GaN-based laser diodes(LDs)extend the wavelength of semiconductor LDs into the visible and ultraviolet spectrum ranges,and are therefore expected to be widely used in quantum technology,bio&medical instruments,las...GaN-based laser diodes(LDs)extend the wavelength of semiconductor LDs into the visible and ultraviolet spectrum ranges,and are therefore expected to be widely used in quantum technology,bio&medical instruments,laser displays,lighting and materials processing.The development of blue and green LDs is still challenging,even though they are based on the sameⅢ-nitride materials as GaN-based lightemitting diodes.The challenges and progress of GaN-based blue and green LDs are reviewed from the aspects of epitaxial growth and layer structure design.Due to large differences in lattice constants and growth conditions for InN,GaN,and AlN,considerable effort is required to improve the quality of InGaN multiple quantum well(MQW)gain medium for blue and especially green LDs.p-type doping profiles,conditions and layer structures are critical to reduce the internal losses and to mitigate the degradation of InGaN MQWs.Hole injection is also a key issue for GaN-based LDs.展开更多
BACKGROUND Cupping therapy is used across the globe since ancient Egypt.It is used as a complementary or alternative to daily clinical practice.Cupping therapy could be dry or wet(Al-hijamah)type.It is considered a re...BACKGROUND Cupping therapy is used across the globe since ancient Egypt.It is used as a complementary or alternative to daily clinical practice.Cupping therapy could be dry or wet(Al-hijamah)type.It is considered a relatively safe procedure for a variety of clinical problems like lower backache,shoulder pain,neck pain,headache,and migraine.Application of cupping therapy over body orifices is contraindicated.CASE SUMMARY A 27-year-old gentleman presented with sudden left-sided hearing loss and tinnitus for 7 d.He gave a history of upper respiratory tract infection 14 d before his complaints.He received Al-hijamah over his left ear 3 d before seeking advice from the Otolaryngology clinic,but without benefit.Physical examination showed a dull-looking left ear drum,hemotympanum in the posterior part of the tympanic cavity,two blood clots over the eardrum,and multiple bleeding points over the external ear canal and tympanic membrane.A pure tone audiogram and tympanogram confirmed the diagnosis of middle ear effusion.Conservative treatment(avoidance of water entry,antibiotics,and local and systemic decongestants)was given for 5 d.The presenting symptoms as well as ear injuries resolved completely two weeks after the follow-up.CONCLUSION We do not recommend using Al-hijamah directly over the ear as a treatment option for hearing loss to avoid unwanted ear trauma as well as there is no benefit from this kind of treatment.展开更多
采用陶瓷工艺制备了 Al 替代的 Ni0．5 Zn0．5 Alx Fe2-x O 4（x ＝0～0．10）铁氧体材料,用 XRD、B-H分析仪和阻抗分析仪对其结构和磁性能进行了研究.实验发现,最佳烧结温度为1250℃,过高和过低的烧结温度不利于降低磁芯损耗.当 Al3＋...采用陶瓷工艺制备了 Al 替代的 Ni0．5 Zn0．5 Alx Fe2-x O 4（x ＝0～0．10）铁氧体材料,用 XRD、B-H分析仪和阻抗分析仪对其结构和磁性能进行了研究.实验发现,最佳烧结温度为1250℃,过高和过低的烧结温度不利于降低磁芯损耗.当 Al3＋替代量 x ＝0．06时,铁氧体能获得较好综合磁性能.展开更多
基金financially supported by the National Key Research and Development Program of China(2016YFB0401803,2017YFE0131500 and 2017YFB0405000)National Natural Science Foundation of China(61834008,61574160,61804164,and 61704184)+1 种基金Natural Science Foundation of Jiangsu province(BK20180254)China Postdoctoral Science Foundation(2018M630619)。
文摘GaN-based laser diodes(LDs)extend the wavelength of semiconductor LDs into the visible and ultraviolet spectrum ranges,and are therefore expected to be widely used in quantum technology,bio&medical instruments,laser displays,lighting and materials processing.The development of blue and green LDs is still challenging,even though they are based on the sameⅢ-nitride materials as GaN-based lightemitting diodes.The challenges and progress of GaN-based blue and green LDs are reviewed from the aspects of epitaxial growth and layer structure design.Due to large differences in lattice constants and growth conditions for InN,GaN,and AlN,considerable effort is required to improve the quality of InGaN multiple quantum well(MQW)gain medium for blue and especially green LDs.p-type doping profiles,conditions and layer structures are critical to reduce the internal losses and to mitigate the degradation of InGaN MQWs.Hole injection is also a key issue for GaN-based LDs.
文摘BACKGROUND Cupping therapy is used across the globe since ancient Egypt.It is used as a complementary or alternative to daily clinical practice.Cupping therapy could be dry or wet(Al-hijamah)type.It is considered a relatively safe procedure for a variety of clinical problems like lower backache,shoulder pain,neck pain,headache,and migraine.Application of cupping therapy over body orifices is contraindicated.CASE SUMMARY A 27-year-old gentleman presented with sudden left-sided hearing loss and tinnitus for 7 d.He gave a history of upper respiratory tract infection 14 d before his complaints.He received Al-hijamah over his left ear 3 d before seeking advice from the Otolaryngology clinic,but without benefit.Physical examination showed a dull-looking left ear drum,hemotympanum in the posterior part of the tympanic cavity,two blood clots over the eardrum,and multiple bleeding points over the external ear canal and tympanic membrane.A pure tone audiogram and tympanogram confirmed the diagnosis of middle ear effusion.Conservative treatment(avoidance of water entry,antibiotics,and local and systemic decongestants)was given for 5 d.The presenting symptoms as well as ear injuries resolved completely two weeks after the follow-up.CONCLUSION We do not recommend using Al-hijamah directly over the ear as a treatment option for hearing loss to avoid unwanted ear trauma as well as there is no benefit from this kind of treatment.
基金National Natural Science Foundation of China(51975286)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX18_0272)+1 种基金Opening Project of Jiangsu Key Laboratory of Advanced Metallic MaterialsPriority Academic Program Development of Jiangsu Higher Education Institution。
文摘采用陶瓷工艺制备了 Al 替代的 Ni0．5 Zn0．5 Alx Fe2-x O 4（x ＝0～0．10）铁氧体材料,用 XRD、B-H分析仪和阻抗分析仪对其结构和磁性能进行了研究.实验发现,最佳烧结温度为1250℃,过高和过低的烧结温度不利于降低磁芯损耗.当 Al3＋替代量 x ＝0．06时,铁氧体能获得较好综合磁性能.
