期刊文献+
共找到1,220篇文章
< 1 2 61 >
每页显示 20 50 100
Warburg effect mimicking inborn errors of metabolism in childhood hematologic malignancies:A case-based systematic review
1
作者 Khanittha Permtawee Maliwan Tengsujaritkul +5 位作者 Chane Choed-Amphai Supapitch Chanthong Kanittha Mankhemthong Lalita Sathitsamitphong Rungrote Natesirinilkul Pimlak Charoenkwan 《World Journal of Clinical Pediatrics》 2023年第5期350-358,共9页
BACKGROUND Type B lactic acidosis and hypoglycemia can occur in various pediatric conditions.In young children with a history of fasting preceding these metabolic derangements,inborn errors of metabolism should be pri... BACKGROUND Type B lactic acidosis and hypoglycemia can occur in various pediatric conditions.In young children with a history of fasting preceding these metabolic derangements,inborn errors of metabolism should be primarily considered.However,the Warburg effect,a rare metabolic complication,can also manifest in children with hematologic malignancies.Only a few reports of this condition in children have been published in the literature.AIM To identify the clinical course,treatment strategies,and outcomes of childhood hematologic malignancies with type B lactic acidosis.METHODS We performed a comprehensive search of the PubMed,Scopus,and Cochrane databases without any time restriction but limited to English language articles.The databases were last accessed on July 1st,2023.RESULTS A total of 20 publications were included in the analysis,all of which were case reports or case series.No higher quality evidence was available.Among children with hematologic malignancies and Warburg effect,there were 14 cases of acute lymphoblastic leukemia and 6 cases of non-Hodgkin’s lymphoma including our illustrative case.Lactic acidosis occurred in 55%of newly diagnosed cases and 45%of relapsed cases.The mean age was 10.3±4.5 years,and 80%of cases were male.The mean serum lactate was 16.9±12.6 mmol/L,and 43.8%of the cases had concomitant hypoglycemia.Lactic acidosis initially subsided in 80%of patients receiving chemotherapy compared to 60%in the contrast group.The mortality rate of newly diagnosed cases was 45.5%,while the relapsed cases represented a 100%mortality rate.All 8 patients reported before 2001 died from disease-related complications.However,patients described in reports published between 2003 and 2023 had a 54.5%rate of complete remission.CONCLUSION This complication has historically led to fatal outcome;however,patients who received chemotherapy showed a more favorable response.Therefore,it is crucial to promptly initiate specific treatment in this context. 展开更多
关键词 Warburg effect Lactic acidosis type B Inborn errors of metabolism LEUKEMIA LYMPHOMA CHILDREN
下载PDF
What is the Most Effective Method of Error Correction in L2 Writing? 被引量:2
2
作者 顾红兵 《海外英语》 2011年第10X期37-39,共3页
The efficacy of error correction and various kinds of correction approaches is one of the key issues in second language writing faced by both teachers and researchers. The current paper reviews the definition of error... The efficacy of error correction and various kinds of correction approaches is one of the key issues in second language writing faced by both teachers and researchers. The current paper reviews the definition of error correction and examines the different views on whether error correction in L2 writing should be corrected. In particular, the paper discusses and analyses the three common correction methods: direct correction, peer feedback and indirect correction. Teachers are encouraged to weigh and analyze the advantages and disadvantages of these methods according to the current literature, employ the most beneficial error correction method in L2 writing, and adapt its suitability to their teaching context. 展开更多
关键词 error CORRECTION L2 WRITING effective method
下载PDF
Effect of Modulation Error on All Optical Fiber Current Transformers 被引量:3
3
作者 Zhengping Wang Yuekun Wang Shuai Sun 《Journal of Sensor Technology》 2012年第4期172-176,共5页
For actively modulated In-line Sagnac interferential all optic fiber current transformers (AOFCTs), the accuracies are directly affected by the amplitude of the modulation signal. In order to deeply undertand the func... For actively modulated In-line Sagnac interferential all optic fiber current transformers (AOFCTs), the accuracies are directly affected by the amplitude of the modulation signal. In order to deeply undertand the function of the modulator, a theoretical model of modulation effect to AOFCTs is built up in this paper. The effect of the amplitude of the modulation signal to the output intensity of AOFCTs is theoretically formulated and numerical calculated. The results show that the modulation voltage variation could affect the output accuracies significantly. This might be some references on the investigation for practical applications of AOFCTs. 展开更多
关键词 Electronic CURRENT TRANSFORMER All Optical FIBER CURRENT TRANSFORMER Faraday effect Active MODULATION MODULATION error
下载PDF
ADC border effect and suppression of quantization error in the digital dynamic measurement 被引量:3
4
作者 白丽娜 刘海东 +7 位作者 周渭 张勇 翟鸿启 崔震健 赵明英 谷小倩 刘蓓玲 黄李贝 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第9期91-97,共7页
The digital measurement and processing is an important direction in the measurement and control field. The quantization error widely existing in the digital processing is always the decisive factor that restricts the ... The digital measurement and processing is an important direction in the measurement and control field. The quantization error widely existing in the digital processing is always the decisive factor that restricts the development and applications of the digital technology. In this paper, we find that the stability of the digital quantization system is obviously better than the quantization resolution. The application of a border effect in the digital quantization can greatly improve the accuracy of digital processing. Its effective precision has nothing to do with the number of quantization bits, which is only related to the stability of the quantization system. The high precision measurement results obtained in the low level quantization system with high sampling rate have an important application value for the progress in the digital measurement and processing field. 展开更多
关键词 quantization error border effect digital converter(ADC)
下载PDF
Practice and Effect of Appropriate Error-correction in English Teaching 被引量:2
5
作者 任静明 胡蓉 《Journal of Donghua University(English Edition)》 EI CAS 2002年第2期140-142,共3页
This paper points out that with interference from their native language and culture, Chinese students will inevitably make some errors in the process of learning English. It is important for teachers to know when and ... This paper points out that with interference from their native language and culture, Chinese students will inevitably make some errors in the process of learning English. It is important for teachers to know when and how to correct the students’ errors. By employing error-correction skillfully and appropriately, one can expect to improve the present English teaching and learning, to develop the self-confidence and self-esteem in students themselves. 展开更多
关键词 error-correction practice effect
下载PDF
Introduction of New Method on Engineering Risk Assessment:Engineering Errors and Effects Analysis(3EA)
6
作者 Mohammad Mahdi Izadi 《Management Studies》 2018年第6期527-530,共4页
Construction and commissioning accidents investigation shows that engineer’s errors in basic and detailed phases are the main causes.It will be gained more efficiency of investment when a relevant method is applied f... Construction and commissioning accidents investigation shows that engineer’s errors in basic and detailed phases are the main causes.It will be gained more efficiency of investment when a relevant method is applied for error identification and risk assessment in basic and detailed phases.Most of risk assessment methods are related to construction phase,meanwhile hidden risks that were happen in previous phases cannot be found by these methods.Although HAZOP study can be applied in detail phase but it can help to find process defections.Importance of identifying risks in basic and detailed phases is to apply preventive actions against birth and grows risks.This risk assessment method can reduce costs and improve environmental protection,safety,and reliability of designs.The main purpose of this study is to identify engineer’s errors and analyse their HSE effects.The method is applied in seven oil and gas engineering projects in Iran,raising the level of engineer’s attention to safety precautions and environmentally-friendly design,reducing the cost of improving the level of safety and environmental protection,improving environmental protection,safety,and design reliability,and improving procedures related to design process and control have been achieved. 展开更多
关键词 ENGINEERING errorS and effectS Analysis(3EA) ENGINEERING error detailed effectIVENESS control risk assessment
下载PDF
Effect of Healthcare Failure Mode and Effect Analysis on Reducing Error Risk of Neonatal Parenteral Nutrition Solution Dispensing
7
作者 Xinhong ZHAO Zhenhua LIU +3 位作者 Chao SUN Xu XIAO Lixue ZHAO Chunhua CAI 《Medicinal Plant》 CAS 2022年第2期63-69,共7页
[Objectives]To investigate the effect of healthcare failure mode and effect analysis(HFMEA)on reducing error risk of neonatal parenteral nutrition solution dispensing.[Methods]A research team was established to identi... [Objectives]To investigate the effect of healthcare failure mode and effect analysis(HFMEA)on reducing error risk of neonatal parenteral nutrition solution dispensing.[Methods]A research team was established to identify the failure mode(FM)in each link of the formulation process of neonatal parenteral nutrition solution by HFMEA,quantify the severity(S),occurrence(O)and detection(D)of FM,and evaluate FM by risk priority number(RPN).For FM with the values of RPN>16,failure cause analysis was conducted,and corresponding improvement measures were formulated.The weight coefficient and random consistency ratio(CR)of deployment process were calculated in Matlab R2018a by compiling the Analytic Hierarchy Process(AHP)program.Six months after the implementation of improvement measures,the implementation effect was evaluated by comparing the changes of the values of RPN which was evaluated comprehensively and the rate of dispensing errors before and after the implementation of HFMEA.[Results]In the preparation process of neonatal parenteral nutrition solution,a total of 13 FMs with medium and above risk were found,the weight coefficient of medical order review,dosing and mixing was 0.2703,the weight coefficient of drug dispensing check and review was 0.1432,the weight coefficient of print label was 0.1015,the weight coefficient of distribution was 0.0716,and CR=0.0491<0.1.After six months of intervention,the total RPN value decreased by 64.81%from 127.8 to 45.0.The deployment error rates were significantly lower after the implementation,and the difference was statistically significant(P<0.05).[Conclusions]HFMEA can effectively reduce the error risk in preparation of neonatal parenteral nutrition solution,improve the quality of dispensing and promote the safety of neonatal medication. 展开更多
关键词 Healthcare failure mode and effect analysis(HFMEA) Neonatal parenteral nutrition solution Dispensing errors Risk management Analytic hierarchy process(AHP)
下载PDF
Error Analysis of CET-4 Translation Produced by Vocational & Techni⁃ cal College Students and the Backwash Effect of English Teaching
8
作者 马理明 《海外英语》 2020年第24期150-151,共2页
CET-4 is a national standardized English proficiency test designed and developed by the National College English Ex⁃amination Committee.The purpose of the test is to accurately measure the comprehensive English applic... CET-4 is a national standardized English proficiency test designed and developed by the National College English Ex⁃amination Committee.The purpose of the test is to accurately measure the comprehensive English application ability of college stu⁃dents in China.The more important the test,the more obvious its backwash effect.With the increase of the proportion of subjective questions in CET-4,teachers should pay more attention to the transfer of skills and correct English expression while teaching the basic knowledge of English.In particular,the students in vocational and technical colleges are weak in English abilities,and their errors in translation are even more numerous and varied.Therefore,this study will analyze the translation errors produced by 200 vocational and technical college students in CET-4 of June 2019.By interviewing and investigating the students’actual situation of English learning,tips and proposals on backwash effect on teaching can be achieved. 展开更多
关键词 vocational&technical college students CET-4 translation error analysis backwash effect on teaching
下载PDF
Effectiveness and failure modes of error correcting code in industrial 65 nm CMOS SRAMs exposed to heavy ions
9
作者 童腾 王晓辉 +4 位作者 张战刚 丁朋程 刘杰 刘天奇 苏弘 《Nuclear Science and Techniques》 SCIE CAS CSCD 2014年第1期47-52,共6页
Single event upsets(SEUs) induced by heavy ions were observed in 65 nm SRAMs to quantitatively evaluate the applicability and effectiveness of single-bit error correcting code(ECC) utilizing Hamming Code.The results s... Single event upsets(SEUs) induced by heavy ions were observed in 65 nm SRAMs to quantitatively evaluate the applicability and effectiveness of single-bit error correcting code(ECC) utilizing Hamming Code.The results show that the ECC did improve the performance dramatically,with the SEU cross sections of SRAMs with ECC being at the order of 10^(-11) cm^2/bit,two orders of magnitude higher than that without ECC(at the order of 10^(-9) cm^2/bit).Also,ineffectiveness of ECC module,including 1-,2- and 3-bits errors in single word(not Multiple Bit Upsets),was detected.The ECC modules in SRAMs utilizing(12,8) Hamming code would lose work when 2-bits upset accumulates in one codeword.Finally,the probabilities of failure modes involving 1-,2- and 3-bits errors,were calcaulated at 39.39%,37.88%and 22.73%,respectively,which agree well with the experimental results. 展开更多
关键词 SRAM 重离子 CMOS 故障模式 纳米 纠错码 工业 ECC
下载PDF
非圆齿轮电火花线切割加工工艺参数对齿廓误差的影响
10
作者 王亚洲 马晓文 +2 位作者 赵家黎 陈柏昕 王真 《兰州理工大学学报》 CAS 北大核心 2024年第2期36-43,共8页
线切割加工非圆齿轮时电参数是影响齿廓误差的关键因素之一.设计正交试验,分别采用非圆齿轮齿根、齿廓中部和齿顶的最大齿廓误差对线切割加工非圆齿轮进行分析.通过方差分析方法和主效应分析法,研究线切割加工电参数峰值电流、脉冲宽度... 线切割加工非圆齿轮时电参数是影响齿廓误差的关键因素之一.设计正交试验,分别采用非圆齿轮齿根、齿廓中部和齿顶的最大齿廓误差对线切割加工非圆齿轮进行分析.通过方差分析方法和主效应分析法,研究线切割加工电参数峰值电流、脉冲宽度、脉冲间隔和跟踪对非圆齿轮齿根、齿廓中部和齿顶的齿廓误差影响规律.同时,对齿廓误差、加工时长和工艺参数进行回归分析,并建立回归模型,基于灰狼优化算法对回归模型进行多目标优化求解.通过研究结果可以得出线切割加工非圆齿轮齿廓不同部位的最优参数组合,可为实际加工提供参考. 展开更多
关键词 非圆齿轮 齿廓误差 工艺参数 方差分析 主效应分析
下载PDF
FMEA模型和6S管理方法在降低儿童专科医院PIVAS调剂差错中的应用 被引量:1
11
作者 何林峰 杨亚亚 +2 位作者 林芸竹 杨春松 张伶俐 《中国药房》 CAS 北大核心 2024年第2期237-241,共5页
目的降低儿童专科医院静脉药物配置中心(PIVAS)的调剂差错。方法采用失效模式和效应分析(FMEA)模型,对我院PIVAS调剂流程进行风险识别,找出各环节中可能导致调剂差错的潜在失效模式,分析其失效原因,并对潜在失效模式的严重度、发生率和... 目的降低儿童专科医院静脉药物配置中心(PIVAS)的调剂差错。方法采用失效模式和效应分析(FMEA)模型,对我院PIVAS调剂流程进行风险识别,找出各环节中可能导致调剂差错的潜在失效模式,分析其失效原因,并对潜在失效模式的严重度、发生率和检测度进行量化评分,计算其风险优先指数,从而筛选需要优先改善的失效模式;应用6S管理方法,从整理(seiri)、整顿(seiton)、清扫(seiso)、清洁(seiketsu)、素养(shitsuke)和安全(safety)6个方面制定相应的改善措施,并对实施前后的干预效果进行评价。结果根据风险优先指数评估筛选出32个潜在失效模式,其中需要优先改善的关键失效模式共18个。根据6S管理方法采取相应措施后,18个关键失效模式的风险优先指数均有所下降,风险优先指数值由497降至142,降幅达71.43%;其中15个关键失效模式的差错率均较实施前显著降低(P<0.05)。结论应用FMEA模式和6S管理方法对PIVAS工作流程的各环节进行风险管控的预测和改进,能有效降低PIVAS调剂差错风险,保障儿童静脉用药安全。 展开更多
关键词 静脉药物配置中心 调剂差错 风险评估 失效模式和效应分析 6S管理
下载PDF
空间混合辐射环境器件单粒子在轨错误率预估及不确定度分析方法
12
作者 张付强 张峥 +5 位作者 肖舒颜 龚毅豪 韩金华 陈启明 曾传滨 郭刚 《原子能科学技术》 EI CAS CSCD 北大核心 2024年第4期945-951,共7页
针对空间混合辐射对器件单粒子在轨错误率的影响,基于典型静态随机存储器利用中国原子能科学研究院HI-13串列加速器以及钴源总剂量模拟辐照试验装置开展协合效应研究,发展了一种器件在混合辐射环境下的单粒子在轨错误率计算方法。并利... 针对空间混合辐射对器件单粒子在轨错误率的影响,基于典型静态随机存储器利用中国原子能科学研究院HI-13串列加速器以及钴源总剂量模拟辐照试验装置开展协合效应研究,发展了一种器件在混合辐射环境下的单粒子在轨错误率计算方法。并利用该方法计算了协合效应影响下的航天器典型任务周期器件的在轨错误率,同时分析了器件在轨错误率计算中的不确定度来源并计算了在轨错误率不确定度。结果表明,对于该类型器件,空间混合辐射场导致的协合效应将降低器件单粒子在轨错误率。 展开更多
关键词 单粒子在轨错误率 协合效应 不确定度分析 混合辐射
下载PDF
基于末端触觉传感器的智能机器人压力补偿
13
作者 朱慧珍 王凯 王丽君 《计算机仿真》 2024年第4期446-450,共5页
末端触觉是智能机器人实现对外部环境做出直接反应的必需媒介。触觉传感器的弹性层易导致表面接触压力测量结果出现偏差,降低机械手的抓取力度的合理性。提出智能机器人末端触觉传感器压力误差补偿方法。建立触觉传感器三维力学模型,分... 末端触觉是智能机器人实现对外部环境做出直接反应的必需媒介。触觉传感器的弹性层易导致表面接触压力测量结果出现偏差,降低机械手的抓取力度的合理性。提出智能机器人末端触觉传感器压力误差补偿方法。建立触觉传感器三维力学模型,分析表面接触应力与弹性层之间的关系,得到传感器压力特征;计算弹性层的低通效应值,通过传感器测量值推理得到表面压力值,利用线性迭代反卷积算法对压力误差补偿。实验结果表明,研究方法应用下,压力误差补偿的均方误差接近于10-3,精度与理想效果更接近,上述方法获取的传感器对不同大小作用力的电学响应结果与实际数据具有较高一致性。 展开更多
关键词 智能机器人 触觉传感器 压力误差补偿 三维力学模型 低通效应
下载PDF
地基空间目标监视雷达大气折射误差修正方法研究
14
作者 汪昭凯 计一飞 +5 位作者 董臻 唐飞翔 张永胜 张庆君 赵秉吉 高贺利 《电波科学学报》 CSCD 北大核心 2024年第3期570-578,共9页
大气介质垂向非均匀分布会使穿行其中的电磁波发生折射现象,尤其是其中的对流层和电离层,可造成电磁波传播延迟及路径弯曲,进而导致地基空间目标监视雷达测距和测角误差。本文基于射线追踪法实现了大气折射误差建模,推导了雷达测距和测... 大气介质垂向非均匀分布会使穿行其中的电磁波发生折射现象,尤其是其中的对流层和电离层,可造成电磁波传播延迟及路径弯曲,进而导致地基空间目标监视雷达测距和测角误差。本文基于射线追踪法实现了大气折射误差建模,推导了雷达测距和测角误差关于大气折射指数垂向分布的精确表达式,并详细阐述了地基空间目标监视雷达大气折射误差修正原理及流程,相比于传统的误差近似模型及修正方法,本文所提出的误差模型更准确、修正方法更有效。基于对流层和电离层模型获取大气折射指数垂向分布特性曲线,进行大气折射误差数值仿真,结果表明,本文方法在大气分层不同间隔取值下的误差补偿精度更高、性能更稳健,特别是在低仰角情况下,其性能优势更加明显。 展开更多
关键词 对流层 电离层 大气折射效应 地基空间目标监视雷达 大气折射误差修正
下载PDF
回声测深仪典型问题与对策分析
15
作者 谷东亮 李明海 +1 位作者 马海瑞 纪守博 《船电技术》 2024年第8期62-65,共4页
针对现有测深仪在舰艇离靠码头倒车、高速航行等情况下会出现明显测速不准这一情况,本文通过仪器实操的形式从测量误差、外界影响、操作使用影响三个方面进行了分析,并讨论了相应的解决对策,提出了基于潮汐值的水深获取方法,为提升测深... 针对现有测深仪在舰艇离靠码头倒车、高速航行等情况下会出现明显测速不准这一情况,本文通过仪器实操的形式从测量误差、外界影响、操作使用影响三个方面进行了分析,并讨论了相应的解决对策,提出了基于潮汐值的水深获取方法,为提升测深仪工作的稳定性与可靠性提供参考。 展开更多
关键词 测量误差 外界影响 操作影响 潮汐
下载PDF
声速剖面精简的有效面积算法
16
作者 王雅鹏 李林阳 +2 位作者 邝英才 王文博 宋学成 《导航定位学报》 CSCD 北大核心 2024年第3期137-144,共8页
针对海洋大地基准网建立过程中,深海环境下水声定位声速数据量庞大、声线跟踪耗时长、效率低的问题,提出一种采用有效面积算法的声速剖面高效精简方法,通过计算声速曲线上相邻三点间的有效面积,设定比例系数搜索阈值,并将各数据点计算... 针对海洋大地基准网建立过程中,深海环境下水声定位声速数据量庞大、声线跟踪耗时长、效率低的问题,提出一种采用有效面积算法的声速剖面高效精简方法,通过计算声速曲线上相邻三点间的有效面积,设定比例系数搜索阈值,并将各数据点计算得到的面积值与阈值进行比对,来判断是否剔除数据点,实现声速剖面的高效精简。采用南海某海域的实测水声数据进行实验分析,结果表明,提出的方法对声速剖面的简化率可达到84%以上,声线跟踪效率提高6倍以上。并给出了方法中阈值系数的最优解,使定位误差控制在0.2 m以内,为声速剖面精简提供参考。 展开更多
关键词 水声定位 声速剖面精简 有效面积 阈值系数 声线跟踪误差
下载PDF
分离式霍普金森压杆试验中金属材料端面摩擦效应误差分析
17
作者 张柱柱 毛海涛 +7 位作者 周圣林 焦鹏 胡文林 吴省均 刘军 张旸 沈沛 刘宇麟 《机械工程材料》 CAS CSCD 北大核心 2024年第2期89-96,共8页
采用分离式霍普金森压杆(SHPB)试验结合有限元模拟方法计算重构38CrMoAl高强度钢的应力-应变曲线,研究了端面摩擦因数(0,0.1,0.2,0.3,0.4,0.5)、子弹入射速度(20,30,40 m·s^(-1))、试样长径比(0.25,0.50,1.00)和试样形状(圆柱体,... 采用分离式霍普金森压杆(SHPB)试验结合有限元模拟方法计算重构38CrMoAl高强度钢的应力-应变曲线,研究了端面摩擦因数(0,0.1,0.2,0.3,0.4,0.5)、子弹入射速度(20,30,40 m·s^(-1))、试样长径比(0.25,0.50,1.00)和试样形状(圆柱体,立方体)对端面摩擦效应引入的峰值应力、峰值应变测试误差的影响。结果表明:测试误差随端面摩擦因数的增大而增大,随长径比的增加而减小;截面面积相同的圆柱体和立方体试样的测试误差差值小于2%;端面摩擦因数较大时,控制子弹入射速度不能有效减小误差;将端面摩擦因数降到0.1以下,或是选用长径比1.00以上的试样,可以有效减小端面摩擦效应误差;试样中部和端面边缘处发生应力集中,随着试样长径比增大,应力集中部位占试样总长度比例减小,端面摩擦效应影响减小。 展开更多
关键词 分离式霍普金森压杆 端面摩擦效应 数值模拟 误差分析
下载PDF
固定式双向体积管清洗效果影响因素研究
18
作者 陈佳羽 吕思禹 毛睿琪 《石油化工应用》 CAS 2024年第1期54-57,共4页
本文以长庆油田某油库固定式双向体积管的清洗工作为例,介绍了清洗工艺,并详细剖析了结污情况、清洗介质、设备器具、操作运行四个方面对体积管清洗效果的影响,提出相应建议。通过本次标定容积值较上一次结果的对比,论证了分析的成效,... 本文以长庆油田某油库固定式双向体积管的清洗工作为例,介绍了清洗工艺,并详细剖析了结污情况、清洗介质、设备器具、操作运行四个方面对体积管清洗效果的影响,提出相应建议。通过本次标定容积值较上一次结果的对比,论证了分析的成效,证明了研究的必要性和可靠性。 展开更多
关键词 体积管 清洗效果 酸洗法 测量误差 误差分析
下载PDF
屈光手术联合预防性角膜胶原交联矫正屈光不正的疗效及安全性研究进展
19
作者 莫菲(综述) 李莹(审校) 《中华实验眼科杂志》 CAS CSCD 北大核心 2024年第4期376-385,共10页
角膜屈光手术是一种安全、有效的屈光不正矫正方式。尽管因术后角膜组织完整性改变,导致角膜生物力学稳定性下降,但术后角膜结构绝大多数是安全的。如果术前存在危险因素,如屈光度数高、角膜薄、角膜地形图形态欠规则、散光度数高、双... 角膜屈光手术是一种安全、有效的屈光不正矫正方式。尽管因术后角膜组织完整性改变,导致角膜生物力学稳定性下降,但术后角膜结构绝大多数是安全的。如果术前存在危险因素,如屈光度数高、角膜薄、角膜地形图形态欠规则、散光度数高、双眼对称性差、过敏体质、有揉眼习惯等,术后有可能发生屈光回退和角膜膨隆。角膜胶原交联术可增强角膜生物力学,有效阻止角膜膨隆、圆锥角膜或其他扩张性疾病的发生和发展。近年来,国内外一些研究者相继尝试一种新型的屈光手术设计,即角膜屈光手术联合预防性角膜胶原交联术,以期改善屈光术后角膜的生物力学稳定性,进而潜在预防角膜扩张和屈光回退。多项研究已经观察到联合手术具有良好的视力和屈光预后,尤其是对于术前评估角膜存在相对扩张风险的患者。本文将主要从有效性、安全性、可预测性、稳定性及并发症5个方面综述该联合手术矫治屈光不正的疗效及安全性。 展开更多
关键词 屈光不正 角膜交联 屈光手术 疗效 安全性 角膜扩张 角膜生物力学
下载PDF
基于多重降质复合信道的UWOC系统误码率性能研究
20
作者 张建磊 张鹏伟 +4 位作者 朱云周 田雨欣 李婕妤 杨祎 贺锋涛 《光子学报》 EI CAS CSCD 北大核心 2024年第3期195-206,共12页
针对海水信道吸收、散射、气泡和湍流效应等对水下无线光通信系统性能的影响,建立融合多重降质效应的水下无线光复合信道模型。基于Mie散射理论计算水下微气泡群的体散射函数、散射系数和散射相函数。湍流信道模型采用混合指数广义伽玛... 针对海水信道吸收、散射、气泡和湍流效应等对水下无线光通信系统性能的影响,建立融合多重降质效应的水下无线光复合信道模型。基于Mie散射理论计算水下微气泡群的体散射函数、散射系数和散射相函数。湍流信道模型采用混合指数广义伽玛分布进行建模。随后,将复合信道对信号的衰减以及湍流噪声等效传递至光信号,推导出了复合信道在通断键控调制方式下误码率的封闭表达式。此外,研究了湍流强度、气泡数量、链路距离和海水水质等参数对误码率性能的影响。研究结果显示,随着链路距离的延伸,误码率线性增长,表现出退化趋势;港口海水因其较高浊度和丰富的悬浮颗粒,难以保证系统通信的可靠性。此外,气泡的存在和链路距离的扩展同样会显著加剧误码率的恶化。 展开更多
关键词 水下无线光通信 多重降质效应 水下复合信道 MIE散射 系统误码率
下载PDF
上一页 1 2 61 下一页 到第
使用帮助 返回顶部