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跳数加权DV-Hop定位算法 被引量:14
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作者 刘凯 余君君 谭立雄 《传感技术学报》 CAS CSCD 北大核心 2012年第11期1539-1542,共4页
针对DV-Hop定位算法中距离估计误差对定位结果的影响,提出了一种信标节点优选方案和跳数加权DV-Hop定位算法。首先通过设定跳数阈值,保留跳数较少的信标节点,然后剔除近似在一条直线上的信标节点,完成信标节点优选,避免未知节点无法定... 针对DV-Hop定位算法中距离估计误差对定位结果的影响,提出了一种信标节点优选方案和跳数加权DV-Hop定位算法。首先通过设定跳数阈值,保留跳数较少的信标节点,然后剔除近似在一条直线上的信标节点,完成信标节点优选,避免未知节点无法定位的情形。此外,利用Friis模型推导出距离估计误差与信号传播跳数之间的映射关系,采用传播跳数作为加权因子对定位结果进行了修正。仿真结果表明该算法降低了距离估计误差对定位精度的影响,提高了定位精度。 展开更多
关键词 无线传感器网络 节点定位 加权定位 信标节点优选方案
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基于雷电定位系统的雷电多回击地闪参数统计及影响因素分析
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作者 杨雷 韩永霞 +6 位作者 廖志铭 李谦 赵晓凤 李志峰 黄健宁 张杰 刘柏炫 《广东电力》 2023年第7期115-123,共9页
根据2010—2021年广东省雷电定位系统(lightning location system,LLS)数据,以不同定位站数的筛选方式对多回击地闪参数进行统计,发现随着选取的定位站数增加,多回击地闪的占比、雷电流幅值和时间间隔增加,由此指出:开展多回击地闪次数... 根据2010—2021年广东省雷电定位系统(lightning location system,LLS)数据,以不同定位站数的筛选方式对多回击地闪参数进行统计,发现随着选取的定位站数增加,多回击地闪的占比、雷电流幅值和时间间隔增加,由此指出:开展多回击地闪次数及占比统计时应选取定位站数S≥2,避免大部分小雷被忽略;开展雷电流幅值统计时应选取定位站数S≥3,确保雷电流幅值精度。对比分析人工引雷时LLS测量的雷电流幅值差异,发现雷电流幅值越大,LLS中能监测到雷电流的定位站数越多,此时LLS测量的雷电流幅值与人工引雷测量结果的偏差越小。选取定位站数S≥3,统计分析多回击地闪中首次回击雷电流幅值与后续回击的关系及其变化趋势,发现首次至后续回击雷电流幅值中值依次递减、回击时间间隔依次递增,但随着回击次数的增加,所有后续回击的雷电流幅值大于首次回击的概率呈现先增大后略减小的趋势,由此提出后续回击雷电流幅值大于首次回击雷电流幅值的概率计算公式。 展开更多
关键词 多回击地闪 雷电定位系统 人工引雷 定位 回击次 雷电流峰值 时间间隔
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中医时空相数定位与康复治疗 被引量:1
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作者 王金生 王刚 《现代康复》 CSCD 2000年第2期299-300,共2页
关键词 中医 时空相定位 康复治疗
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关于除法余数值定位法的补充
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作者 梅大兴 陈宝森 《黑龙江珠算》 1996年第6期36-37,共2页
读过贵刊1996年第3期所载山西省供销学校卫永红老师的《除法余数值定位法值得推广》一文,除了赞同之外,还有点补充,如蒙不弃,求借一纸表述,并请师友们指教。 原文指出:“绝大多数除算题是除不尽的,除不尽必然有余数”,“现在珠算界对余... 读过贵刊1996年第3期所载山西省供销学校卫永红老师的《除法余数值定位法值得推广》一文,除了赞同之外,还有点补充,如蒙不弃,求借一纸表述,并请师友们指教。 原文指出:“绝大多数除算题是除不尽的,除不尽必然有余数”,“现在珠算界对余数的表示,无论是比赛还是技术鉴定。 展开更多
关键词 除法 珠算 公式定位 定位
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时空相数定位与中医现代化
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作者 王金生 王刚 《光明中医》 2002年第6期4-5,共2页
关键词 中医现代化 时空相定位 天人合一 负反馈调节
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《新乡医学院学报》计量单位和数字的用法
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《新乡医学院学报》 CAS 2014年第10期864-864,共1页
(1)计量单位:实行《中华人民共和国法定计量单位》,请参照《法定计量单位在医学上的应用》第3版(人民军医出版社2004年出版)。单位名称与单位符号不可混合使用,如ng·kg^-1·天-1应改为ng·kg^-1·d^-1;组合单位... (1)计量单位:实行《中华人民共和国法定计量单位》,请参照《法定计量单位在医学上的应用》第3版(人民军医出版社2004年出版)。单位名称与单位符号不可混合使用,如ng·kg^-1·天-1应改为ng·kg^-1·d^-1;组合单位符号中表示相除的斜线,应采用负数幂的形式表示,如g/L应改为g·L^-1,ng/kg/min应改为ng·kg^-1·min^-1。在叙述中, 展开更多
关键词 计量单位 组合单位 医学院学报 字的 人民军医出版社 部队番号 修约 定位数 有效位
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关于碳碳重键自由基加成及定位规律的探讨
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作者 战长友 《山东教育学院学报》 2000年第3期75-77,共3页
本文以结构为基础 ,以电子效应为主线 ,讨论了碳碳重键自由基加成反应的特点 ,特别着重研究了自由基加成反应的定位规律以及定位效应指数的应用。
关键词 碳碳重键 自由基加成 定位数 加成反应
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让Excel数据随机输入值实现正态分布
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作者 王志军 《电脑知识与技术(经验技巧)》 2015年第6期44-44,共1页
最近在工作中遇到一个特殊的问题,要求在表格的E-J列随机填充指定范围的数字,例如要求这六个单元格的平均值为"55±0.5",并且要求这些随机数实现正态分布。除了手工填充数据之外,有没有更简便一些的方法呢? 我们可以利用RAND函... 最近在工作中遇到一个特殊的问题,要求在表格的E-J列随机填充指定范围的数字,例如要求这六个单元格的平均值为"55±0.5",并且要求这些随机数实现正态分布。除了手工填充数据之外,有没有更简便一些的方法呢? 我们可以利用RAND函数实现上述要求,可以使用"=NORMINV(RAND(),55,0.5)"的公式,RAND函数用于随机产生0-1之间的数字,NORMINV函数用来返回指定平均值和标准方差的正态累积分布函数的区间点,55表示指定的平均值,0.5为标准方差。 展开更多
关键词 EXCEL 标准方差 累积分布函 指定范围 单元格 随机输入 定位数 选择性粘贴 SPEC
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新突破!超声波定位实现3D打印复合材料
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《塑料制造》 2016年第3期26-26,共1页
日前,来自英国Bristol大学的一支研究团队,开发出了用超声波控制3D打印部件微观结构的方法以实现复合材料的3D打印。据介绍,这种独特的方法使用超声波来定位数以百万计的微小增强纤维,使其在微观尺度上形成一种增强框架,从而显著提升材... 日前,来自英国Bristol大学的一支研究团队,开发出了用超声波控制3D打印部件微观结构的方法以实现复合材料的3D打印。据介绍,这种独特的方法使用超声波来定位数以百万计的微小增强纤维,使其在微观尺度上形成一种增强框架,从而显著提升材料强度。这种微观结构的生成会与一个聚焦的激光束协调同步,而后者的作用是固化环氧树脂。" 展开更多
关键词 超声波定位 固化环氧树脂 增强纤维 定位数 光敏树脂 激光束 微观结构 材料强度 BRISTOL 微观尺度
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一种基于FCM的DV-HOP定位算法
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作者 孙爱晶 李益佳 《西安邮电大学学报》 2023年第2期10-18,共9页
对锚节点稀少且未知节点分布不均匀的定位环境下距离矢量跳数(Distance Vector Hop,DV-HOP)定位算法定位误差大的问题进行研究,提出一种基于模糊C-均值(Fuzzy C-means,FCM)的DV-HOP定位算法。在DV-HOP定位算法中引入FCM算法将锚节点进... 对锚节点稀少且未知节点分布不均匀的定位环境下距离矢量跳数(Distance Vector Hop,DV-HOP)定位算法定位误差大的问题进行研究,提出一种基于模糊C-均值(Fuzzy C-means,FCM)的DV-HOP定位算法。在DV-HOP定位算法中引入FCM算法将锚节点进行分簇并提出分簇策略,未知节点则按照设定的算法流程选择入簇,在通过簇内定位后进行簇间坐标的融合从而实现全局定位。为了验证基于FCM的DV-HOP定位算法的有效性,将所提算法与DV-HOP定位算法、基于粒子群的DV-HOP(DV-HOP for Particle Swarm Optimization,PSODV-HOP)定位算法以及基于几何改进的DV-HOP(Improved DV-HOP,IDV-HOP)定位算法等3种算法对比。仿真结果表明,基于FCM的DV-HOP定位算法与其他3种定位算法相比,其平均定位误差分别降低了52%、45%与31%,能更好地适应不均匀的节点分布环境。 展开更多
关键词 无线传感器网络 节点定位 距离矢量跳定位算法 模糊C-均值算法 最小二乘法
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简析珠算乘除定位的选择与应用
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作者 李玉清 方成民 尹衍波 《黑龙江珠算》 1996年第4期24-25,共2页
俗话说:“算盘易打,数位难定。”我国古代珠算书中也强调了“凡算之法,先识其位”。实践中算题即便准确,而位定错了,其结果还是错误的。可见,定位是珠算教学和实践的重要环节,而乘除算的定位更显重要。关于珠算乘除定位的方法很多,,教... 俗话说:“算盘易打,数位难定。”我国古代珠算书中也强调了“凡算之法,先识其位”。实践中算题即便准确,而位定错了,其结果还是错误的。可见,定位是珠算教学和实践的重要环节,而乘除算的定位更显重要。关于珠算乘除定位的方法很多,,教材中已有介绍,不再重述。 展开更多
关键词 珠算 乘法 除法 固定个位法 公式定位 定位 首档定位
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Censored Composite Conditional Quantile Screening for High-Dimensional Survival Data
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作者 LIU Wei LI Yingqiu 《应用概率统计》 CSCD 北大核心 2024年第5期783-799,共17页
In this paper,we introduce the censored composite conditional quantile coefficient(cC-CQC)to rank the relative importance of each predictor in high-dimensional censored regression.The cCCQC takes advantage of all usef... In this paper,we introduce the censored composite conditional quantile coefficient(cC-CQC)to rank the relative importance of each predictor in high-dimensional censored regression.The cCCQC takes advantage of all useful information across quantiles and can detect nonlinear effects including interactions and heterogeneity,effectively.Furthermore,the proposed screening method based on cCCQC is robust to the existence of outliers and enjoys the sure screening property.Simulation results demonstrate that the proposed method performs competitively on survival datasets of high-dimensional predictors,particularly when the variables are highly correlated. 展开更多
关键词 high-dimensional survival data censored composite conditional quantile coefficient sure screening property rank consistency property
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The influences of canopy temperature measuring on the derived crop water stress index
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作者 WANG Hongxi LI Fei +4 位作者 SHEN Hongtao LI Mengyu YIN Gongchao FANG Qin SHAO Liwei 《中国生态农业学报(中英文)》 CAS CSCD 北大核心 2024年第9期1503-1519,共17页
Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the... Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the influences of atmospheric conditions,settled height,view angle of infrared thermography,and investigating time of temperature measuring on the performance of the CWSI.Three irrigation treatments were used to create different soil water conditions during the 2020-2021 and 2021-2022 winter wheat-growing seasons.The CWSI was calculated using the CWSI-E(an empirical approach)and CWSI-T(a theoretical approach)based on the T_(c).Weather conditions were recorded continuously throughout the experimental period.The results showed that atmospheric conditions influenced the estimation of the CWSI;when the vapor pressure deficit(VPD)was>2000 Pa,the estimated CWSI was related to soil water conditions.The height of the installed infrared thermograph influenced the T_(c)values,and the differences among the T_(c)values measured at height of 3,5,and 10 m was smaller in the afternoon than in the morning.However,the lens of the thermometer facing south recorded a higher T_(c)than those facing east or north,especially at a low height,indicating that the direction of the thermometer had a significant influence on T_(c).There was a large variation in CWSI derived at different times of the day,and the midday measurements(12:00-15:00)were the most reliable for estimating CWSI.Negative linear relationships were found between the transpiration rate and CWSI-E(R^(2)of 0.3646-0.5725)and CWSI-T(R^(2)of 0.5407-0.7213).The relations between fraction of available soil water(FASW)with CWSI-T was higher than that with CWSI-E,indicating CWSI-T was more accurate for predicting crop water status.In addition,The R^(2)between CWSI-T and FASW at 14:00 was higher than that at other times,indicating that 14:00 was the optimal time for using the CWSI for crop water status monitoring.Relative higher yield of winter wheat was obtained with average seasonal values of CWSI-E and CWSI-T around 0.23 and 0.25-0.26,respectively.The CWSI-E values were more easily influenced by meteorological factors and the timing of the measurements,and using the theoretical approach to derive the CWSI was recommended for precise irrigation water management. 展开更多
关键词 Canopy temperature Measuring time Measuring height and direction Crop water stress index
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Bus transit travel time reliability evaluation based on automatic vehicle location data 被引量:4
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作者 严亚丹 过秀成 +2 位作者 李岩 孔哲 何明 《Journal of Southeast University(English Edition)》 EI CAS 2012年第1期100-105,共6页
In order to provide important parameters for schedule designing, decision-making bases for transit operation management and references for passengers traveling by bus, bus transit travel time reliability is analyzed a... In order to provide important parameters for schedule designing, decision-making bases for transit operation management and references for passengers traveling by bus, bus transit travel time reliability is analyzed and evaluated based on automatic vehicle location (AVL) data. Based on the statistical analysis of the bus transit travel time, six indices including the coefficient of variance, the width of travel time distribution, the mean commercial speed, the congestion frequency, the planning time index and the buffer time index are proposed. Moreover, a framework for evaluating bus transit travel time reliability is constructed. Finally, a case study on a certain bus route in Suzhou is conducted. Results show that the proposed evaluation index system is simple and intuitive, and it can effectively reflect the efficiency and stability of bus operations. And a distinguishing feature of bus transit travel time reliability is the temporal pattern. It varies across different time periods. 展开更多
关键词 bus transit travel time reliability evaluation andanalysis automatic vehicle location data statistical analysis
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An Entropy-based Index for Fine-scale Mapping of Disease Genes 被引量:2
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作者 李玉梅 向阳 +1 位作者 邓红文 孙振球 《Journal of Genetics and Genomics》 SCIE CAS CSCD 北大核心 2007年第7期661-668,共8页
By comparing the entropy and the conditional entropy in a marker, an entropy-based index has been presented for fine-scale linkage disequilibrium gene mapping using high-density marker maps for human disease genes. Th... By comparing the entropy and the conditional entropy in a marker, an entropy-based index has been presented for fine-scale linkage disequilibrium gene mapping using high-density marker maps for human disease genes. The index can quantify the level of linkage disequilibrium (LD) between the marker and the disease susceptibility locus (DSL) of genes. The advantage of using the index is attributed to the fact that it does not depend on marker allele frequencies across loci. Moreover, it is parallel to Hardy-Weinberg disequilibrium (HWD) measure for DSL fine mapping. Through various simulations, the fine mapping perform- ances of the proposed entropy-based index was extensively investigated under various genetic parameters. The results show that the index presented is both robust and powerful for DSL mapping in genes. 展开更多
关键词 ENTROPY entropy-based index fine mapping
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An Entropy-based Index for Fine-scale Mapping of QTL
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作者 向阳 李玉梅 +1 位作者 刘再明 孙振球 《Journal of Genetics and Genomics》 SCIE CAS CSCD 北大核心 2007年第4期373-380,共8页
By comparing the entropy and conditional entropy in a marker, an entropy-based index for fine-scale linkage-disequilibrium gene mapping is presented using high-density marker maps in extreme samples for quantitative t... By comparing the entropy and conditional entropy in a marker, an entropy-based index for fine-scale linkage-disequilibrium gene mapping is presented using high-density marker maps in extreme samples for quantitative trait. The entropy-based index is the function of LD between the marker and the traitlocus and does not depend on marker allele frequencies across the loci. It is parallel to Hardy-Weinberg disequilibrium (HWD) measure for QTL fine mapping, but its power of fine mapping QTL is higher than that of HWD measure. Through simulations, the fine mapping performance of this entropy-based index is investigated extensively under various genetic parameters. The results show that the indices presented here are both robust and powerful. 展开更多
关键词 ENTROPY entropy-based Index QTL fine mapping
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浅谈常用的两个算理问题
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作者 张姬玉 文武 《珠算与珠心算》 2008年第4期32-36,共5页
珠算界算理的发展可以说品类繁多,但更重要的是确定计算化数和二元示数两个问题。这两个问题虽然人们在推导算法中经常用到,但是并不是都做到了系统的掌握。
关键词 珠算界 算理法 定位数 标示方法
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QTL Mapping of Yield and Yield Components for Elite Hybrid Derived-RILs in Upland Cotton 被引量:7
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作者 汪保华 郭旺珍 +3 位作者 朱协飞 武耀廷 黄乃泰 张天真 《Journal of Genetics and Genomics》 SCIE CAS CSCD 北大核心 2007年第1期35-45,共11页
A population of 180 recombinant inbred lines (RILs) was developed by single seed descended from the cross of high yield Upland cotton (Gossypium hirsutum L.) varieties Zhongmiansuo12 (ZMSI2) and 8891, the two pa... A population of 180 recombinant inbred lines (RILs) was developed by single seed descended from the cross of high yield Upland cotton (Gossypium hirsutum L.) varieties Zhongmiansuo12 (ZMSI2) and 8891, the two parents of Xiangzamian2 (XZM2). A genetic linkage map consisting of 132 loci and covering 865.20 cM was constructed using the RIL population chiefly with SSR markers. Yield and yield components were investigated for RILs in three environments in China. The purpose of the present research was to analyze the relationship between yield and its components and to map QTL for yield and yield components in cotton. QTL were tagged with data sets from single environment (separate analysis) and a set of data from means of the three environments (joint analysis). A total of 34 QTL for yield and yield components were independently detected in three environments, whereas fifteen QTL were found in joint analysis. Notably, a stable lint percentage QTL qLP-A10-1 was detected both in joint analysis and in two environments of separate analysis, which might be of special value for marker-assisted selection. The QTL detected in the present study provide new information on improving yield and yield components. Results of path analysis showed that bolls/plant had the largest contribution to lint yield, which is consistent with the mid-parent heterosis value in F1. Accordingly, in cotton breeding, bolls/plant can be considered first and other yield components measured as a whole to implement variety enhancement and hybrid selection of cotton. 展开更多
关键词 QTL mapping yield and yield components recombinant inbred lines cotton breeding
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Determination of Stability Constants of Cadmium-Glycine Complexes by a Unified Treatment for Potentiometric and Polarographic Data
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作者 张建民 石秋芝 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2006年第2期164-168,共5页
The cadmium(Ⅱ)-glycine system was studied by the two experimental techniques, ion sensitive electrode (ISE) and differential pulse polarography (DPP), and the experimental data obtained were used by a unified m... The cadmium(Ⅱ)-glycine system was studied by the two experimental techniques, ion sensitive electrode (ISE) and differential pulse polarography (DPP), and the experimental data obtained were used by a unified mathematical treatment to calculate the complex stability constants. The combination of the two techniques is of many advantages as ISE can be performed at low [LT]:[MT] ratios and significantly higher [MT], whereas DPP could be used well at large [LT]:[MT] ratios and much smaller [MT]. This makes it possible to study a metal-ligand system in a relatively broader range of experimental conditions that, in turn, provides more information about the metakligand system of interest. Applying the unified mathematical treatment to the cadmium-glycine system, two new complexes MHL and ML2(OH) as well as three complexes ML, ML2 and ML3, reported in literatures, could be modeled and all their stability constants have been refined. 展开更多
关键词 Metal complex POLAROGRAPHY POTENTIOMETRY Stability constant
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STC汉字系统生成报表的技巧和方法
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作者 刘世祥 《干旱气象》 1991年第3期41-,56,共2页
在计算机上生成报表要解决的问题有以下几个方面:报表的格式大体上要符合常用的,而且是人们习贯的格式;要有一套与报表划线相匹配的划线符号;字符要控制到合适的位置上等。现从以上几方面探讨在STC 汉字系统下生成报表的方法以及处理上... 在计算机上生成报表要解决的问题有以下几个方面:报表的格式大体上要符合常用的,而且是人们习贯的格式;要有一套与报表划线相匹配的划线符号;字符要控制到合适的位置上等。现从以上几方面探讨在STC 汉字系统下生成报表的方法以及处理上述问题的技巧。 展开更多
关键词 系统生成 STC 报表格式 控制语句 最大长度 位置控制 下边界 内部连接 问题解决 定位数
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