中文摘要：

通过对12对双中子星（DNS）系统进行质量分布统计，得到其质量加权平均值为（1．339±0．042）M⊙，其中主星和伴星的质量加权平均值分别为（1．439±0．036）M⊙（1．239±0．020）A孙．主星平均质量比伴星平均质量高，表明主星可能通过吸积获得质量，或者主星的前身星的质量更大．据此可以分析大质量恒星通过超新星爆发形成中子星的物理过程．此外还发现，DNS的总质量集中在一个比较狭小的范围（2．5—2．8M），这说明DNS的质量形成受到伴星的影响．经过进一步的分析注意到DNS的质量比接近于1（略大于1），这可能暗示DNS系统的前身星质量比较相近．通过分析12对DNS在中子星的磁场强度一自旋周期关系图（B-Ps图）中的分布，发现DNS主星磁场强度约10^10Gs，自转周期约50ms；PSRJ1906＋0746和PSRJ0737-3039B处在正常脉冲星序列，磁场强度约10^12Gs，这说明两者没有吸积加速过程．

英文摘要：

By statistically analyzing the masses of the twelve double neutron star （DNS） systems, it is conclude that the weighted mean value of their neutron star （NS） masses is （1.339±0.042）M⊙, where the weighted mean masses of the primaries and companions are （1.439±0.036）M⊙and （1.239±0.020） M⊙, respectively. The mean value of the masses of the primaries is higher than that of the companions, which indicates that the primaries may increase their masses by accretion, or the mass of progenitors of the primaries is higher. Therefore, the physical process of supernova explosion through which the high-mass stars become NSs can be investigated. Also it is found that the total masses of the DNSs span a narrow range of 2.5-2.8 Me, implying that the companions might impact on the mass formation of DNSs. Moreover, the mass ratios of the DNSs （primaries to companions） approximate 1 （slightly larger than i）, indicating that the masses of the progenitors of the primaries are approximately equal to the masses of the progenitors of the companions. By analyzing the distribution of the 12 DNSs in the surface magnetic field strength versus spin period （B-Ps） diagram, it is found that the surface magnetic field strength of the primaries of the DNSs is -10^10 Gs and the spin period is - 50 ms; while two pulsars, i.e. PSR J1906＋0746 and PSR J0737- 3039B, are located in the region of normal pulsars in the B-Ps diagram, whose surface magnetic field strength is - 1012 Gs, suggesting that they might not be accelerated through accretion.