Mafic and ultramafic rocks are widely distributed in Myanmar and form major tectonic belts and su... more Mafic and ultramafic rocks are widely distributed in Myanmar and form major tectonic belts and suture zones representing remnants of the Mesotethyan Ocean. They occur as deformed and disrupted ophiolitic sequences and in forearc slivers as part of an accretionary wedge, intimately associated with siliciclastic and limestone units. They commonly host chromitenickel-manganese, copper (gold) and jadeite mineralization. In this chapter, the nature, distribution, geological setting, petrological, mineralogical and ore characteristics of the mafic and ultramafic rocks in Myanmar are reviewed and described, and their tectonic setting and mineralization potential are discussed. Regional geological setting Myanmar is characterized by north-south-trending major tectonic domains. From west to east, these include: the Rakhine coastal strip, an ensimatic foredeep; the Indo-Myanmar Ranges, an outer arc or forearc; the Western Inner-Myanmar Tertiary Basin, an inter-arc basin; the Central Volcanic Belt (Central Volcanic Line), an inner magmatic-volcanic arc; the Eastern Inner-Myanmar Tertiary Basin, a back-arc basin; and the Shan
Arrays of titania nanotubes (TiO2NTs) were developed by electrochemical anodization and doped wit... more Arrays of titania nanotubes (TiO2NTs) were developed by electrochemical anodization and doped with silver on their surface by photodeposition to achieve TiO2NTs/Ag. It is found that only anatase TiO2NTs were formed, with the preferential growth direction perpendicular to the titanium substrate, and with the length and diameter of ~2 µm and 90–120 nm, respectively. The presence of Ag on the surface of TiO2NTs was also confirmed. The TiO2NTs and TiO2NTs/Ag were used as photocatalysts to decolorize the methylene blue (MB) aqueous solution. The photodegradation efficiency (PDE) is as high as 83% for TiO2NTs and 98% for TiO2NTs/Ag photocatalysts. This work focused on the investigation of the stability and recyclability of these photocatalysts in terms of efficiency and its physical origin by surface analysis using X-ray photoelectron spectroscopy (XPS). It is found that PDE diminishes from 83% to 76% in TiO2NTs upon eight recycling runs and from 98% to 80% in TiO2NTs/Ag upon six recyclin...
The present nanotechnological trend is promising for the devices based on nanocomposites. We focu... more The present nanotechnological trend is promising for the devices based on nanocomposites. We focus on three application areas, biosensing, energy storage and photocatalyst. A newer frontier trend is related to individual nano-devices based on individual nano-objects giving the exciting advantages. In the present work, the MnO2 and TiO2 nanocomposites were developed by simple and economical means. The MnO2 and Cu/MnO2 were potentiodynamically deposited on stainless steel sheets and ITO coated glass substrates for energy storage and sensing applications. The electrochemically anodized TiO2 nanotubes and Ag nanoparticles decorated TiO2 nanotubes were fabricated on Ti base for photocatalysis. The MnO2 film electrode, Cu/MnO2 film electrode, Ag/TiO2 nanotubes were preliminarily demonstrated as macroscopic devices in capacitors, glucose sensors and photocatalysis water treatments. The specific capacitance of MnO2 film electrode is as high as 135 Fg−1and the Cu/MnO2 sensor has the low dete...
Wethey-Pheshy area is located 80 km north of Mandalay at Thabeikkyin Township, Mandalay Region. X... more Wethey-Pheshy area is located 80 km north of Mandalay at Thabeikkyin Township, Mandalay Region. X-ray Diffraction (XRD) Analysis and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) were applied in this study. Geochemical studies on the host rocks indicate that major and minor oxides compositions of metamorphicrocks show some degree of variation. CaO, MgO, FeO, TiO2 and P2O5 concentration of the metamorphic rock samples show a coherent negative correlation with SiO2 whereas Na2O is positively correlated with SiO2. The metamorphic rocks are strongly enriched in light rare earth elements (LREE) and relatively depleted in heavy rare earth element (HREE). The depleted Eu-nomalies in the chondrite-normalized REE diagrams indicate a plagioclase-depleted Eu crustal source or fractionation during magmatic differentiation. Intrusion of granitic rocks in the diopside marble caused the base metal ore mineralization and associated skarn alterations. Granite shows the sub-alkaline nature an...
Journal of Materials Science and Engineering B, 2017
Natural dyes were extracted from green leaves (henna and pomegranate) and red fruits (dragon frui... more Natural dyes were extracted from green leaves (henna and pomegranate) and red fruits (dragon fruit, rosella and red beet) and used as photosensitizer in DSSCs (dye sensitized solar cells). Two groups of green and red dye extracts exhibit a complementary absorption characteristic. Adsorption capacity of dye on TiO 2 scaffolds was accessed by the red-shift of the UV-Vis and Fourier transform infrared absorption peaks while electrochemical energy levels were estimated by cyclic voltammetry measurement. This optical and electrochemical characterization reveals that henna dye (among green leaf extracts) and rosella dye (among red fruit extracts) present lower band gap energy, better dye adsorption on TiO 2 scaffolds and better energy alignment. It is thus expecting a lower energy photon harvest, increased dye surface area, reduced electron trapping and better electron injection which are favorable for solar cells. Relatively higher efficiency of DSSC using henna and rosella dye extracts is attributed to the speculated optical and electrical characteristics mentioned above.
The n-type semiconducting titanium oxide thin films are well-known as electron transporting inter... more The n-type semiconducting titanium oxide thin films are well-known as electron transporting interlayer in photovoltaic cells. The favorable characteristics of interlayers in photovoltaics are high optical transmittance (T%), wide band gap energy (E g) and high electrical conductivity (σ). Modifying titanium oxide films with metal nanoparticles would increase electrical conductivity but reduce optical band gap energy. We developed the sol-gel derived titanium suboxide (TiO x) films modified with silver (Ag) or gold (Au) or copper (Cu) nanoparticles (NPs). This study explores a tradeoff between narrowing optical band gap and enhancing electrical conductivity of nanostructured TiO x films by controlling the Au-or Ag-or Cu-NPs loading concentrations (mol%) in titania. The Au-and Cu-NPs loading concentration of 4 mol% should meet a tradeoff which yields the higher T%, wider E g and higher σ compared to those of pure TiO x films. In addition, since the pure Cu is not thermodynamically stable in ambience as compared to Au and Ag, the stability of as-obtained colloidal CuNPs is also examined. A careful examination of the time evolution of surface plasmon resonance (SPR) bands of CuNPs indicates that their stability is only up to 4 h.
ABSTRACT Solution processed graphene oxide (GO) sheets are electronically insulating and are gene... more ABSTRACT Solution processed graphene oxide (GO) sheets are electronically insulating and are generally reduced by chemical treatment or heat treatment in a reducing environment to recover their electronic properties, forming reduced graphene oxide (rGO). Here, GO sheets were photocatalytically reduced using 5-(4-hydroxyphenyl)-10,15,20-tri(p-tolyl) zinc(II) porphyrin (Zn(II)TTPOH) under ambient conditions. After illumination in the presence of a hole scavenger and Zn(II)TTPOH, the formation of rGO was confirmed through optical absorption measurements and monitoring of the D/G peak ratios from Raman measurements. The resultant rGO formed stable aqueous suspensions with the Zn(II)TTPOH. The electron transfer from photoexcited porphyrin to GO was studied through photoluminescence measurements. Utilising this photoreduction process as a post processing strategy, an increase in conductivity and an ambipolar field effect transistor (FET) behaviour were demonstrated on prepatterned GO devices. We have also confirmed the photoreduction process at low energy wavelengths (588 nm), indicating the versatility of using metalloporphyrins as photocatalysts for graphene oxide reduction.
A cost-effective approach to enhancing broadband light trapping in ultra-thin bulk heterojunction... more A cost-effective approach to enhancing broadband light trapping in ultra-thin bulk heterojunction organic photovoltaic (OPV) devices is proposed. This is achieved by simply inserting an array of Al nanodisks at the interface of the ITO anode and the organic active layer; forming circular plasmonic nano-patch cavities (between the nanodisks and the Al cathode) that sandwich the active layer. Through interactions between the surface plasmon polaritons (SPP) localized at the nanodisk and the cathode, a tunable broadband resonance peak spanning 450-700 nm in the scattering cross-section spectrum is formed, thereby enhancing the electromagnetic field in the active layer. Compared to an OPV device with a 60 nm thick PCPDTBT:PC 60 BM layer, our numerical simulations reveal that integrated absorption enhancements of up to 40% can be achieved in an equivalent device integrated with an array of nanodisks with a diameter of 100 nm and a periodicity of 250 nm. From the analysis of the structureperformance relationships, implications for the design of these nano-patch cavities for light harvesting in ultra-thin OPV devices are discussed.
... Antennae in Organic Photovoltaics Than Z. Oo 1 , Nripan Mathews 1 *, Guichuan Xing 2 , Bo Wu ... more ... Antennae in Organic Photovoltaics Than Z. Oo 1 , Nripan Mathews 1 *, Guichuan Xing 2 , Bo Wu 2 , Bengang Xing 2 , Lydia H. Wong 1 , ... optical chopper set at 60 Hz and Merlin radiometry system. The light power-density was calibrated with Hamamatsu silicon photodiode. ...
Acta Crystallographica Section E Structure Reports Online, 2009
The title compound, C 15 H 10 ClNO, is a functionalized isoxazole with a chlorophenyl and a pheny... more The title compound, C 15 H 10 ClNO, is a functionalized isoxazole with a chlorophenyl and a phenyl substitutent. The mean plane of the isoxazole ring is inclined to those of the two benzene ring mean planes by 38.32 (16) and 43.91 (18). Related literature For the chemistry and biological properties of isoxazoles, see:
Acta Crystallographica Section E Structure Reports Online, 2009
Sulfone compounds, similar to sulfonamides, show strong in vitro and in vivo antibacterial activi... more Sulfone compounds, similar to sulfonamides, show strong in vitro and in vivo antibacterial activity, and for almost 60 years they have been used successfully in medicine (Mandell & Sande, 1985). Certain sulfones also exhibit fungicidal activity.
Australian and New Zealand Journal of Ophthalmology, 1999
Background: As part of a project to improve diabetes care in Fiji, we assessed the magnitude of p... more Background: As part of a project to improve diabetes care in Fiji, we assessed the magnitude of problems posed by diabetic retinopathy in that country and compared the findings with those from an Australian diabetes centre. The relationship between diabetic retinopathy and nephropathy was also examined in a subset of patients. Methods: A medical team from Australia screened a total of 446 type 2 diabetic patients (ethnicity: Fijian/Indian 16/84%) for diabetic retinopathy in five towns from the Western Division of Viti Levu, Fiji. The findings were compared with data obtained from 1659 type 2 diabetic patients who had attended an Australian diabetes centre (ethnicity: Indian/ Anglo‐Celtic 12/88%). In both cohorts, retinopathy was assessed by direct fundoscopy and a spot urine sample was collected for determination of albuminuria (defined as a concentration > 50 mg/L). Results: The prevalence of diabetic retinopathy increased linearly with duration of diabetes. It was higher in Fij...
Solution processed, high electron mobility and highly transparent Zinc Tin Oxide (ZTO) was succes... more Solution processed, high electron mobility and highly transparent Zinc Tin Oxide (ZTO) was successfully exploited as electron transporting buffer layer in an inverted organic solar cell. The device configuration of FTO/ZTO/P3HT:PCBM/WO 3 /Ag was employed. For comparison, an identical device using a sol-gel derived TiO x electron extracting layer was also fabricated. Increased short-circuit density (J sc) and open-circuit voltage (V oc) were generated in the devices with ZTO layer in comparison to the ones with TiO x layer. It is attributed to a better electron transporting, hole blocking capacities and reduced recombination probabilities at electron collecting electrode with ZTO layer. A power conversion efficiency of 3.05% was achieved with ZTO devices.
Mafic and ultramafic rocks are widely distributed in Myanmar and form major tectonic belts and su... more Mafic and ultramafic rocks are widely distributed in Myanmar and form major tectonic belts and suture zones representing remnants of the Mesotethyan Ocean. They occur as deformed and disrupted ophiolitic sequences and in forearc slivers as part of an accretionary wedge, intimately associated with siliciclastic and limestone units. They commonly host chromitenickel-manganese, copper (gold) and jadeite mineralization. In this chapter, the nature, distribution, geological setting, petrological, mineralogical and ore characteristics of the mafic and ultramafic rocks in Myanmar are reviewed and described, and their tectonic setting and mineralization potential are discussed. Regional geological setting Myanmar is characterized by north-south-trending major tectonic domains. From west to east, these include: the Rakhine coastal strip, an ensimatic foredeep; the Indo-Myanmar Ranges, an outer arc or forearc; the Western Inner-Myanmar Tertiary Basin, an inter-arc basin; the Central Volcanic Belt (Central Volcanic Line), an inner magmatic-volcanic arc; the Eastern Inner-Myanmar Tertiary Basin, a back-arc basin; and the Shan
Arrays of titania nanotubes (TiO2NTs) were developed by electrochemical anodization and doped wit... more Arrays of titania nanotubes (TiO2NTs) were developed by electrochemical anodization and doped with silver on their surface by photodeposition to achieve TiO2NTs/Ag. It is found that only anatase TiO2NTs were formed, with the preferential growth direction perpendicular to the titanium substrate, and with the length and diameter of ~2 µm and 90–120 nm, respectively. The presence of Ag on the surface of TiO2NTs was also confirmed. The TiO2NTs and TiO2NTs/Ag were used as photocatalysts to decolorize the methylene blue (MB) aqueous solution. The photodegradation efficiency (PDE) is as high as 83% for TiO2NTs and 98% for TiO2NTs/Ag photocatalysts. This work focused on the investigation of the stability and recyclability of these photocatalysts in terms of efficiency and its physical origin by surface analysis using X-ray photoelectron spectroscopy (XPS). It is found that PDE diminishes from 83% to 76% in TiO2NTs upon eight recycling runs and from 98% to 80% in TiO2NTs/Ag upon six recyclin...
The present nanotechnological trend is promising for the devices based on nanocomposites. We focu... more The present nanotechnological trend is promising for the devices based on nanocomposites. We focus on three application areas, biosensing, energy storage and photocatalyst. A newer frontier trend is related to individual nano-devices based on individual nano-objects giving the exciting advantages. In the present work, the MnO2 and TiO2 nanocomposites were developed by simple and economical means. The MnO2 and Cu/MnO2 were potentiodynamically deposited on stainless steel sheets and ITO coated glass substrates for energy storage and sensing applications. The electrochemically anodized TiO2 nanotubes and Ag nanoparticles decorated TiO2 nanotubes were fabricated on Ti base for photocatalysis. The MnO2 film electrode, Cu/MnO2 film electrode, Ag/TiO2 nanotubes were preliminarily demonstrated as macroscopic devices in capacitors, glucose sensors and photocatalysis water treatments. The specific capacitance of MnO2 film electrode is as high as 135 Fg−1and the Cu/MnO2 sensor has the low dete...
Wethey-Pheshy area is located 80 km north of Mandalay at Thabeikkyin Township, Mandalay Region. X... more Wethey-Pheshy area is located 80 km north of Mandalay at Thabeikkyin Township, Mandalay Region. X-ray Diffraction (XRD) Analysis and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) were applied in this study. Geochemical studies on the host rocks indicate that major and minor oxides compositions of metamorphicrocks show some degree of variation. CaO, MgO, FeO, TiO2 and P2O5 concentration of the metamorphic rock samples show a coherent negative correlation with SiO2 whereas Na2O is positively correlated with SiO2. The metamorphic rocks are strongly enriched in light rare earth elements (LREE) and relatively depleted in heavy rare earth element (HREE). The depleted Eu-nomalies in the chondrite-normalized REE diagrams indicate a plagioclase-depleted Eu crustal source or fractionation during magmatic differentiation. Intrusion of granitic rocks in the diopside marble caused the base metal ore mineralization and associated skarn alterations. Granite shows the sub-alkaline nature an...
Journal of Materials Science and Engineering B, 2017
Natural dyes were extracted from green leaves (henna and pomegranate) and red fruits (dragon frui... more Natural dyes were extracted from green leaves (henna and pomegranate) and red fruits (dragon fruit, rosella and red beet) and used as photosensitizer in DSSCs (dye sensitized solar cells). Two groups of green and red dye extracts exhibit a complementary absorption characteristic. Adsorption capacity of dye on TiO 2 scaffolds was accessed by the red-shift of the UV-Vis and Fourier transform infrared absorption peaks while electrochemical energy levels were estimated by cyclic voltammetry measurement. This optical and electrochemical characterization reveals that henna dye (among green leaf extracts) and rosella dye (among red fruit extracts) present lower band gap energy, better dye adsorption on TiO 2 scaffolds and better energy alignment. It is thus expecting a lower energy photon harvest, increased dye surface area, reduced electron trapping and better electron injection which are favorable for solar cells. Relatively higher efficiency of DSSC using henna and rosella dye extracts is attributed to the speculated optical and electrical characteristics mentioned above.
The n-type semiconducting titanium oxide thin films are well-known as electron transporting inter... more The n-type semiconducting titanium oxide thin films are well-known as electron transporting interlayer in photovoltaic cells. The favorable characteristics of interlayers in photovoltaics are high optical transmittance (T%), wide band gap energy (E g) and high electrical conductivity (σ). Modifying titanium oxide films with metal nanoparticles would increase electrical conductivity but reduce optical band gap energy. We developed the sol-gel derived titanium suboxide (TiO x) films modified with silver (Ag) or gold (Au) or copper (Cu) nanoparticles (NPs). This study explores a tradeoff between narrowing optical band gap and enhancing electrical conductivity of nanostructured TiO x films by controlling the Au-or Ag-or Cu-NPs loading concentrations (mol%) in titania. The Au-and Cu-NPs loading concentration of 4 mol% should meet a tradeoff which yields the higher T%, wider E g and higher σ compared to those of pure TiO x films. In addition, since the pure Cu is not thermodynamically stable in ambience as compared to Au and Ag, the stability of as-obtained colloidal CuNPs is also examined. A careful examination of the time evolution of surface plasmon resonance (SPR) bands of CuNPs indicates that their stability is only up to 4 h.
ABSTRACT Solution processed graphene oxide (GO) sheets are electronically insulating and are gene... more ABSTRACT Solution processed graphene oxide (GO) sheets are electronically insulating and are generally reduced by chemical treatment or heat treatment in a reducing environment to recover their electronic properties, forming reduced graphene oxide (rGO). Here, GO sheets were photocatalytically reduced using 5-(4-hydroxyphenyl)-10,15,20-tri(p-tolyl) zinc(II) porphyrin (Zn(II)TTPOH) under ambient conditions. After illumination in the presence of a hole scavenger and Zn(II)TTPOH, the formation of rGO was confirmed through optical absorption measurements and monitoring of the D/G peak ratios from Raman measurements. The resultant rGO formed stable aqueous suspensions with the Zn(II)TTPOH. The electron transfer from photoexcited porphyrin to GO was studied through photoluminescence measurements. Utilising this photoreduction process as a post processing strategy, an increase in conductivity and an ambipolar field effect transistor (FET) behaviour were demonstrated on prepatterned GO devices. We have also confirmed the photoreduction process at low energy wavelengths (588 nm), indicating the versatility of using metalloporphyrins as photocatalysts for graphene oxide reduction.
A cost-effective approach to enhancing broadband light trapping in ultra-thin bulk heterojunction... more A cost-effective approach to enhancing broadband light trapping in ultra-thin bulk heterojunction organic photovoltaic (OPV) devices is proposed. This is achieved by simply inserting an array of Al nanodisks at the interface of the ITO anode and the organic active layer; forming circular plasmonic nano-patch cavities (between the nanodisks and the Al cathode) that sandwich the active layer. Through interactions between the surface plasmon polaritons (SPP) localized at the nanodisk and the cathode, a tunable broadband resonance peak spanning 450-700 nm in the scattering cross-section spectrum is formed, thereby enhancing the electromagnetic field in the active layer. Compared to an OPV device with a 60 nm thick PCPDTBT:PC 60 BM layer, our numerical simulations reveal that integrated absorption enhancements of up to 40% can be achieved in an equivalent device integrated with an array of nanodisks with a diameter of 100 nm and a periodicity of 250 nm. From the analysis of the structureperformance relationships, implications for the design of these nano-patch cavities for light harvesting in ultra-thin OPV devices are discussed.
... Antennae in Organic Photovoltaics Than Z. Oo 1 , Nripan Mathews 1 *, Guichuan Xing 2 , Bo Wu ... more ... Antennae in Organic Photovoltaics Than Z. Oo 1 , Nripan Mathews 1 *, Guichuan Xing 2 , Bo Wu 2 , Bengang Xing 2 , Lydia H. Wong 1 , ... optical chopper set at 60 Hz and Merlin radiometry system. The light power-density was calibrated with Hamamatsu silicon photodiode. ...
Acta Crystallographica Section E Structure Reports Online, 2009
The title compound, C 15 H 10 ClNO, is a functionalized isoxazole with a chlorophenyl and a pheny... more The title compound, C 15 H 10 ClNO, is a functionalized isoxazole with a chlorophenyl and a phenyl substitutent. The mean plane of the isoxazole ring is inclined to those of the two benzene ring mean planes by 38.32 (16) and 43.91 (18). Related literature For the chemistry and biological properties of isoxazoles, see:
Acta Crystallographica Section E Structure Reports Online, 2009
Sulfone compounds, similar to sulfonamides, show strong in vitro and in vivo antibacterial activi... more Sulfone compounds, similar to sulfonamides, show strong in vitro and in vivo antibacterial activity, and for almost 60 years they have been used successfully in medicine (Mandell & Sande, 1985). Certain sulfones also exhibit fungicidal activity.
Australian and New Zealand Journal of Ophthalmology, 1999
Background: As part of a project to improve diabetes care in Fiji, we assessed the magnitude of p... more Background: As part of a project to improve diabetes care in Fiji, we assessed the magnitude of problems posed by diabetic retinopathy in that country and compared the findings with those from an Australian diabetes centre. The relationship between diabetic retinopathy and nephropathy was also examined in a subset of patients. Methods: A medical team from Australia screened a total of 446 type 2 diabetic patients (ethnicity: Fijian/Indian 16/84%) for diabetic retinopathy in five towns from the Western Division of Viti Levu, Fiji. The findings were compared with data obtained from 1659 type 2 diabetic patients who had attended an Australian diabetes centre (ethnicity: Indian/ Anglo‐Celtic 12/88%). In both cohorts, retinopathy was assessed by direct fundoscopy and a spot urine sample was collected for determination of albuminuria (defined as a concentration > 50 mg/L). Results: The prevalence of diabetic retinopathy increased linearly with duration of diabetes. It was higher in Fij...
Solution processed, high electron mobility and highly transparent Zinc Tin Oxide (ZTO) was succes... more Solution processed, high electron mobility and highly transparent Zinc Tin Oxide (ZTO) was successfully exploited as electron transporting buffer layer in an inverted organic solar cell. The device configuration of FTO/ZTO/P3HT:PCBM/WO 3 /Ag was employed. For comparison, an identical device using a sol-gel derived TiO x electron extracting layer was also fabricated. Increased short-circuit density (J sc) and open-circuit voltage (V oc) were generated in the devices with ZTO layer in comparison to the ones with TiO x layer. It is attributed to a better electron transporting, hole blocking capacities and reduced recombination probabilities at electron collecting electrode with ZTO layer. A power conversion efficiency of 3.05% was achieved with ZTO devices.
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