Currently, crude oil still remains an irreplaceable energy source for chemical industrial processes, transportation systems, electricity, and other human activities. However, crude oil contains sulfur elements as the major impurities in the form of aliphatic and aromatic organosulfur compounds. During the combustion of fuel, these organosulfur compounds are converted to harmful SOx gases; thus, many countries strictly limit the maximum sulfur content in the fuels. To fulfill the government regulation, refineries are trying to decrease the maximum sulfur content in crude oil through several desulfurization technologies, such as hydrodesulfurization, adsorption, oxidative‐desulfurization, alkylation, and biodesulfurization. Each desulfurization technology has its own advantages and disadvantages. In this review article, we aimed to briefly summarize the progress in the developing science and technology of each desulfurization process of crude oil. Several fields in the desulfurization process are still facing challenges to create better designs and development for a safer future of the world.

A novel method of gauge block measurement without wringing onto a glass platen is proposed. By using tandem low-coherence interferometry to perform remote measurements, wringing is rendered unnecessary. To measure its length, a gauge block for measurement without wringing is set several millimeters above a glass platen that is positioned on a triangle interferometer such that the distances between the surfaces of the block and the reflection surface of the platen can be measured from opposite directions. By using tandem low-coherence interferometry with a He–Ne laser as a reference length standard, gauge blocks with nominal lengths of 5, 10 and 75 mm have been measured remotely with an expanded uncertainty of about 86 nm.

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<p>The open-loop educational computer numerical control (CNC) milling machine requires accuracy verification in order to ensure its accuracy and functionality. In this paper, the new verification method is proposed based on the length measurement using the fringe counting of He-Ne laser interferometry. The ideal translation length is defined by the number of electric pulses generated by the micro-stepping driver, while the actual length is measured using He-Ne laser interferometry. In the experimental process, the data of the fringe pattern of the He-Ne laser and the number of electric pulses which drive the stepper motors were simultaneously acquired using an oscilloscope. Hence, the data has been analyzed to obtain the ideal and actual lengths by using an in-house program developed in Python. By comparing the actual translation and ideal length, the accuracy of the educational CNC milling machine has been evaluated to be 50 µm for the length up to 200 mm.</p>

We propose a novel absolute measurement method for precisely measuring the internal distance between two points, using a tandem low-coherence interferometer. In this method, a beam splitter is positioned between two plane mirrors, the locations of which are accurately determined at the nanometre level using tandem low-coherence interferometry. Using a He–Ne laser interferometer as a reference length standard, an internal distance of up to 100 mm was measured remotely, with a measurement uncertainty of 178 nm (k  =  2).