NTP协议(Network Time Protocol)的出现就是为了解决网络内设备系统时钟的同步问题。不幸的是,在通常的互联网环境中,数据传输的延迟不是恒定的,即使相同的路由,从NTP服务器到NTP客户端延迟与从NTP客户端到NTP服务器延迟,即单向延迟(OWD...NTP协议(Network Time Protocol)的出现就是为了解决网络内设备系统时钟的同步问题。不幸的是,在通常的互联网环境中,数据传输的延迟不是恒定的,即使相同的路由,从NTP服务器到NTP客户端延迟与从NTP客户端到NTP服务器延迟,即单向延迟(OWD)不总是相同的。这对时间同步的准确性有很大的影响。目前广泛应用的PTP也同样存在这个问题。因此,为了提高时间的准确性,需要通过测量,提供有关实际传输OWD的时间分布和OWD的不对称性的研究。展开更多
Applications of Atomic Force Microscopy (AFM) in optical disc technology are summarized. AFM is ideally suited to the characterization of nanometerscale pit and bump structures in CD/DVD manufacturing, so the relati...Applications of Atomic Force Microscopy (AFM) in optical disc technology are summarized. AFM is ideally suited to the characterization of nanometerscale pit and bump structures in CD/DVD manufacturing, so the relationship between production variables and pits/bumps geometry as well as relations between pits/bumps geometry and electrical performance of discs can be established to perform direct quality control of CD/DVD manufacturing. Applications of AFM in optical disc technology mainly fall into three parts: qualitative analysis of topography of discs/stampers, semiquantitative analysis of pits/bumps geometry of discs/stampers and length analysis of data marks on bump with statistics technology. Qualitative analysis of topography of discs/stampers and semiquantitative analysis of pits/bumps geometry of discs/stampers are chiefly oriented to the measurements of high error rate at beginning of play, pit morphology and block error rate, track pitch variations, pit depth monitoring as well as bump morphology and its surface roughness. It is discovered that the efficiency of the cooling channels of the mold has deteriorated, resulting in the discs being separated from the stamper while they are too soft due to inadequate cooling in the area where high error rate and block error rate are frequently produced. Length analysis of data marks with statistics technology is aimed at the analysis of track pitch and pitch variation, bump length (offset, deviation, asymmetry) and AFM jitter, bump width and width variation, bump height and height variation as well as side wall angle (slope) and slope variation. Statistical analysis of AFM images yields important information about optical disc microstructure and in turn provides information about the performance of the manufacturing process. It is very useful to analyze geometric parameters by considering the fundamental length groups of the data marks. The obtained results demonstrate that AFM have particular advantages in the quality control of discs/stampers manufacturing.展开更多
文摘NTP协议(Network Time Protocol)的出现就是为了解决网络内设备系统时钟的同步问题。不幸的是,在通常的互联网环境中,数据传输的延迟不是恒定的,即使相同的路由,从NTP服务器到NTP客户端延迟与从NTP客户端到NTP服务器延迟,即单向延迟(OWD)不总是相同的。这对时间同步的准确性有很大的影响。目前广泛应用的PTP也同样存在这个问题。因此,为了提高时间的准确性,需要通过测量,提供有关实际传输OWD的时间分布和OWD的不对称性的研究。
文摘Applications of Atomic Force Microscopy (AFM) in optical disc technology are summarized. AFM is ideally suited to the characterization of nanometerscale pit and bump structures in CD/DVD manufacturing, so the relationship between production variables and pits/bumps geometry as well as relations between pits/bumps geometry and electrical performance of discs can be established to perform direct quality control of CD/DVD manufacturing. Applications of AFM in optical disc technology mainly fall into three parts: qualitative analysis of topography of discs/stampers, semiquantitative analysis of pits/bumps geometry of discs/stampers and length analysis of data marks on bump with statistics technology. Qualitative analysis of topography of discs/stampers and semiquantitative analysis of pits/bumps geometry of discs/stampers are chiefly oriented to the measurements of high error rate at beginning of play, pit morphology and block error rate, track pitch variations, pit depth monitoring as well as bump morphology and its surface roughness. It is discovered that the efficiency of the cooling channels of the mold has deteriorated, resulting in the discs being separated from the stamper while they are too soft due to inadequate cooling in the area where high error rate and block error rate are frequently produced. Length analysis of data marks with statistics technology is aimed at the analysis of track pitch and pitch variation, bump length (offset, deviation, asymmetry) and AFM jitter, bump width and width variation, bump height and height variation as well as side wall angle (slope) and slope variation. Statistical analysis of AFM images yields important information about optical disc microstructure and in turn provides information about the performance of the manufacturing process. It is very useful to analyze geometric parameters by considering the fundamental length groups of the data marks. The obtained results demonstrate that AFM have particular advantages in the quality control of discs/stampers manufacturing.
