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基于浮动基准体系的生成型特征设计 被引量:1
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作者 黄永红 吴红明 +1 位作者 季鹏斌 唐荣锡 《计算机辅助设计与图形学学报》 EI CSCD 北大核心 1998年第3期233-240,共8页
生成型特征的形状是由二维参数化勾画轮廓扫描而成;浮动基准体系用来引导特征的设计,特征与特征以及特征与产品模型之间的依赖关系都可以通过浮动基准体系来建立;基准所依赖的对象被删除时,通过将此基准拷贝成虚基准,使此基准以及... 生成型特征的形状是由二维参数化勾画轮廓扫描而成;浮动基准体系用来引导特征的设计,特征与特征以及特征与产品模型之间的依赖关系都可以通过浮动基准体系来建立;基准所依赖的对象被删除时,通过将此基准拷贝成虚基准,使此基准以及依附于它的特征仍然可以保留并悬浮在模型里.这样就可以对特征进行局部修改. 展开更多
关键词 成型特征 勾画轮廓 浮动基准体系 CAD
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生成型特征设计中的剪贴操作 被引量:1
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作者 黄永红 季鹏斌 +1 位作者 吴红明 唐荣锡 《计算机辅助设计与图形学学报》 EI CSCD 北大核心 1998年第6期506-515,共10页
提出并实现了生成型特征设计中的特征剪贴的方法.允许从已构建的产品模型中“剪切”下一部分特征和约束几何对象,然后“粘贴”在模型的另一地方.本文的方法支持对模型的重用、交互构建特征标准件库和特征轮廓库以及用这些标准件进行... 提出并实现了生成型特征设计中的特征剪贴的方法.允许从已构建的产品模型中“剪切”下一部分特征和约束几何对象,然后“粘贴”在模型的另一地方.本文的方法支持对模型的重用、交互构建特征标准件库和特征轮廓库以及用这些标准件进行设计. 展开更多
关键词 成型特征设计 特征剪贴 标准件 CAD
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棒材等离子喷涂法制备Fe_(72)Cr_8P_(13)C_7非晶态合金涂层成型特征 被引量:1
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作者 雷阿利 唐文浩 《铸造技术》 CAS 北大核心 2007年第7期965-967,共3页
采用棒材等离子喷涂法制备Fe72Cr8P13C7非晶态合金涂层,分析了涂层的组织,测定了晶化温度、显微硬度和结合强度,采用扫描电镜观察涂层的微观形貌和截面形貌,能谱分析涂层正面和截面的成分变化。结果表明,涂层组织致密,均匀,Cr、P在涂层... 采用棒材等离子喷涂法制备Fe72Cr8P13C7非晶态合金涂层,分析了涂层的组织,测定了晶化温度、显微硬度和结合强度,采用扫描电镜观察涂层的微观形貌和截面形貌,能谱分析涂层正面和截面的成分变化。结果表明,涂层组织致密,均匀,Cr、P在涂层中片状结构表面有富集现象,涂层与基材之间有冶金结合、机械结合的成型特征。 展开更多
关键词 棒材 等离子喷涂 非晶涂层 成型特征
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基于UG的工艺符号和成型特征开发
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作者 郑顺水 杨金华 陈阳 《兵工自动化》 2003年第4期25-28,共4页
针对工艺设计中工艺符号和成型特征的开发,以Unigraphics软件为基础,系统地论述了应用GRIP、User Tools 和UG/Open MenuScript等二次开发工具进行成型特征生成、工艺符号定义、用户工具条和菜单文件的编写,以及将用户开发的功能集成到U... 针对工艺设计中工艺符号和成型特征的开发,以Unigraphics软件为基础,系统地论述了应用GRIP、User Tools 和UG/Open MenuScript等二次开发工具进行成型特征生成、工艺符号定义、用户工具条和菜单文件的编写,以及将用户开发的功能集成到UG中等应用开发的方法和过程。 展开更多
关键词 UG 工艺符号 工艺设计 成型特征模型 GRIP UNIGRAPHICS 工序图 工具条 用户菜单
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3D模型重建中成型特征识别与参数提取技术
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作者 孙秀峰 张树生 +1 位作者 范海涛 王成 《微处理机》 2011年第5期58-61,65,共5页
以数字化工艺卡片为研究对象,在已知成型特征类型的前提下,提出一种新的面向三维工序模型重建的成型特征识别与参数提取方法。首先对工序图进行连通域的划分,然后采用最小转角法从连通域中提取成型特征的轮廓线,并与预定义特征进行匹配... 以数字化工艺卡片为研究对象,在已知成型特征类型的前提下,提出一种新的面向三维工序模型重建的成型特征识别与参数提取方法。首先对工序图进行连通域的划分,然后采用最小转角法从连通域中提取成型特征的轮廓线,并与预定义特征进行匹配,对于标准类特征采用编码法进行特征识别,随后进行尺寸标注识别,从中提取出成型特征的特征参数,重建成型特征的三维模型。最后,开发了原型系统,并进行了应用验证。 展开更多
关键词 成型特征 三维工序模型重建 特征识别 参数提取
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压铸件成型特征与建模方法的研究
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作者 高峰 《煤矿机械》 2015年第2期107-109,共3页
研究压铸件形状特征,给出了压铸件形状特征数学描述方法,建立了基于特征的压铸件脱模方向与压铸件内、外轮廓曲面判别条件,为压铸模具分型面与成型零件设计方法研究提供了初始数学模型。
关键词 成型特征 建模方法 压铸件
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基于特征成型方式的可重构机床配置优化方法 被引量:1
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作者 江来臻 刘永 +2 位作者 杨明顺 高新勤 李言 《制造业自动化》 2016年第11期104-109,共6页
可重构机床作为可重构制造系统的重要组成部分是解决未来机械制造业大批量定制化生产的核心技术之一,可重构机床结构的有效配置是准确快速响应客户需求的关键。故以可重构机床为研究对象,提出一种基于零件特征成型方式的可重构机床结构... 可重构机床作为可重构制造系统的重要组成部分是解决未来机械制造业大批量定制化生产的核心技术之一,可重构机床结构的有效配置是准确快速响应客户需求的关键。故以可重构机床为研究对象,提出一种基于零件特征成型方式的可重构机床结构配置优化方法。根据零件特征及其成型方式,分别从刀具和工件侧进行机床模块关联,实现机床功能部件群的构建;利用多色集合理论建立特征成型元素与可重构机床功能部件的映射关系模型,通过搜索该模型的围道布尔矩阵,获得可行的可重构机床配置方案;设计以可重构机床模块数、成本、功能冗余度为综合评价指标的配置方案优化方法,并以实例验证其正确性和有效性。 展开更多
关键词 可重构机床 特征成型方式 多色集合理论 配置方案优化
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联合波束成型分组排序线性离散码及其检测方法 被引量:1
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作者 金江 汪俊芳 朱光喜 《电子学报》 EI CAS CSCD 北大核心 2007年第B06期93-97,共5页
针对多入多出(MIMO)相关信道,提出联合波束成型分组排序线性离散码(BO-JBLDC)及其解码方法.发送天线被分割成多个组,每组进行独立的线性离散码(LDC)编码来获得空分复用增益.采用发送和接收特征波束成型降低信道相关性的影响.提出新的后... 针对多入多出(MIMO)相关信道,提出联合波束成型分组排序线性离散码(BO-JBLDC)及其解码方法.发送天线被分割成多个组,每组进行独立的线性离散码(LDC)编码来获得空分复用增益.采用发送和接收特征波束成型降低信道相关性的影响.提出新的后排序分组干扰抑制与抵消解码方法及其循环迭代机制,消除组间干扰,使得各组均获得满接收分集增益.结果显示BO-JBLDC能获得高频谱效率并适用于任意天线配置,尤其在大天线数、高速率情况下可以明显降低解码复杂度,提高编码增益. 展开更多
关键词 多天线系统 特征波束成型 分组排序线性离散码 干扰抑制与抵消 迭代解码
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基于协方差反馈的多天线系统优化发送研究 被引量:2
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作者 金江 汪俊芳 朱光喜 《微电子学与计算机》 CSCD 北大核心 2006年第12期4-7,11,共5页
为了克服多天线信道相关性的影响,提出一种新的自适应发送方案。应用空时分组码特征波束成型技术和格形编码调制(TCM)来获得分集增益和编码增益。针对采用和不采用交织器两种情况,基于成对差错概率(PEP)准则,分析了系统的统计性能,分别... 为了克服多天线信道相关性的影响,提出一种新的自适应发送方案。应用空时分组码特征波束成型技术和格形编码调制(TCM)来获得分集增益和编码增益。针对采用和不采用交织器两种情况,基于成对差错概率(PEP)准则,分析了系统的统计性能,分别得到了使系统编码增益和分集增益最大化的TCM设计准则。根据注水法则和Lagrange乘子法求得波束间功率分配算法最优解。此外,码距作为优化功率加载算法中的权重因子,有效降低了获取波束成形分集的信噪比门限。分析和实验结果表明此方案复杂度低,能有效克服相关衰落。 展开更多
关键词 无线通信 特征波束成型 功率分配 协方差反馈 交织 格形编码调制
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Characterization and formation mechanisms of fractures and their significance to hydrocarbon accumulation: A case study of Lower Ordovician mid-assemblage Formations in central Ordos Basin, China 被引量:2
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作者 ZHAO Zi-long ZHAO Jing-zhou +2 位作者 REN Hai-jiao LI Jun WU Wei-tao 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第11期2766-2784,共19页
The lower Ordovician mid-assemblage Formations in the central Ordos Basin of China host prolific gas resources,and most hydrocarbon reserves are stored in naturally-fractured reservoirs.Thus,fracture pathway systems m... The lower Ordovician mid-assemblage Formations in the central Ordos Basin of China host prolific gas resources,and most hydrocarbon reserves are stored in naturally-fractured reservoirs.Thus,fracture pathway systems may have a significant impact on reservoir performance.This article focuses on the core-and laboratory-based characterization of fractures.Through the developmental degrees,extended scale,output state and filling characteristics of various types of fractures,the results show that there are three distinct fracture types:1)nearly vertical fractures,2)oblique fractures,and 3)horizontal fractures.Based on a systematic study of the characterization of reservoir space,the main geologic setting of natural gas accumulation and the regional tectonic background,type 1 is mainly driven by the tectonic formation mechanism,and type 3 and parts of low-angle fractures in type 2 are induced by the diagenetic formation mechanism.While recovered paleopressure for methane-rich aqueous inclusions trapped in fracture-filling cement indicates that the fracture opening and growth are consistent with gas maturation and charge and such high-angle fractures in type 2 are caused by the compound formation mechanism.The fractures to hydrocarbon accumulation may play a more significant role in improving the quality of reservoir porosity.Furthermore,connected fractures,dissolved pores and cavities together constitute the three-dimensional pore-cave-fracture network pathway systems,with faults serving as the dominant charge pathways of highly pressurized gas in the study area.Our results demonstrate that protracted growth of a pervasive fracture system is not only the consequence of various formation mechanisms but also intrinsic to quasi-continuous accumulation reservoirs. 展开更多
关键词 characterization of fracture formation mechanism quasi-continuous accumulation Ordovician mid-assemblage formations Ordos basin
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Characterization of Lay Phase in Three Genetic Types of Heavy Broilers Breeder in Tropical Conditions
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作者 Jose Angel Miguel Edilberto Acevedo +1 位作者 Jesus Ciria Begona Asenjo 《Journal of Agricultural Science and Technology(A)》 2013年第10期766-774,共9页
The objective of the present work is characterizing some parameters in the lay phase in the lines of heavy broilers breeder Cobb Avian 48, Arbor Acres Plus and Ross 208, reared under the same commercial conditions in ... The objective of the present work is characterizing some parameters in the lay phase in the lines of heavy broilers breeder Cobb Avian 48, Arbor Acres Plus and Ross 208, reared under the same commercial conditions in the tropics. Monitored three batches of approximately 18,000 females each (one for each genetic type), from weeks 24 to 64, according to the conditions of handling and power described by the generic lines distribution companies. Although no differences were found for feed intake, Cobb Avian was presented a lower rate of feed conversion, being also that presented the highest percentage of implementation and production of incubables eggs, which meant that it was in line with the highest cumulative production of chickens by bird and week for tropical conditions studied. To adjust the lay data to a Gorssman model, in order to predict the parameters that characterize the lay modeling, estimated the best behavior for Cobb Avian 48 females, because while it takes more time to reach the level of putting constant (5.30 weeks) and maintain it for less time (2.4 weeks), they manage to put constant high (79.11%) level, considering that the largest number of eggs per bird (171.19 vs. 164.54 and 160.11 in Arbor Acres and Ross 208, respectively). 展开更多
关键词 Arbor acres plus Cobb Avian 48 heavy broilers breeder lay intensity lay modeling Ross 208.
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Study on Automatic Generation Algorithm of LOD Model based on Complex Features
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作者 Sun DaPeng Yang ChengJie 《International Journal of Technology Management》 2013年第9期45-47,共3页
For certain applications, the paper proposes a LOD generation algorithm based on model feature, to measure the value of certain features as weight, and to just the geometrical characteristics and retains the full feat... For certain applications, the paper proposes a LOD generation algorithm based on model feature, to measure the value of certain features as weight, and to just the geometrical characteristics and retains the full feature in the simplified model. Algorithm is simple and intuitive, LOD models can be generated by a continuous smooth transition and meet the requirements of real-time display. Experimental results show the effectiveness of the algorithm. Algorithm is simple and quick, broad applicability, the improve simplified algorithm is very suitable for modulation texture operator, generating algorithm based on a lookup table to meet the model requirements for real-time display. 展开更多
关键词 virtual reality LOD models improved model
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Classification of breast lesions based on a dual S-shaped logistic model in dynamic contrast enhanced magnetic resonance imaging 被引量:8
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作者 DANG Yi GUO Li +2 位作者 LV DongJiao WANG XiaoYing ZHANG Jue 《Science China(Life Sciences)》 SCIE CAS 2011年第10期889-896,共8页
This study proposes a novel dual S-shaped logistic model for automatically quantifying the characteristic kinetic curves of breast lesions and for distinguishing malignant from benign breast tumors on dynamic contrast... This study proposes a novel dual S-shaped logistic model for automatically quantifying the characteristic kinetic curves of breast lesions and for distinguishing malignant from benign breast tumors on dynamic contrast enhanced (DCE) magnetic resonance (MR) images.D(,) is the diagnostic parameter derived from the logistic model.Significant differences were found in D(,) between the malignant benign groups.Fisher's Linear Discriminant analysis correctly classified more than 90% of the benign and malignant kinetic breast data using the derived diagnostic parameter (D(,)).Receiver operating characteristic curve analysis of the derived diagnostic parameter (D(,)) indicated high sensitivity and specificity to differentiate malignancy from benignancy.The dual S-shaped logistic model was effectively used to fit the kinetic curves of breast lesions in DCE-MR.Separation between benign and malignant breast lesions was achieved with sufficient accuracy by using the derived diagnostic parameter D(,) as the lesion's feature.The proposed method therefore has the potential for computer-aided diagnosis in breast tumors. 展开更多
关键词 logistic model breast cancer dynamic contrast enhanced magnetic resonance imaging
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The Effect of Corporate Governance on Debt Financing Cost of Listed Companies 被引量:2
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作者 LI Lin DONG Fangyu +2 位作者 LIU Yifang HUANG Haijun WANG Shouyang 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2016年第3期772-788,共17页
In recent years, bank credit business is booming with the increasing borrowing retention o~ China's listed companies, and debt financing has become the major approach among listed companies' financing strategies. As... In recent years, bank credit business is booming with the increasing borrowing retention o~ China's listed companies, and debt financing has become the major approach among listed companies' financing strategies. As a series of institutional arrangements about rights, responsibilities and benefits between different shareholders, corporate governance mechanism has a significant influence on the cost of debt financing. This paper employs variable coefficient panel data model to investigate the relationship of the listed company's debt financing costs and corporate governance mechanism in terms of structural characteristics and time series characteristics. The results show that optimizing the structure of both Board of Directors and Board of Supervisors, establishing a reasonable management incentive system and reducing the concentration of ownership properly can directly contribute to a lower company's debt financing costs. Meanwhile, property rights have an interactive influence on corporate governance from four aspects, which indirectly effect in company's debt financing costs. 展开更多
关键词 Corporate governance debt financing cost property rights.
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