Which three technologies are used to reduce chromatic dispersion accumulation in fiber-optic transmission systems? （）(Choose three.) [" PIN photodiodes"," zero-chirped lasers"," Erbium-doped fiber amplifiers"," dispersion compensating fiber"," dispersion compensating Bragg grating"]
客流特征包括
下面关于天然气说法正确的是（） ["天然气的熔露点是指第一滴熔点液体析出时的平衡温度","提高天然气输送温度和压力可以防止水化物生成","天然气中水汽含量的大小取决于海上乙二醇注入量的大小"]
苗床发现立枯病苗，应（）。 ["拔除病苗，留在行间","保留病苗，在周围消毒","除病苗，带出田外","拔除病苗，埋入行间"]
影响抑郁复发的因素有（） ["维持治疗的药物剂量或时间不足","心理、生理应激","社会适应不良","有心境障碍家族史","抑郁发作时的严重程度"]
间隙固溶体
