“双碳”背景下国有交通企业转型发展新路径

党的二十大报告指出,要积极稳妥推进碳达峰碳中和,推进工业、建筑、交通等领域清洁低碳转型,加快推动产业结构、能源结构、交通运输结构等调整优化,加快规划建设新型能源体系,积极参与应对气候变化全球治理。交通运输是碳排放的重要领域之一,推进交通运输行业碳达峰碳中和工作,是交通类国有企业的重要社会责任,也是加快产业转型升级、实现企业高质量发展的必由之路。

面向密文数据的OPTICS聚类模型

OPTICS(Ordering Points To Identify the Clustering Structure)是一种在机器学习领域中发挥重要作用的密度聚类算法.随着外包聚类服务的发展和用户隐私保护意识的日益提高,OPTICS需要对密文数据提供聚类支持,进而保证用户数据的隐私性.为此,利用全同态加密(Fully Homomorphic Encryption,FHE)技术构建了面向密文数据的OPTICS聚类模型(OPTICS Clustering Model over Encrypted Data,OPTICS-CMED),该模型是一个包括客户端与服务器的两方外包密文数据聚类模型.首先,给出了模型的实体描述和形式化定义.设计了OPTICS-CMED的通信协议,包括距离计算协议和排序协议.基于上述通信协议,给出了OPTICS-CMED的聚类过程.对模型的正确性、安全性分别进行了分析,并利用FCPS标准数据集进行性能测试,结果表明该模型能够在保证聚类正确性和安全性的前提下实现密文数据聚类,解决了聚类过程中的用户数据隐私保护问题.

Influence of Billet Size on Flow,Solidification and Solute Transport in Continuous Casting

The dead load crown of hydraulic elastic bulging roll was discussed using the theory of elastically supported beam, and the dead load experiment was carried out. The theoretical calculation is consistent with the experimental result. The structure parameters for the thickness of roll sleeve, the length of the oil groove and the crown of roll were discussed. The fundamental principle of determining the parameters was put forward. The theoretical basis of the application of the hydraulic elastic bulging roll was established.

基于STIRPAT模型的陕西省交通运输业碳排放影响因素分析

为了系统地从行业角度测算及分析陕西省交通运输业碳排放的影响因素,采用灰色关联度法识别交通系统内部影响因素,再结合人口、经济及技术的基础因素,建立STIRPAT扩展模型,对2000—2020年陕西省交通运输碳排放进行量化分析。研究结果表明:城镇化率、能耗强度、人均国内生产总值为交通运输碳排放量增加的正向驱动因素;交通运输需求方面,货运需求增加对陕西省交通运输碳排放有促进作用;运输结构方面,降低公路运输量占比会对交通运输碳排放量有抑制作用;基础设施建设方面,近20年来完善公路网络基础设施建设对陕西省交通运输碳排放有促进作用;运输装备方面,民用汽车拥有量增加会使陕西省交通运输碳排放量增加。因此在经济正常发展情景下,优化交通运输结构,提升铁路、公共交通等低碳运输方式的比例,积极推进绿色交通技术和产品的推广应用,加强新能源汽车安全技术标准与配套设施建设,加快智慧交通发展,有助于控制交通运输碳排放水平。

Composition and partition of biomass in a smith fir (Abies georgei var.smithii) timberline forest on the Sergyemla Mountain,southeastern Tibetan Plateau

The southeastern Tibetan Plateau has the highest timberlines in the world and climate change affects this area to a considerable extent. Quantification of vegetation biomass in the forests at the timberline is essential for understanding carbon balance, forest structure and functional changes in the forests at timberlines. We describe biomass and its constituent components of a smith fir tim- berline forest occurring at an elevation of 4320 m on the Sergyemla Mountain in the southeastern Tibetan Plateau. The results show that, in the tree layer, the average diameter at breast height （DBH） was 35.6 cm, the density 251 trees per hectare with a total biomass of 309.9 t.ha 1. Of the total biomass, the tnmks accounted for 70.49%, branches for 9.09%, leaves for 5.57% and roots for 14.85%. The total biomass in the shrub layer was 77.9 t＇ha-~ of which the biomass of trunks, branches, leaves and roots accounted for 42.8, 14.9, 4.6 and 15.6 t.ha-1, respectively. The total biomass in the herb layer was 3.0 t.ha-1. The total vegetation biomass in the smith fir timberline forest was 390.9 t-ha-l, to which the tree layer contributed the most （79.3%）, followed by shrubs （19.9%） and herbs （0.8%）. We estimate that the smith fir forest stand at the timberline had a higher total biomass than other fir or spruce forest stands in the surrounding area.

Solidification in Soft-Contact Continuous Casting Mold with Alternating Electromagnetic Field

The mechanical behavior of the mushy zone was studied in detail. Based on the analysis of conventional high temperature mechanical model, considering the physical phenomenon in casting process, a mechanical model suitable for describing the mechanical behavior of the casting material in twin roll casting process was built. Comparing experimental results to the numerical simulated ones, the mechanical model was proved to be correct.

Estimation of the Aircraft CO_2 Emissions of China's Civil Aviation during 1960-2009

Based on data collected by Chinese Civil Aviation Statistic Center, the annual CO2 emissions of aircrafts during 1960-2009 were calculated, and the emission intensity and its dynamic characteristics were analyzed. The results show that the total CO2 emissions of aircrafts in China increased from 120×10^3 t in 1960 to 41.44×10^6 t in 2009. The CO2 emission intensity decreased from 2.9 kg （converted t kra）-1 in 1960 to 0.96 kg （converted t km）-1 in 2009 at an average rate of 0.04 kg （converted t km）-I per year. The average share of CO2 emissions of aircrafts on the total CO2 emissions from the sector of transportation, storage and post was 6.6% during 1980-2005, and 0.25% on the total emissions from fossil fuel combustion during 1971-2008.

Kinetics of Oxidation Reaction for Magnetite Pellets

An experiment for the oxidation process of single magnetite pellet and theoretical analysis based on modi lied unreacted core shrinking （MUCS） model were carried out, and the controlling mechanisms of the initial and de veloping reactions were examined, respectively. From the study of the initial reaction, it was found that the chemical reaction of surface is the controlling step of the overall reaction when the temperature is up to about 750 K, while the mass transfer through the gaseous boundary layer dominates the reaction rate when the temperature is above 750 K. As the reaction developing within the pellet, the mass transfer through the produced layer becomes the controlling step. In addition, the effects of reaction conditions （such as oxygen concentration, temperature） on the fractional oxidation of magnetite pellet were determined.

Study on the Characteristics of Fluid Flow in Stirring Vessel of New Type Stirring of KR Desulphurization

Aimed at the problem of short life of mixing head in KR mechanical mixing method for desulfurization of hot metal,a new type of mixing stir was proposed.CFD theory was used to simulate the characteristics of the fluid flow for the new type of stirring vessel of water model for KR mechanical desulfurization.Flow characteristics and structures of the flow field were investigated and compared with the traditional cross-flow type.The results show that the new type of impeller can not only improve the defects of the flow caused by stir structure of the traditional type,but also reduce the separation of mixing zone in the stirred tank and make the flow field more uniform to make the desulfurization more fully, thus shortening the mixing time,and improving the life of mixing head.Numerical simulation method has been proven to be sound by comparing with the experimental ones.

A New Steel Teeming Technology by Using Electromagnetic Induction Heating System in Ladle

In order to overcome the pollution of the tratitional nozzle sand into the molten steel in tundish,a new method is proposed in this paper.In this method,the nozzle sand is substituted with iron-carbon alloy particles which have the same or similar compositions as the liquid steel.During casting processes,iron-carbon alloy forms solidification shell and the sintered layer in the upper nozzle to block the molten steel.When the slide gate is opened,the eletromagnetic induction heating is used to melt them so as to achieve 100%smoothly steel teeming.The electromagnetic induction heating effects were analyzed theoretically in the new slide gate system.Then the new method has been experimentally tested by using self-designed experimental device.The results show that the electromagnetic induction heating can complete the steel teeming within the required time.Furthermore,this steel-teeming technology can further improve the cleanliness of liquid steel.

Suppression of Effect of Uneven Velocity in Submerged Entry Nozzle in Round Billet Continuous Casting Process Using Electromagnetic Swirling Flow

Sliding gate control system is widely employed in continuous casting process of steel to control flow rate of molten steel.As molten steel passes through a sliding gate,uneven flow develops.This will cause asymmetrical distribution of flow and temperature field in mold consequently,formation of vortex near the nozzle and entrapment of CC powder into the molten steel.etc,which have negative effect on process productivity and product quality.To suppress the uneven flow,electromagnetic swirling flow has been proposed to impose on the flow in submerged entry nozzle below the sliding gate.In this study the uneven flow developed by incompletely open sliding gate and the suppression of this uneven flow using electromagnetic swirling flow are numerically studied in round billet continuous casting of steel process.The improvement of the flow and temperature filed in the submerged entry nozzle and mold are investigated.It is found that:The uneven velocity in nozzle can be suppressed by electromagnetic swirling flow,and the flow and temperature field in mold be improved obviously;With the increase of electromagnetic swirling intensity,the effect of uneven flow can be almost completely suppressed.

Improvement of Inner Quality of High Carbon Wire Rod Steel Using Combined Electromagnetic Stirring

To improve the quality of high carbon wire rods,combined electromagnetic stirring was introduced in the continuous casting of round billets with a diameter of 250mm at Tianjin Rockcheck Steel Group Co.In this paper,the positioning of final electromagnetic stirring(F-EMS)was determined by nail-shooting method.Furthermore,the effect of mold electromagnetic stirring(M-EMS)on the macrostructure and internal defects in the round billets was investigated to find out the optimal operating parameters for continuous casting of SWRH 82B round billets.The results show the desirable positioning of F-EMS locates 9.7m below the mold level where the molten steel can be effectively driven by electromagnetic force and disperse central composition segregation.The shrinkage cavity is totally eliminated with the rotational M-EMS.The ratio and index of central composition segregation and center porosity can be reduced significantly. Furthermore,the equiaxed crystal ratio is considerably increased to 64%under 480A/3Hz M-EMS and 500A/10Hz F-EMS. Fine microstructure and mechanical property of wire rod are presented after optimization of combined electromagnetic stirring.Accordingly,the probability of occurrence of cup-cone fracture of wire rod is reduced dramatically.

Modeling of Orientation and Alignment of Primary Al_3Ni Crystal in Al-Ni Alloy by Imposing a High Magnetic Field

Regarding Al_3Ni crystal as a rigid ellipsoid,a model describing the orientation and alignment of a primary paramagnetic Al_3Ni crystal in Al- Ni alloy solidification under a high magnetic field is developed.The model is based on rigid body rotation dynamics model as well as the magnetic dipole model,respectively.It describes the rotational motion of a magnetic anisotropic crystal around its centroid and around one endpoint of its crystal axis.The orientation time and the orientation characteristics with the intensity of magnetic field,the aspect ratio of the crystal and the effective viscosity of the melt,as well as the crystal growth,are deeply discussed for single grain.Furthermore,the interaction between two crystals during the alignment in high magnetic field are analyzed based on the magnetic dipole model,in which the final state of the grain is dependent on the attractive interaction force between two neighboring grains and the magnetization force acting on each grain.The prediction shows fitness with the experimental and theoretical results in literature.

Effect of 31.2T Magnetic Field on Microstructure and Performance of an Ag-45.8wt%Ni Alloy

Ag/Ni Multilayers were prefabricated by Accumulative Roll-Bonding(ARB),with an average layer thickness ranging 20-100 nm.The Ag-45.8wt%Ni alloys were annealed under 31.2T high magnetic field to study its effect on microstructure and performance.31.2T high magnetic field significantly suppressed the coarsening of layer structure during annealing,the magnetic field parallel to the layer has a larger suppression effect.As the annealing temperature increased,the resistivity of Ag/Ni multilayers increased,and the hardness decreased.The case of perpendicular high magnetic field has the largest resistivity and the largest hardness,compared with the other two cases.The hysteresis loops shows that Ag-Ni has a hard ferromagnetic property.The case of parallel magnetic field has the largest coercivity about 90Gs.

Fundamental Study on Continuous Casting Process With Swirling Flow by Electromagnetic Force

Swirling flow in a submerged entry nozzle is effective on improving quality of casting block and casting speed in continuous casting of steel.A new method for swirling flow generation in the nozzle has been proposed by the authors,that is a rotating electromagnetic field is set up around a submerged entry nozzle(SEN)to induce swirling flow in it by Lorentz force.In this study,the magnetic field in molten steel in the submerged entry nozzle,the flow and temperature field in the SEN and mold in round,square billet and slab continuous casting process of steel are numerically studied.The model experiment of electromagnetic swirling continuous casting is also conducted with low melting point alloy.The commercial test for slab is undergoing.Results by numerical simulation and experiment show that the swirling flow by the optimum designed electromagnetic swirling generator can not only improve the distribution of flow and temperature in mold but also achieve the same effects generated by the swirling blade process. And,more effects on continuous casting process can be expected after this electromagnetic swirling process is optimized.

Effect of Electromagnetic Stirring on the Distribution of Nb Phase in Cu-5wt%Nb Alloys

The effect of electromagnetic stirring(EMS)on the distribution of Nb particles in solidified microstructure of a Cu-5wt%Nb alloy were studied.In this paper,we have Cu-5wt%Nb alloy remelted and solidified with or without electromagnetic stirring,to study the effect of EMS on the distribution of Nb phase and the hardness of ingots.The 300A/16Hz EMS has refined the mircostrucrure of Cu-5%Nb alloy,with smaller particles sizes and larger amounts,and is benefit to the homogenous distribution of particles.The fitted lognormal distribution of particles diameter that in case without or with EMS are compared,and the EMS case has the highest frequency percentage in the range of smaller size. EMS considerably increased the hardness of Cu-5%Nb alloy ingot.

Effect of M-EMS Parameters on Quality of 82B High Carbon Steel

In this paper,the rule of M-EMS on Φ250mm 82B high carbon steel during the casting process was investigated by numerical simulation and experiments.The influence of M-EMS current and frequency on distribution of flow field was researched.The simulation results show that:At the same current,velocity increases with the frequency increase.With the increase of frequency,the velocity first decreases and then increases as the frequency increase along the casting direction. At the same frequency,velocity increases with the current increase.The turbulence zone also become more strenuous, especially in free surface,the suitable turbulence is benefit to uniform steel temperature.Experiment results show that the quality defects of 82B high carbon steel can be significantly improved with M-EMS.The zone of central pipe decreases. With the increase of current,equiaxed zone ratio increases.Considered the results of numerical simulation and experiments, the optimized EMS parameters of Φ250mm high carbon steel are the stirring current of 480A and the stirring frequency of 3Hz,which can improve strand quality greatly.

Research on Refining Technology of Clean Steel in a Plasma Ladle Furnace

The clean steel refining tests carried out in a 100 kg plasma ladle furnace(PLF)were to show the metallurgical effects of the different plasma gases such as Ar-H_2 and Ar-CO_2.The variations of carbon,nitrogen contents in steels and the mechanism of denitrogenation were studied.Compared with the conventional ladle furnace,when the plasma gases were injected into the ladle furnace,there was a decarburization process,the carburetion rates were reduced obviously. The carburetion rate is 3.6×10^(-6) per minute for the steel heated by conventional LF,and is 2.20 and 1.35 times of the heats blown 85%Ar-15%H_2 and 85%Ar-15%CO_2,respectively.When the plasma ladle furnace operated with Ar-H_2 plasma gas, the denitrogenation of the molten steel occurs.The lowest denitrogenation rate is 0.30×10^(-6)per minute when Ar-H_2 gas mixtures were used.The main reactant gas is monatomic hydrogen and the main product of denitrogenation is NH_3 for Ar-H_2 injection.

The Research on Soft-Contacting Electromagnetic Continuous Casting in Baosteel

The paper introduces the research and new development on soft-contacting electromagnetic continuous casting in Baosteel.At the year of 2008,Baosteel successfully completed the carbon steel SCEMCC industrial experiment in a 6-strand curved type round billet caster.At the year of 2011,Baosteel selected another 3-strand curved billet caster. Baosteel successfully developed the SCEMCC mold for the first time to do the industrial production experiment for stainless steel round billet continuous casting.Then,in the same stainless steel caster,the square billet SCEMCC mold was successfully developed too.And at the beginning of the year 2012,the square billet SCEMCC of SUS304 and SUS303Cu was implemented up to now.It was proved the machine system was reliable for the long time production.The industrial experimental result shows the soft-contacting electromagnetic continuous casting can reduce the depth of oscillation mark from about 0.7mm to near zero.The SCEMCC billets without surface grinding were transferred to mill tubes,of which the quality is satisfied.

Effect of High Magnetic Field on Solidified Structure and Properties of Cu-Cr In Situ Composite

The microstructure of ripening processed Cu-15%Cr alloys and deformed samples were examined under a 12T high magnetic field.The high magnetic field has accelerated the Ostwald Ripening process of Cr phase,the Cr-rich particles in 12T HMF case are coarser compared with 0T case.The 12T high magnetic field increased the peak strength of Cu(111)crystal plane and Cr(110)crystal plane,and appeared to has an orientation effect.Compared with the 0T case, the 12T high magnetic field case decreased the tensile strength and hardness.