排序方式: 共有13条查询结果,搜索用时 15 毫秒
1.
Improved geopolymerization of bottom ash by incorporating fly ash and using waste gypsum as additive
Kornkanok Boonserm Vanchai Sata Kedsarin Pimraksa Prinya Chindaprasirt 《Cement and Concrete Composites》2012,34(7):819-824
This research studied the improvement of the geopolymerization of bottom ash (BA) by incorporating fly ash (FA) and using flue gas desulfurization gypsum (FGDG) as additive. The BA:FA ratios of 100:0, 75:25, 50:50, 25:75, and 0:100 were used as the blended source materials. The source materials were then replaced with 0%, 5%, 10%, and 15% of FGDG. NaOH, sodium silicate and temperature curing were used to activate the geopolymer. Test results indicated that the increase in FA content in the BA–FA blends improved the strengths of geopolymer mortars owing to the high glassy phase content and high reactivity of FA compared to those of BA. The use of up to 10% of FGDG as additive also significantly increased the strengths of geopolymer. In this case, the compressive strength enhancement was due to the increase in the Al3+ leached from BA in the presence of and the formation of additional calcium silicate hydrate. 相似文献
2.
Kongsak Anuntahirunrat Worapong Tangsrirat Vanchai Riewruja Wanlop Surakampontorn 《International Journal of Electronics》2013,100(4):227-239
A circuit design technique that employs translinear current-controlled current conveyors as active circuit elements to design a sinusoidal frequency doubling and full-wave rectifying circuit is proposed. The circuit can realize the sinusoidal frequency doubler and full-wave rectifier without changing the circuit configuration. The proposed frequency doubling and rectifying action is exploited from the translinear characteristic of the current conveyor. Simulation and experimental results are given to confirm the theoretical predictions. 相似文献
3.
Accurate CMOS-based current conveyors 总被引:12,自引:0,他引:12
Surakampontorn W. Riewruja V. Kumwachara K. Dejhan K. 《IEEE transactions on instrumentation and measurement》1991,40(4):699-702
An integrable circuit technique for implementing both positive and negative second-generation current conveyors (CCII) is described. Since the proposed circuits consist of a differential pair, current sources, and current mirrors, the realization method can result in a fully integrated current conveyor. The realization method is suitable for fabrication in CMOS technology. The performance of the CMOS-based CCIIs is discussed in detail. The basic performances are demonstrated and simulation and experimental results are presented. The DC transfer characteristics for converting resistors are linear over the total dynamic range 相似文献
4.
Temperature compensation of translinear current conveyor and OTA 总被引:1,自引:0,他引:1
A simple and integrable temperature compensation scheme for translinear current conveyor-based circuits and OTA-based circuits is introduced. It uses a new bias circuit which has a current that is directly proportional to the absolute temperature, and can also be electronically varied. Performance of the scheme is confirmed through PSPICE simulation results 相似文献
5.
W. Petchmaneelumka P. Mano K. Songsuwankit V. Riewruja 《International Journal of Electronics》2018,105(9):1520-1534
A high-accuracy resolver-to-linear signal converter for the measurement of angular displacement is proposed in this paper. The proposed converter comprises two sections: a demodulator and linear shaper. In the first section, the demodulator makes use of the sample-and-hold circuit (SHC) to sample the peak amplitude of the resolver signal. The control signal of the SHC is provided from the resolver signals instead of the excitation signal used in traditional approaches. The proposed demodulator requires no analogue multiplier and low-pass filter. Therefore, the fast response time of the proposed demodulator is achieved. In the second section, the linear shaper consists of the inverse-sine function scheme together with a switched-gain amplifier to produce the linear signal proportional to the shaft angle. The hyperbolic tangent characteristic of the operational transconductance amplifier is utilised to realise the inverse-sine function scheme. The proposed technique requires one phase of the resolver signal to obtain the linear signal. Therefore, the position error caused by amplitude imbalance between the two resolver signals is avoided. The performances of the proposed converter are discussed in detail and demonstrated by an experimental implementation using commercial devices. The experimental results show that the maximum relative error and response time for the excitation frequency of 3 kHz are measured as 0.06% and 0.11 ms, respectively. 相似文献
6.
Vanchai Sata Apha Sathonsaowaphak Prinya Chindaprasirt 《Cement and Concrete Composites》2012,34(5):700-708
This paper presents an investigation of the compressive strength and the durability of lignite bottom ash geopolymer mortars in 3% sulfuric acid and 5% sodium sulfate solutions. Three finenesses of ground bottom ash viz., fine, medium and coarse bottom ash were used to make geopolymer mortars. Sodium silicate, sodium hydroxide and curing temperature of 75 °C for 48 h were used to activate the geopolymerization. The results were compared to those of Portland cement and high volume fly ash mortars. It was found that the fine bottom ash was more reactive and gave geopolymer mortars with higher compressive strengths than those of the coarser fly ashes. All bottom ash geopolymer mortars were less susceptible to the attack by sodium sulfate and sulfuric acid solutions than the traditional Portland cement mortars. 相似文献
7.
A simple circuit design technique for realising both a sinusoidal frequency doubler and a full-wave rectifier, employing a translinear current conveyor and current mirrors as active circuit elements, is proposed. The implementation method uses the inherited translinear loop of the translinear current conveyor to perform frequency doubling and rectification. The performance of the scheme is demonstrated by PSPICE simulations 相似文献
8.
A method for implementing square-rooting and absolute function circuits using operational amplifiers (opamps) as only active elements is introduced. The realisation technique is provided through the use of the opamp supply-current sensing, which utilises an inherently quadratic characteristic of the opamp class-AB output stage. The proposed circuits are attractive in terms of simple configuration and low cost. The performances of the circuits are discussed in detail. Experimental results demonstrating the characteristics of the circuits using commercially available opamps are also included. 相似文献
9.
Kanyakorn Riewruja Suphattra Phakham Patlapa Sompolpong Rangsima Reantragoon Aree Tanavalee Srihatach Ngarmukos Wanvisa Udomsinprasert Tanyawan Suantawee Sinsuda Dechsupa Sittisak Honsawek 《International journal of molecular sciences》2022,23(2)
Osteoarthritis (OA) is a degenerative joint disease leading to joint pain and stiffness. Due to lack of effective treatments, physical and psychological disabilities caused by OA have a detrimental impact on the patient’s quality of life. Emerging evidence suggests that intra-articular injection of platelet-rich plasma (PRP) may provide favorable results since PRP comprises not only a high level of platelets but also a huge amount of cytokines, chemokines, and growth factors. However, the precise mechanism and standardization method remain uncertain. This study aimed to examine cytokine profiling in both PRP and platelet-poor plasma (PPP) of knee OA patients and to determine the effects of PRP on OA chondrocytes and knee OA patients. PRP contained a wide variety of cytokines, chemokines, growth factors, and autologous intra-articular PRP injection resulted in favorable outcomes in knee OA patients. Significant increases in levels of IL-1, IL-2, IL-7, IL-8, IL-9, IL-12, TNF-α, IL-17, PDGF-BB, bFGF, and MIP-1β were detected in PRP compared to PPP (p < 0.001). An in vitro study showed a marked increase in proliferation in OA chondrocytes cultured with PRP, compared to PPP and fetal bovine serum (p < 0.001). In a clinical study, knee OA patients treated with PRP showed improvement of physical function and pain, assessed by physical performance, Western Ontario and McMaster Universities Arthritis Index and visual analog scale. Our findings from both in vitro and clinical studies suggest that intra-articular PRP injection in knee OA patients may be a potential therapeutic strategy for alleviating knee pain and delaying the need for surgery. 相似文献
10.
A method for realizing high-speed algorithmic analogue-to-digital converter (ADC) is presented in this paper. The realization method based on the proposed absolute function circuit, which performs a low-distortion in the transfer characteristic, is utilized. The proposed ADC is simple, small in size and suitable for implementing a high-resolution ADC. Performances of the proposed circuit are discussed in detail and confirmed through Cadence Spectre simulation results. 相似文献