http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Suttichai Assabumrungrat,Nattapong Kasempremchit,Piyasan Praserthdam 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.10
We examined the catalyst bed design of MgO and WO3/SiO2 for production of propylene via metathesis of 1-butene. WO3/SiO2 was used as a bi-functional catalyst for isomerization and metathesis reactions. Addition of MgO was proposed to help improve the isomerization activity and hence the propylene yield. Experimental studies were carried out to determine activity and reaction kinetics of 1-butene isomerization over MgO isomerization catalyst and 1- butene metathesis over WO3/SiO2 bi-functional catalyst for designing a suitable catalyst bed. Two types of catalyst bed arrangement--physically mixed bed and separated bed--were considered and compared by computer simulation. The simulations reveal that adding MgO in the separated bed by packing MgO before WO3/SiO2 offers superior propylene yield to the physically mixed bed. The appropriate %MgO loading in catalyst bed which offers a maximum propylene yield was found to vary (3 and 23%), depending on operating condition.
Suttichai Assabumrungrat,Atittahn Wongkia,Kongkiat Suriye,Anuwat Nonkhamwong,Piyasan Praserthdam 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.3
We investigated the catalytic performance improvement of styrene hydrogenation in a trickle bed reactor by using periodic operation. The effects of cycle period and split on relative conversion, which is defined as styrene conversion obtained from periodic operation over that from steady state operation, were examined at various operating conditions including gas and average liquid flow rates, pressure and temperature. The experimental results reveal that both cycle period and split have strong influence on the catalytic performance. The fast mode (short cycle period) is a favorable condition. The improvement by the periodic operation becomes less pronounced for operations at high average liquid flow rate, pressure and temperature. From this study, a maximum improvement of styrene conversion of 18% is observed.
Heng, Suttichai,Sirichaisutdhikorn, Daranee Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.5
Purpose: To determine the incidence of high-grade cervical intraepithelial neoplasia (CIN2-3) among patients with atypical squamous cells of undetermined significance (ASC-US) Papanicolaou (Pap) smears. Materials and Methods: One-hundred and eighty-seven patients with ASC-US Pap smears who underwent colposcopy with histological study were enrolled between September 2007 and August 2015. Patient factors (including age, parity, current pills used, HIV status, age at first sexual intercourse and number of sexual partners) were obtained. Logistic regression analysis was used to evaluate clinical factors associated with CIN2-3. Results: CIN was diagnosed in 92 of 187 women (49.2%). Sixty-one of these (32.6%) had CIN1 and 31 (16.6%) had CIN2-3. There was no woman who had invasive cancer. There was no correlation of high-grade CIN with factors in this study including age, parity, current pills used, HIV status, age at first sexual intercourse and number of sexual partners. Conclusions: Data from this study showed no invasive cervical cancer was found in patients with ASC-US. There was no patient factor associated with high grade intraepithelial neoplasia in patients with ASC-US Pap smears.
Preoperative Thrombocytosis and Poor Prognostic Factors in Endometrial Cancer
Heng, Suttichai,Benjapibal, Mongkol Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.23
This study aimed to evaluate the prevalence of preoperative thrombocytosis and its prognostic significance in Thai patients with endometrial cancer. We retrospectively reviewed the medical records of 238 cases who had undergone surgical staging procedures between January 2005 and December 2008. Associations between clinicopathological variables and preoperative platelet counts were analyzed using Pearson's chi square or two-tailed Fisher's exact tests. Survival analysis was performed with Kaplan-Meier estimates. Univariate and Cox-regression models were used to evaluate the prognostic impact of various factors including platelet count in terms of disease-free survival and overall survival. The mean preoperative platelet count was $315,437/{\mu}L$ (SD $100,167/{\mu}L$). Patients who had advanced stage, adnexal involvement, lymph node metastasis, and positive peritoneal cytology had significantly higher mean preoperative platelet counts when compared with those who had not. We found thrombocytosis (platelet count greater than $400,000/{\mu}L$) in 18.1% of our patients with endometrial cancer. These had significant higher rates of advanced stage, cervical involvement, adnexal involvement, positive peritoneal cytology, and lymph node involvement than patients with a normal pretreatment platelet count. The 5-year disease-free survival and overall survival were significantly lower in patients who had thrombocytosis compared with those who had not (67.4% vs. 85.1%, p=0.001 and 86.0% vs. 94.9%, p=0.034, respectively). Thrombocytosis was shown to be a prognostic factor in the univariate but not the multivariate analysis. In conclusion, presence of thrombocytosis is not uncommon in endometrial cancer and may reflect unfavorable prognostic factors but its prognostic impact on survival needs to be clarified in further studies.
Sakorn Panta,Suttichai Premrudeepreechachar 전력전자학회 2007 ICPE(ISPE)논문집 Vol.- No.-
This paper presents an optimal economic dispatch of electrical power plants by using back-propagation neural networks. The method of economic dispatch for generating units at different loads must have total fuel cost at the minimum point. There are many conventional methods that can use to solve economic dispatch problem such as Lagrange multiplier method, Lamda iteration method and Newton-Raphson method. However, an obstacle in optimal economic dispatch of conventional methods is the changed load. They are necessary to find the optimal economic dispatch from time to time. Moreover, they need a lot of time to repeat calculation for a new solution again. This paper presents back-propagation neural networks model to carry out instead the conventional Lamda iteration method. It is compared with the experimental results of electrical power system of 3 and 10 generating units respectively. The testing results of the back-propagation neural networks are compared with the Lamda iteration method by testing the teaching data and non-teaching data. It shows clearly that the back-propagation neural networks can find out the solutions accurately and use time to calculate less than other systems that are tested. Error of prediction will be increased slightly by the number of generating units in electrical power plants because it needs to learn a lot of input and output data in the neural network dramatically.
Yuttana Kumsuwan,Suttichai Premrudeepreechachar,Hamid A. Toliyat 대한전기학회 2008 Journal of Electrical Engineering & Technology Vol.3 No.1
This paper proposes the design and implementation of a direct torque controlled induction motor drive system. The method is based on control of decoupling between amplitude and angle of reference stator flux for determining reference stator voltage vector in generating PWM output voltage for induction motors. The objective is to reduce electromagnetic torque ripple and stator flux droop which result in a decrease in current distortion in steady state condition. In addition, the proposed technique provides simplicity of a control system. The direct torque control is based on the relationship between instantaneous slip angular frequency and rotor angular frequency in adjustment of the reference stator flux angle. The amplitude of the reference stator flux is always kept constant at rated value. Experimental results are illustrated in this paper confirming the capability of the proposed system in regards to such issues as torque and stator flux response, stator phase current distortion both in dynamic and steady state with load variation, and low speed operation.
Watcharin Srirattanawichaikul,Suttichai Premrudeepreechachar,Yuttana Kumsuwan 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.2
This paper presents a simple modified unipolar carrier-based pulsewidth modulation (CBPWM) strategy for the three-level neutral-point-clamped (NPC) voltage source inverter (VSI). Analytical expressions for the relationship between modulation reference signals and output voltages are derived. The proposed modulation technique for the three-level NPC VSI includes the maximum and minimum of the three-phase sinusoidal reference voltages with zero-sequence voltage injection concept. The proposed modified CB-PWM strategy incorporates a novel method that requires only of one triangular carrier wave for generate the gating pulses in three-level NPC VSI. It has the advantages of being simplifying the algorithm with no need of complex two/multi-carrier pulsewidth modulation or space vector modulation (SVM) and it’s also simple to implement. The possibility of the proposed CB-PWM technique has been verified though computer simulation and experimental results.