A phenomenological model for the prediction of the forming limit curve (FLC) based on basic mechanical properties through a uniaxial tensile test can tremendously shorten the design time of the forming process and reduce the measuring costs. In this paper, a novel phenomenological model named the IMR-Baosteel model (abbreviated as the IB model) is proposed for efficient and accurate FLC prediction of hot-rolled steel sheets featuring distinct variations in thickness and mechanical properties. With a systematic test of the plane strain forming limit (FLC0), it was found that a higher regression correlation exists between the FLC0 and the total elongation under different sheet thicknesses. For accurate assessment of the FLC0 from tensile properties, compared using experiments, the error of FLC0 calculated with the proposed model is within 10%. In the IB model, the left side of FLC can be calculated using a line with a slope of −1 while the right side of the FLC is obtained via a modified Keeler model with the exponent (p) determined as 0.45 for hot-rolled steels. Complete experimental FLCs of hot-rolled steels from measurements and the literature were used to validate the reliability of the proposed model. Resultantly, the prediction of FLCs with the proposed IB model is greatly improved, and agrees much better with the experimental FLCs than the predictions of the well-known Keeler model, Arcelor model and Tata Steel model.

The forming limit curve (FLC) has been commonly used tool to predict the metal forming cracking in engineering. Whereas, based on the assumption of plane stress state, the formability prediction of thick sheet of hot-rolled high-strength steels is quite different from the experimental measurement. Finite element simulation was used to study the effect of sheet thickness. It is found that extra stress along thickness is introduced between inside and outside the instability region, which become larger increased. Additionally, the visco-plastic self-consistent (VPSC) model and the M-K model are combined to establish the VPSC-MK model for investigating the influence of thickness difference. With reasonable capture of thickness stress, accurate prediction of FLC under different sheet thickness of hot rolled high-strength steel (HR-HSS) is well realized via VPSC-MK model. That is, it is revealed that the sheet thickness effect for HR-HSS mainly origins from normal stress induced during necking process.

As one of the key safety components in motor vehicles, the steel wheel rim is commonly fabricated with the roll forming process. However, due to the varied cross-sections of the rim and the low formability of high-strength steel, it is difficult to produce thin-wall and defect-free wheel rims to realize the purpose of light weight. To solve these problems, a novel hydroforming process by combining internal and external pressures (HIEP) was proposed to produce thin-wall wheel rims in the current study. The designed initial tube with diameter between the maximum and minimum diameter of the wheel rim ensures dispersed deformation and effectively avoids local excessive thinning. During HIEP, a hydroforming process was performed with two successive stages: the external pressure and internal pressure stages. Theoretical analysis and finite element method (FEM) were jointly used to investigate the effect of process parameters on the wrinkling and thinning. With the optimized parameters for internal and external pressure, the wrinkling of wheel rims is prevented under compressive state during the external pressure forming stage. Additionally, HIEP was experimentally carried out with high-strength steel rims of 650 MPa ultimate tensile strength (UTS). Finally, wheel rims with weight reduction of 13% were produced successfully, which shows a uniform thickness distribution with a local maximum thinning ratio of 11.4%.

According to the current development of commercial vehicles, a novel structure of the double-layer exhaust pipe with gap was designed. Hydroforming through the combination of internal and external pressures (HIEP) was proposed to form the complex structure of the new exhaust pipe. The double-layer tube without gap was used as the initial tube blank. High-pressure liquid was introduced into the inner tube and between the two tubes. The outer tube would bulge outward and fit the die cavity as its inner surface was subjected to hydraulic pressure. Meanwhile, the inner tube would not deform due to both the inner and outer surfaces were subjected to hydraulic pressure. In addition, before the HIEP, it is necessary to pre-bend the double-layer tube. The feasibility of the process was analyzed by numerical simulation. The process parameters were optimized by response surface methodology (RSM). The objective functions such as the maximum thinning rate, unevenness of wall thickness and gap dispersion were established in RSM models, whose accuracy was verified by a statistical method of analysis of variance. Subsequently, the die of HIEP was designed and developed. The verification experiments were carried out and the double-layer exhaust pipe with gap was successfully manufactured.

以厚度为2.0 mm的S500MC微合金高强钢板为材料,采用液压成形工艺制造汽车轮辋,通过有限元方法分析该轮辋的疲劳性能,并与常规滚压成形2.3 mm均匀壁厚SPFH540中强度低合金钢轮辋和2.0 mm均匀壁厚S500MC微合金高强钢轮辋进行对比.结果表明:液压成形轮辋壁厚的最大减薄率为10.9％;液压成形轮辋的截面弯曲应力和径向应力变化趋势与2种滚压成形轮辋的一致,说明轮辋局部减薄不会使其所受应力发生明显变化;液压成形轮辋的最大弯曲应力和最大径向应力低于该钢的屈服强度,最大弯曲应变和最大径向应变均远小于屈服应变,且疲劳性能安全系数均大于1,表明壁厚局部减薄不会影响轮辋的弯曲和径向疲劳性能.

研究了580DP与700DP热轧双相钢的拉伸性能、扩孔性能和成形极限曲线,并与QStE550TM热轧微合金高强钢的进行对比;采用成形极限经验公式和MK模型对成形极限曲线进行预测,并与试验结果进行对比;对热轧双相钢的成形极限曲线最低点的主应变进行拟合,进而对成形极限经验公式进行修正.结果 表明:与QStE550TM钢相比,580DP与700DP钢的断后伸长率和加工硬化指数较高,屈强比较低,加工性能较好;580DP与700DP钢的扩孔率均低于QStE550TM钢的,扩孔性能较差;580DP钢的成形极限曲线高于700DP钢的,且均高于QStE550TM钢的,热轧双相钢的成形性能较好;成形极限经验公式与MK模型均不能很好地预测580DP与700DP钢的成形极限曲线;采用修正的成形极限经验公式计算得到的热轧双相钢的成形极限曲线与试验结果较吻合,其中580DP钢的相对误差小于5.6％,700DP钢在平面应变区域的相对误差小于9.4％,在其他区域的相对误差小于6.5％.

实验测试了酸洗汽车结构钢QStE系列热轧钢板不同方向(与轧向分别成0°、45°和90°)的单向拉伸力学性能,获得了其各向异性屈服行为.依据Hill48、Hill90和Barlat89各向异性屈服准则及其参数计算方法,分别建立了QStE系列钢种的各向异性屈服模型,并将模型预测的不同方向屈服应力及r值与实验结果进行对比分析.结果 表明,经优化后的参数求解方法可很好的同时预测单向屈服应力和r值.在r值的预测能力上,不论r值呈抛物线型变化还是单调递增变化,Hill48屈服准则均能很好的预测,Hill90屈服准则仅能很好的预测单调递增变化的情况,而Barlat89屈服准则对两种情况下的预测能力均较弱.

EBOV is one of the deadliest viruses to humans. It has been over 40 years since EBOV was first reported, but no cure is available. Research breakthroughs over the past 5 years have shown that MAbs constitute an effective therapy for EBOV infections. However, MAbs are expensive and difficult to produce in large amounts and therefore may only play a limited role during an epidemic. A cheaper alternative is required, especially since EBOV is endemic in several third world countries with limited medical resources. Here, we used a standard protocol to produce large amounts of antiserum F(ab′) 2 fragments from horses vaccinated with an EBOV vaccine, and we tested the protectiveness in monkeys. We showed that F(ab′) 2 was effective in 100% of monkeys even after the animals were visibly ill with EBOV disease. Thus, F(ab′) 2 could be a very good option for large-scale treatments of patients and should be advanced to clinical testing.

保温杯、水壶及锅具、餐盘等不锈钢食用器皿在人们日常生活中的使用极为频繁且用量较大,品类更新速度极快,故其经济效益十分可观.而且伴随人们生活水平的不断提高,除了食用器皿自身的功能性以外,消费者越发注重其美观度,因而产品在外观设计上往往出现有大量的复杂截面变化和图案纹理特征.因此,高效低成本的加工技术对于新兴食用器皿制造行业而言至关重要,受到广泛关注.

The invention provides horse anti-EBOV (Ebola virus) immune globulin F (ab')2 and a preparation method thereof. The preparation method comprises steps as follows: virus-like particles of a GP gene and a VP40 gene expressing EBOV-Z simultaneously are inactivated and purified and then are mixed with an immunologic adjuvant to be taken as immunogens, highly immunized plasma is obtained through repeated immunization of healthy horses, IgG protein is separated and purified, then the IgG protein is subjected to pepsase digestion, an enzyme-digested product is processed by a DEAE ion-exchange chromatographic column, an eluent is collected and subjected to desalination and freeze-drying, and the horse anti-EBOV immune globulin F (ab')2 is obtained. The horse anti-EBOV immune globulin F (ab')2 is an effective drug for preventing and treating Ebola hemorrhagic fever caused by EBOV and has remarkable curative effects for critical patients infected with the EBOV; the preparation method is controlled by adopting unique technological parameters and is suitable for industrial production, and the product is safe and reliable.

Recent successes with monoclonal antibody cocktails ZMapp TM and MIL77 against Ebola virus (EBOV) infections have reignited interest in antibody-based therapeutics. Since the production process for monoclonal antibodies can be prolonged and costly, alternative treatments should be investigated. We produced purified equine antisera from horses hyperimmunized with EBOV virus-like particles, and tested the post-exposure efficacy of the antisera in a mouse model of infection. BALB/c mice were given up to 2 mg of purified equine antisera per animal, at 30 minutes, 1 or 2 days post-infection (dpi), in which all animals survived. To decrease the possibility of serum sickness, the equine antisera was digested with pepsin to generate F(ab′) 2 fragments, with in vitro neutralizing activity comparable to whole immunoglobulin. Full protection was achieved with when treatment was initiated at 1 dpi, but the suboptimal protection observed with the 30 minute and 2 dpi groups demonstrate that in addition to virus neutralization, other Fc-dependent antibody mechanisms may also contribute to survival. Guinea pigs given 20 mg of antisera or F(ab′) 2 at or starting at 1 or 2 dpi were also fully protected from EBOV infection. These results justify future efficacy studies for purified equine products in NHPs.

A number of activated carbons derived from waste tires were further impregnated by gaseous elemental sulfur at temperatures of 400 and 650 degrees C, with a carbon and sulfur mass ratio of 1:3. The capabilities of sulfur diffusing into the micropores of the activated carbons were significantly different between 400 and 650 degrees C, resulting in obvious dissimilarities in the sulfur content of the activated carbons. The sulfur-impregnated activated carbons were examined for the adsorptive capacity of gas-phase mercuric chloride (HgC1) by thermogravimetric analysis (TGA). The analytical precision of TGA was up to 10(-6) g at the inlet HgCl2 concentrations of 100, 300, and 500 microg/m3, for an adsorption time of 3 hr and an adsorption temperature of 150 degrees C, simulating the flue gas emitted from municipal solid waste (MSW) incinerators. Experimental results showed that sulfur modification can slightly reduce the specific surface area of activated carbons. High-surface-area activated carbons after sulfur modification had abundant mesopores and micropores, whereas low-surface-area activated carbons had abundant macropores and mesopores. Sulfur molecules were evenly distributed on the surface of the inner pores after sulfur modification, and the sulfur content of the activated carbons increased from 2-2.5% to 5-11%. After sulfur modification, the adsorptive capacity of HgCl2 for high-surface-area sulfurized activated carbons reached 1.557 mg/g (22 times higher than the virgin activated carbons). The injection of activated carbons was followed by fabric filtration, which is commonly used to remove HgCl2 from MSW incinerators. The residence time of activated carbons collected in the fabric filter is commonly about 1 hr, but the time required to achieve equilibrium is less than 10 min. Consequently, it is worthwhile to compare the adsorption rates of HgCl2 in the time intervals of < 10 and 10-60 min.

BACKGROUND:Antigenic variation is an effective way by which viruses evade host immune defense leading to viral persistence. Little is known about the inhibitory mechanisms of viral variants on CD4 T cell functions.RESULTS:Using sythetic peptides of a HLA-DRB1*15-restricted CD4 epitope derived from the non-structural (NS) 3 protein of hepatitis C virus (HCV) and its antigenic variants and the peripheral blood mononuclear cells (PBMC) from six HLA-DRB1*15-positive patients chronically infected with HCV and 3 healthy subjects, the in vitro immune responses and the phenotypes of CD4+CD25+ cells of chronic HCV infection were investigated. The variants resulting from single or double amino acid substitutions at the center of the core region of the Th1 peptide not only induce failed T cell activation but also simultaneously up-regulate inhibitory IL-10, CD25-TGF-β+ Th3 and CD4+IL-10+ Tr1 cells. In contrast, other variants promote differentiation of CD25+TGF-β+ Th3 suppressors that attenuate T cell proliferation.CONCLUSIONS:Naturally occuring HCV antigenic mutants of a CD4 epitope can shift a protective peripheral Th1 immune response into an inhibitory Th3 and/or Tr1 response. The modulation of antigenic variants on CD4 response is efficient and extensive, and is likely critical in viral persistence in HCV infection.

The evaluation of clustering validity is important for clustering analysis, and is one of the hottest spots of cluster analysis. The quality of the evaluation of clustering is that optimal number of clusters is reasonable. For fuzzy clustering, the paper surveys the widely known fuzzy clustering validity evaluation based on the methods of fuzzy partition, geometry structure and statistics.

The problem of fatigue is becoming one of the factors impacting on the working and studying people. Therefore, how to detect whether the people are tired simply and effectively is paid attention to by more and more researchers. A novel method of fatigue testing based on fuzzy logic and image processing is proposed in this paper. Firstly, positive map and side elevation are extracted through camera device. Then motion detection determined to locate human faces and the frequency of eyes opening and closing is derived by using image processing techniques. Finally the angle between the head and the shoulder is calculated combined with a representation of time function and a fatigue threshold is set up. All of these are determined to estimate the degree of fatigue. Experimental results show that, the method can quickly detect the degree of fatigue simply.

A number of activated carbons had been produced from waste tires by pyrolysis and water activation methods, and they had been modified by sulfur steam at high temperature. Produced sulfur-impregnated activated carbons were examined for their mercuric chloride adsorptive ability by thermal gravimetric analysis. The experiment data show that sulfur should be evenly distributed in the activated carbon surface and pores after sulfur modification, and the sulfur content would obviously be improved from about 2% to 10%~6%. There was efficaciously improvement on mercuric chloride saturated adsorption capacity after sulfur modification, which of high surface area activated carbon reached 1.557 mg/g (above 22 times comparing with un-modifying activated carbon). The mercuric chloride adsorption curves could divide into two adsorption stages: (i) at the first adsorption stage (in 10 min), the adsorption velocity of mercuric chloride kept quickly as the mercuric chloride molecules only entered into macropores and mesopores belonging to surface physical adsorption; (ii) at the second adsorption stage (after 10min), the adsorption velocity of mercuric chloride became slowly and slowly for the mercuric chloride molecules gradually turned into mesopores and micropores. The mercuric chloride adsorption velocities of activated carbons before 10min were all in the range of 0.0089 μg/g · min to 0.0299μg/g · min, and adsorption velocities improved with increasing of the mercuric chloride concentration. The mercuric chloride adsorption velocities of activated carbons between 10min and 60 min were all in the range of 0.0007 μg/g · min to 0.0041μg/g · min, obviously lower than former 10min. There was no penetrating case of mercuric chloride in 1h and the high sulfur activated carbon possessed best adsorption capacity of mercuric chloride. Consequently, it would be quite feasible that sulfur-impregnated activated carbon from wa- - ste tires was applied in municipal incinerator to remove mercuric chloride.

RNA干扰已成为当前肿瘤基因治疗的新策略[1],以前我们曾报道了靶向血管内皮生长因子(VEGF)短发夹RNA有效抑制胃癌细胞VEGF mRNA表达[2],本实验旨在探讨该载体在抑制了VEGFmRNA表达后,对人胃癌细胞体内外抑制作用.

In order to investigate the inhibitory effect of plasmid-mediated short hairpin RNA targeting vascular endothelial growth factor (VEGF) on the expression of VEGF mRNA in human gastric cancer cells, a plasmid vector for transcribing specific short hairpin RNA targeting VEGF (pU6-VEGF) was constructed, and then transfected into human gastric cancer cells using Lipofectamine2000. The VEGF mRNA expression level was detected by RT-PCR. RPMI1640 was used for blank control, and pSilencer 1.0-U6 empty plasmid for the negative control. Results showed the clone and sequence analysis revealed that the recombinant plasmid vector of pU6-VEGF was successfully constructed. The VEGF mRNA expression levels in blank control group, experimental group (pU6-VEGF) and negative control group (pSilencer1.0-U6) were 100%, 49% and 94%, respectively, indicating VEGF mRNA expression in the cells transfected with pU-VEGF vector was inhibited significantly as compared with blank control group and negative control group. It was concluded that the short hairpin RNA could significantly inhibit the expression of VEGF mRNA, which provided an experimental basis for treating human cancer with anti-angiogenesis.

RNA干扰是由双链RNA介导的序列特异性转录后基因沉默过程,为双链RNA分子在mRNA水平上关闭相关基因表达的过程。现综述RNAi技术在抗肿瘤研究等方面的研究进展。