不间断电源(Uninterruptible Power Supply,UPS)是广播电视发射台进行信号传输的关键部分,也是广播电视发射台的重要组成部分。UPS可以保证广播电视发射台不间断供电,保障电视节目顺利播出。广播电视发射台应高度重视UPS的管理维修工作...不间断电源(Uninterruptible Power Supply,UPS)是广播电视发射台进行信号传输的关键部分,也是广播电视发射台的重要组成部分。UPS可以保证广播电视发射台不间断供电,保障电视节目顺利播出。广播电视发射台应高度重视UPS的管理维修工作,加强对智能UPS的研究,充分发挥智能UPS在广播电视发射台中的应用价值。从UPS的相关概述入手,分析UPS系统设计,针对智能UPS在广播电视发射台中应用时存在的常见问题提出针对性的解决策略。展开更多
Background. Lichen sclerosus (LS) is characterized histologically by an inflammatory T-cell infiltrate, sclerosis and thickening of the dermis, and epidermal atrophy. Ultraviolet (UV) A1 therapy has been shown to be e...Background. Lichen sclerosus (LS) is characterized histologically by an inflammatory T-cell infiltrate, sclerosis and thickening of the dermis, and epidermal atrophy. Ultraviolet (UV) A1 therapy has been shown to be effective in the management of morphea and scleroderma, diseases that have some histological and clinical similarities with LS, and more recently in extragenital LS. Aim. To determine the effectiveness of UVA1 therapy for genital LS. Methods. Seven women with severe genital LS uncontrolled by ultrapotent topical corticosteroids, with a median age of 62 years (range 48-78) and disease duration of 6-47 years, were treated with UVA1 therapy from a high output source. After completion of UVA1 therapy, a clinician and the patient graded the overall response of symptoms and physical signs. Results. Five patients improved with therapy. Three obtained moderate improvement in overall disease severity and two had minimal improvement. Of these five, one relapsed within 3 months and another after a year. Both had a further course of UVA1 therapy, resulting in minimal improvement in one and moderate improvement in the other. In the remaining three, disease severity had improved to a point where intermittent use of topical corticosteroids resulted in acceptable control. Discussion. UVA1 therapy may be of benefit in the management of vulval LS, a disease that is often poorly responsive to standard therapies. The therapy is well tolerated and could provide an acceptable therapeutic option for patients with severe disease.展开更多
The UPS （uninterruptible power supplies） are essential power infrastructure components of systems designed for critical application, including data centers. High availability achievement is a very important factor r...The UPS （uninterruptible power supplies） are essential power infrastructure components of systems designed for critical application, including data centers. High availability achievement is a very important factor related to UPS performance, consequently to proper critical application functionality. Generally, UPS have a limited input voltage window, referring to the nominal input voltage value. Goal of this paper is to prove larger voltage window, without affecting normal UPS operation. Larger window will result on less commutation, backup and normal mode reduction, and consequently duty time of batteries reduction, too. Thus, under these conditions, it is to be expected availability improvement. The stabilizing node model, applied at UPS＇s control part through this paper is presented. UPS＇s behavior with an implemented stabilizing node is observed at few sites. In order to analyze and conclude about UPS＇s performance under these technical conditions, simulation results are further presented.展开更多
The adapted DC-DC converters should be smaller in size and have a small output current ripple to meet the increasing demand for low voltages with high performance and high density micro processors for several microele...The adapted DC-DC converters should be smaller in size and have a small output current ripple to meet the increasing demand for low voltages with high performance and high density micro processors for several microelectronic load applications. This paper proposes a DC-DC converter using variable on-time and variable switching frequency control enhanced constant ripple current control and reduced magnetic components. The proposed converter is realized by making the turn-offtime proportional to the on-time of the converter, according to the input and output voltage, thereby reducing the corresponding current ripple on output voltage in the continuous conduction mode. A Buck DC-DC converter using the proposed control strategy is analyzed in detail, along with some experimental results to show the performance and effectiveness of this converter.展开更多
In the presence of applied magnetic fields H such that |lnε|《H《1/ε2,the author evaluates the minimal Ginzburg-Landau energy with discontinuous constraint.Its expression is analogous to the work of Sandier and Serf...In the presence of applied magnetic fields H such that |lnε|《H《1/ε2,the author evaluates the minimal Ginzburg-Landau energy with discontinuous constraint.Its expression is analogous to the work of Sandier and Serfaty.展开更多
文摘不间断电源(Uninterruptible Power Supply,UPS)是广播电视发射台进行信号传输的关键部分,也是广播电视发射台的重要组成部分。UPS可以保证广播电视发射台不间断供电,保障电视节目顺利播出。广播电视发射台应高度重视UPS的管理维修工作,加强对智能UPS的研究,充分发挥智能UPS在广播电视发射台中的应用价值。从UPS的相关概述入手,分析UPS系统设计,针对智能UPS在广播电视发射台中应用时存在的常见问题提出针对性的解决策略。
文摘Background. Lichen sclerosus (LS) is characterized histologically by an inflammatory T-cell infiltrate, sclerosis and thickening of the dermis, and epidermal atrophy. Ultraviolet (UV) A1 therapy has been shown to be effective in the management of morphea and scleroderma, diseases that have some histological and clinical similarities with LS, and more recently in extragenital LS. Aim. To determine the effectiveness of UVA1 therapy for genital LS. Methods. Seven women with severe genital LS uncontrolled by ultrapotent topical corticosteroids, with a median age of 62 years (range 48-78) and disease duration of 6-47 years, were treated with UVA1 therapy from a high output source. After completion of UVA1 therapy, a clinician and the patient graded the overall response of symptoms and physical signs. Results. Five patients improved with therapy. Three obtained moderate improvement in overall disease severity and two had minimal improvement. Of these five, one relapsed within 3 months and another after a year. Both had a further course of UVA1 therapy, resulting in minimal improvement in one and moderate improvement in the other. In the remaining three, disease severity had improved to a point where intermittent use of topical corticosteroids resulted in acceptable control. Discussion. UVA1 therapy may be of benefit in the management of vulval LS, a disease that is often poorly responsive to standard therapies. The therapy is well tolerated and could provide an acceptable therapeutic option for patients with severe disease.
文摘The UPS （uninterruptible power supplies） are essential power infrastructure components of systems designed for critical application, including data centers. High availability achievement is a very important factor related to UPS performance, consequently to proper critical application functionality. Generally, UPS have a limited input voltage window, referring to the nominal input voltage value. Goal of this paper is to prove larger voltage window, without affecting normal UPS operation. Larger window will result on less commutation, backup and normal mode reduction, and consequently duty time of batteries reduction, too. Thus, under these conditions, it is to be expected availability improvement. The stabilizing node model, applied at UPS＇s control part through this paper is presented. UPS＇s behavior with an implemented stabilizing node is observed at few sites. In order to analyze and conclude about UPS＇s performance under these technical conditions, simulation results are further presented.
文摘The adapted DC-DC converters should be smaller in size and have a small output current ripple to meet the increasing demand for low voltages with high performance and high density micro processors for several microelectronic load applications. This paper proposes a DC-DC converter using variable on-time and variable switching frequency control enhanced constant ripple current control and reduced magnetic components. The proposed converter is realized by making the turn-offtime proportional to the on-time of the converter, according to the input and output voltage, thereby reducing the corresponding current ripple on output voltage in the continuous conduction mode. A Buck DC-DC converter using the proposed control strategy is analyzed in detail, along with some experimental results to show the performance and effectiveness of this converter.
文摘In the presence of applied magnetic fields H such that |lnε|《H《1/ε2,the author evaluates the minimal Ginzburg-Landau energy with discontinuous constraint.Its expression is analogous to the work of Sandier and Serfaty.
