Fluorite deposits occur in a variety of geologic environments throughout the globe. It may occur as the main or only economically recoverable ore mineral in deposits or may present as the accessory gangue minerals wit...Fluorite deposits occur in a variety of geologic environments throughout the globe. It may occur as the main or only economically recoverable ore mineral in deposits or may present as the accessory gangue minerals with other ores. It is therefore necessary to understand various genetic types of the fluorite deposit. The present paper synthesises the information of some of the known fluorite mineralisation from the world so that an understanding of them can help in establishing reliable criteria for further search of fluorite deposit. On the basis of a combination of geological background information and fluorite geochemistry, a new classification scheme is proposed.展开更多
Intracranial hypotension (ICH) is a benign syndrome which is often under-diagnosed. It is characterized by orthostatic headache which is predominantly occipital. ICH is diagnosed in the presence of a typical history a...Intracranial hypotension (ICH) is a benign syndrome which is often under-diagnosed. It is characterized by orthostatic headache which is predominantly occipital. ICH is diagnosed in the presence of a typical history and characteristic imaging findings. Further confirmation by lumbar puncture to document low CSF pressure might be necessary in some cases. Treatment is mainly conservative in the form of bed rest and intravenous saline infusion. However, surgical intervention may be required if conservative measures fail. In this report we presented a case of 42-year-old male patient who presented with symptoms of orthostatic occipital headache of three-month duration and was subsequently diagnosed with intracranial hypotension based on characteristic MRI findings of pachymeningeal enhancement on gadolinium enhanced MRI of the brain with sagging of the mid-brain.展开更多
High photovoltages and power conversion efciencies of perovskite solar cells(PSCs)can be realized by controlling the undesired nonradiative charge carrier recombination.Here,we introduce a judicious amount of guanidin...High photovoltages and power conversion efciencies of perovskite solar cells(PSCs)can be realized by controlling the undesired nonradiative charge carrier recombination.Here,we introduce a judicious amount of guanidinium iodide into mixed-cation and mixed-halide perovskite flms to suppress the parasitic charge carrier recombination,which enabled the fabrication of>20%efcient and operationally stable PSCs yielding reproducible photovoltageas high as 1.20 V.By introducing guanidinium iodide into the perovskite precursor solution,the bandgap of the resulting absorber material changed minimally;however,the nonradiative recombination diminished considerably as revealed by time-resolved photoluminescence and electroluminescence studies.Furthermore,using capacitance-frequency measurements,we were able to correlate the hysteresis features exhibited by the PSCs with interfacial charge accumulation.Tis study opens up a path to realize new record efciencies for PSCs based on guanidinium iodide doped perovskite flms.展开更多
文摘Fluorite deposits occur in a variety of geologic environments throughout the globe. It may occur as the main or only economically recoverable ore mineral in deposits or may present as the accessory gangue minerals with other ores. It is therefore necessary to understand various genetic types of the fluorite deposit. The present paper synthesises the information of some of the known fluorite mineralisation from the world so that an understanding of them can help in establishing reliable criteria for further search of fluorite deposit. On the basis of a combination of geological background information and fluorite geochemistry, a new classification scheme is proposed.
文摘Intracranial hypotension (ICH) is a benign syndrome which is often under-diagnosed. It is characterized by orthostatic headache which is predominantly occipital. ICH is diagnosed in the presence of a typical history and characteristic imaging findings. Further confirmation by lumbar puncture to document low CSF pressure might be necessary in some cases. Treatment is mainly conservative in the form of bed rest and intravenous saline infusion. However, surgical intervention may be required if conservative measures fail. In this report we presented a case of 42-year-old male patient who presented with symptoms of orthostatic occipital headache of three-month duration and was subsequently diagnosed with intracranial hypotension based on characteristic MRI findings of pachymeningeal enhancement on gadolinium enhanced MRI of the brain with sagging of the mid-brain.
基金Essa A.Alharbi gratefully acknowledges King Abdulaziz City for Science and Technology(KACST)for the fellowship.M.Ibrahim Dar acknowledges the fnancial support from the Swiss National Science Foundation under the project number P300P2174471M.Ibrahim Dar,Shaik M.Zakeeruddin,Wolfgang Tress,and Michael Gratzel thank the King Abdulaziz City for Science and Technology(KACST)for fnancial support.Neha Arora gratefully acknowledges fnancial support from Greatcell Solar.
文摘High photovoltages and power conversion efciencies of perovskite solar cells(PSCs)can be realized by controlling the undesired nonradiative charge carrier recombination.Here,we introduce a judicious amount of guanidinium iodide into mixed-cation and mixed-halide perovskite flms to suppress the parasitic charge carrier recombination,which enabled the fabrication of>20%efcient and operationally stable PSCs yielding reproducible photovoltageas high as 1.20 V.By introducing guanidinium iodide into the perovskite precursor solution,the bandgap of the resulting absorber material changed minimally;however,the nonradiative recombination diminished considerably as revealed by time-resolved photoluminescence and electroluminescence studies.Furthermore,using capacitance-frequency measurements,we were able to correlate the hysteresis features exhibited by the PSCs with interfacial charge accumulation.Tis study opens up a path to realize new record efciencies for PSCs based on guanidinium iodide doped perovskite flms.
