排序方式: 共有13条查询结果,搜索用时 31 毫秒
1.
Sruthi Guru Shubham Kumar Sankeerthana Bellamkonda Ranga Rao Gangavarapu 《International Journal of Hydrogen Energy》2021,46(30):16414-16430
A nanocomposite CuTi layered double hydroxide (LDH) supported on g-C3N4 (15 wt% of g-C3N4) is facilely synthesized by hydrothermal method. There are electrostatic interactions between positive layers of CuTi-LDH and negatively charged inner g-C3N4 sheets. The nanocomposite and its precursors are characterized through various analytical techniques, which affirmed the presence of both g-C3N4 and CuTi-LDH characteristic features. The pore-enriched hybrid geometry of CuTi-LDH@g-C3N4 with high specific surface area (146 m2/g), and suitable band gap of 2.46 eV enables the nanocomposite to act as both an electrocatalyst and photoelectrocatalyst for oxygen evolution reaction (OER). Both the electrochemical and photoelectrochemical studies are done using 1 M KOH (pH = 13.6) with applied potential of ?0.2 V to 1.5 V vs. Ag/AgCl. The onset potential of CuTi-LDH@g-C3N4 for OER appears at η = 0.36 V in dark and η = 0.32 V under visible light illumination of 30 min. Also, Mott-Schottky analysis shows n-type semiconductor behaviour for CuTi-LDH@g-C3N4 and its precursors. The photoelectrochemical water oxidation proceeds by charge transfer across a Type II heterojunction formed between the CuTi-LDH and g-C3N4 materials. 相似文献
2.
Krishnan Thadiappan Ramaswami Bellamkonda 《Industry Applications, IEEE Transactions on》1974,(5):643-651
This paper describes the design, construction, and testing of a thyristorized speed control unit for a separately excited dc motor. The motor is fed from a three-phase six-pulse fully controlled thyristor bridge. A speed loop with a proportional plus integral controller maintains the desired speed irrespective of the load variations on the motor. An inner current control loop protects the thyristors from overcurrents. This loop also provides fast response overcoming the effect of disturbances such as variations in supply voltage. The design aspects of the control loops are discussed, and experimental results are given. 相似文献
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Subrahmanyam V. Yuvarajan S. Ramaswami Bellamkonda 《Industry Applications, IEEE Transactions on》1980,(3):332-341
A method for analyzing the performance of an induction motor fed from a current source inverter and especially for computing the currents during commutation of the inverter is presented. A mathematical model of an inverter-fed induction motor is given in terms of Park's vector. Based on this model a closed form time domain expression is developed for the current during commutation. The stator voltage of a current-controlled inverter-fed induction motor is shown to be almost sinusoidal with superimposed spikes during commutation of current. The computed performance of the machine is verified experimentally, and there is a very close agreement between the computed and test results. The method presented also provides information regarding the voltages across the commutating capacitors and thyristors based on which proper selection of the thyristors and commutating capacitors can be made. 相似文献
4.
One of the grand challenges in neuroengineering is to stimulate regeneration after central nervous system (CNS) or peripheral nervous system (PNS) injury to restore function. The state of the art today is that PNS injuries heal to a limited extent, whereas CNS injuries are largely intractable to regeneration. In this context, we examine the underlying biochemical and cellular constraints on endogenous healing of neural tissues. Identification and characterization of endogenous "rate-limiting" processes that constrain regeneration would allow one to craft solutions to overcome critical impediments for accelerated healing. It is increasingly evident that biochemical pathways triggered by the nature and duration of injury-triggered inflammatory response may determine the endogenous constraints and subsequently determine regenerative fate. In this paper, critical endogenous constraints of PNS and CNS regeneration are identified, and the effects of modulating the phenotypes of immune cells on neuronal regeneration are discussed. 相似文献
5.
Hafeez Yusuf Hafeez Sandeep Kumar Lakhera Sankeerthana Bellamkonda G. Ranga Rao M.V. Shankar D.W. Bahnemann Bernaurdshaw Neppolian 《International Journal of Hydrogen Energy》2018,43(8):3892-3904
Reduced graphene oxide (rGO) supported g-C3N4-TiO2 ternary hybrid layered photocatalyst was prepared via ultrasound assisted simple wet impregnation method with different mass ratios of g-C3N4 to TiO2. The synthesized composite was investigated by various characterization techniques, such as XRD, FTIR, Raman Spectra, FE-SEM, HR-TEM, UV vis DRS Spectra, XPS Spectra and PL Spectra. The optical band gap of g-C3N4-TiO2/rGO nanocomposite was found to be red shifted to 2.56 eV from 2.70 eV for bare g-C3N4. It was found that g-C3N4 and TiO2 in a mass ratio of 70:30 in the g-C3N4-TiO2/rGO nanocomposite, exhibits the highest hydrogen production activity of 23,143 μmol g?1h?1 through photocatalytic water splitting. The observed hydrogen production rate from glycerol-water mixture using g-C3N4-TiO2/rGO was found to be 78 and 2.5 times higher than g-C3N4 (296 μmol g?1 h?1) and TiO2 (11,954 μmol g?1 h?1), respectively. A direct contact between TiO2 and rGO in the g-C3N4-TiO2/rGO nanocomposite produces an additional 10,500 μmol g?1h?1 of hydrogen in 4 h of photocatalytic reaction than the direct contact between g-C3N4 and rGO. The enhanced photocatalytic hydrogen production activity of the resultant nanocomposite can be ascribed to the increased visible light absorption and an effective separation of photogenerated electron-hole pairs at the interface of g-C3N4-TiO2/rGO nanocomposite. The effective separation and transportation of photogenerated charge carriers in the presence of rGO sheet was further confirmed by a significant quenching of photoluminescence intensity of the g-C3N4-TiO2/rGO nanocomposite. The photocatalytic hydrogen production rate reported in this work is significantly higher than the previously reported work on g-C3N4 and TiO2 based photocatalysts. 相似文献
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Vivek Mukhatyar Lohitash Karumbaiah Julie Yeh Ravi Bellamkonda 《Advanced materials (Deerfield Beach, Fla.)》2009,21(46):4670-4679
http://doi.wiley.com/10.1002/adma.v21:32/33 Bridging peripheral nerve gaps without the use of autografts has significant clinical importance. But in order to rationally design novel scaffolds, a good understanding of the nerve regeneration process is vital. Appropriate amount of structural and chemical cues are required to stimulate the endogenous mechanisms of repair and functional recovery. Synthetic and natural materials present various opportunities to induce the growth of supporting cells as well as promote axon regeneration. An overview of tissue engineering strategies currently being explored that stimulate the different steps of the regenerative sequence is presented. 相似文献
8.
Ramamurthi V. P. Ramaswami Bellamkonda 《Industrial Electronics, IEEE Transactions on》1982,(3):235-240
A hybrid circuit for producing a three-phase reference sine wave required with PWM inverters is described in this paper. The principle of the circuit is simple and the implementation of the circuit is easy. The circuit has all the features discussed in the literature. The unit built has, apart from the three-phase sine waves, balanced three-phase square and triangular waves. A high-frequency triangular wave already available in the circuit can be used for the PWM control circuitry. The scheme can easily be extended to generate sine waves of any number of phases. 相似文献
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M Taborelli L Eng P Descouts JP Ranieri R Bellamkonda P Aebischer 《Canadian Metallurgical Quarterly》1995,29(6):707-714
We investigated the adsorption of albumin on chemically modified gold surfaces by scanning force microscopy operating both in contact and noncontact mode. The surface modification was performed with thiol-based self-assembling molecules carrying amine or methyl groups. The albumin on the aminoethanethiol-coated gold formed a uniform layer and single molecules could be distinguished. On the dodecanethiol-coated surface the protein adsorbed in aggregates or single isolated molecules depending on the incubation time. The width of the albumin molecule on both surface was similar, but the height was much lower on the amine than on the methyl surface. This was interpreted as a difference in the conformation of albumin depending on the substrate, and could explain the promotion of cell adhesion on amine-treated polymers coated with albumin. 相似文献