http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
오늘 본 자료
GCR-LIGHTLIKE SUBMANIFOLDS OF A SEMI-RIEMANNIAN PRODUCT MANIFOLD
Kumar, Sangeet,Kumar, Rakesh,Nagaich, Rakesh Kumar Korean Mathematical Society 2014 대한수학회보 Vol.51 No.3
We introduce GCR-lightlike submanifold of a semi-Riemannian product manifold and give an example. We study geodesic GCR-lightlike submanifolds of a semi-Riemannian product manifold and obtain some necessary and sufficient conditions for a GCR-lightlike submanifold to be a GCR-lightlike product. Finally, we discuss minimal GCR-lightlike submanifolds of a semi-Riemannian product manifold.
INTEGRABILITY OF DISTRIBUTIONS IN GCR-LIGHTLIKE SUBMANIFOLDS OF INDEFINITE KAEHLER MANIFOLDS
Kumar, Rakesh,Kumar, Sangeet,Nagaich, Rakesh Kumar Korean Mathematical Society 2012 대한수학회논문집 Vol.27 No.3
In present paper we establish conditions for the integrability of various distributions of GCR-lightlike submanifolds and obtain conditions for the distributions to define totally geodesic foliations in GCR-lightlike submanifolds.
Radioprotective and Antioxidant Activity of Fractionated Extracts of Berries of Hippophae rhamnoides
Rakesh Kumar Sharma,Raman Chawla,Rajesh Arora,Shikha Singh,Ravinder Kumar Sagar,Raj Kumar,Ashok Sharma,Manju L. Gupta,Surender Singh,Jagdish Prasad,Haider A. Khan,Anand Swaroop,A.K. Sinha,A.K. Gupta,R 한국식품영양과학회 2007 Journal of medicinal food Vol.10 No.1
Plants are an abundant source of medicinal compounds, some of which are useful in combating free radical-1002 (flavonoid-poor fraction) of Hippophae rhamnoideswere screened on the basis of their reducing power in the aqueousphase. REC-1001 was selected for further study, since it exhibited 27.38 times higher antioxidant activity than REC-1002.REC-1001 also showed significant (P. .05) membrane protection potential at 50 .g/mL, which was attributed to its abilityto scavenge peroxyl radicals (64.82. 1.25% scavenging within 1,440 min). A significant (P. .05) difference of 67.02% infree radical scavenging activity at 1,000 ng/mL between REC-1001 and vitamin E demonstrated the extract fraction’s worthc-tion. Further, REC-1001 was found to be nontoxic up to 200 mg/kg of body weight. This research suggests that the REC-1001 fraction of H. rhamnoidesextract is a safe and effective antioxidant nutraceutical product.
GCR-LIGHTLIKE SUBMANIFOLDS OF A SEMI-RIEMANNIAN PRODUCT MANIFOLD
Sangeet Kumar,Rakesh Kumar,Rakesh Kumar Nagaich 대한수학회 2014 대한수학회보 Vol.51 No.3
We introduce GCR-lightlike submanifold of a semi-Riemann- ian product manifold and give an example. We study geodesic GCR- lightlike submanifolds of a semi-Riemannian product manifold and obtain some necessary and sufficient conditions for a GCR-lightlike submanifold to be a GCR-lightlike product. Finally, we discuss minimal GCR-lightlike submanifolds of a semi-Riemannian product manifold.
Pawan Kumar,Rakesh Kumar Dwivedi,Pawan Kumar,Ravikant Prasad,Praveen Kumar Siwach,Hari Krishna Singh 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.1
Thin films of La_(0.80)Sr_(0.20)Mn_(1−x)Cu_xO_3 with x = 0.00, 0.04, 0.08, 0.10, 0.15, and 0.20 were deposited on single-crystal LaAlO_3 (100) (LAO) substrates at 250 ± 10 ℃ by using a nebulized spray pyrolysis technique. Structural, surface, and transport characterizations were done by X-ray diffraction (XRD), atomic force microscopy (AFM) and the standard four probe technique, respectively. XRD patterns revealed the formation of single-phase polycrystalline films with a rhombohedral crystal structure. Cu substitution resulted in a uniform decrease in the metal insulator transition (T_(IM)) temperature up to x = 0.10, followed by a drastic decrease in T_(IM) for x = 0.15. Finally, the metal-insulator transition vanished for higher Cu concentrations (x = 0.20) in the observed temperature range. The variation in T_(IM) with the amount of added Cu is explained on the basis of the double exchange mechanism. Cu substitution has been found to perturb the Mn^(3+)-O-Mn^(4+) network and has a strong influence on T_(IM). The variation in resistivity maxima with temperature for different Cu concentrations showed a systematic trend up to x ∼ 0.10. We also explored the electrical conduction at T > T_(IM) in the framework of small polaron hopping in the adiabatic limit. The activation energy showed a strong dependence on the Cu concentration. The maximum magneto-resistance (MR) up to 10%, was observed for x = 0.15 at low temperatures.
Oxidative Stress and Antioxidants in Disease and Cancer: A Review
Gupta, Rakesh Kumar,Patel, Amit Kumar,Shah, Niranjan,Choudhary, Arun Kumar,Jha, Uday Kant,Yadav, Uday Chandra,Gupta, Pavan Kumar,Pakuwal, Uttam Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.11
Reactive oxygen species (ROS), highly reactive molecules, are produced by living organisms as a result of normal cellular metabolism and environmental factors, and can damage nucleic acids and proteins, thereby altering their functions. The human body has several mechanisms to counteract oxidative stress by producing antioxidants. A shift in the balance between oxidants and antioxidants in favor of oxidants is termed as "oxidative stress". Paradoxically, there is a large body of research demonstrating the general effect of oxidative stress on signaling pathways, less is known about the initial and direct regulation of signaling molecules by ROS, or what we term the "oxidative interface." This review focuses on the molecular mechanisms through which ROS directly interact with critical signaling molecules to initiate signaling in a broad variety of cellular processes, such as proliferation and survival (MAP kinases and PI3 kinase), ROS homeostasis, and antioxidant gene regulation (Ref-1 and Nrf-2). This review also deals with classification as well as mechanisms of formation of free radicals, examining their beneficial and deleterious effects on cellular activities and focusing on the potential role of antioxidants in preventing and repairing damage caused by oxidative stress. A discussion of the role of phytochemical antioxidants in oxidative stress, disease and the epigenome is included.
Rakesh Kumar Jha,Preety D Swami 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.10
Health monitoring of a rotating machine is mainly done by investigation of the vibration patterns generated by the machine. Leveraging the fact that faults occurring in different parts of a machine generate unique fault signatures, a fault diagnosis methodology is proposed that can identify nine different healthy and faulty categories under varying load and noisy conditions. Neural network is employed for classification of faults in various categories. The robustness of features such as semivariance, kurtosis and Shannon entropy make them strong candidates to train the artificial neural network. The matching of vibration textural patterns with wave atom basis functions ensures removal of noise. As a result, the enhanced features used to train the neural network have led to high accuracy in classification. The algorithm is tested at various load conditions for both bearing and gear fault experimental data sets acquired by machinery fault simulator in laboratory. Simulation results show high degree of accuracy for both bearing and gear fault diagnosis under no load to heavy load noisy conditions.
Rakesh Sharma,Arpan Choudhary,Ranjit Kumar Das,Supriya Basu,Ranjan Kumar Dey,Rupesh Gupta,Partha Pratim Deb 대한비뇨의학회 2017 Investigative and Clinical Urology Vol.58 No.2
Purpose: Extracorporeal shock wave lithotripsy (ESWL) is an established modality for renal calculi. Its role for large stones is being questioned. A novel model of temporary double J (DJ) stenting followed by ESWL was devised and outcomes were assessed. Materials and Methods: The study included 95 patients with renal calculi sized 1 to 2 cm. Patients were randomized into 3 groups. Group 1 received ESWL only, whereas group 2 underwent stenting followed by ESWL. In group 3, a distinct model was applied in which the stent was kept for 1 week and then removed, followed by ESWL. Procedural details, analgesic requirements, and outcome were analyzed. Results: Eighty-eight patients (male, 47; female, 41) were available for analysis. The patients' mean age was 37.9±10.9 years. Stone profile was similar among groups. Group 3 received fewer shocks (mean, 3,155) than did group 1 (mean, 3,859; p=0.05) or group 2 (mean, 3,872; p=0.04). The fragmentation rate was similar in group 3 (96.7%) and groups 1 (81.5%, p=0.12) and 2 (87.1%, p=0.16). Overall clearance in group 3 was significantly improved (83.3%) compared with that in groups 1 (63.0%, p=0.02) and 2 (64.5%, p=0.02) and was maintained even in lower pole stones. The percentage successful outcome in groups 1, 2, and 3 was 66.7%, 64.5%, and 83.3%, respectively (p=0.21). The analgesic requirement in group 2 was higher than in the other groups (p=0.00). Group 2 patients also had more grade IIIa (2/3) and IIIB (1/2) complications. Conclusions: Stenting adversely affects stone clearance and also makes the later course uncomfortable. Our model of brief stenting followed by ESWL provided better clearance, comfort, and a modest improvement in outcome with fewer sittings and steinstrasse in selected patients with large renal calculi.
GCR-LIGHTLIKE SUBMANIFOLDS OF INDEFINITE NEARLY KAEHLER MANIFOLDS
Kumar, Sangeet,Kumar, Rakesh,Nagaich, R.K. Korean Mathematical Society 2013 대한수학회보 Vol.50 No.4
We introduce CR, SCR and GCR-lightlike submanifolds of indefinite nearly Kaehler manifolds and obtain their existence in indefinite nearly Kaehler manifolds of constant holomorphic sectional curvature $c$ and of constant type ${\alpha}$. We also prove characterization theorems on the existence of totally umbilical and minimal GCR-lightlike submanifolds of indefinite nearly Kaehler manifolds.
In-situ braking torque and temperature analysis of two-wheeler drum brake in friction braking
Rakesh Kumar Singh,Chiranjit Sarkar 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4
Generally, two-wheelers consist of a drum brake on the rear wheel. The performance of the brake deteriorates drastically due to the continuous use of brakes during driving. Thus, studying brake performance in the worst conditions, where brakes are applied back to back after a fixed time interval, becomes essential. To fulfill this, the in-situ braking torque behavior of the two-wheeler drum brake is studied experimentally, and the in-situ thermal behavior is studied experimentally and numerically in the present paper. A new test rig is designed using a motor, torque sensor, data acquisition system, and drum brake of the twowheeler. The effect of speed and braking cycles on the torque and thermal behavior of drum brake is studied. The torque required for approximately the same deceleration is dependent on the speed of drum and brake cycles. Similarly, results are found for thermal analysis, and drum surface temperature depends on the speed of the drum. Moreover, the drum surface temperature increases steadily with the increase of brake cycles.