Sri Lankan Journal of Physics最新文献

{"title":"Adaptation of a technique to estimate rainfall from satellite data in Bangladesh","authors":"Md. Nazrul Islam, Cm Wahid","doi":"10.4038/SLJP.V4I0.188","DOIUrl":"https://doi.org/10.4038/SLJP.V4I0.188","url":null,"abstract":"st1:*{behavior:url(#ieooui) } \u0000 /* Style Definitions */ \u0000 table.MsoNormalTable \u0000 {mso-style-name:\"Table Normal\"; \u0000 mso-tstyle-rowband-size:0; \u0000 mso-tstyle-colband-size:0; \u0000 mso-style-noshow:yes; \u0000 mso-style-parent:\"\"; \u0000 mso-padding-alt:0cm 5.4pt 0cm 5.4pt; \u0000 mso-para-margin:0cm; \u0000 mso-para-margin-bottom:.0001pt; \u0000 mso-pagination:widow-orphan; \u0000 font-size:10.0pt; \u0000 font-family:\"Times New Roman\"; \u0000 mso-ansi-language:#0400; \u0000 mso-fareast-language:#0400; \u0000 mso-bidi-language:#0400;} \u0000 In order to estimate rainfall from satellite data GMS (Geo-stationary Meteorological Satellite) Precipitation Index (GPI) was calculated for northeastern part (Sylhet) of Bangladesh. GPI was calibrated with ground-based raingauge rainfall. As was found, GPI underestimated i.e., raingauge rainfall overestimated for a few stations. Then GPI was adapted as Adjusted GMS Precipitation Index (AGPI). Satisfactory results were found using AGPI in estimating rainfall from satellite data. As expected, the raingauge rainfall was found about 68% of AGPI. doi:10.4038/sljp.v4i0.188 Sri Lankan Journal of Physics, Vol.4 (2003) 1-9","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75534402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of mass pectrometry to characterize the components present in curcumin Sample","authors":"Ramal V. Coorey, P. Håkansson","doi":"10.4038/SLJP.V4I0.189","DOIUrl":"https://doi.org/10.4038/SLJP.V4I0.189","url":null,"abstract":"","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89195556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relativistic calculations of secondary ions produced in plasma desorption mass spectrometry","authors":"R. Yoosoofmiya, K. Gamalath","doi":"10.4038/SLJP.V4I0.190","DOIUrl":"https://doi.org/10.4038/SLJP.V4I0.190","url":null,"abstract":"I d Time of Flight (TOF) mass spectrometry, the ratio; mass/charge of ions of the sample under investigation is determined by a relationship between time of flight and spectrometer parameters. Usually this relationship is derived using classical (Newtonian) mechanics. Since high energies are involved in the flight of the particles a relativistic treatment is considered. It is investigated whether the relativistic effects are significant or not, for the motion of secondary ions produced in the Plasma Desorption Mass Spectrometer. Treating the motion of these ions relativistically, a relationship between the Time of Flight (TOF) and mass/charge of the ion was derived. Using advanced mathematical software package Maple 6, the derived relationship was compared with classically obtained results. Then it was found that relativistic effects are not significant and they can be ignored for the linear Plasma Desorption Mass Spectrometer.","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84165943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phase space studies of complex Henon Heiles potentials","authors":"A. Nanayakkara, Chula Abayaratne","doi":"10.4038/SLJP.V3I0.182","DOIUrl":"https://doi.org/10.4038/SLJP.V3I0.182","url":null,"abstract":"","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86961128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Some Properties of Lightning Ground Flashes Observed in and around Sri Lanka, and their Seasonal Variations","authors":"Jp Liyanage, D. Sonnadara, I. Fernando, A. Weerasekera, R. Lelwala, T. Ariyaratne","doi":"10.4038/SLJP.V3I0.187","DOIUrl":"https://doi.org/10.4038/SLJP.V3I0.187","url":null,"abstract":"st1:*{behavior:url(#ieooui) } \u0000 /* Style Definitions */ \u0000 table.MsoNormalTable \u0000 {mso-style-name:\"Table Normal\"; \u0000 mso-tstyle-rowband-size:0; \u0000 mso-tstyle-colband-size:0; \u0000 mso-style-noshow:yes; \u0000 mso-style-parent:\"\"; \u0000 mso-padding-alt:0cm 5.4pt 0cm 5.4pt; \u0000 mso-para-margin:0cm; \u0000 mso-para-margin-bottom:.0001pt; \u0000 mso-pagination:widow-orphan; \u0000 font-size:10.0pt; \u0000 font-family:\"Times New Roman\"; \u0000 mso-ansi-language:#0400; \u0000 mso-fareast-language:#0400; \u0000 mso-bidi-language:#0400;} \u0000 Two lightning locating systems were utilised in obtaining the cloud-to-ground flash characteristics in Sri Lanka and in the surrounding area of the Indian Ocean. Over 5,000 flashes were recorded during the year 1999 covering 39 thunder days. The lightning data are presented in terms of polarity, multiplicity, and first return stroke peak current. The percentage of positive flashes observed in this study is fairly lower than that of temporal regions but when compared with similar studies in tropical regions there is no clear difference. Out of the 3% of the positive flashes reported, 95% were single stroke. On the contrary only 56% of the reported negative flashes were single stroke. The highest percentage of single stroke negative flashes was 74% in June and lowest was 38% in February. The monthly variation of the percentage of positive flashes ranged from 17% in June to 1% in September. The highest monthly average multiplicity of negative flashes of 2.6 was recorded in February and for all other months it was below 2. The monthly averages of the negative first stroke peak currents ranged from about 39kA in August to about 56kA in September. The data obtained in the study also clearly indicates the bias in DF data for longer distances. doi:10.4038/sljp.v3i0.187 Sri Lankan Journal of Physics, Vol.3 (2002) 75-80","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76461572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Approximate energy expressions for confining polynomial potentials","authors":"A. Nanayakkara, V. Bandara","doi":"10.4038/SLJP.V3I0.183","DOIUrl":"https://doi.org/10.4038/SLJP.V3I0.183","url":null,"abstract":"tly developed asymptotic energy expansion (AEE) method is applied to obtain totic energy expansions (AEEs) of general polynomial potentials. These sions contain coefficients of the polynomial potentials explicitly. The asymptotic sions produce very accurate eigen energies. Recurrence relations derived here can d to obtain asymptotic expansions of polynomial potentials of any degree. Energy value expressions are presented for the 4th, 6th, 8th and 10th degree polynomial ials. The expansions obtained with AEE method for polynomial potentials have blance with WKB expressions obtained by Bender et al for the potentials ( even). N x = N UCTION re have been great interest in anharmonic oscillator potentials due to their in quantum field theory, nuclear physics, particle physics, solid-state d atomic and molecular physics. Both perturbative and non-perturbative have been used in the literature to study these potentials with varying this paper, first, we study general polynomial potentials of even degree ly developed AEE method and then explicit expansions are derived for sixth, eighth, and tenth degree polynomial potentials. The asymptotic eigen ansions are written as h ) 2 1 ( + = n g author (E-mail: asiri@ifs.ac.lk) A. Nanayakkara and V. Bandara /Sri Lankan Journal of Physics, Vol.3 (2002) 17-37 where is the k n E α k α th power of the eigen energy, corresponding to nth excited state and coefficients are known explicitly as polynomials in coefficients of the polynomial potential. The AEE method is well suited for polynomial potentials because they have the property s bk '","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89904377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of Ni Substitution for Cu in Bi(Pb)-Sr-Ca-Cu-O Superconductor by AC Magnetic Susceptibility Measurements","authors":"N. Pathmanathan, A. Thomson","doi":"10.4038/SLJP.V3I0.185","DOIUrl":"https://doi.org/10.4038/SLJP.V3I0.185","url":null,"abstract":"st1:*{behavior:url(#ieooui) } \u0000 /* Style Definitions */ \u0000 table.MsoNormalTable \u0000 {mso-style-name:\"Table Normal\"; \u0000 mso-tstyle-rowband-size:0; \u0000 mso-tstyle-colband-size:0; \u0000 mso-style-noshow:yes; \u0000 mso-style-parent:\"\"; \u0000 mso-padding-alt:0cm 5.4pt 0cm 5.4pt; \u0000 mso-para-margin:0cm; \u0000 mso-para-margin-bottom:.0001pt; \u0000 mso-pagination:widow-orphan; \u0000 font-size:10.0pt; \u0000 font-family:\"Times New Roman\"; \u0000 mso-ansi-language:#0400; \u0000 mso-fareast-language:#0400; \u0000 mso-bidi-language:#0400;} \u0000 In this work we have investigated the effect of doping of magnetic element Ni for copper into the copper site of Bi(Pb)-Sr-Ca-Cu-O superconductor by means of AC magnetic susceptibility measurements. Three samples with composition Bi 1.6 Pb 0.4 Sr 2 Ca 2 Ni x Cu 3-x O y with x=0, x=0.05 and x=0.1 were prepared using sol-gel method and the measurements of χ'(T) and χ''(T) were carried out on these samples in zero and in applied d.c magnetic fields. The χ'(T) data for the samples in zero d.c field show single drops indicating that the samples had one superconducting phases and the superconducting transition temperatures of the samples were determined to be 108.7 K, 98.9 K and 56.7 K respectively. Obviously superconducting transition temperatures of the samples decrease with increasing Ni concentration. The χ' (T) data for the samples in d.c magnetic fields show broad superconducting transitions indicating that the magnetic fields quenched superconductivity of the samples. The χ''(T) data in d.c magnetic fields show broad intergrain peaks associated with energy dissipation inside the samples. In low d.c magnetic fields χ' (T) data for the x=0 and x=0.05 samples show two drops associated with inter and intragrain regions of the samples. In high magnetic fields χ' (T) data show single transitions indicating that the magnetic fields simultaneously penetrated into the superconducting grains and the weak links. The χ' (T) data for the x=0.1 sample shows single drops in low and in high d.c. magnetic fields. The high d.c magnetic fields pushed the superconducting transition temperatures of the samples to lower temperatures and the intergrain peaks in χ''(T) shifted to lower temperatures with increasing applied d.c magnetic fields. doi:10.4038/sljp.v3i0.185 Sri Lankan Journal of Physics, Vol.3 (2002) 53-61","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75217051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Forecasting the Occurrence of Rainfall in Selected Weather Stations in the Wet and Dry Zones of Sri Lanka","authors":"Hkwi Perera, D. Sonnadara, Jayewardene","doi":"10.4038/SLJP.V3I0.184","DOIUrl":"https://doi.org/10.4038/SLJP.V3I0.184","url":null,"abstract":"st1:*{behavior:url(#ieooui) } \u0000 /* Style Definitions */ \u0000 table.MsoNormalTable \u0000 {mso-style-name:\"Table Normal\"; \u0000 mso-tstyle-rowband-size:0; \u0000 mso-tstyle-colband-size:0; \u0000 mso-style-noshow:yes; \u0000 mso-style-parent:\"\"; \u0000 mso-padding-alt:0cm 5.4pt 0cm 5.4pt; \u0000 mso-para-margin:0cm; \u0000 mso-para-margin-bottom:.0001pt; \u0000 mso-pagination:widow-orphan; \u0000 font-size:10.0pt; \u0000 font-family:\"Times New Roman\"; \u0000 mso-ansi-language:#0400; \u0000 mso-fareast-language:#0400; \u0000 mso-bidi-language:#0400;} \u0000 Two models were developed based on the Markov method to predict the occurrence of rainfall. Daily rainfall data from 9 meteorology stations in Sri Lanka namely, Colombo, Ratnapura, Kandy, Galle, Hambanthota, Batticaloa, Anuradhapura, Badulla and Trincomalee were analysed using these models. The results show that the models can forecast the status of a given day at an average of 73%. Higher agreement is seen for stations in the dry zone of Sri Lanka when compared with those in the wet zone. No significant difference was observed between the results obtained using the 1 st order Markov process and the 2 nd order Markov process. The models were not sensitive to the range of data used or the short-term fluctuations. doi:10.4038/sljp.v3i0.184 Sri Lankan Journal of Physics, Vol.3 (2002) 39-52","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81967384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dielectric Behaviour of Ba x Sr 1–x TiO 3 Perovskites","authors":"Ashok Kumar, U. Naithani, B. Semwal","doi":"10.4038/SLJP.V3I0.186","DOIUrl":"https://doi.org/10.4038/SLJP.V3I0.186","url":null,"abstract":"","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88596652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Activity of cloud-to-ground lightning observed in Sri Lanka and in surrounding area of the Indian Ocean","authors":"A. Weerasekera, D. Sonnadara, I. Fernando, Jp Liyanage, R. Lelwala, T. Ariyaratne","doi":"10.4038/SLJP.V2I0.177","DOIUrl":"https://doi.org/10.4038/SLJP.V2I0.177","url":null,"abstract":"Birthday UNIVERSITY OF COLOMBO Birthday 11.6568 Normal 0 false false false MicrosoftInternetExplorer4 \u0000st1:*{behavior:url(#ieooui) } \u0000 /* Style Definitions */ \u0000 table.MsoNormalTable \u0000 {mso-style-name:\"Table Normal\"; \u0000 mso-tstyle-rowband-size:0; \u0000 mso-tstyle-colband-size:0; \u0000 mso-style-noshow:yes; \u0000 mso-style-parent:\"\"; \u0000 mso-padding-alt:0cm 5.4pt 0cm 5.4pt; \u0000 mso-para-margin:0cm; \u0000 mso-para-margin-bottom:.0001pt; \u0000 mso-pagination:widow-orphan; \u0000 font-size:10.0pt; \u0000 font-family:\"Times New Roman\"; \u0000 mso-ansi-language:#0400; \u0000 mso-fareast-language:#0400; \u0000 mso-bidi-language:#0400;} \u0000 Activity of cloud-to-ground lightning flashes observed during the monsoon thunderstorms over Sri Lanka with a lightning locating system consisting of two direction finders (DF) is presented. The Northeast monsoon produced over 884 cloud-to-ground flashes with a peak lightning rate of 96 flashes per hour whereas Southwest monsoon produced 3,294 flashes with a peak rate of 104 flashes per hour. A relative flash density maximum of 198 flashes per 28×28 km 2 was observed over Ratnapura area (6.68N, 80.40E). The percentage of positive flashes and average peak lightning current values for negative flashes are found to be 6.4% and 36 kA respectively for the Northeast monsoon period and 1.7% and 40 kA respectively for the Southwest monsoon period for the flashes that struck within 10-250 km range. No significant difference in average peak lightning current values were observed for the negative and positive flashes in both monsoons. doi:10.4038/sljp.v2i0.177 Sri Lankan Journal of Physics, Vol.2 (2001) 13-19","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85993969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}