In normal conditions, the Critical Flicker Frequency is usually 60Hz. But in some special conditions, such as low spatial frequency and high contrast between frames, these special conditions have high probability to occur in some TPVMbased applications. So it’s extremely important to verify if a visual signal with a combination of temporal and spatial frequency can be recognize by human eyes. Based on the research in the last paper ’ ’Window of Visibility’ inspired security lighting system’, this paper introduces the measuring method of WoV of human eyes. In this paper we will measure critical flicker frequency in low spatial frequency and high contrast conditions, and we can witness a different conclusion from the normal conditions.

Eugene Schuyler was the first American to travel to Central Asia. Recognized as a scholar diplomat, he had written extensively on Russia and served as the US consul to Reval and the secretary of the American legation in St. Petersburg. During his diplomatic service in Russia, Schuyler was granted absence of leave to visit Central Asia and witnessed the Russian conquest of the region. He was also accompanied by the Russian army to visit the Ili region in Xinjiang amid the Dungan Revolt (1862–1877). Schuyler’s unusual experience was detailed in his travelogue Turkistan, Notes of a Journey in Russian Turkistan, Khokand, Bukhara, and Kuldja. This paper aims to analyze his travelogue to track down the earliest American contact with Central Asia. It argues that the US, even though aware of Russian military activity in the region from Schuyler’s report, tacitly acknowledged Russia’s hegemony in Asia. This could be attributable to Schuyler’s partiality to Russia’s cause, the generally congenial atmosphere in the US-Russia relations in the 1870s, and the absence of perceived US interests in Central Asia. The US foreign policy decision of the 1870s had far-reaching economic consequences and lasting political implications into the 19 ^th century and beyond.