Cohen R, Cluzel J, Cohen H, Male P, Moignier M, Soulie C
Biophys Chem. 1976 Jul;5(1-2):77-96. doi: 10.1016/0301-4622(76)80027-0.
The various hardware components of this scanning system, a mechanical split-beam scanner with its photomultiplier measuring slit, minimum analog electronics and an important digital part (computer, interface), are intimately interwoven by an elaborate software. A high degree of automation and sophistication is thus reached. On the one hand, all the photoelectrons coming from each light pulse are integrated. The result, after conversion to digital form enters the computer; a high precision is thus reached: 10(-5) absorbance unit (A.U.) under very favorable conditions, and 10(-4) A.U. for conventional sedimentation studies. On the other hand, during its motion along the image, the precise slit position is permanently known by the system: the sector image is thus segmented into precisely defined zones, inside which the average absorbancies are determined, punched, plotted and printed. New and very useful utilizations and improvements of analytical ultracentrifugation are now possible: the fixed radius mode, permits precise s determination by following the radial dilution; s can be precisely measured by time difference curves even when the solution absorbancy is comparable to the base line variations (0.01 A.U.); round trip analyses permit very long analyses without the absorbancies distributions distorsions due to very long one-way scans during sedimentations runs; reductions of the effect of the stray light by a factor of ten. This system has been in routine use for four years.
该扫描系统的各种硬件组件，即带有光电倍增管测量狭缝的机械分束扫描器、最小模拟电子设备以及重要的数字部分（计算机、接口），通过精心设计的软件紧密交织在一起。从而实现了高度的自动化和精密性。一方面，来自每个光脉冲的所有光电子都被积分。积分结果在转换为数字形式后进入计算机；因此达到了高精度：在非常有利的条件下为10^(-5)吸光度单位（A.U.），对于传统沉降研究为10^(-4) A.U.。另一方面，在沿图像移动过程中，系统始终知道精确的狭缝位置：扇形图像因此被精确分割成明确定义的区域，在这些区域内确定平均吸光度、打孔、绘图并打印。现在，分析超速离心有了新的且非常有用的应用和改进：固定半径模式允许通过跟踪径向稀释精确测定沉降系数（s）；即使溶液吸光度与基线变化相当（0.01 A.U.），也可以通过时间差曲线精确测量s；往返分析允许进行非常长时间的分析，而不会因沉降运行期间非常长的单向扫描导致吸光度分布失真；将杂散光的影响降低了十分之一。该系统已常规使用四年。
