Orthogonal time frequency space(OTFS)modulation is a recently proposed modulation scheme that exhibits robust performance in high-Doppler environments.It is a two-dimensional modulation scheme where information symbol...Orthogonal time frequency space(OTFS)modulation is a recently proposed modulation scheme that exhibits robust performance in high-Doppler environments.It is a two-dimensional modulation scheme where information symbols are multiplexed in the de⁃lay-Doppler(DD)domain.Also,the channel is viewed in the DD domain where the chan⁃nel response is sparse and time-invariant for a long time.This simplifies channel estima⁃tion in the DD domain.This paper presents an overview of the state-of-the-art approaches in OTFS signal detection and DD channel estimation.We classify the signal detection ap⁃proaches into three categories,namely,low-complexity linear detection,approximate max⁃imum a posteriori(MAP)detection,and deep neural network(DNN)based detection.Simi⁃larly,we classify the DD channel estimation approaches into three categories,namely,separate pilot approach,embedded pilot approach,and superimposed pilot approach.We compile and present an overview of some of the key algorithms under these categories and illustrate their performance and complexity attributes.展开更多
目的:探究防护型急救车底盘抵御爆炸性武器手雷、地雷的毁伤效果。方法:在满足防护型急救车防护要求的前提下,采用12 mm厚聚乙烯(polyethylene,PE)防护板和复合陶瓷PE防护板(1 mm铝板+6 mm B4C陶瓷+12 mm高分子量聚乙烯纤维)对急救车底...目的:探究防护型急救车底盘抵御爆炸性武器手雷、地雷的毁伤效果。方法:在满足防护型急救车防护要求的前提下,采用12 mm厚聚乙烯(polyethylene,PE)防护板和复合陶瓷PE防护板(1 mm铝板+6 mm B4C陶瓷+12 mm高分子量聚乙烯纤维)对急救车底盘进行防护。通过理论计算和仿真模拟,分别分析某62 g TNT手雷对PE防护板和某6000 g TNT当量地雷对复合陶瓷PE防护板的爆炸毁伤效果。结果:PE防护板和复合陶瓷PE防护板能够分别抵御某手雷和某地雷在1.1 m炸距下的爆炸毁伤作用,且均未出现明显破坏。结论:PE防护板和复合陶瓷PE防护板均能满足抵御爆炸性武器手雷、地雷毁伤作用及机动性、轻量化要求,该研究可为防护型急救车底盘防护设计提供参考。展开更多
目的研究某部推进剂作业人员的健康状况。方法分析某部168名推进剂作业人员的一般资料、实验室检查及辅助检查相关指标的差异,探讨推进剂职业暴露对机体的影响。结果观察组人员的年龄、脉搏、血压、体质量指数(body mass index,BMI)等...目的研究某部推进剂作业人员的健康状况。方法分析某部168名推进剂作业人员的一般资料、实验室检查及辅助检查相关指标的差异,探讨推进剂职业暴露对机体的影响。结果观察组人员的年龄、脉搏、血压、体质量指数(body mass index,BMI)等一般资料与对照组比较差异均无统计学意义(P>0.05)。观察组人员的血常规、肝功能、肾功能等实验室检查及胸片、心电图、腹部超声等辅助检查结果,与对照组比较差异均无统计学意义(P>0.05)。长期组作业人员的年龄、脂肪肝人员比例显著高于短期组人员(P<0.001),其余指标与短期组比较差异均无统计学意义(P>0.05)。结论推进剂作业人员的健康状况总体良好,并未受到职业暴露危险因素的显著影响,今后仍需加强职业健康监测,做好职业卫生防护,全力保障推进剂作业人员的身心健康。展开更多
文摘Orthogonal time frequency space(OTFS)modulation is a recently proposed modulation scheme that exhibits robust performance in high-Doppler environments.It is a two-dimensional modulation scheme where information symbols are multiplexed in the de⁃lay-Doppler(DD)domain.Also,the channel is viewed in the DD domain where the chan⁃nel response is sparse and time-invariant for a long time.This simplifies channel estima⁃tion in the DD domain.This paper presents an overview of the state-of-the-art approaches in OTFS signal detection and DD channel estimation.We classify the signal detection ap⁃proaches into three categories,namely,low-complexity linear detection,approximate max⁃imum a posteriori(MAP)detection,and deep neural network(DNN)based detection.Simi⁃larly,we classify the DD channel estimation approaches into three categories,namely,separate pilot approach,embedded pilot approach,and superimposed pilot approach.We compile and present an overview of some of the key algorithms under these categories and illustrate their performance and complexity attributes.
文摘目的:探究防护型急救车底盘抵御爆炸性武器手雷、地雷的毁伤效果。方法:在满足防护型急救车防护要求的前提下,采用12 mm厚聚乙烯(polyethylene,PE)防护板和复合陶瓷PE防护板(1 mm铝板+6 mm B4C陶瓷+12 mm高分子量聚乙烯纤维)对急救车底盘进行防护。通过理论计算和仿真模拟,分别分析某62 g TNT手雷对PE防护板和某6000 g TNT当量地雷对复合陶瓷PE防护板的爆炸毁伤效果。结果:PE防护板和复合陶瓷PE防护板能够分别抵御某手雷和某地雷在1.1 m炸距下的爆炸毁伤作用,且均未出现明显破坏。结论:PE防护板和复合陶瓷PE防护板均能满足抵御爆炸性武器手雷、地雷毁伤作用及机动性、轻量化要求,该研究可为防护型急救车底盘防护设计提供参考。
文摘目的研究某部推进剂作业人员的健康状况。方法分析某部168名推进剂作业人员的一般资料、实验室检查及辅助检查相关指标的差异,探讨推进剂职业暴露对机体的影响。结果观察组人员的年龄、脉搏、血压、体质量指数(body mass index,BMI)等一般资料与对照组比较差异均无统计学意义(P>0.05)。观察组人员的血常规、肝功能、肾功能等实验室检查及胸片、心电图、腹部超声等辅助检查结果,与对照组比较差异均无统计学意义(P>0.05)。长期组作业人员的年龄、脂肪肝人员比例显著高于短期组人员(P<0.001),其余指标与短期组比较差异均无统计学意义(P>0.05)。结论推进剂作业人员的健康状况总体良好,并未受到职业暴露危险因素的显著影响,今后仍需加强职业健康监测,做好职业卫生防护,全力保障推进剂作业人员的身心健康。
