Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

2000

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 2551 - 2580 of 2647

Full-Text Articles in Physical Sciences and Mathematics

The Influence Of Cave Tourism On Co2 And Temperature In Baiyun Cave, Hebei, China, Linhua Song, Wei Xiaoning, Liang Fuyuan Jan 2000

The Influence Of Cave Tourism On Co2 And Temperature In Baiyun Cave, Hebei, China, Linhua Song, Wei Xiaoning, Liang Fuyuan

International Journal of Speleology

Baiyun Cave in Hebei Province is one of the main show caves in North China. The speleothem landscape is wonderful, but strongly weathered. In order to set up the relationship between visitor flow and CO2 content and temperature, these parameters were measured at observation sites No. 1 and No. 2 in the tourist peak period of May Day Holiday from May 1 to May 7, 2000. and general tourist season August and October, 2000. The results show that visitor flow strongly affects the fluctuations of cave CO2 content and temperature, that the cave topography and dimensions affect the …


Is It Always Dark In Caves?, Giovanni Badino Jan 2000

Is It Always Dark In Caves?, Giovanni Badino

International Journal of Speleology

Underground natural sources of visible light are considered. The main light producer is Cerenkov radiation emitted in air, water and rock by cosmic ray muons, that depends, in a complex way, on shape of mountain and of caves. In general the illumination increases linearly with the cavity dimensions. Other light sources are from secondary processes generated by radioactive decays in rock from minerals luminescence. The natural light fluxes in caves are in general easy to detect but are not used from underground life.


Measurement Of Diffractive Photoproduction Of Vector Mesons At Large Momentum Transfer At Hera, J. Breitweg, S. Chekanov, M. Derrick, D. Krakauer, S. Magill, B. Musgrave, A. Pellegrino, J. Repond, R. Stanek, R. Yoshida, Margarita C. K. Mattingly, G. Abbiendi, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti Jan 2000

Measurement Of Diffractive Photoproduction Of Vector Mesons At Large Momentum Transfer At Hera, J. Breitweg, S. Chekanov, M. Derrick, D. Krakauer, S. Magill, B. Musgrave, A. Pellegrino, J. Repond, R. Stanek, R. Yoshida, Margarita C. K. Mattingly, G. Abbiendi, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

No abstract provided.


Measurement Of The Spin-Density Matrix Elements In Exclusive Electroproduction Of Ρ0 Mesons At Hera, J. Breitweg, S. Chekanov, M. Derrick, D. Krakauer, S. Magill, B. Musgrave, A. Pellegrino, J. Repond, R. Stanek, R. Yoshida, Margarita C. K. Mattingly, G. Abbiendi, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti Jan 2000

Measurement Of The Spin-Density Matrix Elements In Exclusive Electroproduction Of Ρ0 Mesons At Hera, J. Breitweg, S. Chekanov, M. Derrick, D. Krakauer, S. Magill, B. Musgrave, A. Pellegrino, J. Repond, R. Stanek, R. Yoshida, Margarita C. K. Mattingly, G. Abbiendi, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

Exclusive electroproduction of ρ0 mesons has been measured using the ZEUS detector at HERA in two Q2 ranges, 0.25 < Q2 < 0.85 GeV2 and 3 < Q2 < 30 GeV2. The low-Q2 data span the range 20 < W < 90 GeV; the high-Q2 data cover the 40 < W < 120 GeV interval. Both samples extend up to four-momentum transfers of |t| = 0.6 GeV2. The distribution in the azimuthal angle between the positron scattering plane and the ρ0 production plane shows a small but significant violation of s-channel helicity conservation, corresponding to the production of longitudinally polarised (i.e. helicity zero) ρ0 mesons from transverse photons. Measurements of the 15 combinations of spin-density matrix elements which completely define the angular distributions are presented and discussed.


Measurement Of High-Q2 Charged-Current E+P Deep Inelastic Scattering Cross Sections At Hera, J. Breitweg, S. Chekanov, M. Derrick, D. Krakauer, S. Magill, B. Musgrave, A. Pellegrino, J. Repond, R. Stanek, R. Yoshida, Margarita C. K. Mattingly, G. Abbiendi, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti Jan 2000

Measurement Of High-Q2 Charged-Current E+P Deep Inelastic Scattering Cross Sections At Hera, J. Breitweg, S. Chekanov, M. Derrick, D. Krakauer, S. Magill, B. Musgrave, A. Pellegrino, J. Repond, R. Stanek, R. Yoshida, Margarita C. K. Mattingly, G. Abbiendi, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

The e+p charged-current deep inelastic scattering cross sections, dσ/dQ2 for Q2 between 200 and 60000 GeV2, and dσ/dx and dσ/dy for Q2 > 200 GeV2, have been measured with the ZEUS detector at HERA. A data sample of 47.7 pb-1, collected at a center-of-mass energy of 300 GeV, has been used. The double-differential cross-section dσ/dQ2 falls by a factor of about 50000 as Q2 increases from 280 to 30000 GeV2. The double differential cross section d2σ/dxdQ2 has also been measured. A comparison between the data and Standard Model (SM) predictions shows that contributions from antiquarks (ū and c̄) and quarks (d …


Wetland Vegetation Monitoring, 1999/2000 (Salinity Action Plan), R. Gurner, R. Froend, G. Ogden, B. Franke Jan 2000

Wetland Vegetation Monitoring, 1999/2000 (Salinity Action Plan), R. Gurner, R. Froend, G. Ogden, B. Franke

Research outputs pre 2011

This report represents the vegetation component of a project designed to provide on-going monitoring of wetland salinity and biological resources in wetlands of the agricultural zone of south-west Western Australia. Maintenance of wetland biological diversity in the agricultural zone is one of the major objectives of the Salinity Action Plan. Due to their low position in the landscape, wetlands are the habitat most affected by salinisation.


Persistence Framework For Multiple Legacy Databases Of Patient Information Systems, Chin Heong Khor Jan 2000

Persistence Framework For Multiple Legacy Databases Of Patient Information Systems, Chin Heong Khor

Student Works (2000-2009)

The use of object-oriented technologies has led to a gap between object-oriented applications and legacy relational databases. A persistence framework can fill this gap by providing services to convert and store objects in relational databases and other forms of storage. A persistent object lasts beyond the execution of the application and can be retrieved at a later time. This project involves the development of an object persistence framework in the Java language to work with different storage mechanisms. while concentrating on transparency and reusability aspects. The persistence framework is made up of reusable and extendable sets of classes that provide …


The Effects Of Argon Dilution On Hydrogenated Amorphous Silicon Prepared By D.C. Plasma Glow Discharge : Optical And Infrared Spectroscopic Studies, Aniszawati Azis Jan 2000

The Effects Of Argon Dilution On Hydrogenated Amorphous Silicon Prepared By D.C. Plasma Glow Discharge : Optical And Infrared Spectroscopic Studies, Aniszawati Azis

Student Works (2000-2009)

Hydrogenated amorphous silicon (a-Si :H) films were prepared from the discharge of pure silane and silane diluted in argon using a home-built hori zontal direct current(d.c.) plasma glow discharge system. The effects of argon dilution of silane on the optical properties, chemical bonding properties, hydrogen content and microstructure parameter of the films produced were studied and analyzed. Film thickness, refractive index, optical energy gap and the Urbach tail bandwidth were obtained from the optical transmission spectra of the films while the H content and the microstructure parameter were derived from the Fourier Transform infra-red(FTIR) spectra of the films. The FTIR …


A Study Of Traffic Noise From Selected Urban And Suburban Areas, Savitri Ramiah Jan 2000

A Study Of Traffic Noise From Selected Urban And Suburban Areas, Savitri Ramiah

Student Works (2000-2009)

The main aim of this study is to determine the noise levels in selected urban and suburban roads and to compare the difference in traffic noise levels between these areas. 1be noise attenuated by noise barrier was also surveyed as a small portion of this study. Analysis of traffic noise was surveyed at five locations. Two locations were surveyed for the urban area and two locations for the suburban area and one location for noise barrier. The traffic volume for the duration of the survey was also recorded. Both day time and night time noise levels were studied. The survey …


Clinical Waste Management In The Northern States Of Peninsular Malaysia, Sabah And Sarawak, Abdul Hai Akbar Ali Jan 2000

Clinical Waste Management In The Northern States Of Peninsular Malaysia, Sabah And Sarawak, Abdul Hai Akbar Ali

Student Works (2000-2009)

Clinical waste management and disposal methods are quite unique due to their infectious and harmful nature. Unlike municipal waste, clinical waste is pathogenic which jeopardizes the biotic community including human beings, if not quelled of its pathogenic effect.. However, shortcomings or drawbacks are still possible in areas of source separation. inappropriate containment and labeling. Improper incineration may also lead to incomplete combustion ultimately leading to air pollution. Though existing system of clinical waste disposal and management in Malaysia seem adequate, still efficient and cost effective mechanisms are needed. The focus of this research is to survey and study the administrative …


Gas Chromatographic-Mass Spectrometric Analysis Of Captopril And Its Application In Pharmacokinetic Studies In Healthy Subjects, Zamri Chik Jan 2000

Gas Chromatographic-Mass Spectrometric Analysis Of Captopril And Its Application In Pharmacokinetic Studies In Healthy Subjects, Zamri Chik

Student Works (2000-2009)

Captopril is a highly specific competitive inhibitor of the angiotensin-convening enzyme (ACE). This enzyme converts angiotensin I, a relatively inactive decapeptide, to angiotensin II , a potent endogenous vasoconstrictor substance. Captopril is widely used for the treatment of hypertension and congestive heart failure. This drug, which contains a sulphydryl group binds readily to albumin and to other plasma proteins. Captopril is unstable in blood and plasma ex vivo because of the reactivity of sulphydryl group which results in oxidation and rapid formation of disulphides. Therefore a fixative or a stabiliser must be added to each blood sample immediately following collection. …


Policy For Integrated Solid Waste Management In Malaysia, Dennis Jeyakumar Jan 2000

Policy For Integrated Solid Waste Management In Malaysia, Dennis Jeyakumar

Student Works (2000-2009)

Solid waste management problems have been gaining prominence in Malaysia due to increasing waste generation and the ineffectiveness of the existing mechanism to tackle the problem holistically. This study seeks to formulate a policy for Integrated Solid Waste Management (ISWM) in Malaysia. This has been done by reviewing the legislative and institutional framework as well as the existing practices and trends in Malaysia. Based on this, key issues and needs of solid waste management in Malaysia have been derived. These key issues were then used as a basis to formulate policy instruments to achieve the main objective of ISWM in …


Distribution Of Petrogenic Hydrocarbons In Water, Sediment And Cockles (Anadara Granosa) From Kuala Sungai Sepetang And Kuala Sungai Selangor, Mohd Hilmi Jaafar Jan 2000

Distribution Of Petrogenic Hydrocarbons In Water, Sediment And Cockles (Anadara Granosa) From Kuala Sungai Sepetang And Kuala Sungai Selangor, Mohd Hilmi Jaafar

Student Works (2000-2009)

In order to assess the level of oil pollution in the cockle culture areas along the Straits of Malacca, water, sediment and cockle samples were collected from the culture beds of Kuala Sepetang and Kuala Selangor, two of the largest cockle producing areas of Malaysia. The samples were analysed for petrogenic hydrocarbons by employing a spectrofluorometric technique which measures the content of polycyclic aromatic hydrocarbons (PAH) in oil. The content of aliphatic straight chain hydrocarbons were measured by using gas chromatography􀀐mass spectrometry (GCMS) which also allowed for the estimation of carbon preference indices and hence providing a means of estimating …


Development Of Multiple Channels Edf Lasers, Muhammad Zamzuri Abdul Kadir Jan 2000

Development Of Multiple Channels Edf Lasers, Muhammad Zamzuri Abdul Kadir

Student Works (2000-2009)

This thesis presents the research work carried out on the development and analysis of single wavelength EDFL and multiple wavelength EDFL. Two types of single wavelength EDF ring laser were studied namely a fixed signal wavelength system and a tuneable signal wavelength system. However, emphasis was given to the first case. The analyses made, were based on the following parameters: pump and signal stability, pump power, reflectivity, EDF length and cavity loss. The influence of each cavity component such as isolator, polarisation controller, attenuator and tuneable filter were also investigated and reported here. Only one type of multiple wavelength EDFL …


Development Of A Reusable Object Oriented Application Framework For Library Systems Domain, Roy Teck Choye Chew Jan 2000

Development Of A Reusable Object Oriented Application Framework For Library Systems Domain, Roy Teck Choye Chew

Student Works (2000-2009)

The main goal of developing an application framework on an application domain or a business domain is to facilitate development of application systems within the same domain by reusing components through customisation and not from scratch. These components would have to be analysed and designed with reusable features so that they can be reused to develop different applications in the related domain. In the case of an object-oriented application framework in the technical view, it is made up of a set of interrelated abstract (generic) and concrete classes that underlie the components of a domain model and form the domain …


Development Of Object Oriented Components For Atm Network Simulation With Emphasis On Congestion Control, Wen Dee Lee Jan 2000

Development Of Object Oriented Components For Atm Network Simulation With Emphasis On Congestion Control, Wen Dee Lee

Student Works (2000-2009)

Asynchronous Transfer Mode (ATM) provides the required flexibility for the support of heterogeneous services for Broadband Integrated Services Digital Networks (8-ISDN) environment. A TM has proven to be efficient and flexible in handling a wide range of integrated service traffic. The most outstanding feature of ATM is that it provides the Quality of Service (QoS) guarantees between connections. In a network environment, congestion control is an important factor to consider as to guarantee the negotiated QoS. To study, observe and develop the congestion control mechanism in an ATM network, simulation modelling provides the ideal domain. The aim of this project …


Development Of Object Oriented Components For Atm Network Simulation With Emphasis On Switch Architecture, Meng Kiat Gan Jan 2000

Development Of Object Oriented Components For Atm Network Simulation With Emphasis On Switch Architecture, Meng Kiat Gan

Student Works (2000-2009)

Asynchronous Transfer Mode (ATM) is considered to be the foundation on which B­ISON is to be built. It is the new generation of communication protocol that being deployed throughout the telecommunication industry. An important component of this communication networks is the ATM switch whose basic functions are to direct cells from input port to output port and to buffer cell destined to the same output port from different input port. Understanding an ATM switch before building it, is a challenging task as one must consider the design of switching architecture and cell buffering at the same time. As the switching …


Disaster Recovery Planning : Local And Remote Data Backup System, Chin Seng Low Jan 2000

Disaster Recovery Planning : Local And Remote Data Backup System, Chin Seng Low

Student Works (2000-2009)

This dissertation studies about the disaster recovery planning focusing on data backup and which there is a data recovery capability in the event of a sudden, severe and unplanned disruption in an organization with network computing environment. The planning must ensure continuity of all the critical data and functions with minimum disruption and recover quickly during such calamity. The elements of a comprehensive and complete disaster recovery planning must include risk analysis, business impact analysis in order to recommend a suitable disaster recovery strategy. Hence, Local and Remote Data Backup System is the designed strategy based on the literature review …


Digital Holography And Application In Laser Metrology, Thian Khok Yong Jan 2000

Digital Holography And Application In Laser Metrology, Thian Khok Yong

Student Works (2000-2009)

A digital holography system has been developed in this study. The object is recorded and the hologram is stored electronically with a charged-couple-device (CCD) camera without any focusing optics. The reconstruction of the digitally sampled hologram is done numerically with a computer. The algorithm and software for numerical reconstruction, which consists in a numerical realization of the Fresnel-Kirchhoff diffraction integral, are designed and implemented with two­dimensional and three-dimensional simple objects. The characteristics of the system have been studied. For the CCD camera (768x494 pixels) been used with spatial resolution of about I 00 lines/mm, the angle between reference and object …


Dynamic Modeling Of Cell Flow For An Atm Network, Sok Kem Tay Jan 2000

Dynamic Modeling Of Cell Flow For An Atm Network, Sok Kem Tay

Student Works (2000-2009)

This project is to study dynamic modeling of cell flow for an A TM network using Simulink tools. The A TM network consists of a maximum of four nodes configured into single hop, multi hop, ring, mesh and star topology. The dynamic simulation will examining the cell flow (bit per second), cell dropped cell received and link utilization for above topology.


Direct Titrimetric Determination And Of Sulphate, Chee Kin Tan Jan 2000

Direct Titrimetric Determination And Of Sulphate, Chee Kin Tan

Student Works (2000-2009)

Interference by foreign ions in direct titrimetric determination of sulphate with barium perchlorate using dimethylsulphonazo III (DMSA Ill) as indicator were studied in this research project. The use of certain water miscible solvents as titration medium has enhanced the determination of end-point. Among the methanol, ethanol, n-propanol and acetone used in the investigation, it was found that medium containing 40 to 50% n-propanol or acetone delivered distinct end-points. The effects of nine cations and eight anions were studied in the above sulphate titration. It was found that the interference caused by Li",Na",K",Mg2"·Mn2", Cd2", NH4", CI and Br are not significant. …


Evaluation Of Academic Library Web Sites In Malaysia, Kee Hiong Lee Jan 2000

Evaluation Of Academic Library Web Sites In Malaysia, Kee Hiong Lee

Student Works (2000-2009)

Academic libraries have dynamically created Web sites on the World Wide Web. However, they have to keep the content and design of their Web sites in line with their missions. Currently, there is lack of a mixed-method approach that combines both quantitative and qualitative analyses for academic library Web sites evaluation and integration of results. This study evaluates the content and design of academic library Web sites in Malaysia by using a mixed-method approach. A total of twelve library Web sites of public and private institutions of higher learning in Malaysia are selected for evaluation. For qualitative analysis, a matrix …


Factor Criteria Metric (Fcm) For Requirements Analysis Phase In The Development Of Management Information Systems, Wei Yin Chew Jan 2000

Factor Criteria Metric (Fcm) For Requirements Analysis Phase In The Development Of Management Information Systems, Wei Yin Chew

Student Works (2000-2009)

This project establishes a way to measure a characteristic of a product and a characteristic of a process involved in the requirements analysis phase for the development of management information systems (M!Ss) by adapting and enhancing McCall's Factor Criteria Metric (FCM) model. The two selected characteristics are the understandability of a software requirements specification (SRS) and effectiveness of a requirements gathering interview (RGI). To define the measurement for these two characteristics, a structure of factors, criteria, checklists and metrics for the characteristics of the products and processes is established based on McCall's FCM model. In addition, a software tool, FCMware, …


An Analysis Of Design Effects For Media Index Survey In Peninsular Malaysia, Leang Hai Tee Jan 2000

An Analysis Of Design Effects For Media Index Survey In Peninsular Malaysia, Leang Hai Tee

Student Works (2000-2009)

This study has attempted to analyze the sampling errors and design effects of Media Index Survey (MIS). MIS is a nationwide survey of sample size of 8738 interviews carried out in Peninsular Malaysia adopting stratified 2-stage cluster sampling, a complex sampling design that widely use in most of the general public surveys Taylor Expansion of ratio estimates method is employed in this study to compute the sampling errors. A total of 60 variables concerning ownership of household durable goods, daily consumer products bought in the past I month, media consumption habits, hanking services, leisure activities and literacy rate are analyzed …


E-Jurnal Ilmiah Di Malaysia : Status Dan Sikap Ahli Akademik, Roosfa Hashim Jan 2000

E-Jurnal Ilmiah Di Malaysia : Status Dan Sikap Ahli Akademik, Roosfa Hashim

Student Works (2000-2009)

Sejak American Association for the Advancement of Science mcnerbitkan The Online Journal Current Clinical Trial pada 1992, muncul pada hari ini ribuan e-jurnal di Internet dalam pelbagai bidang dan bahasa dan dari pelbagai negara di segenap penjuru dunia. Internet menyediakan medium baru kepada para sarjana dalam semua bidang untuk melapor penemuan terbaru mereka secara pantas, mudah, murah dan tersebar luas. Kajian ini bertujuan untuk mengkaji kedudukan terkini e-jurnal di negara ini. Kajian ini penting bagi mengetahui status penerbitan e-jurnal ilmiah di ncgara ini serta penerimaan sarjana kita terhadapnya. Persoalan yang ingin dijawab adalah: Apakah judul-judul jurnal Malaysia yang sedang beredar …


Enhanced Password-Based Authentication Protocol, Chee Kiam Lee Jan 2000

Enhanced Password-Based Authentication Protocol, Chee Kiam Lee

Student Works (2000-2009)

This dissertation introduces Enhanced Password-Based Authentication Protocol (E­PAP) System. E-PAP System combines asymmetric (public-key) and symmetric (secret-key) cryptography that allow two parties sharing a small shared secret to provide authentication service, exchange confidential and authenticated information over an insecure network like lntemet. E-PAP System also provides authentication service by using somelhing you know concept. It has some advantages over biometric which uses something you are concept and smancard that uses something you have concept, as it is free of equipment's physical limitations, accuracy and cost problem as well as other constraints. The core for E-PAP System is FreeSPEKE SDK, a …


Energy Losses Of Solar Neutrinos, Zamri Zainal Abidin Jan 2000

Energy Losses Of Solar Neutrinos, Zamri Zainal Abidin

Student Works (2000-2009)

Using the stopping power of matter. the effects of oscillations on the energy losses of solar neutrinos are investigated. The adiabatic and non-adiabatic survival probabilities of the neutrino oscillations, the mixing angles and Am² are the parameter.; in the calculations. The total energy losses for ⁸B neutrinos with maximum spectral energy of 14.06 MeV is 5 x 10⁻⁷ MeV and is slightly lower than the losses from the non-adiabatic conversion which is ~7 x 10⁻⁷ MeV. From the calculation, we found that the maximum total energy loss for solar neutrinos is of the order 10⁻⁶ MeV. We also include the …


Electrodeposition Of Copper On Polished Copper Electrode, Jia Tsung Ling Jan 2000

Electrodeposition Of Copper On Polished Copper Electrode, Jia Tsung Ling

Student Works (2000-2009)

This project studies the surface morphology of the copper deposit from three different bath solutions on polished copper (3.1 mm in diameter) electrode by using Scanning Electron Microscopy. The behaviour of glycine as an additive in a bath solution containing 0.3 M of copper (II) sulphate and 2.2 M of sulphuric acid was studied by using cyclic voltammetry. In this project, glycine did not involved directly in the reaction of CU²⁺/CU couple but increased the potential and current density of the plating process. However, glycine has the properties for inhibiting the deposition of copper onto the copper disc. Moreover, block …


Erbium-Ytterbium Codoped Fiber Amplifiers, Wai Yee Chan Jan 2000

Erbium-Ytterbium Codoped Fiber Amplifiers, Wai Yee Chan

Student Works (2000-2009)

The amplification characteristics of an Erbium/Ytterbium codoped fiber amplifier(EYDFA) pumped in both the 800nm and 980nm pump bands is reported. With -3m long Er-Yb fiber, the 813nm pumped-EYDFA shows small-signal gain exceeding 20dB over a 20nm bandwidth in the l.Sµm region where the peak gain of 38.4dB is achieved at 1535nm. A low noise figure of ~3.6d8 is also achieved at 1550nm. However, it is found that 980nm pumped­EYDF A suffers lower gain due to the effect of nonsaturable absorption by Yb³⁺ ions which causes high pump poWer loss, thus degrades the signal amplification in Er³⁺ system. Compared to the …


Awareness And Attitude Towards Environmental Issues : A Case Study In Section 17, Petaling Jaya, Selangor Darul Ehsan, Peck Leong Tan Jan 2000

Awareness And Attitude Towards Environmental Issues : A Case Study In Section 17, Petaling Jaya, Selangor Darul Ehsan, Peck Leong Tan

Student Works (2000-2009)

The purpose of this study is to understand the level of knowledge and awareness on environmental issues. It also seeks to understand and examine the attitude and participation of the public in dealing with wastes and other environmental issues. It is generally believed that knowledge on environmental issues would increase participation in environmental programmes. However, the traditional measures of high awareness and knowledge are found not to be closely linked with public participation on environmental issues. As in other studies, this study found that some 93 per cent of the respondents know the adverse effects of environmental pollution. However. only …