有限元模拟是研究金属材料塑性变形制定加工工艺参数、预测加工后表面残余应力分布以及塑性变形层厚度的有利工具。利用有限元数值模拟软件对表面机械多重碾磨(Machinery Multi-Grinding of Surface,MMGS)过程进行了研究,目的是为了确...有限元模拟是研究金属材料塑性变形制定加工工艺参数、预测加工后表面残余应力分布以及塑性变形层厚度的有利工具。利用有限元数值模拟软件对表面机械多重碾磨(Machinery Multi-Grinding of Surface,MMGS)过程进行了研究,目的是为了确定合理的MMGS加工工艺参数。结果表明:碾磨头下压量大小、碾磨道次和碾磨头转速是影响碾磨后材料表面有效应变大小和塑形应变层深度的主要加工参数,碾磨加工过程中碾磨头转速不超过1 800 rpm、平移进给速度为60～120 mm/min、多道次的反复碾磨方式更加有利于获得较高的有效应变大小和较大的塑形变形层深度,研究结果可以为MMGS的实验研究提供理论指导。展开更多
Effect of different particle sizes of cordierite on properties of castable refractory by different heat treatment temperatures were investigated respectively with mullite and bauxite as raw materials, calcium aluminat...Effect of different particle sizes of cordierite on properties of castable refractory by different heat treatment temperatures were investigated respectively with mullite and bauxite as raw materials, calcium aluminate cement as binders. After 24 h curing in mould and another 24 h curing at 110 ℃ after demoulding, the specimens were heat treated at 1 000 ℃, 1 300℃ and 1 500℃ for 3 h, respectively. The bulk density （ BD）, permanent linear change （ PLC）, modulus of rupture（MOR） and clod crushing strength（CCS）, thermal expansion coefficient and thermal shock resistance were examined. The results show that there is no obvious effect on adjusting permanent linear change and bulk density of castables by adding different particle sizes of cordierite at low temperature and intermediate temperature. Modulus of rupture of castable increase with the decreasing of the particle sizes of cordierite after heat treated by 1 000 ℃ and 1 300℃. In this experiment, thermal shock resistance of the castable with cordierite whose particle size is 0 - 1 mm is the best.展开更多
This study presents the use of the method of wavelet transform modulus maxima(WTMM) to detect boundaries of potential field sources.The boundaries of causative sources can be judged by calculating the local modulus ma...This study presents the use of the method of wavelet transform modulus maxima(WTMM) to detect boundaries of potential field sources.The boundaries of causative sources can be judged by calculating the local modulus maxima of wavelet coefficients at different scales.For the potential field data with noise,the detected boundaries at small scales are easy to be distorted by noise,however,at large scales,the noise can be suppressed greatly and presents more accurate boundary detection results.Therefore,we can get a better boundary judgment by considering the detected boundaries at all scales.Applying the WTMM method to synthetic models and a real data set of Meishan iron deposit,both get a good effect.展开更多
Objective： To investigate effects of different treatment on celiac mast cell degranulation in mice with allergic rhinitis induced with ovum albumin （OVA）. Methods： 60 female mice were randomly divided into five gr...Objective： To investigate effects of different treatment on celiac mast cell degranulation in mice with allergic rhinitis induced with ovum albumin （OVA）. Methods： 60 female mice were randomly divided into five groups, 12 mice in each, which were treated with different methods. Then, the celiac mast cells were separated and degranulation rate was calculated after stained with neutral red. Results： the rates of mast cell degranulation were （15±6）%, （53±11）%, （37±13）%, （31±15）%, and （47±14）% in normal group, OVA group, point application group, hormone group, and PBS group. There is obvious degranulation in the celiac mast cells of mice with OVA-induced allergic rhinitis. Point application and dexamethasone treatment could relieve the mast cell degranulation, whereas, PBS has no effect on the mast cell degranulation. Conclusion： the mechanism of antianaphylaxis of point application may lie on stabilizing the mast cell membrane, and inhibiting degranulation to reduce the inflammatory mediator.展开更多
文摘Effect of different particle sizes of cordierite on properties of castable refractory by different heat treatment temperatures were investigated respectively with mullite and bauxite as raw materials, calcium aluminate cement as binders. After 24 h curing in mould and another 24 h curing at 110 ℃ after demoulding, the specimens were heat treated at 1 000 ℃, 1 300℃ and 1 500℃ for 3 h, respectively. The bulk density （ BD）, permanent linear change （ PLC）, modulus of rupture（MOR） and clod crushing strength（CCS）, thermal expansion coefficient and thermal shock resistance were examined. The results show that there is no obvious effect on adjusting permanent linear change and bulk density of castables by adding different particle sizes of cordierite at low temperature and intermediate temperature. Modulus of rupture of castable increase with the decreasing of the particle sizes of cordierite after heat treated by 1 000 ℃ and 1 300℃. In this experiment, thermal shock resistance of the castable with cordierite whose particle size is 0 - 1 mm is the best.
文摘This study presents the use of the method of wavelet transform modulus maxima(WTMM) to detect boundaries of potential field sources.The boundaries of causative sources can be judged by calculating the local modulus maxima of wavelet coefficients at different scales.For the potential field data with noise,the detected boundaries at small scales are easy to be distorted by noise,however,at large scales,the noise can be suppressed greatly and presents more accurate boundary detection results.Therefore,we can get a better boundary judgment by considering the detected boundaries at all scales.Applying the WTMM method to synthetic models and a real data set of Meishan iron deposit,both get a good effect.
文摘Objective： To investigate effects of different treatment on celiac mast cell degranulation in mice with allergic rhinitis induced with ovum albumin （OVA）. Methods： 60 female mice were randomly divided into five groups, 12 mice in each, which were treated with different methods. Then, the celiac mast cells were separated and degranulation rate was calculated after stained with neutral red. Results： the rates of mast cell degranulation were （15±6）%, （53±11）%, （37±13）%, （31±15）%, and （47±14）% in normal group, OVA group, point application group, hormone group, and PBS group. There is obvious degranulation in the celiac mast cells of mice with OVA-induced allergic rhinitis. Point application and dexamethasone treatment could relieve the mast cell degranulation, whereas, PBS has no effect on the mast cell degranulation. Conclusion： the mechanism of antianaphylaxis of point application may lie on stabilizing the mast cell membrane, and inhibiting degranulation to reduce the inflammatory mediator.
