BACKGROUND Coronavirus disease 2019(COVID-19)is a major public health emergency with obvious characteristics of human-to-human transmission,and there are infective asymptomatic carriers.Early identification and proper...BACKGROUND Coronavirus disease 2019(COVID-19)is a major public health emergency with obvious characteristics of human-to-human transmission,and there are infective asymptomatic carriers.Early identification and proper management of patients with COVID-19 are important.Features in chest computed tomography(CT)can facilitate identifying newly infected individuals.However,CT findings of some lung contusions are similar to those of COVID-19,as shown in the present case.CASE SUMMARY A 46-year-old woman was admitted to hospital for backache and foot pain caused by a fall injury 1 d before hospitalization.She was suspected of having COVID-19,since there was a confirmed COVID-19 case near her residence.But she had no fever,cough,chest tightness,difficult breathing,nausea,vomiting,or diarrhea,etc.On physical examination,the lower posterior chest of both sides showed dullness on percussion and moist rales at the end of inspiration on auscultation.The white blood cell count and lymphocyte count were 10.88×109/L and 1.04×109/L,respectively.CT performed on February 7,2020 revealed that both lungs were scattered with patchy ground-glass opacity.The patient was diagnosed with pulmonary contusion with thoracic spinal fracture(T12),calcaneal fracture,and pelvic fracture.On day 9 after conservative treatment,her condition was alleviated.On review of the chest CT,the previous shadows were significantly reduced.CONCLUSION Differential diagnosis of lung contusion and COVID-19 must be emphasized.Both conditions require effective prompt actions,especially COVID-19.展开更多
介绍了一种数字处理技术实现对光栅编码器所产生莫尔条纹信号的细分。莫尔信号经过光电转换后输出两路正余弦信号并通过光栅解码电路对其AD(analog to digital)采样,利用正切值消除正余弦信号的非线性误差,根据正余弦信号的正负将一个...介绍了一种数字处理技术实现对光栅编码器所产生莫尔条纹信号的细分。莫尔信号经过光电转换后输出两路正余弦信号并通过光栅解码电路对其AD(analog to digital)采样,利用正切值消除正余弦信号的非线性误差,根据正余弦信号的正负将一个周期信号分割成8份,通过反正切角度值实现对每一份的细分。最后将此设计应用于单轴转台。实验结果表明,光栅编码器输出的的静态位置精度可以达到0.000 1°,动态位置及速度曲线无跳变,满足使用要求。展开更多
文摘BACKGROUND Coronavirus disease 2019(COVID-19)is a major public health emergency with obvious characteristics of human-to-human transmission,and there are infective asymptomatic carriers.Early identification and proper management of patients with COVID-19 are important.Features in chest computed tomography(CT)can facilitate identifying newly infected individuals.However,CT findings of some lung contusions are similar to those of COVID-19,as shown in the present case.CASE SUMMARY A 46-year-old woman was admitted to hospital for backache and foot pain caused by a fall injury 1 d before hospitalization.She was suspected of having COVID-19,since there was a confirmed COVID-19 case near her residence.But she had no fever,cough,chest tightness,difficult breathing,nausea,vomiting,or diarrhea,etc.On physical examination,the lower posterior chest of both sides showed dullness on percussion and moist rales at the end of inspiration on auscultation.The white blood cell count and lymphocyte count were 10.88×109/L and 1.04×109/L,respectively.CT performed on February 7,2020 revealed that both lungs were scattered with patchy ground-glass opacity.The patient was diagnosed with pulmonary contusion with thoracic spinal fracture(T12),calcaneal fracture,and pelvic fracture.On day 9 after conservative treatment,her condition was alleviated.On review of the chest CT,the previous shadows were significantly reduced.CONCLUSION Differential diagnosis of lung contusion and COVID-19 must be emphasized.Both conditions require effective prompt actions,especially COVID-19.
文摘介绍了一种数字处理技术实现对光栅编码器所产生莫尔条纹信号的细分。莫尔信号经过光电转换后输出两路正余弦信号并通过光栅解码电路对其AD(analog to digital)采样,利用正切值消除正余弦信号的非线性误差,根据正余弦信号的正负将一个周期信号分割成8份,通过反正切角度值实现对每一份的细分。最后将此设计应用于单轴转台。实验结果表明,光栅编码器输出的的静态位置精度可以达到0.000 1°,动态位置及速度曲线无跳变,满足使用要求。
