期刊文献+
共找到27篇文章
< 1 2 >
每页显示 20 50 100
Seismic Hazard Assessment of District Mansehra,Khyber Pakhtoonkhawa,Pakistan 被引量:1
1
作者 MONA Lisa 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第4期1157-1168,共12页
The site of Mansehra is located seismically in an active regime, known as the Crystalline Nappe Zone and Hazara-Kashmir Syntaxis in NW Himalayas, Pakistan. Seismic Hazard Assessment (SHA) for the site has been carri... The site of Mansehra is located seismically in an active regime, known as the Crystalline Nappe Zone and Hazara-Kashmir Syntaxis in NW Himalayas, Pakistan. Seismic Hazard Assessment (SHA) for the site has been carried out by considering the earthquake source zones, selection of appropriate attenuation equations, near fault effects and maximum potential magnitude estimation. The Mansehra Thrust, Oghi Fault, Banna Thrust, Balakot Shear Zone, Main Boundary Thrust, Panjal Thrust, Jhelum Fault and Muzaffarabad Fault and, further to the south, the Sanghargali, Nathiagali, and Thandiani Thrusts are the most critical tectonic features within the 50 km radius of Mansehra. Using the available instrumental seismological data from 1904 to 2007, SHA has been carried out. Other reactivated critical tectonic features in the area have been investigated. Among them the Balakot-Bagh fault, with the fault length of 120 km from Balakot to Poonch, has been considered as the most critical tectonic feature on the basis of geological/structural/seismological data. The potential earthquake of maximum magnitude 7.8 has been assigned to the Balakot-Bagh fault using four regression relations. The peak ground acceleration value of 0.25 g (10% probability of exceedance for 50 years) and 0.5 g has been calculated with the help of the attenuation equation using probabilistic and deterministic approaches. 展开更多
关键词 Seismic Hazard Assessment Mansehra District NW Himalayas Pakistan Probabilistic and Deterministic Approaches Balakot-Bagh Fault
在线阅读 下载PDF
Efficient Energy Performance within Smart Grid 被引量:1
2
作者 Khizer Ayaz Muhammad Sohail Sulemani Naseer Ahmed 《Smart Grid and Renewable Energy》 2017年第3期75-86,共12页
The Smart Grid, regarded as the next generation power grid, uses two-way flows of electricity and information to create a widely distributed automated energy delivery network. Energy/power plays a critical role for so... The Smart Grid, regarded as the next generation power grid, uses two-way flows of electricity and information to create a widely distributed automated energy delivery network. Energy/power plays a critical role for social, economic and industrial development. Because of industrial generalization, especially in agricultural and economical activities, the energy demand has increased rapidly in developed countries. Generation and usage of energy has direct impact on modern power grid. In this scenario energy management is a hard task because load is dynamic and we don’t have control over it. Renewable or undepleted energy resources have great applications and impact in current electric power system situation. For example it gives pollution free (green) energy which is environment and user friendly. It is cost effective;it uses natural resources for its generation and hence do not waste any coal, gas etc. There are many inducements to empower energy productivity. As current smart grid is complex and non linear in operation and design, it used an optimized method that provides maximum efficiency with minimum input. Our work depicts a case study of hybrid electric aircraft for achieving high performance. 展开更多
关键词 Smart GRID (SG) DEMAND Response (DR) RENEWABLE Energy Distributed Generators (DG)
在线阅读 下载PDF
Application of Seismic Attributes for Delineation of Channel Geometries and Analysis of Various Aspects in Terms of Lithological and Structural Perspectives of Lower Goru Formation, Pakistan 被引量:1
3
作者 Tayyab Muhammad Naseer Shazia Asim +2 位作者 Mirza Naseer Ahmad Farrukh Hussain Shahid Nadeem Qureshi 《International Journal of Geosciences》 2014年第12期1490-1502,共13页
Miano area is one of the distinct major hydrocarbon producing fields of the Lower Indus basin. Lower Goru is the reservoir strait in this area. The aim of the present study is to exploit the channels reservoirs and ot... Miano area is one of the distinct major hydrocarbon producing fields of the Lower Indus basin. Lower Goru is the reservoir strait in this area. The aim of the present study is to exploit the channels reservoirs and other stratigraphic features in such a terrain where there is always a challenge for the geoscientist to search and exploit the channeled reservoirs. To resolve this issue we have utilized attribute analysis on high resolution 3D-seismic data for the detailed comparative studies for the channels. There are many astonishing features that are identified in the current study, which could not otherwise be easily enhanced with the help of 2D Seismic Data. Seismic attributes such as coherency, frequency (are also appropriate for lithological discrimination), which are sensitive to the channel edges are applied for the channel delineation and their geometrical analysis. Spectral decomposition techniques are also applied for the delineation of channels and to appropriately select the best band for channels identification. Three types of channel geometries are recognized: 1) highly sinuous channel;2) narrow-broad meandering belts;3) moderate to high sinuous channel. NW-SE, N-W trending faults can be helpful to compartmentalize the reservoir. Instantaneous and dominant frequency are more beneficial for further field development based on Gamma Ray logs from nearby drilled wells and dimensional perspectives analysis of the channel reservoir. 展开更多
关键词 SEISMIC Attributes Spectral Decomposition LOWER Goru STRAIT Miano LOWER Indus Basin Channels
暂未订购
Delay Optimized Architecture for On-Chip Communication 被引量:1
4
作者 Sheraz Anjum Jie Chen +1 位作者 Pei-Pei Yue Jian Liu 《Journal of Electronic Science and Technology of China》 2009年第2期104-109,共6页
Networks-on-chip (NoC), a new system on chip (SoC) paradigm, has become a great focus of research by many groups during the last few years. Among all the NoC architectures that have been proposed until now, 2D-Mes... Networks-on-chip (NoC), a new system on chip (SoC) paradigm, has become a great focus of research by many groups during the last few years. Among all the NoC architectures that have been proposed until now, 2D-Mesh has proved to be the best architecture for implementation due to its regular and simple interconnection structure. In this paper, we propose a new interconnect architecture called 2D-diagonal mesh (2DDgl-Mesh) for on-chip communication. The 2DDglMesh is almost similar to traditional 2D-Mesh in aspects of cost, area, and implementation, but it can outperform the later in delay. The both architectures are compared by using NS-2 (a network simulator) and CINS1M (a component based interconnection simulator) under the same traffic models and parametric conditions. The results of comparison show that under the proposed architecture, the packets can almost always be routed to their destinations in less time. In addition, our archi- tecture can sometimes perform better than 2D-Mesh in drop ratio for special fixed traffic models. 展开更多
关键词 Index Terms-2D-Mesh NETWORKS-ON-CHIP networksimulator 2 traffic models system on chip.
在线阅读 下载PDF
Identification and genomic analysis of a novel member of Microviridae, IME-16, through high-throughput sequencing
5
作者 Peng Shu Azeem Mehmood Butt +8 位作者 Zhiqiang Mi Wei Wang Xiaoping An Guangqian Pei Zhiyi Zhang Yong Huang Xianglilan Zhang Taoxing Shi Yigang Tong 《Virologica Sinica》 SCIE CAS CSCD 2015年第4期301-304,共4页
Dear Editor,Bacteriophages predominate in the biosphere and outnumber their hosts by at least one order of magnitude(Srinivasiah et al.,2008).They have been used for over90 years as an alternative to antibiotics in Ea... Dear Editor,Bacteriophages predominate in the biosphere and outnumber their hosts by at least one order of magnitude(Srinivasiah et al.,2008).They have been used for over90 years as an alternative to antibiotics in Eastern Europe(Deresinski,2009).With the increasing emergence of antibiotic resistance,the therapeutic potential of bacteriophages is being reevaluated(Kutter et al.,2010).Until recently,phages possessing ds DNA genomes have 展开更多
关键词 SEQUENCING THROUGHPUT GENOMIC ANTIBIOTICS magnitud
原文传递
Seimatoric acid and colletonoic acid:Two new compounds from the endophytic fungi,Seimatosporium sp.and Colletotrichum sp. 被引量:2
6
作者 Hidayat Hussain Natalia Root +14 位作者 Farah Jabeen Ahmed Al-Harrasi Ahmed Al-Rawahi Manzoor Ahmad Zahid Hassan Ghulam Abbas Fazal Mabood Afzal Shah Amin Badshah Amjad Khan Riaz Ahmad Ivan R.Green Siegfried Draeger Barbara Schulz Karsten Krohn 《Chinese Chemical Letters》 SCIE CAS CSCD 2014年第12期1577-1579,共3页
A new metabolite,named seimatoric acid(1),representing a new oxobutanoic acid derivative has been isolated from Seimatosporium sp., in addition to four known compounds viz.,2-hydroxymethyl-4β,5α,6β-trihydroxycycl... A new metabolite,named seimatoric acid(1),representing a new oxobutanoic acid derivative has been isolated from Seimatosporium sp., in addition to four known compounds viz.,2-hydroxymethyl-4β,5α,6β-trihydroxycyclohex-2-enone(2),(-)-phyllostine(3),(+)-epiepoxydon(4) and(+)-epoxydon monoacetate(5).Similarly one new benzoic acid derivative,named colletonoic acid(6) was isolated from the ethyl acetate fraction of Colletotrichum sp.The structures of the new compounds were elucidated by detailed ^1 H NMR,^13C NMR,COSY,HMQC.HMBC spectroscopic analysis,and HR-E1-MS.Seimatoric acid(1)was also isolated from another taxonomical unidentified fungal strain 4295 in ourgroup.The structures of the known compounds were elucidated by their spectral data comparison to literature data.Preliminary studies showed that colletonoic acid(6) showed good antibacterial,antifungal,and antialgal activities. 展开更多
关键词 Seimatosporium sp. Colletotrichum sp. Activity Natural product
原文传递
Assessment of Sea Water Inundation Along Daboo Creek Area in Indus Delta Region, Pakistan
7
作者 ZIA Ibrahim ZAFAR Hina +2 位作者 SHAHZAD Muhammad I. MERAJ Mohsin KAZMI Jamil H. 《Journal of Ocean University of China》 SCIE CAS CSCD 2017年第6期1055-1060,共6页
Indus Deltaic Region(IDR) in Pakistan is an erosion vulnerable coast due to the high deep water wave energy. Livelihood of millions of people depends on the fisheries and mangrove forests in IDR. IDR consists of many ... Indus Deltaic Region(IDR) in Pakistan is an erosion vulnerable coast due to the high deep water wave energy. Livelihood of millions of people depends on the fisheries and mangrove forests in IDR. IDR consists of many creeks where Daboo is a major creek located at southeast of the largest city of Pakistan, Karachi. Unfortunately, there has been no detailed study to analyze the damages of sea water intrusion at a large temporal and spatial scale. Therefore, this study is designed to estimate the effects of sea water inundation based on changing sea water surface salinity and sea surface temperature(SST). Sea surface salinity and SST data from two different surveys in Daboo creek during 1986 and 2010 are analyzed to estimate the damages and extent of sea water intrusion. Mean salinity has increased 33.33% whereas mean SST decreased 13.79% from 1987 to 2010. Spatio-temporal analysis of creek area using LANDSAT 5 Thematic mapper(TM) data for the years 1987 and 2010 shows significant amount of erosion at macro scale. Creek area has increased approximately 9.93%(260.86 m^2 per year) which is roughly equal to 60 extensive sized shrimp farms. Further Land Use Land Cover(LULC) analyses for years 2001 and 2014 using LANDSAT 7 Enhanced Thematic Mapper Plus(ETM+) has indicated 42.3% decrease in cultivated land. Wet mud flats have spread out at the inner mouth of creek with enormous increase of 123.3%. Significant sea water intrusion has increased the area of barren land by 37.9%. This also resulted in overall decrease of 6.7% in area covered by mangroves. Therefore, this study recorded a significant evidence of sea water intrusion in IDR that has caused serious damages to community living in the area, economical losses. Additionally, it has also changed the environment by reducing creek biological productivity as reported by earlier studies over other regions of the world. 展开更多
关键词 sea water INTRUSION SST SALINITY Ambro CREEK CTD
在线阅读 下载PDF
Mass Transfer: a Deciding Factor for the Multiplicity of an Event in Deep Inelastic Collisions
8
作者 Tabassum Nasir J.J.Baluch +2 位作者 E.U.Khan F.N.Khattak M.I.Shahzad 《Chinese Physics Letters》 SCIE CAS CSCD 2006年第10期2714-2716,共3页
Intermediate stage of the three and four-pronged events is investigated in the reaction ^208Pb+^197Au at beam energy 11.67 MeV/u. Multiprong events are analysed numerically using an empirical mass-dependent velocityr... Intermediate stage of the three and four-pronged events is investigated in the reaction ^208Pb+^197Au at beam energy 11.67 MeV/u. Multiprong events are analysed numerically using an empirical mass-dependent velocityrauge relation. Using the measured three-dimensional coordinates of correlated tracks, it is possible to determine the quantities such as mass transfer and total kinetic energy loss. These quantities are then used to study the intermediate stage of the reaction. It has been observed that mass transfer and total kinetic energy loss at the first step of the reaction decides the multiplicity of an event at the second stage of the sequential fission process. 展开更多
关键词 HEAVY-ION INTERACTION MICA TRACK DETECTORS CHANNELS FISSION U-238
原文传递
Study of an Uplift of Sargodha High by Stratigraphical and Structural Interpretation of an East-West Seismic Profile in Central Indus Basin, Pakistan
9
作者 Shazia Asim Shahid Nadeem Qureshi Nasir Khan 《International Journal of Geosciences》 2014年第9期1027-1036,共10页
Research Area comprises of Punjab Monocline, Sulaiman Foredeep and Eastern Part of Sulaiman Fold Belt (from east to west) in Central Indus Basin, Pakistan. Sargodha High is located in northeast of a Seismic Profile AB... Research Area comprises of Punjab Monocline, Sulaiman Foredeep and Eastern Part of Sulaiman Fold Belt (from east to west) in Central Indus Basin, Pakistan. Sargodha High is located in northeast of a Seismic Profile AB. Time and Depth models show the subsurface crustal variations near Sargodha High, which separates Upper Indus Basin from Central Indus Basin. The deposition of Pre-Cambrian sediments is uniform in area and Paleozoic sediments (Permian & Cambrian) are thinning in west. Mesozoic sediments (Cretaceous, Jurassic & Triassic) and younger sediments (Paleocene) are not deposited in this part suggesting an uplift of Sargodha High during Paleozoic time. An uneven distribution of Paleozoic rocks shows some thickness in east but erosion, thinning and almost truncation in west indicate their depocenter in east. This also represents a time of uplift of Sargodha High that shifts depocenter westward. Seismic data show a thick Mesozoic deposition in west, which onlaps on the Permo-Triassic unconformity suggesting an area of non-deposition. The gradual uplift of Sargodha high continues, which tilts the Mesozoic strata forming wedge shape geometry. 展开更多
关键词 UPLIFT UNCONFORMITIES STRUCTURAL TRUNCATIONS Depo-Center BASEMENT
在线阅读 下载PDF
Study of a Stratigraphic Trap of Paleocene/Late Cretaceous Age with the Help of Seismic Data in Sulaiman Foredeep and Kirthar Foredeep Area (Central &Southern Indus Basin, Pakistan)
10
作者 Shazia Asim Nasir Khan +2 位作者 Shahid Nadeem Qureshi Farrukh Hussain Saeed Ahmed Bablani 《International Journal of Geosciences》 2014年第10期1049-1061,共13页
The Research work comprises area of Punjab Platform, Sulaiman Foredeep and Eastern Part of Sulaiman Fold Belt (from east to west), which is further extended to Zamzama and Dadu area of Lower Indus Basin. Seismic data ... The Research work comprises area of Punjab Platform, Sulaiman Foredeep and Eastern Part of Sulaiman Fold Belt (from east to west), which is further extended to Zamzama and Dadu area of Lower Indus Basin. Seismic data interpretation suggests a presence of a stratigraphic trap of Paleocene/Late Cretaceous age. It can act as a stratigraphic trap of reservoir quality for hydrocarbons. This feature is marked and discussed on various seismic sections. Sometimes it is difficult to locate this feature due to effect of folding, resulting from later compressions associated with a collision of Indian Plate. This structure could be explored for a hydrocarbon prospect in future. Such stratigraphic traps were not explored in the past. 展开更多
关键词 STRATIGRAPHIC Trap Shelf Margin Seismic Interpretation CENTRAL Indus BASIN
暂未订购
Controls and Implications of Geo-Technical Variation in Quartzose Rocks from Peshawar Basin, North-Western Pakistan
11
作者 Khanzada Wazir Mohammad Arif Muhammad Sajid 《Geomaterials》 2015年第4期85-98,共14页
Petrographic and geo-mechanical properties of samples representing quartzose rocks of Tanawal Formation (Baja Bamkhel area, Swabi) and Misri Banda quartzite (Nowshera) from Peshawar Basin, NW Pakistan, have been inves... Petrographic and geo-mechanical properties of samples representing quartzose rocks of Tanawal Formation (Baja Bamkhel area, Swabi) and Misri Banda quartzite (Nowshera) from Peshawar Basin, NW Pakistan, have been investigated. Although formerly referred to as quartzite, mineralogical composition and textural details support characterization of the studied quartzose samples of Tanawal Formation as blasto-psammite and those of Misri Banda as sub-arkose. The two rock types also show significant differences in terms of matrix and heavy mineral concentrations as well as the degree and frequency of intra-granular deformation. On the basis of unconfined compressive strength (UCS), both fall in the category of very strong rocks. Correspondingly, their specific gravity and water absorption values are high and low respectively and lie well within the range permissible for use as construction material. However, both contain high amounts of deleterious components, i.e. reactive forms of silica (chert and/or strained quartz) and clay minerals. Therefore, they cannot be used as coarse aggregate with Ordinary Portland Cement (OPC) and asphalt. The modal abundance of quartz is higher in the Misri Banda than the Tanawal samples, but the quartz to feldspar ratios are higher for the latter. Yet, the sub-arkosic Misri Banda rocks are stronger than the Tanawal blasto-psammites, most probably because they are i) almost totally devoid of matrix;ii) finer grained;iii) having a higher percentage of grains with irregular and sutured contacts and iv) lesser abundance of grains displaying intra-granular deformation. 展开更多
关键词 Quartzose ROCKS PETROGRAPHY Strength Physical Properties Geo-Technical FEASIBILITY
暂未订购
Implementation &Comparative Analysis of 10, 18 &24 Level Diode Clamped Inverters Using “Trust Region Dog Leg” Method
12
作者 Haider Ali Mohamed Z. H. Qawaqzeh +1 位作者 Muhammad Abbas Takialddin Al Smadi 《Circuits and Systems》 2015年第3期70-80,共11页
Multilevel inverters are used in many industrial applications because of good power quality, minimum losses and less harmonics contents. Multilevel inverters require no series connected synchronized switching devices,... Multilevel inverters are used in many industrial applications because of good power quality, minimum losses and less harmonics contents. Multilevel inverters require no series connected synchronized switching devices, transformer and complex filters. In this paper 10, 18, 24 diode clamped multi-level inverters (DCMLI) are implemented using trust region dog leg optimization method to find the optimized values of switching angles (θ). It decreases the total harmonic distortion (THD) of the output voltages and to reduce the complexity of external filter required. The multi-level inverters are implemented in MATLAB Simulation and results are compared in terms of harmonics, system complexity and efficiency. 展开更多
关键词 DCMLI THD Switching ANGLES IGBTs Trust Region DOG LEG
暂未订购
Structural and Stratigraphical Correlation of Seismic Profiles between Drigri Anticline and Bahawalpur High in Central Indus Basin of Pakistan
13
作者 Shazia Asim S. N. Qureshi +3 位作者 Summyia Khatoon Asif Shabeer Ahmed Abbasi Sarfraz Solangi M. Qasim Mirza 《International Journal of Geosciences》 2014年第11期1231-1240,共10页
Publicly available seismic and well data are used to study the subsurface structure and stratigraphy of an area on the southern margin of the Central Indus Basin (CIB), Pakistan. Study area includes southern parts of ... Publicly available seismic and well data are used to study the subsurface structure and stratigraphy of an area on the southern margin of the Central Indus Basin (CIB), Pakistan. Study area includes southern parts of the Punjab Platform and Sulaiman Foredeep tectonic units of the CIB. A regional scale East-West depth cross-section is prepared in South of hydrocarbon bearing Safed Koh Trend to Punjab Platform. It gives the structural configuration of various formations of Paleozoic-Cenozoic times. Reflectors are marked and correlated with the help of wells Drigri-01 and Bahawalpur East-01, located on seismic lines 914-RPR-03 and 916-YZM-05 respectively. These reflectors/formations are correlated with respect to ages to avoid the confusions as there are many truncations in the area. Average velocities are used for the depth computation. Depth cross-section (AB) shows that Punjab Monocline is a stable area with a shallow basement. In Punjab Platform all the formations dip gently to the West. Then they attain steep dips in the Sulaiman Foredeep/Depression area. Depth cross-section along the Drigri anticline which lies in the SE of Sakhi Sarwar anticline reveals that it is extended E-W over 17 km approx. and the reverse faults are present on both flanks of a fold, due to that a pop up structure is formed. It’s a low amplitude fold, as it marks the southern end of Safed Koh Trend (first line of folding of the folded flank of Sub-Sulaiman Fore Deep). Subsurface structural variations at Bahawalpur show a buried high of Jurassic-Permian age. A sedimentary cover is 9 km thick in West and 3 m thick in East. Basement is uplifted at Bahawalpur High. 展开更多
关键词 SEISMIC Interpretation CENTRAL Indus BASIN Burried RIDGE
暂未订购
Nuclear Track Detectors for Relativistic Nuclear Fragmentation Studies: Comparison with Other Competitive Techniques
14
作者 Mukhtar Ahmed Rana Gul Sher +2 位作者 Shahid Manzoor Fariha Malik Kanwal Naz 《Modern Instrumentation》 2013年第3期49-59,共11页
The potential of the high resolution nuclear track detector (NTD) CR-39 is examined carefully for the measurement of relativistic nuclear projectile fragmentation cross sections and studies of related processes using ... The potential of the high resolution nuclear track detector (NTD) CR-39 is examined carefully for the measurement of relativistic nuclear projectile fragmentation cross sections and studies of related processes using the experience of many years of such measurements. The charge resolution and the charge resolving power of CR-39 detectors for the measurements of 158 A GeV 207Pb projectiles and their fragments are presented. Exposures of target-detector stacks, the chemical etching procedure and the nuclear track measurements are described in detail discussing precautions and possible errors. The procedures discussed are also valid for other NTDs. A comparison with electronic active detectors is also made considering important detection and measurement aspects. An experimental design proposing the co-use of NTDs with in-use active detectors is described. 展开更多
关键词 NUCLEAR Track Detection Methodology (NTDM) CR-39 Detectors NUCLEAR FRAGMENTATION Charge Resolution FRAGMENTATION Cross SECTIONS
在线阅读 下载PDF
Etch Induction Time in CR-39 Detectors Etched in Na2CO3 Mixed NaOH Solution
15
作者 N. Ali E. U. Khan K. Khan 《Chinese Physics Letters》 SCIE CAS CSCD 2009年第9期105-107,共3页
Six different solutions of 6M NaOH, containing different amounts of Na2CO3 at 70℃ were used for the revelation of latent damage trails in CR-39 plastic track detectors. These detectors were earlier exposed to fission... Six different solutions of 6M NaOH, containing different amounts of Na2CO3 at 70℃ were used for the revelation of latent damage trails in CR-39 plastic track detectors. These detectors were earlier exposed to fission fragments from ^252 Cf source for 30 min in vacuum and were then etched in the respective solutions for different etching time intervals of 5-20 min starting from 5min up to 160min. The etch induction time in each detector was obtained by extrapolating the intersection of resulting curves of track lengths and track diameters with the time axis. 展开更多
原文传递
Varying Track Etch Rates along the Fission Fragments' Trajectories in CR-39 Detectors
16
作者 N. All E. U. Khan +3 位作者 A. Waheed S. Karim F. Khan A. Majeed 《Chinese Physics Letters》 SCIE CAS CSCD 2010年第5期76-79,共4页
We determine the behavior of track etch rate VT along the tracks in CR-39 detectors exposed to fission fragments from ^252Cf source. CR-39 detectors are etched at 70℃ in different concentrations of Na2COa-mixed 6M Na... We determine the behavior of track etch rate VT along the tracks in CR-39 detectors exposed to fission fragments from ^252Cf source. CR-39 detectors are etched at 70℃ in different concentrations of Na2COa-mixed 6M NaOH solutions for different etching time intervals of 5-10min starting from 15 min up to 210min. Two values of track etch rate are determined along the fission fragment trajectories. The variation in VT is correlated with the energy loss rate of the fission fragment in the detector material. 展开更多
原文传递
High Voltage Direct Current (HVDC) Transmission: Future Expectation for Pakistan 被引量:8
17
作者 Kamran Hafeez Shahid A.Khan 《CSEE Journal of Power and Energy Systems》 SCIE CSCD 2019年第1期82-86,共5页
An HVDC transmission system for bulk power transfer over longer distance offers numerous advantages over an alternating current(AC)transmission system,such as direct integration of networks operating at different freq... An HVDC transmission system for bulk power transfer over longer distance offers numerous advantages over an alternating current(AC)transmission system,such as direct integration of networks operating at different frequencies,comparatively low line losses on account of constant current and absence of reactance.This paper presents details about HVDC power transmission systems and power converter technologies.Issues concerning integration of electrical power generated by alternate sources(i.e.,wind,onshore and offshore)into the national grid of Pakistan using HVDC technology are also discussed.Research studies revealed that the energy crisis of countries like Pakistan can be mitigated to a larger extent with the use of HVDC transmission systems. 展开更多
关键词 HVDC renewable energy transmission systems wind Energy
原文传递
Characterization of Drought and Its Assessment over Sindh,Pakistan During 1951-2010 被引量:3
18
作者 Shahzada ADNAN Kalim ULLAH 高守亭 《Journal of Meteorological Research》 SCIE CSCD 2015年第5期837-857,共21页
Drought is one of the complex meteorological disasters affecting water resources, agriculture, livestock, and socioeconomic patterns of a region. Although drought prediction is difficult, it can be monitored based on ... Drought is one of the complex meteorological disasters affecting water resources, agriculture, livestock, and socioeconomic patterns of a region. Although drought prediction is difficult, it can be monitored based on climatological information. In this study, we provide high spatiotemporal resolution drought climatology, using observational, gridded precipitation data (0.5°×0.5°) from the Global Precipitation Climatological Center and soil moisture data from the Climate Prediction Center for the 60-yr period 1951-2010. The standardized precipitation index (SPI) based on a fitted Gamma distribution and Run method has been calculated from the regional drought identification model (ReDIM) for 3, 6, 9, 12, and 24 months. The results show strong temporal correlations among anomalies of precipitation, soil moisture, and SPI. Analysis of long-term precipitation data reveals that the drought vulnerability concentrates on monsoon season (July- September), which contributes 72.4% and 82.1% of the annual precipitation in northern and southern Sindh, respectively. Annual and seasonal analyses show no significant changes in the observed precipitation. The category classification criteria are defined to monitor/forecast drought in the selected area. Further analysis identifies two longest episodes of drought, i.e., 1972 1974 and 2000 2002, while 1969, 1974, 1987, and 2002 are found to be the most severe historical drought years. A drought hazard map of Sindh was developed, in which 10 districts are recognized as highly vulnerable to drought. This study helps to explain the time, duration, intensity, and frequency of meteorological droughts over Sindh as well as its neighboring regions, and provides useful information to disaster management agencies and forecasters for assessing both the regional vulnerabilitv of drought and its seasonal predictability in Pakistan. 展开更多
关键词 CLIMATOLOGY DROUGHT standardized precipitation index (SPI) regional drought identification model (ReDIM) SINDH
原文传递
Transmit Power Optimization for Relay-Aided Multi-Carrier D2D Communication 被引量:2
19
作者 Muhammad Waqas Guftaar Ahmad Sardar Sidhu +2 位作者 Tayyaba Jabeen Muhammad Afaq Ahmad Muhammad Awais Javed 《Tsinghua Science and Technology》 SCIE EI CAS CSCD 2018年第1期65-74,共10页
In this paper, we consider the power optimization problem in Orthogonal Frequency Division Multiplexing (OFDM)-based relay-enhanced device-to-device (D2D) communication. In a single cell transmission scenario, dua... In this paper, we consider the power optimization problem in Orthogonal Frequency Division Multiplexing (OFDM)-based relay-enhanced device-to-device (D2D) communication. In a single cell transmission scenario, dual- hop communication is assumed in which each D2D user re-uses the spectrum of just one Cellular User (CU). In this work, we formulate a joint optimization scheme under a Decode-and-Forward (DF) relaying protocol to maximize the sum throughput of D2D and cellular networks via power allocation over different sub-carriers. The problem is thus transformed into a standard convex optimization, subject to individual power constraints at different transmitting nodes. We exploit the duality theory to decompose the problem into several sub-problems and use Karush-Kuhn- Tucker (KKT) conditions to solve each sub-problem. We provide simulation results to validate the performance of our proposed scheme. 展开更多
关键词 device-to-device communication Orthogonal Frequency Division Multiplexing (OFDM) Decode-and-Forward (DF) relay transmission power optimization
原文传递
Crustal structure beneath Tien Shan orogenic belt and its adjacent regions from multi-scale seismic data 被引量:3
20
作者 N.Ghani KHAN BAI Ling +4 位作者 ZHAO JunMeng LI GuoHui M.Moklesur RAHMAN CHENG Cheng YANG JianYa 《Science China Earth Sciences》 SCIE EI CAS CSCD 2017年第10期1769-1782,共14页
As one of the world's most active intracontinental mountain belts, Tien Shan has posed questions for researchers regarding the formation of different tectonic units and active shallow seismicity. Here, we used a h... As one of the world's most active intracontinental mountain belts, Tien Shan has posed questions for researchers regarding the formation of different tectonic units and active shallow seismicity. Here, we used a huge data set comprising of 7094 earthquakes from local, regional and teleseismic seismic stations. We used waveform modeling and multi-scale double-difference earthquake relocation technique to better constrain the source parameters of the earthquakes. The new set of events provided us with better initial earthquake locations for further tomographic investigation. We found that reverse-faulting earthquakes dominate the whole study area while the fault plane solutions for earthquakes beneath the northwestern Tarim Basin and the Main Pamir Thrust are diverse. There is a low-velocity anomaly beneath Bashkaingdy at depth of 80 km, and high-velocity anomalies beneath central Tien Shan at shallower depths. These observations are the keys to understand the mechanism of Tien Shan's formation because of Tarim Basin northward and Kazakh Shield's southward subduction in the south and north respectively. Velocities beneath western Tien Shan are relatively high. We thus infer that the Western Tien Shan is relatively less deformed than the eastern Tien Shan primarily due to a relatively brittle mantle. 展开更多
关键词 Tien Shan Earthquake relocation Velocity anomalies Differential subduction
原文传递
上一页 1 2 下一页 到第
使用帮助 返回顶部