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Microstructural, mechanical, and electrochemical analysis of carbon doped AISI carbon steels
Ishtiaq Muhammad,Inam Aqil,Tiwari Saurabh,설재복 한국현미경학회 2022 Applied microscopy Vol.52 No.1
The effect of carbon doping contents on the microstructure, hardness, and corrosion properties of heat-treated AISI steel grades of plain carbon steel was investigated in this study. Various microstructures including coarse ferrite-pearlite, fine ferrite-pearlite, martensite, and bainite were developed by different heat treatments i.e. annealing, normalizing, quenching, and austempering, respectively. The developed microstructures, micro-hardness, and corrosion properties were investigated by a light optical microscope, scanning electron microscope, electromechanical (Vickers Hardness tester), and electrochemical (Gamry Potentiostat) equipment, respectively. The highest corrosion rates were observed in bainitic microstructures (2.68–12.12 mpy), whereas the lowest were found in the fine ferritic-pearlitic microstructures (1.57–6.36 mpy). A direct correlation has been observed between carbon concentration and corrosion rate, i.e. carbon content resulted in an increase in corrosion rate (2.37 mpy for AISI 1020 to 9.67 mpy for AISI 1050 in annealed condition).
QoS Priority Based Femtocell User Power Control for Interference Mitigation in 3GPP LTE-A HetNet
Ishtiaq Ahmad(이쉬티아크),Zeeshan Kaleem(지산),KyungHi Chang(장경희) 한국통신학회 2014 韓國通信學會論文誌 Vol.39 No.2(네트워크)
In recent years, development of femtocells are receiving considerable attention towards increasing the network coverage, capacity, and improvement in the quality of service for users. In 3GPP LTE-Advanced (LTE-A) system, to efficiently utilize the bandwidth, femtocell and macro cell uses the same frequency band, but this deployment poses a technical challenge of cross-tier interference to macro users. In this paper, the novel quality of service based fractional power control (QoS-FPC) scheme under the heterogeneous networks environment is proposed, which considers the users priority and QoS-requirements during the power allocation. The proposed QoS-FPC scheme has two focal points: firs, it protects the macrocell users uplink communication by limiting the cross-tier interference at eNB below a given threshold, and second, it ensures the optimization of femtocell users power allocation at each power adjustment phase. Performance gain is demonstrated with extensive system-level simulations to show that the proposed QoS-FPC scheme significantly decreases the cross-tier intereference and improves the overall users throughput.
Ishtiaq, Sheeba,Hassan, Usman,Mushtaq, Sajid,Akhtar, Noreen Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.6
Background: The presence of Epstein-Barr virus (EBV) in Non-Hodgkin's lymphoma can be identified by immunohistochemistry for detection of EBV latent membrane protein (LMP). The role of EBV as an etiologic agent in the development of non-Hodgkin lymphoma has been supported by detection of high levels of latent membrane protein 1 (LMP-1) expression in tumors. However, no study has been conducted in a Pakistani population up till now to determine the frequency of Epstein-Barr virus positivity. The objective of our study was to determine a value for non-Hodgkin lymphoma patients using EBV LMP-1 immunostaining in our institution. Materials and Methods: This study was carried out at the Department of Histopathology, Armed Forces Institute of Pathology (AFIP), Pakistan from December 2011 to December 2012. It was a cross sectional study. A total of 71 patients who were diagnosed with various subtypes of NHL after histological and EBV LMP-1 immunohistochemical evaluation were studied. Sampling technique was non-probability purposive. Statistical analysis was achieved using SPSS version 17.0. Mean and SD were calculated for quantitative variables like patient age. Frequencies and percentages were calculated for qualitative variables like subgroup of NHL, results outcome of IHC for EBV and gender distribution. Results: Mean age of the patients was $53.6{\pm}16$ years (Mean${\pm}$SD). A total of 50 (70.4%) were male and 21 (29.6%) were female. Some 9 (12.7%) out of 71 cases were positive for EBV-LMP-1 immunostaining, 2 (22.2%) follicular lymphoma cases, 1 (11.1%) case of T-cell lymphoblastic lymphoma, 4 (44.4%) cases of diffuse large B cell lymphomas, 1 (11.1%) mantle cell lymphoma and 1 (11.1%) angioimmunoblastic T cell lymphoma case. Conclusion: In our study, frequency of EBV in NHL is 12.7% and is mostly seen in diffuse large B cell lymphoma. This requires further evaluation to find out whether this positivity is due to co-infection or has a role in pathogenesis.
Ishtiaq, Shabnam,Mahmood, Seema,Athar, Mohammad Techno-Press 2014 Advances in environmental research Vol.3 No.1
Macronutrients ($Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$), yield and yield components, bioaccumulation and translocation of metal in plant parts of three Vigna species (V. cylindrica, V. mungo, V. radiata) were evaluated at 0, 50, 100 and $150mgkg^{-1}$ soil of Nickel (Ni). A marked inhibition (p < 0.001) in the distribution of various macronutrients was noticed in these Vigna species except for $Mg^{2+}$ content of the shoot and leaves. Similarly, all species retained more $Ca^{2+}$ in their roots (p < 0.05) as compared to the aerial tissues. Ni induced a drastic decline (p < 0.001) for various yield and yield attributes except for 100 seed weight. Toxicity and accumulation of Ni in plant tissues considerably increased in a concentration dependent manner. Vigna species signify an exclusion approach for Ni tolerance as both bioaccumulation factor (BF) and translocation factor (TF) were less than 1.0. The Ni content of plants being root > shoot > leaves > seeds. Scoring for percentage stimulation and inhibition (respective to control) at varying levels of Ni revealed tolerance of the species in an order of V. radiata > V. cylindrica > V. mungo. The acquisition of Ni tolerance in V. radiata seems to occur through an integrated mechanism of metal tolerance that includes sustainable macronutrients uptake, stronger roots due to greater deposition of $Ca^{2+}$in the roots, restricted transfer of Ni to above ground tissues and seeds as well as exclusion capacity of the roots to bind appreciable amount of metal to them. Thus, metal tolerant potential of V. radiata could be of great significance to remediate metal contaminated soil owing lesser impact of Ni on macro-nutrients, hence the yield.
Game Theoretic Approach for Joint Resource Allocation in Spectrum Sharing Femtocell Networks
Ishtiaq Ahmad,Shang Liu,Zhiyong Feng,Qixun Zhang,Ping Zhang 한국통신학회 2014 Journal of communications and networks Vol.16 No.6
In this paper, we study the joint price and power allocationin spectrum sharing macro-femtocell networks. The proposedgame theoretic framework is based on bi-level Stackelberg gamewhere macro base station (MBS) works as a leader and underlaidfemto base stations (FBSs) work as followers. MBS has fixed datarate and imposes interference price on FBSs for maintaining itsdata rate and earns revenue while FBSs jointly adjust their powerfor maximizing their data rates and utility functions. Since theinterference from FBSs to macro user equipment is kept under agiven threshold and FBSs compete against each other for powerallocation, there is a need to determine a power allocation strategywhich converges to Stackelberg equilibrium. We consider two casesfor MBS power allocation, i.e., fixed and dynamic power. MBS canadjust its power in case of dynamic power allocation according toits minimum data rate requirement and number of FBSs willing toshare the spectrum. For both cases we consider uniform and nonuniformpricingwhereMBS charges same price to all FBSs for uniformpricing and different price to each FBS for non-uniform pricingaccording to its induced interference. We obtain unique closedform solution for each case if the co-interference at FBSs is assumedfixed. And an iterative algorithm which converges rapidly isalso proposed to take into account the effect of co-tier interferenceon interference price and power allocation strategy. The results areexplained with numerical simulation examples which validate theeffectiveness of our proposed solutions.