Due to the depletion of conventional hydrocarbon resources,both China and Russia are giving more attention to the exploration and production of unconventional oil and gas resources,especially those generated and accum...Due to the depletion of conventional hydrocarbon resources,both China and Russia are giving more attention to the exploration and production of unconventional oil and gas resources,especially those generated and accumulated within source rocks.In an attempt to further understand the mechanisms of these resources,detailed mineralogical,lithological,and geochemical studies were performed to compare source rock samples from i)the Longmaxi Formation of the Lower Silurian in the Sichuan Basin(China),and ii)the Semiluksk Formation of the Frasnian Stage of the Upper Devonian in the Volga-Ural region of the East European Platform(Russia).The results showed that the main mineral of the source rocks of both formations is chalcedony that formed during an outpouring of deep fluids onto the sea bed.Simultaneous thermal analyses of this mineral indicated similar thermophysical properties to those of the hydrothermal-sedimentary chalcedony from jasper.Moreover,a direct relationship between the chalcedony content and the total organic matter content in the samples from the two formations was established.The presence of biophilic chemical elements in the siliceous component of the source rock samples indicate that high total organic content values were likely due to the presence of biophilic chemical elements in deep fluids,which led to the large-scale development of biota and subsequent accumulation of organic matter during sedimentation.The findings also revealed that the organic matter in the source rocks of the two regions was at different stages of maturity.The organic matter in samples from the Volga-Ural region was less mature and only at the early stage of oil generation,whereas the organic matter in samples from the Sichuan Basin reached both oil and gas generation stages.The Longmaxi Formation is already in the shale gas exploration and development stage,and the Semiluksk Formation could also be regarded as an exploration target for shale oil reservoirs.展开更多
With the admission of eight Central/East European countries in May 1, 2004 in sight, realization of the objective of EU’s first phase eastern extension will signify a major step toward the concept of "a Europe k...With the admission of eight Central/East European countries in May 1, 2004 in sight, realization of the objective of EU’s first phase eastern extension will signify a major step toward the concept of "a Europe kept far away from war" through promoting regional integration.展开更多
Aim of this paper is to characterize different risk measures in portfolio construction on seven Central and South-East European stock markets;Slovenia, Croatia, Hungary, Poland, Chez Republic, Bulgaria and Romania. Se...Aim of this paper is to characterize different risk measures in portfolio construction on seven Central and South-East European stock markets;Slovenia, Croatia, Hungary, Poland, Chez Republic, Bulgaria and Romania. Selected countries are members of EU, except Croatia and Turkey which have candidate status. Empirical part of this paper consists of three stages;at first descriptive statistic on stock returns was performed, afterwards different risk measures were employed in portfolio construction and in the last part, portfolios were tested in the out-of-sample period. Results indicate presence of extreme kurtosis and skewness in stock return series. Resulting portfolios incorporate stocks with extremely high kurtosis and stocks with negative skewness. Portfolio construction based only on risk and return results in major exposure to extreme returns and unsatisfactory portfolio out of sample results.展开更多
The territory of the Balkan Peninsula in SE Europe is reviewed, from the point of gemmology, as the cradle of gem and decorative minerals and metals in European prehistory. During the local Neolithic period (end of 7 ...The territory of the Balkan Peninsula in SE Europe is reviewed, from the point of gemmology, as the cradle of gem and decorative minerals and metals in European prehistory. During the local Neolithic period (end of 7 th -6 th millennium BC), as material for tools or for beads, nephrite (with the earliest known Balkan nephrite culture), jadeite-omphacite and quartz (different varieties) were introduced to make pendants and idols. Large quantities of copper and gold artifacts are known since the Chalcolithic period (5 th millennium BC)(unique for the region;the largest in number of gold artifacts is the Varna I Chalcolithic necropolis in Bulgaria). The gemmological materials in the Balkans are known for malachite, antigorite serpentinite, turquoise, rock crystal, carnelian, jasper, jet and obsidian. In the Varna I necropolis (mid 5 th millennium BC) are recorded the first known complex faceted carnelian beads with 32 facets, as well as some of the most important gemmological techniques and procedures such as faceting, tumbling, annealing, miniaturization and standardization. As pigments for pottery, cinnabar, graphite and gold were used in different prehistoric sites. The earliest salt production in the Balkans is known from sites in Romania and Bulgaria, and because of its trade, salt is positively linked to a population rich with prestigious goods. The introduced possible Chalcolithic weight unit “van”(2 carats) is supposed to be the earliest known in prehistoric times.展开更多
基金supported by grants from the Russian Foundation for Basic Research(project No.18-35-00136)the Chinese NSFC(project No.41811530094)+1 种基金the Government of the Republic of Tatarstan(project No.18-45-160003)supported by subsidies allocated as part of the state’s support for the Kazan Federal University in order to increase its global competitiveness in leading research and educational centers.
文摘Due to the depletion of conventional hydrocarbon resources,both China and Russia are giving more attention to the exploration and production of unconventional oil and gas resources,especially those generated and accumulated within source rocks.In an attempt to further understand the mechanisms of these resources,detailed mineralogical,lithological,and geochemical studies were performed to compare source rock samples from i)the Longmaxi Formation of the Lower Silurian in the Sichuan Basin(China),and ii)the Semiluksk Formation of the Frasnian Stage of the Upper Devonian in the Volga-Ural region of the East European Platform(Russia).The results showed that the main mineral of the source rocks of both formations is chalcedony that formed during an outpouring of deep fluids onto the sea bed.Simultaneous thermal analyses of this mineral indicated similar thermophysical properties to those of the hydrothermal-sedimentary chalcedony from jasper.Moreover,a direct relationship between the chalcedony content and the total organic matter content in the samples from the two formations was established.The presence of biophilic chemical elements in the siliceous component of the source rock samples indicate that high total organic content values were likely due to the presence of biophilic chemical elements in deep fluids,which led to the large-scale development of biota and subsequent accumulation of organic matter during sedimentation.The findings also revealed that the organic matter in the source rocks of the two regions was at different stages of maturity.The organic matter in samples from the Volga-Ural region was less mature and only at the early stage of oil generation,whereas the organic matter in samples from the Sichuan Basin reached both oil and gas generation stages.The Longmaxi Formation is already in the shale gas exploration and development stage,and the Semiluksk Formation could also be regarded as an exploration target for shale oil reservoirs.
文摘With the admission of eight Central/East European countries in May 1, 2004 in sight, realization of the objective of EU’s first phase eastern extension will signify a major step toward the concept of "a Europe kept far away from war" through promoting regional integration.
文摘Aim of this paper is to characterize different risk measures in portfolio construction on seven Central and South-East European stock markets;Slovenia, Croatia, Hungary, Poland, Chez Republic, Bulgaria and Romania. Selected countries are members of EU, except Croatia and Turkey which have candidate status. Empirical part of this paper consists of three stages;at first descriptive statistic on stock returns was performed, afterwards different risk measures were employed in portfolio construction and in the last part, portfolios were tested in the out-of-sample period. Results indicate presence of extreme kurtosis and skewness in stock return series. Resulting portfolios incorporate stocks with extremely high kurtosis and stocks with negative skewness. Portfolio construction based only on risk and return results in major exposure to extreme returns and unsatisfactory portfolio out of sample results.
文摘The territory of the Balkan Peninsula in SE Europe is reviewed, from the point of gemmology, as the cradle of gem and decorative minerals and metals in European prehistory. During the local Neolithic period (end of 7 th -6 th millennium BC), as material for tools or for beads, nephrite (with the earliest known Balkan nephrite culture), jadeite-omphacite and quartz (different varieties) were introduced to make pendants and idols. Large quantities of copper and gold artifacts are known since the Chalcolithic period (5 th millennium BC)(unique for the region;the largest in number of gold artifacts is the Varna I Chalcolithic necropolis in Bulgaria). The gemmological materials in the Balkans are known for malachite, antigorite serpentinite, turquoise, rock crystal, carnelian, jasper, jet and obsidian. In the Varna I necropolis (mid 5 th millennium BC) are recorded the first known complex faceted carnelian beads with 32 facets, as well as some of the most important gemmological techniques and procedures such as faceting, tumbling, annealing, miniaturization and standardization. As pigments for pottery, cinnabar, graphite and gold were used in different prehistoric sites. The earliest salt production in the Balkans is known from sites in Romania and Bulgaria, and because of its trade, salt is positively linked to a population rich with prestigious goods. The introduced possible Chalcolithic weight unit “van”(2 carats) is supposed to be the earliest known in prehistoric times.
