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In papermaking, pre-flocculation of fillers such as ground calcium carbonate (GCC) improves the tensile strength of paper sheets. However, the pre-flocculated fillers mostly suffer from the instability of the floc shape such as the decrease in floc diameter with time elapse after preparation and no improvement of bulk and stiffness. The addition of calcium compounds such as calcium oxide or calcium hydroxide to the pre-flocculated GCC, and injection with carbon dioxide caused pre-flocculated GCC flocs to be covered with newly formed calcium carbonate. This product, called post hybrid calcium carbonate (pHCC), was found to be more stable in size and gave better sheet strength than the pre-flocculated ones. Furthermore, pHCC gave remarkably higher bulk and stiffness than the pre-flocculated flocs did without impairing smoothness that was essential in printing paper. The proper use of pHCC in papermaking could allow the production of high loaded paper with more than 10% higher filler contents, which could reduce paper production cost and save drying energy. The proportion of the newly formed calcium carbonate in pHCC, turbulence intensity at preparation stage, and the effect of storage time were investigated.

Controlling the size and rigidity of calcium carbonate became possible. HCCs were developed and manufactured by the in situ reaction of carbon dioxide and calcium oxide, which were already preflocculated together with GCC using ionic polymers before the reaction. HCC is deformable under pressure during the papermaking process, and its degree of rigidity can be controlled by adjusting the fraction of calcium oxide. The size of HCC can be further controlled by adjusting shearing force. The more the fraction of calcium oxide, the more rigid the HCC and the smaller the diameter of the HCC. When used in papermaking, HCC increased the tensile strength and bulk of paper simultaneously without lowering other essential paper properties, and its deformable nature under pressure improved paper smoothness. Saving chemical pulp by 10% by replacing it with HCC, which is 3–4 times less expensive than the chemical pulp, was demonstrated successfully without lowering the essential properties of paper. Implementation of HCC in the paper mill may result in saving chemical pulp, drying energy, and production cost. The paper mill may utilize the carbon dioxide from the mill stack after purification for HCC preparation.

Flexible and deformable calcium carbonate (FCC) with a high aspect ratio was developed by forming calcium carbonate on the surface of nanocellulose through an in situ calcium carbonate formation pr...

A portion of the lime mud formed during the causticizing process in the recovery process of kraft pulping should be purged from the calcium cycle as waste before it is fed to the lime kiln; this ensures that the quality of the pulp and pulping chemicals is maintained. The discharged greenish-gray lime mud, which is often disposed as an industrial waste, has been transformed herein into a high-quality papermaking filler via the hybrid calcium carbonate (HCC) and post-HCC (pHCC) technology. Initially, the lime mud was heat-treated and then ground to small-size particles. The ground lime mud was preflocculated with calcium oxide by ionic polymers, and carbon dioxide was injected to the flocs to produce lime mud HCC (LHCC). To produce lime mud pHCC (pLHCC), only the ground lime mud was preflocculated first, calcium oxide was added next, and finally, carbon dioxide was injected to the flocs. The resultant products, LHCC and pLHCC, gave brightness as high as that of the ground calcium carbonate (GCC) in paper while a little higher brightness for pLHCC than for LHCC. They also enabled to increase bulk, stiffness, and tensile strength. Application of the LHCC and pLHCC technology to the lime mud could save waste disposal expenses and produce better-quality paper.

Hybrid calcium carbonate (HCC) was developed to simultaneously increase the bulk, stiffness, and strength of printing paper. It was prepared by the preflocculation of a mixture of ground calcium ca...

An antenna for satellite communication ground terminals exists in many different forms. A mobile antenna for large-volume / high-speed transmission is mostly using of offset antenna among the many antenna. This surface mounted antenna is taken the wind requirements and shall be designed by the level. This paper identifies problems of real artificial wind test by frequency response characteristics after conducting random vibration analysis using wind spectrum. Through these results, this paper also desires to draw a improvement direction that antenna can meet the requirements as developing similar large offset antenna applied the wind requirements of high level.

Wood flours (WFs) are bulky lignocellulosic materials that can increase the bulk and stiffness of paper. To be used in printing paper for replacing chemical pulp, WFs were first fractionated by a 200-mesh screen to improve smoothness, second, they were coated with calcium carbonate by an in-situ CaCO3 formation method (coated wood flours, CWFs) to improve brightness. The performance of CWFs for printing paper was compared to those of bleached wood flours (BWFs) and bleached chemical pulp. Equivalent brightness and much higher smoothness were obtained for the CWFs compared to the BWFs. Furthermore, BWFs caused a significant loss of yield and required wastewater treatment in the bleaching process, while the CWFs increased the yield greatly by attaching CaCO3 to the wood flours, and caused no wastewater burden. An accelerated aging test showed that the CWFs caused lesser brightness and strength loss than the bleached chemical pulp and BWFs. CWFs still had room for improvement to replace chemical pulp, but showed slower aging in optical and close strength properties.

Very well aligned vertical ZnO nanorods with high optical quality were successfully synthesized by sequentially employing an aqueous solution method on a ZnO seed layer and a thermal chemical vapor deposition (CVD). The process is growing the upper ZnO nanorods by using CVD on top of the bottom nanorods synthesized by using an aqueous solution method on a Si substrate with a ZnO seed layer. These double-structured-nanorods showed a significant improvement of optical quality. The CVD re-grown upper nanorods showed orders-of-magnitude enhancement of the band edge emission and complete compression of the deep level emissions, compared with the solution-grown bottom nanorods. By comparing emission spectra from the series of samples with and without the seed layer or the second CVD growth, we can conclude that the improvement can only be achieved by combining the CVD, the solution-based synthesis technique, and the seed layer.

Very narrow ZnO nanowires are synthesized on the sputtered ZnO seed layer by hydrothermal growth method. Varying the growth parameters we can obtain several features of ZnO nanowire. The nanowires with a diameter of about 15nm and with a length longer than 5µm are grown, which are much narrower than ZnO nanowires grown by chemical vapor deposition. The underlying ZnO seed layer enhanced the nucleation of ZnO nanowire during the followed ZnO synthesis by hydrothermal growth but without the seed layer, ZnO grown randomly as a rod shape. The molar ratio of the source is critical to the shape of the ZnO nanowire. Crystal orientation of ZnO nanowire is inestigated by X-ray θ-2θ diffraction and microstructure of the ZnO nanowire is examined by transmission electron microscopy. Hydrogen-gas sensing property is measured and compared from the synthesized ZnO nanowires.

Vertical ZnO nanowires with a very high aspect ratio of more than 250 were synthesized by thermal chemical vapor deposition (CVD) on vertical nanowires grown by hydrothermal growth (HG) without using the metal catalyst. A ZnO seed layer grown by sputtering was crucial to synthesize the vertical nanowires in both the CVD and the HG processes. The underlying vertical nanowires grown by the HG process (HG-nanowire) enhanced nucleation of ZnO during the followed ZnO synthesis by CVD. Hydrogen-gas sensitivity was measured from the synthesized ZnO nanowires. High sensitivity of 72% and response time as fast as 30s was observed at 200°C from the vertical ZnO nanowires grown by CVD on the HG-nanowire, which is much higher than the sensitivity value of 50% from the vertical HG-nanowire and the value of 35% from the vertical CVD nanowires without the HG-nanowire. The results indicate that the method synthesizing the vertical ZnO nanowires by combining the HG process and thermal CVD is a very promising way to fabric...