The effects of some key factors on nitrogen absorption during the smelting process of X70 pipeline steel were studied,and the source of nitrogen pick-up was analyzed to find the bottleneck for nitrogen control.A serie...The effects of some key factors on nitrogen absorption during the smelting process of X70 pipeline steel were studied,and the source of nitrogen pick-up was analyzed to find the bottleneck for nitrogen control.A series of measures were put forward to decrease the nitrogen pick-up.The results indicated that an exponential relationship existed between the nitrogen absorption index and the free oxygen in molten steel.Nitrogen absorption index could decrease below 0.3when free oxygen in molten steel was above 100×10^（-6） after tapping.For low sulfur killed steel,the nitrogen absorption ratio and sulfur content satisfied a linear relationship with a slope of-0.007.Low free-oxygen and sulfur were beneficial to the deep desulfurization during vacuum treatment.The contradiction of high desulfurization ratio and low nitrogen pick-up during LF process could be resolved by skimming oxidizing slag after tapping and making new high basicity top slag.After optimization,the average content of nitrogen in final product decreased from 46×10（-6）to 35×10（-6）.展开更多
This paper analyzes the effect of subgroup size on the x-bar chart characteristics using sample influx (SIF) into forensic science laboratory (FSL). The characteristics studied include changes in out-or-control points...This paper analyzes the effect of subgroup size on the x-bar chart characteristics using sample influx (SIF) into forensic science laboratory (FSL). The characteristics studied include changes in out-or-control points (OCP), upper control limit UCLx, and zonal demarcations. Multi-rules were used to identify the number of out-of-control-points, Nocp as violations using five control chart rules applied separately. A sensitivity analysis on the Nocp was applied for subgroup size, k, and number of sigma above the mean value to determine the upper control limit, UCLx. A computer code was implemented using a FORTRAN code to create x-bar control-charts and capture OCP and other control-chart characteristics with increasing k from 2 to 25. For each value of k, a complete series of average values, Q(p), of specific length, Nsg, was created from which statistical analysis was conducted and compared to the original SIF data, S(t). The variation of number of out-of-control points or violations, Nocp, for different control-charts rules with increasing k was determined to follow a decaying exponential function, Nocp = Ae–α, for which, the goodness of fit was established, and the R2 value approached unity for Rule #4 and #5 only. The goodness of fit was established to be the new criteria for rational subgroup-size range, for Rules #5 and #4 only, which involve a count of 6 consecutive points decreasing and 8 consecutive points above the selected control limit (σ/3 above the grand mean), respectively. Using this criterion, the rational subgroup range was established to be 4 ≤ k ≤ 20 for the two x-bar control chart rules.展开更多
Objective To provide improved manipulative program of body X-knife therapy is to re duce localization and repetition error,increase therapeutic precision and perform accurate quality control.Methods Measure and compar...Objective To provide improved manipulative program of body X-knife therapy is to re duce localization and repetition error,increase therapeutic precision and perform accurate quality control.Methods Measure and compare the actual error in 86therapeutic targets of52patients before body X-knife stereotactic radiotherapy at different positioning.Results The position error is reduced obviou sly in quality control group compared with control group.T here is prominent difference in two g roups about the error of irradiation field accuracy and axial superpo-sition(P value:0.000896and 0.02980).Conclusions The improved positioning method can reduce errors and increase repetiti on precision and veracity in therapy.展开更多
针对舰船直流供电系统中复杂谐波抑制难题,将滤波x最小均方(filtered-x least mean squares,FxLMS)算法应用于主动电力滤波器(active power filter,APF)以实现多频点谐波的主动抑制。通过构建仿真电路模型与决策树相位补偿方法,实现了...针对舰船直流供电系统中复杂谐波抑制难题,将滤波x最小均方(filtered-x least mean squares,FxLMS)算法应用于主动电力滤波器(active power filter,APF)以实现多频点谐波的主动抑制。通过构建仿真电路模型与决策树相位补偿方法,实现了次级通道相位变化的预补偿,确保了FxLMS算法在APF应用中的准确性。仿真结果表明:系统在0.3 s算法运行时间内成功达到了30 dB的抑制效果,应用效率高;系统对相位补偿与频率检测误差有显著适应性,在±60°的相位补偿误差范围、±3 Hz频点检测偏差范围内稳定性良好,可为系统在实际复杂环境中的应用提供有力保障。展开更多
涡桨飞机座舱的主动噪声控制系统普遍采用传统的多通道滤波x最小均方(multichannel filtered-x least mean square,简称McFxLMS)算法,该算法的计算量随着通道数的增加而激增,严重影响控制效果。针对该问题,基于连续局部迭代-McFxLMS(seq...涡桨飞机座舱的主动噪声控制系统普遍采用传统的多通道滤波x最小均方(multichannel filtered-x least mean square,简称McFxLMS)算法,该算法的计算量随着通道数的增加而激增,严重影响控制效果。针对该问题,基于连续局部迭代-McFxLMS(sequential partial update-McFxLMS,简称SPU-McFxLMS)算法,开发了多通道主动噪声控制系统。SPU-McFxLMS算法通过更新部分滤波器权值,在保证收敛精度的同时能够显著降低计算复杂度。首先,对比分析了传统McFxLMS算法与SPU-McFxLMS算法的原理差异,通过理论推导证明其计算效率提升特性;其次,建立了算法仿真模型,通过仿真验证了理论分析结果;最后,基于SOM-TL6678核心板开发了16通道的主动噪声控制系统,并搭建飞机座舱地面模拟实验平台进行实验。结果表明,该系统在108 Hz和216 Hz双频噪声场景下,各位置的平均降噪量能够达到10 dB以上。展开更多
Enriched by the-medium containingchitin and cell wall of Phizoctoniasolani AG-1,a bacterium X2-23 withhigher chitinase activity was isolatedfrom 166 chitinase-producing bacteria.It could distinctly inhibit the fungi
基金Item Sponsored by National Natural Science Foundation of China(51404018)Fundamental Research Funds for the Central Universities of China(FRF-TP-14-125A2)State Key Laboratory of Advanced Metallurgy Foundation of China(KF13-09)
文摘The effects of some key factors on nitrogen absorption during the smelting process of X70 pipeline steel were studied,and the source of nitrogen pick-up was analyzed to find the bottleneck for nitrogen control.A series of measures were put forward to decrease the nitrogen pick-up.The results indicated that an exponential relationship existed between the nitrogen absorption index and the free oxygen in molten steel.Nitrogen absorption index could decrease below 0.3when free oxygen in molten steel was above 100×10^（-6） after tapping.For low sulfur killed steel,the nitrogen absorption ratio and sulfur content satisfied a linear relationship with a slope of-0.007.Low free-oxygen and sulfur were beneficial to the deep desulfurization during vacuum treatment.The contradiction of high desulfurization ratio and low nitrogen pick-up during LF process could be resolved by skimming oxidizing slag after tapping and making new high basicity top slag.After optimization,the average content of nitrogen in final product decreased from 46×10（-6）to 35×10（-6）.
文摘This paper analyzes the effect of subgroup size on the x-bar chart characteristics using sample influx (SIF) into forensic science laboratory (FSL). The characteristics studied include changes in out-or-control points (OCP), upper control limit UCLx, and zonal demarcations. Multi-rules were used to identify the number of out-of-control-points, Nocp as violations using five control chart rules applied separately. A sensitivity analysis on the Nocp was applied for subgroup size, k, and number of sigma above the mean value to determine the upper control limit, UCLx. A computer code was implemented using a FORTRAN code to create x-bar control-charts and capture OCP and other control-chart characteristics with increasing k from 2 to 25. For each value of k, a complete series of average values, Q(p), of specific length, Nsg, was created from which statistical analysis was conducted and compared to the original SIF data, S(t). The variation of number of out-of-control points or violations, Nocp, for different control-charts rules with increasing k was determined to follow a decaying exponential function, Nocp = Ae–α, for which, the goodness of fit was established, and the R2 value approached unity for Rule #4 and #5 only. The goodness of fit was established to be the new criteria for rational subgroup-size range, for Rules #5 and #4 only, which involve a count of 6 consecutive points decreasing and 8 consecutive points above the selected control limit (σ/3 above the grand mean), respectively. Using this criterion, the rational subgroup range was established to be 4 ≤ k ≤ 20 for the two x-bar control chart rules.
文摘Objective To provide improved manipulative program of body X-knife therapy is to re duce localization and repetition error,increase therapeutic precision and perform accurate quality control.Methods Measure and compare the actual error in 86therapeutic targets of52patients before body X-knife stereotactic radiotherapy at different positioning.Results The position error is reduced obviou sly in quality control group compared with control group.T here is prominent difference in two g roups about the error of irradiation field accuracy and axial superpo-sition(P value:0.000896and 0.02980).Conclusions The improved positioning method can reduce errors and increase repetiti on precision and veracity in therapy.
文摘针对舰船直流供电系统中复杂谐波抑制难题,将滤波x最小均方(filtered-x least mean squares,FxLMS)算法应用于主动电力滤波器(active power filter,APF)以实现多频点谐波的主动抑制。通过构建仿真电路模型与决策树相位补偿方法,实现了次级通道相位变化的预补偿,确保了FxLMS算法在APF应用中的准确性。仿真结果表明:系统在0.3 s算法运行时间内成功达到了30 dB的抑制效果,应用效率高;系统对相位补偿与频率检测误差有显著适应性,在±60°的相位补偿误差范围、±3 Hz频点检测偏差范围内稳定性良好,可为系统在实际复杂环境中的应用提供有力保障。
文摘涡桨飞机座舱的主动噪声控制系统普遍采用传统的多通道滤波x最小均方(multichannel filtered-x least mean square,简称McFxLMS)算法,该算法的计算量随着通道数的增加而激增,严重影响控制效果。针对该问题,基于连续局部迭代-McFxLMS(sequential partial update-McFxLMS,简称SPU-McFxLMS)算法,开发了多通道主动噪声控制系统。SPU-McFxLMS算法通过更新部分滤波器权值,在保证收敛精度的同时能够显著降低计算复杂度。首先,对比分析了传统McFxLMS算法与SPU-McFxLMS算法的原理差异,通过理论推导证明其计算效率提升特性;其次,建立了算法仿真模型,通过仿真验证了理论分析结果;最后,基于SOM-TL6678核心板开发了16通道的主动噪声控制系统,并搭建飞机座舱地面模拟实验平台进行实验。结果表明,该系统在108 Hz和216 Hz双频噪声场景下,各位置的平均降噪量能够达到10 dB以上。
文摘Enriched by the-medium containingchitin and cell wall of Phizoctoniasolani AG-1,a bacterium X2-23 withhigher chitinase activity was isolatedfrom 166 chitinase-producing bacteria.It could distinctly inhibit the fungi
