Coherent beam combining(CBC)is an efficient way to scale the brightness of laser arrays.We demonstrate the active phase locking CBC of two slab laser amplifiers based on the multi-dithering technique.The experimental ...Coherent beam combining(CBC)is an efficient way to scale the brightness of laser arrays.We demonstrate the active phase locking CBC of two slab laser amplifiers based on the multi-dithering technique.The experimental investigation on the 102 W coherent beam combining of two slab amplifiers shows that the whole system in a closed loop performs well over a long time observation.The contrast of the coherent combined beam profile is about 87%and the combining efficiency is nearly 85%.In addition,the CBC of two green lasers is realized based on the second-harmonic generation of the phase locking pump lasers.To the best of our knowledge,this is the first report about second-harmonic active phase locking,which indicates further potential applications of CBC.展开更多
Condition based maintenance(CBM) is one of the solutions to machinery maintenance requirements. Latest approaches to CBM aim at reducing human engagement in the real-time fault detection and decision making. Machine l...Condition based maintenance(CBM) is one of the solutions to machinery maintenance requirements. Latest approaches to CBM aim at reducing human engagement in the real-time fault detection and decision making. Machine learning techniques like fuzzy-logic-based systems, neural networks, and support vector machines help to reduce human involvement. Most of these techniques provide fault information with 100% confidence. It is undeniably apparent that this area has a vast application scope. To facilitate future exploration, this review is presented describing the centrifugal pump faults, the signals they generate, their CBM based diagnostic schemes, and case studies for blockage and cavitation fault detection in centrifugal pump(CP) by performing the experiment on test rig. The classification accuracy is above 98% for fault detection. This review gives a head-start to new researchers in this field and identifies the un-touched areas pertaining to CP fault diagnosis.展开更多
The integration of solar and wind energy into the electrical grid has received global research attention due to their unpredictable characteristics.Because wind energy varies across all timescales of utility activity,...The integration of solar and wind energy into the electrical grid has received global research attention due to their unpredictable characteristics.Because wind energy varies across all timescales of utility activity,renewable energy generation should be supplemented and enhanced,from real-time,minute-to-minute variations to annual alterations influencing long-termstrategy.Wind energy generation does not only fluctuate but is also challenging to accurately forecast the timeframes of significance to electricity decision makers;day-ahead and long-term making plans of framework sufficiency such as meeting the network peak load annually.A utility that integrates wind and solar energy into its electricity mix would understand how to adapt to uncertainty and variability in operations while sustaining grid stability.Due to hydropower’s adaptability,a system using hydropower as one of its generating resources could be precisely adapted to absorb the variability of wind and solar energy.The objective of this research study is to create a hybrid system comprising hydro-wind and solar(Hybrid-HWS)integration for power balancing in an isolated electrical network in Klipkop village,Pretoria region,South Africa.The desirability of designing and building goaf storage tank in regard to capability,the fullness of line throughoutwater pumping,dispensing,storage tank spillage,and pressure difference throughout liquid flow within the storage tanks were preliminary assessed using geotechnical and weather forecasting data from a distinctive area of Klipkop town in Pretoria,South Africa.Different facility hours premised on daylight accessibility are scheduled to balance maximum load at early and late hours.However,in the scenario of electrical power,time shift requiring storage for extended periods of time,such as in terms of hours,Hybrid-HWS has been found to have a crucial role.The results of simulations showed a coordinated process design for Hybrid-HWS Energy Storage(ES)to determine everyday strategic planning in reducing the variability of the system resulting from wind-solar-pumped hydro ES output inadequacies and satisfy daily load demands.It could be recommended that by considering the adaptability characteristics,extremely rapidly,ramping,peaking support and maximum stabilizing aid of the system could be archived with pump-hydro into the energy mix which can provide specific guidelines for energy policymakers.展开更多
胰腺癌是一种具有高度侵袭性的肿瘤,嗜神经生长是胰腺癌的重要生物学特点,其对神经的侵犯给患者带来极大的疼痛负担,严重影响患者生存质量和生存意志。世界卫生组织(World Health Organization,WHO)癌痛“三阶梯镇痛原则”是传统治疗癌...胰腺癌是一种具有高度侵袭性的肿瘤,嗜神经生长是胰腺癌的重要生物学特点,其对神经的侵犯给患者带来极大的疼痛负担,严重影响患者生存质量和生存意志。世界卫生组织(World Health Organization,WHO)癌痛“三阶梯镇痛原则”是传统治疗癌性疼痛的治疗方案,但由于其毒副作用明显、疗效差、易成瘾、易耐药以及医师临床用药不规范等因素,无法满足患者病情需要。近年来,随着介人技术的发展以及广泛的临床试验的开展,介入作为癌痛管理的“第四阶梯”,其治疗手段以及各种影像引导方式的发展与应用,如神经毁损术、^(125)I粒子植入术、患者自控镇痛泵技术、鞘内药物输注系统植入术等,临床疗效得到了有力证明,为癌痛患者提供了方便、安全、有效的治疗方式。展开更多
An effective method for the improvement of the characteristics of an erbium-doped L-band superfluorescent fiber source(SFS)is demonstrated using an unpumped erbium-doped fiber(EDF).With a suitable length of unpumped E...An effective method for the improvement of the characteristics of an erbium-doped L-band superfluorescent fiber source(SFS)is demonstrated using an unpumped erbium-doped fiber(EDF).With a suitable length of unpumped EDF section in the single-forward pumped configuration,broadening of the L-band spectral linewidth is achieved and the variation of mean wavelength versus pump power is eliminated.A mean wavelength stable L-band SFS with a spectral linewidth of 50.2 nm and an output power of 60.2 mW is obtained experimentally.The method of using unpumped EDF enables one to offer a stable and wideband L-band SFS with high flexibility and to overcome the shortcomings of the synchronous pumping technique.展开更多
基金by the Innovation Foundation for Graduates in National University of Defense Technology under Grant B090704the Hunan Provincial Innovation Foundation For Postgraduate(No CX2009B006).
文摘Coherent beam combining(CBC)is an efficient way to scale the brightness of laser arrays.We demonstrate the active phase locking CBC of two slab laser amplifiers based on the multi-dithering technique.The experimental investigation on the 102 W coherent beam combining of two slab amplifiers shows that the whole system in a closed loop performs well over a long time observation.The contrast of the coherent combined beam profile is about 87%and the combining efficiency is nearly 85%.In addition,the CBC of two green lasers is realized based on the second-harmonic generation of the phase locking pump lasers.To the best of our knowledge,this is the first report about second-harmonic active phase locking,which indicates further potential applications of CBC.
文摘Condition based maintenance(CBM) is one of the solutions to machinery maintenance requirements. Latest approaches to CBM aim at reducing human engagement in the real-time fault detection and decision making. Machine learning techniques like fuzzy-logic-based systems, neural networks, and support vector machines help to reduce human involvement. Most of these techniques provide fault information with 100% confidence. It is undeniably apparent that this area has a vast application scope. To facilitate future exploration, this review is presented describing the centrifugal pump faults, the signals they generate, their CBM based diagnostic schemes, and case studies for blockage and cavitation fault detection in centrifugal pump(CP) by performing the experiment on test rig. The classification accuracy is above 98% for fault detection. This review gives a head-start to new researchers in this field and identifies the un-touched areas pertaining to CP fault diagnosis.
基金This study was supported by the DUT Scholarship Scheme Masters:2022(RFA Smart Grid)Funding.
文摘The integration of solar and wind energy into the electrical grid has received global research attention due to their unpredictable characteristics.Because wind energy varies across all timescales of utility activity,renewable energy generation should be supplemented and enhanced,from real-time,minute-to-minute variations to annual alterations influencing long-termstrategy.Wind energy generation does not only fluctuate but is also challenging to accurately forecast the timeframes of significance to electricity decision makers;day-ahead and long-term making plans of framework sufficiency such as meeting the network peak load annually.A utility that integrates wind and solar energy into its electricity mix would understand how to adapt to uncertainty and variability in operations while sustaining grid stability.Due to hydropower’s adaptability,a system using hydropower as one of its generating resources could be precisely adapted to absorb the variability of wind and solar energy.The objective of this research study is to create a hybrid system comprising hydro-wind and solar(Hybrid-HWS)integration for power balancing in an isolated electrical network in Klipkop village,Pretoria region,South Africa.The desirability of designing and building goaf storage tank in regard to capability,the fullness of line throughoutwater pumping,dispensing,storage tank spillage,and pressure difference throughout liquid flow within the storage tanks were preliminary assessed using geotechnical and weather forecasting data from a distinctive area of Klipkop town in Pretoria,South Africa.Different facility hours premised on daylight accessibility are scheduled to balance maximum load at early and late hours.However,in the scenario of electrical power,time shift requiring storage for extended periods of time,such as in terms of hours,Hybrid-HWS has been found to have a crucial role.The results of simulations showed a coordinated process design for Hybrid-HWS Energy Storage(ES)to determine everyday strategic planning in reducing the variability of the system resulting from wind-solar-pumped hydro ES output inadequacies and satisfy daily load demands.It could be recommended that by considering the adaptability characteristics,extremely rapidly,ramping,peaking support and maximum stabilizing aid of the system could be archived with pump-hydro into the energy mix which can provide specific guidelines for energy policymakers.
文摘胰腺癌是一种具有高度侵袭性的肿瘤,嗜神经生长是胰腺癌的重要生物学特点,其对神经的侵犯给患者带来极大的疼痛负担,严重影响患者生存质量和生存意志。世界卫生组织(World Health Organization,WHO)癌痛“三阶梯镇痛原则”是传统治疗癌性疼痛的治疗方案,但由于其毒副作用明显、疗效差、易成瘾、易耐药以及医师临床用药不规范等因素,无法满足患者病情需要。近年来,随着介人技术的发展以及广泛的临床试验的开展,介入作为癌痛管理的“第四阶梯”,其治疗手段以及各种影像引导方式的发展与应用,如神经毁损术、^(125)I粒子植入术、患者自控镇痛泵技术、鞘内药物输注系统植入术等,临床疗效得到了有力证明,为癌痛患者提供了方便、安全、有效的治疗方式。
基金Supported by the National Natural Science Foundation of China under Grant No 61108019the Fujian Provincial Natural Science Foundation of China under Grant No 2011J01368.
文摘An effective method for the improvement of the characteristics of an erbium-doped L-band superfluorescent fiber source(SFS)is demonstrated using an unpumped erbium-doped fiber(EDF).With a suitable length of unpumped EDF section in the single-forward pumped configuration,broadening of the L-band spectral linewidth is achieved and the variation of mean wavelength versus pump power is eliminated.A mean wavelength stable L-band SFS with a spectral linewidth of 50.2 nm and an output power of 60.2 mW is obtained experimentally.The method of using unpumped EDF enables one to offer a stable and wideband L-band SFS with high flexibility and to overcome the shortcomings of the synchronous pumping technique.
