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The relationship between the size distribution of inclusions and the total oxygen in steel was studied by following the inclusions' size and number of the samples at different locations. The content of macro-inclusions in liquid steel could be estimated accurately by the fluctuation of total oxygen in the same sample,which quantified the cleanliness evaluation index. The number of inclusions per unit volume decreased exponentially with the increase in sizes. Also,the distribution uniformity of inclusions in steel worsened as the size increased. Thus,micro-inclusions with the size below 10 μm occupied above 95% of total inclusions in the liquid steel,which showed a good relationship between the measured value of total oxygen and the integration oxygen in micro-inclusions.Total oxygen could represent the uniform distribution level of inclusions in steel; good uniform of inclusions in steel meant small fluctuation. Macro-inclusions could result in the fluctuation of total oxygen. Large fluctuation of total oxygen reflected a high amount of macro-inclusions in steel.

Objective To explore the correlation between lymphocyte subtypes and CT pulmonary inflammatory index in patients with coronavirus disease 2019 (COVID-19). Methods Clinical data of 80 COVID-19 patients identified by nucleic acid test and clinical symptoms admitted in our hospital from January to February 2020 were collected in this study. They were 45 males and 35 females, and at an average age of 51.2 years. According to the severity of the disease, they were divided into the non-severe group (ordinary type, n=68) and the severe group (serious and critical type, n=12). The clinical data, chest CT findings and pneumonia index of the patients were observed and analyzed. Spearman analysis was employed to analyze the correlation between pneumonia index and lymphocyte subtypes count. Results The results showed that the T lymphocyte subsets of patients with COVID-19 were normal or decreased, and the levels of C-reactive protein and IL-6 were increased or normal. During the following courses of disease, within 1 week, weeks 1~2 and 2 weeks later, counts of CD3+ and CD4+ T cells in the severe group were decreased significantly at above 3 periods (P < 0.05), CT pulmonary inflammatory index was obviously elevated at the 3 periods (P < 0.05), and CD8+ T cells count was decreased during the former 2 periods (P < 0.05), when compared with the non-severe group. It was found that the peak time of CT pulmonary inflammation was mainly within 2 weeks after onset, and the beginning time of pneumonia absorption was mainly within 1~3 weeks. The pneumonia index was negatively correlated with CD3+, CD4+, CD8+ T cells and Lym counts (P < 0.05). Conclusion The lower counts of lymphocyte subsets are, the severer the CT pulmonary inflammation is, and the more serious the condition is in COVID-19 patients.

At present, hot-rolled strip manufacturing has gradually exhibited more diversity and process complexity. Using the single control strategy, the traditional strip-finishing temperature-control mode shows some defects and deficiencies, for example, low control precision, slow production rhythm, and great fluctuation in the strip-finishing-temperature curve, which cannot meet the requirements for high precision and high-performance product control. For use with domestic 2250 mm hot-strip mills, a multi-mode control model was developed on a quadratic programming algorithm for the strip-finishing temperature. The proposed multi-mode control model has three control modes to regulate the speed, inter-stand cooling, and coupled speed and inter-stand cooling. To obtain the best control effect, the appropriate control mode can be adopted depending on the different steels used and different working conditions in the hot-rolling process. At the same time, based on the cooling capacity of the adjustable rack and the calculated strip-finishing temperature, Newton-Raphson iteration and the acceleration calculation model were used to calculate the large acceleration region and the quadratic programming optimization method to optimize the on-line adjustment of different control modes to meet all the strip-finishing temperature-control requirements. The on-line application of the proposed multi-model realized a 99% hit rate or better on the strip-finishing temperature for three consecutive months, with a deviation in the strip-finishing-temperature control of ±20℃. A 97.2% hit rate or better was realized on the strip-finishing temperature for three consecutive months with a deviation in the strip-finishing-temperature control of ±15℃. These results show that the control model has the advantages of a fast response speed and high precision and meets the requirements of finishing-temperature control for different steels and different working conditions. As such, the proposed method improves the strip-rolling stability and the accuracy of the finishing-temperature control and enhances product competitiveness.

The shape of a hot rolled strip is a main indicator of its quality, and camber is a significant defect arising from problems in shape quality. Differences in the bearing clearance of the two sides of a rough mill can cause a crossed roller, which leads an imbalance in the rolling force and, thereby, camber. A camber defect adversely affects product quality and the stability of the subsequent finish-rolling production process. The simulation and control of asymmetric shapes is one of the hottest topics in the field of modern strip rolling. To solve this problem and enhance the quality and precision of the strips produced, exploring and analyzing the problem of camber in hot rough rolling is necessary. This study investigated the generation of camber in the 1580 mm roughing mill R2 of a steel plant during the hot-continuous-rolling process. This paper established a three-dimensional elastic-plastic dynamic coupling model of the rolls and slab using the finite element (FE) analysis software ABAQUS/Explicit. In addition, the paper used a data analysis method based on the node-set coordinate output. By balancing the relationship between computational precision and efficiency, the study found the FE model to run stably. Using the proposed model, the paper systematically investigated the influence of cross position and angle on the camber, slab wedge, and amount of rolling force under different conditions. Based on the FE results, the paper then characterized the influence law for the occurrence of a cross roll with respect to bearing clearance and slab camber. Numerical examples demonstrate that the relationship between the camber and cross-angle position is linear, and that between the slab camber and clearance is a quadratic curve.

The microstructure, structure, and cracking behavior of Q235-A strip iron oxide skin were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), and a universal tensile testing machine. The results show that the composition of the iron oxide mainly consists of Fe3O4, Fe2O3, and Fe, together with small amount of FeO, the oxide layer has the same thickness all over, about 10 μm, the structure is dense, and the matrix is better connected. The tensile experiments show that with increasing strain, the increase in the number of cracks is at first slow, then fast, then slow again. When the strain reaches 0.05%, its iron oxide skin begins to crack; the number of cracks increases with increasing strain in the range 0.08% -0.10%. When the strain exceeds 0.10%, the crack number increases slowly, and when the strain exceeds 0.15%, the number of cracks stops grow.

Aimed at the frequently occurred problem of slab camber in rough rolling of hot strip mills, the main factors causing slab camber, including the difference in longitudinal stiffness of the mill on both sides, incoming wedge and running deviation of rolled pieces, were analyzed by combining with the spring equations and analytical method in this paper, and the corresponding adjustment values were respectively calculated. Based on rolling force difference on both sides, the tilting control model of slab camber was established. This model could reflect the quantitative relationship between the main factors and camber, such as the difference in longitudinal stiffness of the mill on both sides, incoming wedge and running deviation of rolled pieces, etc., and then the tilting values of roll gap for controlling camber were calculated in each pass of the rough rolling mill. Comparing with the real values by off-line verification, the averaged ratio of measured and calculated values is 0.977. The results show that the tilting values of roll gap can be estimated by the tilting control model of slab camber in each pass. Since putting the model into a 2250 mm hot strip mill, the camber values not complying with tolerance declined from 24.88% to 6.62%. By improving the control effect of camber, the slab camber problem has been greatly eased.

C20H16N2O4, monoclinic, P21 (no. 4), a = 8.0094(5) Å, b = 6.7689(3) Å, c = 29.577(2) Å, β = 95.809(6)°, V =1595.27(16) Å3, Z = 4, Rgt(F) = 0.0457, wRref(F2) = 0.1209, T = 293 K.

Mercury heat pipe has the advantages of good thermal stability and low saturated vapor pressure, which is the best choice for the transition from water heat pipe to liquid metal heat pipe. The effects of heating power and heat pipe structure on start-up time and steady-state heat transfer performance of mercury heat pipe were studied by using transient thermal network model. The results showed that: 1) Increasing the length of condenser is beneficial to reducing the start-up time and thermal resistance; 2) Increasing the heating power or wall thickness will reduce the thermal resistance, but increase the start-up time, and increasing the porosity of wick is just the opposite; 3) Increasing the thickness of wick can increase both the start-up time and the thermal resistance.

Objective To explore the role of ATM/hnRNPK signaling in the adriamycin resistance of acute myeloid leukemia. Methods Expression of ATM was examined in the adriamycin resistant and sensitive leukemia cell strains with Western blot. ATM expression was down-regulated by RNAi and ATM inhibitor in the adriamycin resistant cell strains. Expression level of hnRNPK and LC3Ⅰ/Ⅱ was detected by Western blot and adriamycin sensitivity was measured by CCK8 assay before and after modulation of ATM expression. Results ATM was overexpressed in adriamycin resistant leukemia cell strains. The decreased expression of ATM restored the sensitivity to adriamycin. Expression level of LC3Ⅱ and hnRNPK was consistent with the modulation of ATM expression. Conclusions The ATM/hnRNPK signaling pathway may play a role in the occurrence of adriamycin resistance in acute myeloid leukemia by regulating autophagy.

To get the adsorption data of low-volatile organic compounds,a method for estimating the adsorption isotherm of low concentration and low-volatile organics was proposed based on the Langmuir equation.The desorption activation energy was calculated by a modified temperature program desorption(TPD) model,which is much closer to the intrinsic value,and then the Langmuir equilibrium constant B was obtained.In combination with sorbent characterization results,it was easy to estimate the saturated adsorption capacity.The adsorption isotherm of low concentration naphthalene on SBA-15 was estimated.The desorption activation energy,balance constant,and saturated adsorption capacity are 58.37 kJ·mol-1,0.01149 Pa-1 and 55.11 mg·g-1,respectively.The calculated values are in good agreement with experimental results,and the relative error is about 5%.

Intensive cooling technology is widely used to produce high strength strip steel,but high cooling rate leads to some defects,such as shape waves caused by high residual stress. A numerical model was established to achieve a coupling calculation of temperature,phase transformation and stress for high strength steel(700 MPa) during intensive cooling. Commercial FEM software ABAQUS was used to build coupled models that verified by a series of experiments. The effects of edge masking and initial temperature difference on the residual stress were studied by modifying initial and boundary conditions. It is concluded that reducing the initial temperature difference is more effective to release the residual stress of strip steel during cooling. Proven by industrial experiments,these research results would be used to lower the residual stress and improve the quality of hot-rolled strips.

A coupled heat transfer model of work rolls and an aluminum strip is established to obtain the multi-parameter coupled subsection cooling regulation characteristics of work rolls in aluminum cold rolling. This coupled model includes building the thermal conduction differential equation of the work rolls and strip,solving the strip deformation heat and friction heat,establishing the heat transfer boundary conditions,calculating the work roll thermal crown,and solving the differential equations by using a two-dimensional alternating difference method. Simulation results show that the positive and negative adjustment domains are approximately equal at the same rolling parameters,but each domain is affected by rolling parameters. The increase of rolled length,header pressure and friction coefficient has positive effect on the subsection cooling control ability,while the rolling speed is on the contrary.

The cleanness evolution and inclusion distribution of IF slabs in the thickness direction were studied by original morphology analysis, scanning electron microscopy and energy spectroscopy analysis, and total oxygen (T. O) and nitrogen analysis. The average values of mass fraction of total oxygen and N in the slabs in the thickness direction are within 17 × 10-6. The mass fractions of T. O and N in the area within 1/16 thickness from the slab surface are 5% to 10% higher than the average values, in the area between 1/4 thickness from the inner are and 1/4 thickness from the outer arc are 5% to 10% lower than the average values and in other area are close to the average levels. The average size of inclusions is 5.7 txm based on a total of 963 statistical inclusions. Inclusions with the particle size smaller than 5μm account for 60% and with the particle size smaller than 10 txm account for 90%. Al2O3 mainly exits within 5 mm from the slab surface with the size of 2 to 10μm; TiN-Al2O3 and TiN exist in the area from 5 to 80 mm in the thickness direction, and their particle size grows up as the thickness increasing; TiN-TiS and TiS inclusions mainly exist in the area from 80 to 130 mm in the thickness direction with the size of 1 to 5μm. Inclusions from the slab surface to center are mainly Al2O3, Al2O3-TiN, TiN, TiN-TiS, TiS, and MnS in order.

Scanning electron microscopy (SEM) is used to observe the fracture surface morphology of Q235 steel. The cracking law/crack rule principle of strip surface under tension is studied via universal tensile testing machine. The results show that the thickness of the scale is relatively uniform, about 10 μm, and the structure is dense and well attached to the matrix. Tensile experiments show that as the strain increases, the cracks increase slowly in the initial stage, rapidly in the middle period, and slowly in the final period. When the strain exceeds 0.15%, the cracks are difficult to increase. In order to avoid direct erosion of the abrasive on the substrate, a reasonable range of tension setting should be 0.15%-0.18% in the pretreatment process without acid descaling.