议,分别是接受维生素K拮抗剂、肝素(heparin)桥接、直接口服抗凝药物及抗血小板药物这4类药物需要手术或侵入性操作患者以及围手术期实验室检测提供指导建议。该文就ACCP围手术期抗栓治疗既往版本指南进行比较,同时结合国内发布的《抗栓治疗病人接受非心脏手术围手术期管理上海专家共识(2021版)》和《中国血栓性疾病防治指南》对该指南进行全面解读,以期为临床围手术期应用抗血栓药物提供参考。