Chung Yuan Christian University

About: Chung Yuan Christian University is a education organization based out in Taoyuan City, Taiwan. It is known for research contribution in the topics: Membrane & Fuzzy logic. The organization has 9819 authors who have published 11623 publications receiving 213139 citations. The organization is also known as: Tiong-gôan-tāi-ha̍k & CYCU.

The influence of hydroxyapatite particles on osteoclast cell activities

Abstract: Aseptic loosening after total joint arthroplasty is a major problem in orthopedic surgery Small particles from material wear have been reported as the main cause of implant failure For this reason, investigation into possible wear particles from the materials used in the implant may lead to longevity after arthroplasty Hydroxyapatite (HA) has been extensively investigated and reported as an excellent biomaterial with excellent biocompatibility In this study, we used an in vitro osteoblast/osteoclast model to test the biocompatibility of various-sized HA particles Primary osteoclasts/osteoblasts were co-cultured with different-sized HA particles (05-30 microm, 37-53 microm, 177-205 microm, and 420-841 microm) for 3 h, 1 day, 3 days, and 7 days Cellular responses to the HA particles were evaluated by changes in cell counts and the secretion of transforming growth factor (TGF-beta1), alkaline phosphatase (ALP), tumor necrosis factor (TNF-alpha), prostaglandin (PGE2), and lactate dehydrogenase (LDH) in the supernatant of the culture media The results showed that osteoblasts/osteoclasts co-cultured with HA particles smaller than 53 microm undergo the most significant changes Cellular counts significantly decreased, and the changes were more obvious in the osteoblast population There also was a significant decrease in TGF-beta1 concentration and a significant increase in PGE2 and LDH concentration, but there were no changes in the TNF-alpha or ALP titer It can be concluded that larger HA particles may be quite compatible with bone cells while smaller-sized HA particles can both activate the osteoclasts and decrease the cell population of the osteoblasts Justification for the additional expense incurred with the use of hydroxyapatite in primary total hip arthroplasty should be further evaluated

Controllability of spacecraft systems in a central gravitational field

Abstract: The configuration space for rigid spacecraft systems in a central gravitational field can be modeled by SO(3)/spl times/ IR/sup 3/, where the special orthogonal group SO(3) represents the attitude dynamics and IR/sup 3/ is for the orbital motion. The attitude dynamics of the spacecraft system is affected by the orbital elements through the well-known gravity-gradient torque. On the other hand, the effects of attitude-orbit coupling can also possibly be used to alter orbital motions by controlling the attitude. This controllability property is the primary issue of this paper. The control systems for spacecraft with either reaction wheels or gas jets being used as attitude controllers are proven in this study to be controllable. Rigorously establishing these results necessitates starting with the formal definitions of controllability and Poisson stability. It is then shown that if the drift vector field of the system is weakly positively Poisson stable and the Lie algebra rank condition is satisfied, controllability can be concluded. The Hamiltonian structure of the spacecraft model provides a natural route of verifying the property of weakly positive Poisson stability. Accordingly, the controllability is obtained after confirming the Lie algebra rank condition. Developing a methodology in deriving Lie brackets in the tangent space of T(SO(3)/spl times/IR/sup 3/), i.e., the second tangent bundle is thus deemed necessary. A general formula is offered for the computation of Lie brackets of second tangent vector fields in TT(SO(3)/sup m//spl times/IR/sup n/), in light of its importance in the fields of mechanics, robotics, optimal control, and nonlinear control, among others. With these tools, the controllability results can be proved. The analysis in this paper gives some insight into the attitude-orbit coupling effects and may potentially lead towards new techniques in designing controllers for large spacecraft systems. >

Insight into adsorption mechanism of cationic dye onto agricultural residues-derived hydrochars: Negligible role of π-π interaction

Abstract: Hydrochars derived from golden shower pod (GSH), coconut shell (CCH), and orange peel (OPH) were synthesized and applied to remove methylene green (MG5). The results indicated that the hydrochars possessed low specific surface areas (6.65-14.7m2/g), but abundant oxygen functionalities (1.69-2.12mmol/g). The hydrochars exhibited cellular and spherical morphologies. Adsorption was strongly dependent on the solution pH (2-10) and ionic strength (0-0.5M NaCl). Equilibrium can be quickly established in the kinetic study (60-120 min). The maximum Langmuir adsorption capacities at 30 °C followed the order GSH (59.6mg/g)>CCH (32.7mg/g)>OPH (15.6mg/g)> commercial glucose-prepared hydrochar (12.6mg/g). The dye adsorption efficiency was determined by the concentrations of oxygen-containing functionalities on the hydrochar surface. The adsorption process occurred spontaneously (− ΔGo) and exothermically (−ΔHo). Desorption studies confirmed the reversible adsorption process. Oxygenation of the hydrochar surface through a hydrothermal process with acrylic acid contributed to increasing MG5 adsorption and identifying the negligible role of π-π interaction to the adsorption process. The analysis of Fourier transform infrared spectrometry demonstrated that the aromatic C=C peak did not significantly decrease in intensity or shift toward higher/lower wavenumbers after adsorption, which further confirms the insignificant contribution of π-π interaction. Electrostatic attraction played a major role in adsorption mechanisms, while minor contributions were accounted for hydrogen bonding and n-π interactions. The primary adsorption mechanisms of MG5 onto hydrochar were similar to biosorbent, but dissimilar to biochar and activated carbon (i.e., π-π interaction and pore filling).

Analytical Synthesis of Low-Sensitivity High-Order Voltage-Mode DDCC and FDCCII-Grounded R and C All-Pass Filter Structures

Abstract: The difficulty of realizing the operations of addition and subtraction of a voltage-mode signal renders two special active elements, namely, differential difference current conveyors (DDCCs) and fully differential current conveyors (FDCCIIs), both of which have the ability to perform the operations of addition and subtraction, to become very important for voltage-mode analog filter design. Note that, for the design of operational transconductance amplifier and capacitor (OTA-C) filters, the recently reported analytical synthesis methods (ASMs) have been shown to be very effective for achieving simultaneously the three criteria, namely, all capacitors being grounded, the use of the minimum number of active and passive components, and the use of single-ended input OTAs. However, none of the ASMs uses DDCCs and FDCCIIs in the design of voltage-mode filters. In this paper, a method of realizing DDCC and FDCCII-based all-pass filter structures with either equal capacitances or equal conductances through a new ASM is presented. Only n current conveyors (the least number of active components), n grounded capacitors, and grounded resistors (the minimum number of passive components) are used for realizing an nth-order voltage-mode all-pass filter structure. Moreover, the new all-pass filter structure synthesized by the new ASM achieves very low individual as well as near-null group sensitivities just as in the case of the passive LC ladder filters, has very low power consumption, a low component spread for equal denominator conductance design, and a high input impedance which is attractive from the point of view of cascadability. Finally, H-Spice simulations, using 0.35-mum process and plusmn1.65-V supply voltages, are included and validate theoretical predictions.