We report a newly synthesized inorganic polymer photoresist with a high ceramic yield by the functionalization of polyvinylsilazane (KiON VL20) with 2‐isocyanatoethyl methacrylate via linkage or insertion reaction routes. The chemistry of the synthesis and the pyrolytic conversion as well as the mechanical evaluation were investigated by using various analytical instruments. We show for the first time that this photosensitive resin is a novel precursor for the fabrication of complex 3D SiCN ceramic microstructures with a 210 nm resolution via a two‐photon absorbed crosslinking process and subsequent pyrolysis at 600 °C under a nitrogen atmosphere. Moreover, the dimensional deformation during pyrolysis was significantly reduced by adding silica nanoparticles as a filler. In particular, the ceramic microstructures containing 40 wt % silica nanoparticles exhibited a relatively isotropic shrinkage owing to its sliding free from the substrate during pyrolysis.

Three-dimensional SiC ceramic microstructures with near-zero shrinkage were fabricated from a simple inorganic polymer mixture by inducing dual photocuring routes to produce highly dense polymer features by stereolithography and subsequent pyrolysis at 600 degrees C.

A technique in ultraviolet nanoimprint lithography ͑UV-NIL͒ for the creation of three-dimensional ͑3D͒ nanopatterns in a single step is proposed. The single-step fabrication of 3D or multilevel structures has a multitude of benefits. Inherent in this is the elimination of a need for alignment for multilevel fabrications as well as being a cost effective and simple process. For 3D UV-NIL, a trial in the fabrication of multilayered stamps has been conducted employing two-photon polymerization and diamondlike carbon ͑DLC͒ coating technique. The DLC coating layer enables the polymer patterns to be used effectively as a stamp without the need for an antiadhesion material. Additionally, O 2-plasma ashing has the potential for an epoch-making improvement of the precision of polymer patterns with a linewidth of 60 nm. Overall, several fine patterns are imprinted using the multilayered stamp onto a UV-curable resist via a single-step process without any identifiable damage.

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In this paper, an experimental study on two-phase flow pressure drop of refrigerant FC-72 is carried out in a microchannel. The microchannel has a width and depth of 0.45 and 0.2 mm respectively, and comprises 15 parallel channels with a length of 60 mm. The experiment is conducted under the condition of mass flux of 100.3–458.0 kg/m2s and heat flux of 3.2–49.0 kW/m2. This study analyzed the pressure drop characteristics for two-phase flow by using a separated flow model. To predict the frictional pressure drop, two-phase frictional multiplier obtained from experiments is compared with the existing correlations. The experimental results show that two-phase frictional multipliers rely heavily on the vapor quality. Fractional pressure drop increases as the vapor quality increases. However, the rate of increase in the high vapor quality region decreases as the vapor quality increases. Based on pressure drop characteristics obtained from the experiments, a new correlation is proposed to predict the frictional pressure drop. Two-phase multiplier is modified with the dimensionless parameters such as Reynolds number, Weber number, and Martinelli parameter. The newly developed correlation predicts the experimental results well within a mean absolute error of 8.0%.

This paper deals with an experimental investigation to measure the frictional pressure drops for two-phase flow boiling in a micro-channel with a hydraulic diameter of 500 µm. First, the experimental study is performed under the test conditions: heat fluxes ranging from 100 to 400 kW/m2, vapor qualities from 0 to 0.2, and mass fluxes of 200, 400 and 600 kg/m2s. Then, the frictional pressure drop during flow boiling is estimated using two models: the homogeneous model and the separated flow model. The experimental results show that the two-phase multiplier decreases with the increase of mass flux. In addition, the measured pressure drops are compared with those from a few correlation models available for macro-scales and mini/micro-scales. Finally, the present paper proposes a new correlation for two-phase frictional pressure drops in mini/micro-scales. This correlation model is developed based on the Chisholm constant C as a function of two-phase Reynolds and Weber numbers. It is found that the new correlation satisfactorily predicts the experimental data within mean absolute error (MAE) of 3.9%.

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A regulation on the sulfur emissions of ships sailing in global sea areas has been enforced since 1 January 2020. In this new regulation, ships are required to use low-sulfur fuel oils or to install an after-treatment equipment, such as a scrubber. Open and hybrid scrubbers wash the exhaust gas using seawater and then discharge the wash water overboard. According to the regulation promulgated by the International Maritime Organization (IMO) Marine Environment Protection Committee (MEPC), the wash water must have a pH of 6.5 or higher at 4 m from the discharge point. Wash water is generally acidic, with a pH of 2.5–3.5, whereas seawater is alkaline, with a pH of approximately 8.2. The wash water is dispersed after being discharged overboard through a nozzle, and its pH is restored through dilution with the surrounding seawater. In this study, the pH was calculated by using a theoretical chemical reaction model, and then the dispersion of wash water was analyzed using CFD simulation. This study describes the process of selecting the appropriate turbulent Schmidt number in a wide range of nozzle diameters. Finally, the appropriate nozzle diameter was determined based on the initial pH of the discharged scrubber wash.