碩士 / 國立清華大學 / 化學工程學系 / 89 / For developing a fermentation process, selection of a proper fermenter is an important step. There are many types of fermenter in industrial fermentation processes. Stirred tank fermenters and bubble columns are commonly used. For an aerobic fermentaion, especially, oxygen transfer and liquid mixing are two key factors important for the growth and metabolism of microorganisms. Stirred tank fermenter can provide sufficient oxygen transfer by manipulating both aeration and agitation speed. However, the stirred tank fermenter usually have high shear stress which is not suitable for cultivation of some cells. Bubble column has low shear stress, but it has low capability of oxygen transfer and poor mixing. For some fermentation systems, the cells are sensitive to shear stress and have high oxygen consumption rate. Both stirred tank fermenter and bubble column are not suitable for the fermentation systems. The purpose of this study focuses on the design and scale-up of a bioreactor. In the present study, a pilot scale airlift reactor with multiple wire-mesh draft plates was developed. Mixing and mass transfer were investigated in the air-water hydrodynamic system. The experimental results showed that the airlift reactor still had the characteristics of high oxygen transfer rate and well mixing after scaling up. In addition, the proposed reactor also showed that the performance, such as volumetric mass transfer coefficient, gas holdup and mixing time, of the reactor surpassed those of the other bioreactors, including bubble column and airlift reactor with double net draft tubes. The application of the proposed reactor for cultivates Acetobacter xylinum for bacterial cellulose (BC) production has been carried out. The experimental results demonstrated that using the proposed column gave better productions than those of the conventional bubble column and stirred-tank reactor. Further, we have found that BC produced by the proposed reactor formed a unique ellipse pellet (BC-pellet, the average diameter is 10 mm), which is different from the fibrous BC produced by the agitated stirred-tank. Besides, the physical and morpholocigal properties of the BC-pellet also surpassed those of the fibrous BC. Moreover, the BC-pellet suspension was demonstrated to have a higher volumetric oxygen transfer coefficient and mixing capability than those of the fibrous BC suspension in the proposed reactor. The dissolved oxygen during the fermentation process by using the proposed reactor could be maintained above 35% and the growth or metabolism of cells was not inhibited. After 72 hours, the final concentration of BC was 7.72 (g/L) and the productivity was 0.107 (g / h․L), which was three times higher than that of the conventional bubble column and stirred-tank reactor. Consequently, the proposed reactor is quite suitable for cultivating Acetobacter xylinum for bacterial cellulose production. Keywords: bioreactor design, airlift reactor, scale-up, fermentation, bacterial cellulose, Acetobacter xylinum.

碩士 / 國立清華大學 / 化學工程學系 / 89 /

碩士 / 國立清華大學 / 化學工程學系 / 89 /

碩士 / 國立清華大學 / 化學工程學系 / 89 / The promotion effect of tin on direct copper electroplating process via sulfide was investigated. It is found the direct plating rate on Tin-Palladium sol colloid activated nonconductive substrate can be accelerated about 4-10 times by Na2S, but it only accelerated about 1.5 times for polymer protected palladium colloid activated nonconductive substrate. The increased promotion effect via Na2S of Tin-palladium colloid is due to one of the followings: (1) the higher concentration; (2) the uniform particle size and distribution; (3) an interaction between the Sn and Pd in the colloid. Comparison between polymer protected palladium colloid and Tin-Palladium colloid exclude the possibility of other factors but the interaction between Sn and Pd in the colloid.

碩士 / 國立清華大學 / 化學工程學系 / 89 / Montomorillonite was organically modified with different swelling agents, namely n-dodecylamine, 12-aminolauric acid and 1,12-diaminodecane. The polyamide 6/clay nanocomposite were prepared by solvent blending with formic acid and using a single screw extruder. From X-ray diffraction analysis, it was found that the clay could not exfoliated in the PA6/clay nanocomposite, and these materials are intercalated nanocomposites. The effects of the organoclay contents and the types of swelling agent on the crystallization behavior of the PA6/clay nanocomposites have been studied with a differential scanning calorimeter. The clay behaves as a heterogeneous nucleating agent of polyamide, increasing the crystalling rate. Clay also induces the formation of the γ-form crystal and slightly decreases the melting point of polyamide 6( ~1.5℃). Mechanical tests showed that small amount (less than 9 phr) of organoclay can enormously enhance the flexural strength, flexural modulus and tensile modulus. The increase in flexural strength, flexural modulus and tensile modulus can reach 93%, 107% and 78%, respectively, when adding 5phr organoclay using 1,12-diaminodecane as the swelling agent. The HDT performance is up to 89% (from 63.8℃to 120.7℃)when using 5phr 12NH2-MONT as nanofiller in PA6.

碩士 / 國立清華大學 / 化學工程學系 / 89 / The effects of molecular weights and molecular structure of styrene(st)-based and vinyl acetate(VAc)-based low-profile additive(LPA) on the miscibility , reaction kinetics of UP/LPA system and on the linear shrinkage , water absorption rate , surface roughness , surface gloss and pigmentability and mechanical properties of bulk molding compound (BMC) were investigated . Results showed that the plasticizing effect of LPA on the unsaturated polyester (UP) decreased with the increasing of the molecular weight of LPA . The curing rate of UP/LPA system also decreases with increasing of the molecular weight of LPA due to the chain entanglement effect .Water absorption of BMC increases as the molecular weight of LPA increases implies that more microvoids were formed inside the BMC, results in a lower linear shrinkage rate , and worse pigmentability . However , good shrinkage control LPA does not necessarily lead to a smooth surface and better suface gloss.The mechanical properties of BMC also decreases as the molecular weight of LPA increases due to the poor adhesion between LPA and UP phase. Modified LPAs posses better compatibility with UP , the final curing conversion of UP is elevated , both good shrinkage control and surface properties are also observed.The inhenced adhesion between UP/LPA is responsible for significant improvement of tensile strength , tensile modulus , and flexural modulus .

碩士 / 國立清華大學 / 化學工程學系 / 89 /

碩士 / 國立清華大學 / 化學工程學系 / 89 / Abstract Intermetallic compounds form at the interface of Sn-Cu and Sn-Bi solders on diverse substrates in a relatively short time. However, whether these compounds affect the wetting properties of Sn-Cu and Sn-Bi alloys on diverse substrates remains unknown. Therefore, this study attempts to determine how the intermetallic compounds affect the wetting properties of Sn-Cu and Sn-Bi solders on diverse substrates by using the wetting balance method. A vertical substrate plate is immersed into a molten solder bath. The force performed on the plate is then measured by utilizing a wetting balance. Next, a wetting balance is used to measure the wetting time, wetting force, contact angle and surface tension. Moreover, the operational environment of the wetting balance is altered to obtain discrepant wetting property data under various conditions. Solder temperature, immersion time and solder composition comprise the varying operational environments. Furthermore, OM is used to observe the intermetallic compound at the interface. Experimental results demonstrate the basic wetting properties of Sn-Cu solder on diverse substrates by a wetting balance, such as wetting time, wetting force, contact angle and surface tension. Results in this study clarify the role of reactive wetting in formed intermetallic compounds at the interface by altering the operational environments of the wetting balance.

碩士 / 國立清華大學 / 化學工程學系 / 89 / In more than half of cases requiring penetrating keratoplasty, the only corneal component of tissue that requires replacement is the endothelial cell layer. For the shortage of donor corneas and the potential of the complication of penetrating keratoplasty, there would be a substantial advantage in being able to replace the endothelial layer alone by autologous transplantation of human corneal endothelium. In this study, biodegradable PDLA、PLGA75:25、PLGA50:50 membranes were prepared as the cell carrier for corneal endothelial transplantation. Biodegradability test, cell viability test and cell seeding efficiency test were conducted to evaluate the clinical application of the lactic acid copolymer on endothelial transplantation. The denudation of corneal endothelium and Descemet’s membrane were conducted to establish the animal disease models. The Results of degradation tests show：The degradation rates of membranes increased with the composition ratio of glycolic acid in membranes；The degradation rates of PLGA50:50 was biggest among all of the three copolymer, met the requirement of the clinical much. At day 25 after the three kinds of polylactic acid copolymer membranes were implanted into rabbit’s anterior chamber, that cornea kept clear without corneal edemas, glaucoma and emergent inflammation implies that all of polylactic acid copolymers adopted in this study were well-biocompatible. Tissue-cultured endothelial cells were with polygonal morphology and well-connected each other; the cell enlarged and the cell density decreased from 1267 ± 46 cells/mm2 to 772 ± 116 cells/mm2 after the first passage. The results of human sclera fibroblast cell viability on copolymer membranes shows there was no negative cell response to the materials. Membrane samples modified with FNC Coating Mix® and collagen type I advanced on the seeding efficiency of endothelial cells；however, high concentration of type I collagen may inhibit the plating of corneal endothelial cells. Endothelial cells seeding on concave membranes of PDLA, PLGA75:25, PLGA50:50 modified with FNC Coating Mix® distributed densely and the SEM photographs show the seeding endothelial cells concentrated on the center of concave membranes and plated mostly; the TEM investigation shows cell junctions had formed inter-cellularly. The stripping of endothelium and the denudation of Descemet’s membrane were conducted successfully to establish the syndrome of corneal edemas; however, the denudation of Descemet’s membrane brought about trauma, induced retrocorneal membrane which is unfavorable for endothelial transplantation. Above of all，the PLGA50:50 membrane degrades fast and is well-biocompatible, which modified with FNC exhibits good seeding efficiency of corneal endothelial cells and is promising as cell carrier for the corneal endothelial transplantation. The stripping of endothelium induces corneal edemas of animal model successfully. As a result, a elementary system for corneal endothelial transplantation has been set up in this study.

碩士 / 國立清華大學 / 化學工程學系 / 89 /