The Best Way to Obtain Good Quality CVD-TiN Films from TiCl4 and NH3

1998 ◽  
Vol 514 ◽  
Author(s):  
Hirotaka Hamamura ◽  
Yukihiro Shimogaki ◽  
Yasunobu Akiyama ◽  
Yasuyuki Egashira ◽  
Hiroshi Komiyama
Keyword(s):  
Deposition Rate ◽  
Kinetic Studies ◽  
Chlorine Concentration ◽  
Residual Chlorine ◽  
Order Kinetic ◽  
Kinetic Rate Constant ◽  
Kinetic Rate ◽  
Tin Films ◽  
First Order ◽  
Kinetics Of

ABSTRACTTiN films deposited by CVD utilizing TiCl4 and NH3 are widely used in ULSI processes. The residual chlorine in the film is one of the major issues of TiCl4 based chemistry [1–5]. We have examined the kinetics of TiN-CVD using TiCl4 and NH3 as precursors to determine method for controlling the residual chlorine concentration.We analyzed the deposition rate profiles obtained from a simple tubular isothermal reactor. Deposition was performed over the temperature range from 300°C to 500°C and with varying initial concentrations of TiCl4 and NH3. We found that the deposition rate was independent of the TiCl4 concentration at higher concentrations. The deposition rate was proportional to the TiCl4 concentration in the low concentration range. This phenomenon can be well explained by a Langmuir-Hinshelwood type mechanism. Examination of the deposition rate dependence on the concentration of NH3 showed that both the maximum deposition rate at high TiCl4 concentrations and the first order kinetic rate constant in the lower TiCl4 concentration range were proportional to the NH3 concentration. These results indicate that the deposition was controlled by the Eley-Rideal mechanism. The residual chlorine concentration was found to be proportional to the surface coverage factor of adsorbed TiCl4. We conclude that the best way to obtain good quality TiN films can be obtained theoretically through these kinetic studies.

Biodegradation of Bisphenol-A in aerobic membrane bioreactor sludge

2013 ◽  
Vol 68 (9) ◽  
pp. 1926-1931 ◽  
Author(s):  
Brahima Seyhi ◽  
Patrick Drogui ◽  
Gerardo Buelna ◽  
Jean François Blais
Keyword(s):  
Bisphenol A ◽  
Chemical Oxygen Demand ◽  
Rate Constant ◽  
Membrane Bioreactor ◽  
Oxygen Demand ◽  
Degradation Process ◽  
Order Kinetic ◽  
Kinetic Rate Constant ◽  
Kinetic Rate ◽  
First Order

Bisphenol-A (BPA) biodegradation was studied in a membrane bioreactor under aerobic conditions. The effects of the initial BPA concentration and initial chemical oxygen demand (COD) concentration on BPA biodegradation were investigated. The degradation process followed a first-order kinetic (more than 98% of BPA was removed) with a kinetic rate constant of 1.134 h−1 using an initial BPA concentration of 1.0 mg L−1. The kinetic rate constant decreased to 0.611 h−1 when the initial BPA concentration increased to 5.0 mg L−1. The initial COD concentration (400 and 2,000 mg L−1) did not affect the biodegradation kinetic of BPA.

Kinetics of bioactive compounds in functional spice Jiangpo during thermal processing

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Xiaoyan Dai ◽  
Chenhuan Yu ◽  
Qiaofeng Wu
Keyword(s):  
Kinetic Parameters ◽  
Bioactive Compounds ◽  
Thermal Processing ◽  
Order Rate Constant ◽  
Heat Processing ◽  
Order Kinetic ◽  
Time Intervals ◽  
First Order ◽  
Order Kinetic Model ◽  
Kinetics Of

Abstract Jiangpo is an increasingly popular East Asian spice which is made from Mangnolia officinalis bark and ginger juice. Since it induces bioactive compounds decomposition and has influence on final flavor and fragrance, cooking is regarded as the key operation in preparation of Jiangpo. To evaluate the bioactive compounds content changes of Jiangpo during thermal processing, kinetic parameters including reaction order, rate constant, T1/2 and activation energy of bioactive markers namely honokiol, magnolol and curcumin were determined. Cooking was set at temperatures 60, 90 and 120 °C for selected time intervals. Results displayed the thermal kinetic characteristics of the three compounds. Thermal degradation of Honokiol and magnolol both followed first order kinetic model and the loss of curcumin fitted second order. A mathematical model based on the obtained kinetic parameters has also been developed to predict the degradation of honokiol, magnolol and curcumin in non-isothermal state. All the information in this paper could contribute necessary information for optimizing the existing heat processing of Jiangpo.

scholarly journals Kinetics of K release from soils of Brazilian coffee regions: effect of organic acids

2008 ◽  
Vol 32 (2) ◽  
pp. 533-540 ◽  
Author(s):  
Vladimir Antônio Silva ◽  
Giuliano Marchi ◽  
Luiz Roberto Guimarães Guilherme ◽  
José Maria de Lima ◽  
Francisco Dias Nogueira ◽  
...  
Keyword(s):  
Release Kinetics ◽  
Kinetic Studies ◽  
Release Rates ◽  
First Order ◽  
Potassium Release ◽  
Minas Gerais State ◽  
Soil Clay ◽  
Extractant Solution ◽  
Kinetics Of ◽  
K Release

Kinetic studies on soil potassium release can contribute to a better understanding of K availability to plants. This study was conducted to evaluate K release rates from the whole soil, clay, silt, and sand fractions of B-horizon samples of a basalt-derived Oxisol and a sienite-derived Ultisol, both representative soils from coffee regions of Minas Gerais State, Brazil. Potassium was extracted from each fraction after eight different shaking time periods (0-665 h) with either 0.001 mol L-1 citrate or oxalate at a 1:10 solid:solution ratio. First-order, Elovich, zero-order, and parabolic diffusion equations were used to parameterize the time dependence of K release. For the Oxisol, the first-order equation fitted best to the experimental data of K release, with similar rates for all fractions and independent of the presence of citrate or oxalate in the extractant solution. For all studied Ultisol fractions, in which K release rates increased when extractions were performed with citrate solution, the Elovich model described K release kinetics most adequately. The highest potassium release rate of the Ultisol silt fraction was probably due to the transference of "non-exchangeable" K to the extractant solution, whereas in the Oxisol exchangeable potassium represented the main K source in all studied fractions.

Evidence for the formation of lignin-hexenuronic acid-xylan complexes during modified kraft pulping processes

Holzforschung ◽  
2006 ◽  
Vol 60 (2) ◽  
pp. 137-142 ◽  
Author(s):  
Zhi-Hua Jiang ◽  
Jean Bouchard ◽  
Richard Berry
Keyword(s):  
Acid Hydrolysis ◽  
Kraft Pulp ◽  
Kraft Pulping ◽  
Order Kinetic ◽  
Kraft Pulps ◽  
First Order ◽  
Pseudo First Order ◽  
Hexenuronic Acid ◽  
Kinetics Of ◽  
Hydrolysis Of

Abstract The finding that hexenuronic acid (HexA) groups can be selectively removed from kraft pulps by acid hydrolysis has provided an opportunity to reduce bleaching chemicals. However, there is evidence that the acid hydrolysis is not uniform. In this report, we evaluate the kinetics of acid hydrolysis of HexA in a xylan sample enriched with HexA, a conventional kraft pulp, and three modified kraft pulps: anthraquinone pulp (Kraft-AQ), polysulfide pulp (PS), and polysulfide-anthraquinone pulp (PS-AQ). We found that HexA present in the xylan and conventional kraft pulp behaved similarly toward the acid hydrolysis throughout. On the other hand, HexA present in the Kraft-AQ, PS-AQ and PS pulps was heterogeneous toward acid hydrolysis and the reaction can be separated into two pseudo-first-order kinetic phases, each of which has a different rate constant. The kinetic data provide evidence for the formation of lignin-HexA-xylan complexes during modified kraft pulping processes.

Kinetics of the Ozonation of Tetrabromobisphenol-A in Wastewater

2011 ◽  
Vol 383-390 ◽  
pp. 2945-2950 ◽  
Author(s):  
Jie Zhang ◽  
Shi Long He ◽  
Mei Feng Hou ◽  
Li Ping Wang ◽  
Li Jiang Tian
Keyword(s):  
Rate Constants ◽  
Apparent Rate Constant ◽  
Reaction Rate ◽  
Batch Reactor ◽  
Kinetic Studies ◽  
Tetrabromobisphenol A ◽  
First Order ◽  
Reaction Rate Constants ◽  
Pseudo First Order ◽  
Kinetics Of

The kinetics of TBBPA degradation by ozonation in semi-batch reactor was studied. The reaction rate constants of TBBPA with O3 and •OH were measured by means of direct ozone attack and competition kinetics, and the values of which were 6.10 l/(mol•s), 4.8×109 l/(mol•s), respectively. Results of kinetic studies showed that TBBPA degradation by ozonation under the different conditions tested followed the pseudo-first-order. The values of apparent rate constant of TBBPA degradation increased with the increase of ozone dosage and pH, but decreased with the increase of initial TBBPA concentration.

KINETIC STUDIES OF METHYL-BIS-β-CHLOROETHYLAMINE: III. THE KINETICS OF THE DIMERIZATION IN METHANOL

1948 ◽  
Vol 26b (2) ◽  
pp. 175-180 ◽  
Author(s):  
C. A. Winkler ◽  
A. W. Hay ◽  
A. L. Thompson
Keyword(s):  
Rate Constants ◽  
Initial Rate ◽  
Kinetic Studies ◽  
First Order ◽  
Rate Expression ◽  
Principal Reaction ◽  
Kinetics Of ◽  
Rate Controlling Step

The principal reaction of methyl-bis-β-chloroethylamine in methanol is dimerization, which results in one chlorine from each molecule becoming ionic, but this is accompanied by slight alcoholysis. The rate-controlling step is believed to be the first order formation of an ethylenimonium ion which reacts rapidly with one of its kind to form dimer. The rate expression as calculated from initial rate constants is k (initial) = 4.0 × 1013e−19600/RThr.−1.

scholarly journals Reactivity and kinetic studies of benzofuran hydrodeoxygenation over a Ni2P-O/MCM-41 catalyst

2019 ◽  
Vol 44 (4) ◽  
pp. 307-315 ◽  
Author(s):  
Xueya Dai ◽  
Hua Song ◽  
Hualin Song ◽  
Jing Gong ◽  
Feng Li ◽  
...  
Keyword(s):  
Kinetic Studies ◽  
Time Analysis ◽  
Liquid Ratio ◽  
Order Model ◽  
Free Products ◽  
First Order ◽  
Reaction Rate Constants ◽  
Different Temperatures ◽  
Kinetics Of ◽  
Mcm 41

A nickel phosphide hydrodeoxygenation catalyst (Ni2P-O/MCM-41) was prepared using a new synthetic method. The as-prepared catalyst was evaluated in the hydrodeoxygenation of benzofuran, and the effects of reaction temperature, pressure, and the H2/liquid ratio were investigated. A pseudo first-order model was employed to describe the reaction kinetics of benzofuran hydrodeoxygenation over the Ni2P-O/MCM-41 catalyst. The reaction rate constants ( k1– k5) at different temperatures were determined according to this model. At 533 K, the conversion of 2-ethylphenol in to ethylbenzene began to increase dramatically, and the yield of O-free product, ethylcyclohexane, started to increase rapidly. At 573 K, 3.0 MPa, and a H2/liquid ratio of 500 (V/V), the conversion of benzofuran over Ni2P-O/MCM-41 reached 93%, and the combined yield of O-free products was 91%. Contact time analysis indicated that demethylation was not favored over the Ni2P-O/MCM-41 catalyst.

scholarly journals Biodegradability and kinetic studies on biomethane production from okra (Abelmoschus esculentus) waste

2019 ◽  
Vol 115 (7/8) ◽  
Author(s):  
Samson N. Ugwu ◽  
Christopher C. Enweremadu
Keyword(s):  
Renewable Energy Sources ◽  
Abelmoschus Esculentus ◽  
Methane Yield ◽  
Organic Substrates ◽  
Order Kinetic ◽  
First Order ◽  
Biomethane Potential ◽  
Growth Functions ◽  
Biomethane Production ◽  
Kinetics Of

Emerging from the energy crisis of 2008 in South Africa, climate change concerns and the global desire to reduce high ozone-depleting emissions, renewable energy sources like biogas are gaining wide acceptance in most localities for heating and electricity. The paucity of feedstock varieties is a major challenge plaguing the sustainability of this sector. Biomethane potential, biodegradability and degradation kinetics of organic substrates are essential for assessing the suitability of feedstocks for methane generation and the overall performance of the anaerobic digestion process in biogas plants. Waste from the vegetable okra (Abelmoschus esculentus) is a novel substrate; its biodegradability and degradation dynamics in biomethane production are largely unstudied, and were therefore the aims of this research. The substrate was digested for 25 days at the mesophilic condition and the biomethane potential data were recorded. Measured data of methane yield and the elemental composition of the substrate were used to fit five models (modified Gompertz, Stannard, transference function, logistic and first-order models) to predict degradation parameters and determine biodegradability of the substrate, respectively. Low lag phase (0.143 d), positive kinetic constant (0.2994/d) and the model fitness indicator ( less than 10) showed that transference and first-order kinetic models predicted the methane yield better than did other growth functions. The experimental methane yield was 270.98 mL/gVS, theoretical methane yields were 444.48 mL/gVS and 342.06 mL/gVS and model simulation ranged from 267.5 mL/gVS to 270.89 mL/gVS. With a prediction difference of 0.03–1.28%, all growth functions acceptably predicted the kinetics of A. esculentus waste. The findings of this study offer information on this novel substrate important for its use in large-scale biogas production.

Inhibition kinetics and mechanism of glutathione and quercetin on acrylamide in the low-moisture Maillard systems

2020 ◽  
Author(s):  
Xiping Nan ◽  
Shuli Nan ◽  
Xianpeng Zeng ◽  
Lining Kang ◽  
Xiangying Liu ◽  
...  
Keyword(s):  
Thermal Processing ◽  
Theoretical Data ◽  
Order Kinetic ◽  
Inhibition Kinetics ◽  
Competitive Reaction ◽  
Binding Reaction ◽  
Inhibition Effect ◽  
First Order ◽  
Maximum Inhibition ◽  
Kinetics Of

The inhibition kinetics of glutathione (GSH) and quercetin on Acrylamide (AA) formation in the low-moisture Maillard systems were investigated at 180 °C. The inhibition rates in an equal-molar asparagine/glucose (Asn/Glc) system was higher than those in asparagine/fructose (Asn/Fru) system, and the maximum inhibition rates for AA were 57.75% with GSH of 10 -2 mol L -1 and 51.38% with quercetin of 10 -1 mol L -1 . The Logistic-Index dynamic model and simplified two consecutive first-order kinetic models were well fitted to the changes of AA in the Asn/Glc system. The kinetics results suggested the predominant inhibition effect of GSH on AA could be attributed to the competitive reaction between GSH and Asn for the consumption of Glc. The kinetic results and HPLC-MS/MS analysis of quercetin inhibiting AA indicated that quercetin might mitigate AA through the binding reaction of quercetin decomposition product and Maillard intermediate product. These experimental results can provide theoretical data to control the formation of AA during food thermal processing.

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