目的分析感音神经性听力损失患者耳蜗死区(cochlear dead regions,CDR)检测结果。方法应用均衡噪声阈值TEN(HL)法检测273例302耳感音神经性听力损失患者的耳蜗死区,并分析耳蜗死区与其可能病因及听力曲线类型的关系。结果 273例(302耳)...目的分析感音神经性听力损失患者耳蜗死区(cochlear dead regions,CDR)检测结果。方法应用均衡噪声阈值TEN(HL)法检测273例302耳感音神经性听力损失患者的耳蜗死区,并分析耳蜗死区与其可能病因及听力曲线类型的关系。结果 273例(302耳)感音神经性听力损失患者中,112例117耳存在耳蜗死区,占总耳数的38.74%;存在耳蜗死区的患者在耳蜗死区频率处DPOAE均未引出,其中高频听力下降型占40.22%(74/184),低频下降型占47.14%(33/70),两端下降型占33.33%(2/6),平坦型占19.04%(8/42);噪声、耳毒性药物、突发性聋三种因素致聋者中耳蜗死区检出率较高。结论本组感音神经性听力损失患者耳蜗死区检出率约为38.74%,高频下降型者最多,噪声和/或耳毒性药物致聋者更易出现耳蜗死区。展开更多
In this paper, the subject of mathematical model is a series of math expressions, which is used to calculate different regions＇ volume fraction and analyze flow characterization in multi-strand tundish. But research ...In this paper, the subject of mathematical model is a series of math expressions, which is used to calculate different regions＇ volume fraction and analyze flow characterization in multi-strand tundish. But research about mathematical model for multi-strand tundish is few, and so far, there has been no acknowledged math model for multi- strand tundish to describe its flow characteristic. If Sahai＇s model, which is originally proposed for the case of single-strand tundish （proposed in reference, and this model is widely used in the world）, is applied to describe flow feature in multi-strand tundish, the calculation results would be unreasonable. Based on the data of watermodel experiment results, the sum of each strand＇s dead region＇s volume fraction is bigger than 100%, and this obviously doesn＇T agree with reality; and the value of dead region＇s volume fraction is calculated to be minus according to mathematical simulation results data in another case. What＇s more, Sahai＇s model does not propose the standard of plotting the RTD-curve, and this makes scholars around the world can＇t achieve consensus of views about plotting RTD-curve. And the model doesn＇t consider the bypass flow and can＇t calculate its volume fraction, but bypass flow is critical to tundish metallurgy. And through Sahai＇s model, the calculation result of plug flow region＇s volume fraction is also not reasonable, because the model doesn＇t well describe the essence of plug flow. So these suggest that it is not reliable to apply Sahai＇s single-strand tundish model to multi-strand tundish case. Then a new model is attempted to propose in this paper for your discussion. In the new model, the standard of plotting RTD curve is definitely proposed, and relative calculation method is also proposed; and the feature of dead region is carefully studied and the model proposes a new method to calculate its volume fraction, and the calculation formula about its volume fraction can be adjustable according the actual demand; what＇s more, the new model considers the bypass flow and proposes a method to calculate its volume fraction for the first time, and then volume fraction of plug flow region, backmix flow region, dead region and bypass flow can be calculated and obtained at the same time; and this new model can better capture the deviation of reality flow pattern from ideal plug flow pattern, and reflects the feature of plug flow.展开更多
文摘目的分析感音神经性听力损失患者耳蜗死区(cochlear dead regions,CDR)检测结果。方法应用均衡噪声阈值TEN(HL)法检测273例302耳感音神经性听力损失患者的耳蜗死区,并分析耳蜗死区与其可能病因及听力曲线类型的关系。结果 273例(302耳)感音神经性听力损失患者中,112例117耳存在耳蜗死区,占总耳数的38.74%;存在耳蜗死区的患者在耳蜗死区频率处DPOAE均未引出,其中高频听力下降型占40.22%(74/184),低频下降型占47.14%(33/70),两端下降型占33.33%(2/6),平坦型占19.04%(8/42);噪声、耳毒性药物、突发性聋三种因素致聋者中耳蜗死区检出率较高。结论本组感音神经性听力损失患者耳蜗死区检出率约为38.74%,高频下降型者最多,噪声和/或耳毒性药物致聋者更易出现耳蜗死区。
基金supported by the National Natural Science Foundation of China(No.60672145)
文摘In this paper, the subject of mathematical model is a series of math expressions, which is used to calculate different regions＇ volume fraction and analyze flow characterization in multi-strand tundish. But research about mathematical model for multi-strand tundish is few, and so far, there has been no acknowledged math model for multi- strand tundish to describe its flow characteristic. If Sahai＇s model, which is originally proposed for the case of single-strand tundish （proposed in reference, and this model is widely used in the world）, is applied to describe flow feature in multi-strand tundish, the calculation results would be unreasonable. Based on the data of watermodel experiment results, the sum of each strand＇s dead region＇s volume fraction is bigger than 100%, and this obviously doesn＇T agree with reality; and the value of dead region＇s volume fraction is calculated to be minus according to mathematical simulation results data in another case. What＇s more, Sahai＇s model does not propose the standard of plotting the RTD-curve, and this makes scholars around the world can＇t achieve consensus of views about plotting RTD-curve. And the model doesn＇t consider the bypass flow and can＇t calculate its volume fraction, but bypass flow is critical to tundish metallurgy. And through Sahai＇s model, the calculation result of plug flow region＇s volume fraction is also not reasonable, because the model doesn＇t well describe the essence of plug flow. So these suggest that it is not reliable to apply Sahai＇s single-strand tundish model to multi-strand tundish case. Then a new model is attempted to propose in this paper for your discussion. In the new model, the standard of plotting RTD curve is definitely proposed, and relative calculation method is also proposed; and the feature of dead region is carefully studied and the model proposes a new method to calculate its volume fraction, and the calculation formula about its volume fraction can be adjustable according the actual demand; what＇s more, the new model considers the bypass flow and proposes a method to calculate its volume fraction for the first time, and then volume fraction of plug flow region, backmix flow region, dead region and bypass flow can be calculated and obtained at the same time; and this new model can better capture the deviation of reality flow pattern from ideal plug flow pattern, and reflects the feature of plug flow.
