This article establishes several new geometric inequalities, which refer to the lengthes of the edges of a simplex and interior point, height, lateral area, and the circumradius of another simplex.
The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. An inequality is established, which reveals that the difference between the squared circumradius of the...The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. An inequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex and the squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not less than the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is a tangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that the circumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship between the circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex.展开更多
Recent increases in infectious diseases affecting the central nervous system have raised concerns about their role in neuroinflammation and neurodegeneration.Viral pathogens or their products can invade the central ne...Recent increases in infectious diseases affecting the central nervous system have raised concerns about their role in neuroinflammation and neurodegeneration.Viral pathogens or their products can invade the central nervous system and cause damage,leading to meningitis,encephalitis,meningoencephalitis,myelitis,or post-infectious demyelinating diseases.Although neuroinflammation initially has a protective function,chronic inflammation can contribute to the development of neurodegenerative diseases.Mechanisms such as protein aggregation and cellular disturbances are implicated with specific viruses such as herpes simplex virus type 1 and Epstein-Barr virus being associated with Alzheimer's disease and multiple sclerosis,respectively.Extracellular nucleotides,particularly adenosine triphosphate and its metabolites are released from activated,infected,and dying cells,acting as alarmins mediating neuroinflammation and neurodegeneration.When viruses infect central nervous system cells,adenosine triphosphate is released as an alarmin,triggering inflammatory responses.This process is mediated by purinergic receptors,divided into two families:P1,which responds to adenosine,and P2,activated by adenosine triphosphate and other nucleotides.This review highlights how specific viruses,such as human immunodeficiency virus type 1,Theiler's murine encephalomyelitis virus,herpes simplex virus type 1,Epstein-Barr virus,dengue virus,Zika virus,and severe acute respiratory syndrome coronavirus 2,can initiate inflammatory responses through the release of extracellular nucleotides,particularly adenosine triphosphate,which act as critical mediators in the progression of neuroinflammation and neurodegenerative disorders.A better understanding of purinergic signaling pathways in these diseases may suggest new potential therapeutic strategies for targeting neuroinflammation to mitigate the long-term consequences of viral infections in the central nervous system.展开更多
Several experimental evidence suggests a link between brain Herpes simplex virus type-1 infection and the occurrence of Alzheimer’s disease.However,the molecular mechanisms underlying this association are not complet...Several experimental evidence suggests a link between brain Herpes simplex virus type-1 infection and the occurrence of Alzheimer’s disease.However,the molecular mechanisms underlying this association are not completely understood.Among the molecular mediators of synaptic and cognitive dysfunction occurring after Herpes simplex virus type-1 infection and reactivation in the brain neuroinflammatory cytokines seem to occupy a central role.Here,we specifically reviewed literature reports dealing with the impact of neuroinflammation on synaptic dysfunction observed after recurrent Herpes simplex virus type-1 reactivation in the brain,highlighting the role of interleukins and,in particular,interleukin 1βas a possible target against Herpes simplex virus type-1-induced neuronal dysfunctions.展开更多
BACKGROUND Aseptic meningitis is defined as meningeal inflammation caused by various etio-logies with negative cerebrospinal fluid(CSF)bacterial culture.The most common etiologies are viruses[enteroviruses,arboviruses...BACKGROUND Aseptic meningitis is defined as meningeal inflammation caused by various etio-logies with negative cerebrospinal fluid(CSF)bacterial culture.The most common etiologies are viruses[enteroviruses,arboviruses,and herpes simplex virus type 2(HSV-2)].Aseptic meningitis can have various presentations,including sensori-neural deafness.While sensorineural deafness from mumps meningoencephalitis has been reported,cases of HSV-2-induced hearing loss are rare.Herein,we re-port a case of HSV-2-induced meningitis that presented with sudden deafness.CASE SUMMARY A 68-year-old man experienced a profound sudden onset of left-sided hearing loss for one day.Pure-tone audiograms demonstrated sudden left-sided sensorineural hearing loss(thresholds 80-90 dB).After treatment with high-dose steroids for 1 week,he experienced an acute consciousness change with left hemiparesis.The laboratory data showed no significant abnormalities.Brain computed tomography without contrast and magnetic resonance imaging revealed no intracranial hemo-rrhage or obvious brain lesion.The CSF analysis and the Multiplex PCR panels showed HSV-2 positivity.Hence,under the diagnosis of herpes meningoenceph-alitis,acyclovir was prescribed and his symptoms gradually resolved.CONCLUSION This case report further demonstrates that a viral infection could be a cause of sudden sensorineural hearing loss.展开更多
Quercetin is a natural compound with potent antiviral effects;however,its role in the treatment of herpes simplex keratitis(HSK)remains underexplored.Here,we investigated the antiviral effects of quercetin against her...Quercetin is a natural compound with potent antiviral effects;however,its role in the treatment of herpes simplex keratitis(HSK)remains underexplored.Here,we investigated the antiviral effects of quercetin against herpes simplex virus 1(HSV-1).By examining different phases of viral infection in human corneal epithelial cells(HCECs),we found that 30μmol/L quercetin inhibits HSV-1 replication primarily by disrupting viral attachment.RNA-sequencing and subsequent analyses revealed that the nuclear factor E2-related factor 2(Nrf2)was upregulated by quercetin in a dose-dependent manner.Knocking down Nrf2 partially compromised quercetin's antiviral effect.Importantly,topical application of 100μmol/L quercetin alleviated HSK severity in mice,reduced viral titers in tears,and inhibited VP16 expression in the cornea and trigeminal ganglia.These findings demonstrate the antiviral effect of quercetin against HSV-1 and provide a foundation for mechanistic studies to elucidate its therapeutic potential in HSK.展开更多
With the promotion of potatoes as a staple food,the challenge lies in integrating them into traditional staple grain-based diets.As the primary component of grains,starch plays a crucial role,and its interactions with...With the promotion of potatoes as a staple food,the challenge lies in integrating them into traditional staple grain-based diets.As the primary component of grains,starch plays a crucial role,and its interactions with other heterogeneous starches could significantly influence their functional properties.Therefore,this study aimed to explore the role of substitution ratio(SR,0–100%)of potato starch(PS)in the compatibility with wheat starch(WS)from the perspective of microstructure and physicochemical characteristics using the simplex-centroid method.Results of scaning electron microscopy(SEM)revealed the network structure in SR 30%of PS possessed the smallest size and the most compact gel structure.A higher SR of PS increased the solubility and swelling power of the blended WS and improved its freeze-thaw stability.Peak viscosity and gel hardness of the blended WS exhibited an increasing trend as the SR of PS increased.With the increasing SR of PS,the blended WS exhibited an increased tanδvalue with decreased viscous and elastic moduli.There is a non-additive effect between PS and WS,which should be responsible for their difference between experimental and theoretical values.These findings could provide a new direction for understanding the compatibility interactions between different starches,and provide a theoretical guidance for the development of PS-based foods with desirable properties.展开更多
This article briefly reviews the topic of complex network synchronization,with its graph-theoretic criterion,showing that the homogeneous and symmetrical network structures are essential for optimal synchronization.Fu...This article briefly reviews the topic of complex network synchronization,with its graph-theoretic criterion,showing that the homogeneous and symmetrical network structures are essential for optimal synchronization.Furthermore,it briefly reviews the notion of higher-order network topologies and shows their promising potential in application to evaluating the optimality of network synchronizability.展开更多
The Grey Wolf Optimization(GWO)algorithm is acknowledged as an effective method for rock acoustic emission localization.However,the conventional GWO algorithm encounters challenges related to solution accuracy and con...The Grey Wolf Optimization(GWO)algorithm is acknowledged as an effective method for rock acoustic emission localization.However,the conventional GWO algorithm encounters challenges related to solution accuracy and convergence speed.To address these concerns,this paper develops a Simplex Improved Grey Wolf Optimizer(SMIGWO)algorithm.The randomly generating initial populations are replaced with the iterative chaotic sequences.The search process is optimized using the convergence factor optimization algorithm based on the inverse incompleteГfunction.The simplex method is utilized to address issues related to poorly positioned grey wolves.Experimental results demonstrate that,compared to the conventional GWO algorithm-based AE localization algorithm,the proposed algorithm achieves a higher solution accuracy and showcases a shorter search time.Additionally,the algorithm demonstrates fewer convergence steps,indicating superior convergence efficiency.These findings highlight that the proposed SMIGWO algorithm offers enhanced solution accuracy,stability,and optimization performance.The benefits of the SMIGWO algorithm extend universally across various materials,such as aluminum,granite,and sandstone,showcasing consistent effectiveness irrespective of material type.Consequently,this algorithm emerges as a highly effective tool for identifying acoustic emission signals and improving the precision of rock acoustic emission localization.展开更多
Viral infections of the ocular surface significantly contribute to morbidity and visual impairment globally.The herpes simplex virus(HSV),adenovirus,cytomegalovirus(CMV),and human papillomavirus(HPV)are predominant pa...Viral infections of the ocular surface significantly contribute to morbidity and visual impairment globally.The herpes simplex virus(HSV),adenovirus,cytomegalovirus(CMV),and human papillomavirus(HPV)are predominant pathogens impacting the cornea and conjunctiva,resulting in recurrent illness,epidemic outbreaks,and virus-associated neoplasia.Progress in virology,immunology,and molecular diagnostics has enhanced comprehension of host–virus interactions and introduced novel therapeutic opportunities.A narrative literature review was performed utilizing PubMed,Scopus,and Web of Science,encompassing papers published from 2000 to 2025,with a specific focus on research from 2020 onwards.Eligible publications were peer-reviewed clinical and experimental investigations,together with reviews that focused on epidemiology,etiology,diagnostic methodologies,and therapeutic alternatives.Research indicates that HSV keratitis is the predominant infectious cause of corneal blindness in high-income nations,although adenovirus persists in instigating epidemics of keratoconjunctivitis in the absence of licensed antiviral treatments.CMV keratitis,previously confined to immunocompromised persons,is now acknowledged in immunocompetent patients as a causative agent of corneal endotheliitis.HPV is associated with ocular surface squamous neoplasia,especially in areas with elevated ultraviolet exposure and high human immunodeficiency virus prevalence.Innovative molecular diagnostics,innovative antiviral agents,immunomodulatory approaches,and immunization initiatives signify significant progress that could enhance preventative and therapeutic results.展开更多
Viral reproductive tract infections(VRTIs)are a significant global health concern with severe consequences,including infertility,chronic pelvic pain,and increased risk of HIV transmission.Complex interplay between pat...Viral reproductive tract infections(VRTIs)are a significant global health concern with severe consequences,including infertility,chronic pelvic pain,and increased risk of HIV transmission.Complex interplay between pathogens and the host immune system plays a critical role in the pathogenesis and treatment of VRTIs.This review aims to provide a comprehensive overview of the multifaceted roles of the immune system in both contributing to and combating VRTIs.The review will also address the consequent perturbations in immune homeostasis and the implications for disease manifestation and progression.The interrelation between systemic immunity and local immune responses is discussed,providing insights into the challenges and breakthroughs in managing these infections.By providing a comprehensive overview of the mechanisms,implications,and therapeutic strategies associated with viral reproductive tract infections and immune dysfunction,this review also informs future research and clinical practice in this important area of reproductive health.展开更多
为了改善高压直流系统的故障后的恢复性能,在研究低压限流单元(voltage dependent current order limiter,VDCOL)对直流系统无功功率消耗和电压稳定性影响的基础上,提出了一种分段变速率低压限流单元(piecewise-variable-rate VDCOL,PVR...为了改善高压直流系统的故障后的恢复性能,在研究低压限流单元(voltage dependent current order limiter,VDCOL)对直流系统无功功率消耗和电压稳定性影响的基础上,提出了一种分段变速率低压限流单元(piecewise-variable-rate VDCOL,PVR-VDCOL)的控制方法,该方法通过将电压下降或恢复过程划分为几个不同的阶段,并在每个阶段根据电压水平的不同而设置不同的功率恢复速率。推导了控制器初值的计算公式,制定了利用Simplex算法优化控制器参数的流程,并重点分析了分段数目对控制器性能的影响及其确定方法。在PSCAD/EMTDC中对提出的PVR-VDCOL和传统线性VDCOL的控制效果进行了对比仿真,并对不同分段数目下的仿真结果进行了对比分析,仿真结果表明提出的PVR-VDCOL能够有效改善直流系统的恢复性能。展开更多
基金Supported by the General Project of Education Department of Hunan Province(09C470)
文摘This article establishes several new geometric inequalities, which refer to the lengthes of the edges of a simplex and interior point, height, lateral area, and the circumradius of another simplex.
文摘The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. An inequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex and the squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not less than the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is a tangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that the circumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship between the circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex.
基金supported by funds from the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico do Brasil(CNPq)(312286/2023-6,307201/2023-6,and Instituto Nacional Saude Cerebral INSC,No.406020/2022-1)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior(CAPES)Fundacao de Amparo a Pesquisa do Estado do Rio de Janeiro-FAPERJ(E-26/010.002260/2019,E-26/010.001652/2019,E-26/010.101036/2018,E-26/202.774/2018,E-26/210.240/2020,E-26/211.138/2021,26/210.823/2021,E-26/211.325/2021,E-26/210.779/2021,E-26/201.086/2022,E-26/210.312/2022,E-26/203.262/2023,E-26/200.195/2023)(to LEBS)。
文摘Recent increases in infectious diseases affecting the central nervous system have raised concerns about their role in neuroinflammation and neurodegeneration.Viral pathogens or their products can invade the central nervous system and cause damage,leading to meningitis,encephalitis,meningoencephalitis,myelitis,or post-infectious demyelinating diseases.Although neuroinflammation initially has a protective function,chronic inflammation can contribute to the development of neurodegenerative diseases.Mechanisms such as protein aggregation and cellular disturbances are implicated with specific viruses such as herpes simplex virus type 1 and Epstein-Barr virus being associated with Alzheimer's disease and multiple sclerosis,respectively.Extracellular nucleotides,particularly adenosine triphosphate and its metabolites are released from activated,infected,and dying cells,acting as alarmins mediating neuroinflammation and neurodegeneration.When viruses infect central nervous system cells,adenosine triphosphate is released as an alarmin,triggering inflammatory responses.This process is mediated by purinergic receptors,divided into two families:P1,which responds to adenosine,and P2,activated by adenosine triphosphate and other nucleotides.This review highlights how specific viruses,such as human immunodeficiency virus type 1,Theiler's murine encephalomyelitis virus,herpes simplex virus type 1,Epstein-Barr virus,dengue virus,Zika virus,and severe acute respiratory syndrome coronavirus 2,can initiate inflammatory responses through the release of extracellular nucleotides,particularly adenosine triphosphate,which act as critical mediators in the progression of neuroinflammation and neurodegenerative disorders.A better understanding of purinergic signaling pathways in these diseases may suggest new potential therapeutic strategies for targeting neuroinflammation to mitigate the long-term consequences of viral infections in the central nervous system.
基金supported by UniversitàCattolica(D1 intramural funds to RP)Italian Ministry of University and Research(PRIN 2022ZYLB7B,P2022YW7BP funds to CG).
文摘Several experimental evidence suggests a link between brain Herpes simplex virus type-1 infection and the occurrence of Alzheimer’s disease.However,the molecular mechanisms underlying this association are not completely understood.Among the molecular mediators of synaptic and cognitive dysfunction occurring after Herpes simplex virus type-1 infection and reactivation in the brain neuroinflammatory cytokines seem to occupy a central role.Here,we specifically reviewed literature reports dealing with the impact of neuroinflammation on synaptic dysfunction observed after recurrent Herpes simplex virus type-1 reactivation in the brain,highlighting the role of interleukins and,in particular,interleukin 1βas a possible target against Herpes simplex virus type-1-induced neuronal dysfunctions.
文摘BACKGROUND Aseptic meningitis is defined as meningeal inflammation caused by various etio-logies with negative cerebrospinal fluid(CSF)bacterial culture.The most common etiologies are viruses[enteroviruses,arboviruses,and herpes simplex virus type 2(HSV-2)].Aseptic meningitis can have various presentations,including sensori-neural deafness.While sensorineural deafness from mumps meningoencephalitis has been reported,cases of HSV-2-induced hearing loss are rare.Herein,we re-port a case of HSV-2-induced meningitis that presented with sudden deafness.CASE SUMMARY A 68-year-old man experienced a profound sudden onset of left-sided hearing loss for one day.Pure-tone audiograms demonstrated sudden left-sided sensorineural hearing loss(thresholds 80-90 dB).After treatment with high-dose steroids for 1 week,he experienced an acute consciousness change with left hemiparesis.The laboratory data showed no significant abnormalities.Brain computed tomography without contrast and magnetic resonance imaging revealed no intracranial hemo-rrhage or obvious brain lesion.The CSF analysis and the Multiplex PCR panels showed HSV-2 positivity.Hence,under the diagnosis of herpes meningoenceph-alitis,acyclovir was prescribed and his symptoms gradually resolved.CONCLUSION This case report further demonstrates that a viral infection could be a cause of sudden sensorineural hearing loss.
基金supported by the National Natural Science Foundation of China(No.81970848).
文摘Quercetin is a natural compound with potent antiviral effects;however,its role in the treatment of herpes simplex keratitis(HSK)remains underexplored.Here,we investigated the antiviral effects of quercetin against herpes simplex virus 1(HSV-1).By examining different phases of viral infection in human corneal epithelial cells(HCECs),we found that 30μmol/L quercetin inhibits HSV-1 replication primarily by disrupting viral attachment.RNA-sequencing and subsequent analyses revealed that the nuclear factor E2-related factor 2(Nrf2)was upregulated by quercetin in a dose-dependent manner.Knocking down Nrf2 partially compromised quercetin's antiviral effect.Importantly,topical application of 100μmol/L quercetin alleviated HSK severity in mice,reduced viral titers in tears,and inhibited VP16 expression in the cornea and trigeminal ganglia.These findings demonstrate the antiviral effect of quercetin against HSV-1 and provide a foundation for mechanistic studies to elucidate its therapeutic potential in HSK.
基金Industrial innovation team of Chuzhou CityFengyang County“Fengxiang”talent team+3 种基金Huainan City Science and Technology Plan Project(2023076)Innovation and Entrepreneurship Training Program for College Students(202410879085)the Natural Science Research Projects of Anhui Universities(811904)the Excellent Research and Innovation Team of Anhui Province Universities in 2024(2024AH010007)。
文摘With the promotion of potatoes as a staple food,the challenge lies in integrating them into traditional staple grain-based diets.As the primary component of grains,starch plays a crucial role,and its interactions with other heterogeneous starches could significantly influence their functional properties.Therefore,this study aimed to explore the role of substitution ratio(SR,0–100%)of potato starch(PS)in the compatibility with wheat starch(WS)from the perspective of microstructure and physicochemical characteristics using the simplex-centroid method.Results of scaning electron microscopy(SEM)revealed the network structure in SR 30%of PS possessed the smallest size and the most compact gel structure.A higher SR of PS increased the solubility and swelling power of the blended WS and improved its freeze-thaw stability.Peak viscosity and gel hardness of the blended WS exhibited an increasing trend as the SR of PS increased.With the increasing SR of PS,the blended WS exhibited an increased tanδvalue with decreased viscous and elastic moduli.There is a non-additive effect between PS and WS,which should be responsible for their difference between experimental and theoretical values.These findings could provide a new direction for understanding the compatibility interactions between different starches,and provide a theoretical guidance for the development of PS-based foods with desirable properties.
基金Hong Kong Research Grants Council under the GRF(9043664).
文摘This article briefly reviews the topic of complex network synchronization,with its graph-theoretic criterion,showing that the homogeneous and symmetrical network structures are essential for optimal synchronization.Furthermore,it briefly reviews the notion of higher-order network topologies and shows their promising potential in application to evaluating the optimality of network synchronizability.
基金support from the National Science Foundation of China(52304137,5192780752274124,52325403)Tiandi Science and Technology Co.,Ltd.(2022-2-TDMS012 and SKLIS202417)Sichuan University(SKHL2215).
文摘The Grey Wolf Optimization(GWO)algorithm is acknowledged as an effective method for rock acoustic emission localization.However,the conventional GWO algorithm encounters challenges related to solution accuracy and convergence speed.To address these concerns,this paper develops a Simplex Improved Grey Wolf Optimizer(SMIGWO)algorithm.The randomly generating initial populations are replaced with the iterative chaotic sequences.The search process is optimized using the convergence factor optimization algorithm based on the inverse incompleteГfunction.The simplex method is utilized to address issues related to poorly positioned grey wolves.Experimental results demonstrate that,compared to the conventional GWO algorithm-based AE localization algorithm,the proposed algorithm achieves a higher solution accuracy and showcases a shorter search time.Additionally,the algorithm demonstrates fewer convergence steps,indicating superior convergence efficiency.These findings highlight that the proposed SMIGWO algorithm offers enhanced solution accuracy,stability,and optimization performance.The benefits of the SMIGWO algorithm extend universally across various materials,such as aluminum,granite,and sandstone,showcasing consistent effectiveness irrespective of material type.Consequently,this algorithm emerges as a highly effective tool for identifying acoustic emission signals and improving the precision of rock acoustic emission localization.
文摘Viral infections of the ocular surface significantly contribute to morbidity and visual impairment globally.The herpes simplex virus(HSV),adenovirus,cytomegalovirus(CMV),and human papillomavirus(HPV)are predominant pathogens impacting the cornea and conjunctiva,resulting in recurrent illness,epidemic outbreaks,and virus-associated neoplasia.Progress in virology,immunology,and molecular diagnostics has enhanced comprehension of host–virus interactions and introduced novel therapeutic opportunities.A narrative literature review was performed utilizing PubMed,Scopus,and Web of Science,encompassing papers published from 2000 to 2025,with a specific focus on research from 2020 onwards.Eligible publications were peer-reviewed clinical and experimental investigations,together with reviews that focused on epidemiology,etiology,diagnostic methodologies,and therapeutic alternatives.Research indicates that HSV keratitis is the predominant infectious cause of corneal blindness in high-income nations,although adenovirus persists in instigating epidemics of keratoconjunctivitis in the absence of licensed antiviral treatments.CMV keratitis,previously confined to immunocompromised persons,is now acknowledged in immunocompetent patients as a causative agent of corneal endotheliitis.HPV is associated with ocular surface squamous neoplasia,especially in areas with elevated ultraviolet exposure and high human immunodeficiency virus prevalence.Innovative molecular diagnostics,innovative antiviral agents,immunomodulatory approaches,and immunization initiatives signify significant progress that could enhance preventative and therapeutic results.
基金supported by the Universiti Malaya ArtScience Fellowship Grant(UMG004-2024IAS)UM Community Engagement Grant 2023(Project RUU002-23KS).
文摘Viral reproductive tract infections(VRTIs)are a significant global health concern with severe consequences,including infertility,chronic pelvic pain,and increased risk of HIV transmission.Complex interplay between pathogens and the host immune system plays a critical role in the pathogenesis and treatment of VRTIs.This review aims to provide a comprehensive overview of the multifaceted roles of the immune system in both contributing to and combating VRTIs.The review will also address the consequent perturbations in immune homeostasis and the implications for disease manifestation and progression.The interrelation between systemic immunity and local immune responses is discussed,providing insights into the challenges and breakthroughs in managing these infections.By providing a comprehensive overview of the mechanisms,implications,and therapeutic strategies associated with viral reproductive tract infections and immune dysfunction,this review also informs future research and clinical practice in this important area of reproductive health.
文摘为了改善高压直流系统的故障后的恢复性能,在研究低压限流单元(voltage dependent current order limiter,VDCOL)对直流系统无功功率消耗和电压稳定性影响的基础上,提出了一种分段变速率低压限流单元(piecewise-variable-rate VDCOL,PVR-VDCOL)的控制方法,该方法通过将电压下降或恢复过程划分为几个不同的阶段,并在每个阶段根据电压水平的不同而设置不同的功率恢复速率。推导了控制器初值的计算公式,制定了利用Simplex算法优化控制器参数的流程,并重点分析了分段数目对控制器性能的影响及其确定方法。在PSCAD/EMTDC中对提出的PVR-VDCOL和传统线性VDCOL的控制效果进行了对比仿真,并对不同分段数目下的仿真结果进行了对比分析,仿真结果表明提出的PVR-VDCOL能够有效改善直流系统的恢复性能。
