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SEMI-OPENNESSAND ALMOST-OPENNESS OF INDUCED MAPPINGS 被引量:1
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作者 HuangXianjiu ZengFanping ZhangGengrong 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2005年第1期21-26,共6页
Given a mapping f between continua.Let 2f and C(f) mean the induced mappings between hyperspaces.Relations are studied under the conditions:f is semi-open(almost open,respectively),2f is semi-open(almost open,respecti... Given a mapping f between continua.Let 2f and C(f) mean the induced mappings between hyperspaces.Relations are studied under the conditions:f is semi-open(almost open,respectively),2f is semi-open(almost open,respectively) and C(f) is semi-open(almost open,respectively). 展开更多
关键词 Continuum HYPERSPACE induced mapping semi-openness almost open.
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Experimental study on transient behavior of semi-open two-phase thermosyphon 被引量:1
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作者 朱华 王建新 +1 位作者 张巧惠 屠传经 《Journal of Zhejiang University Science》 EI CSCD 2004年第12期1565-1569,共5页
An experimental system was set up to measure the temperature, pressure, heat transfer rate and mass flow rate in a semi-open two-phase thermosyphon. The behaviors of a semi-open two-phase thermosyphon during startup, ... An experimental system was set up to measure the temperature, pressure, heat transfer rate and mass flow rate in a semi-open two-phase thermosyphon. The behaviors of a semi-open two-phase thermosyphon during startup, shutdown and lack of water were studied to get complete understanding of its thermal characteristics. The variation of wall temperature, heat-exchange condition and pressure fluctuations of semi-open two-phase thermosyphons showed that the startup of SOTPT needs about 60-70 min; the startup speed of SOTPT is determined by the startup speed of the condensation section; the average pressure in the heat pipe is equal to the environmental pressure usually; the shutdown of SOTPT needs about 30-50min; a semi-open two-phase thermosyphon has good response to lack of water accident. 展开更多
关键词 semi-open two-phase thermosyphon (SOTPT) Transient heat transfer STARTUP Lack of water SHUTDOWN
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Theoretical and experimental research on heat transfer performance of the semi-open heat pipe
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作者 Hua ZHU Bo ZHUAN +1 位作者 Jin-jun TAN Rong-hua HONG 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2008年第3期410-415,共6页
This paper focuses on the heat transfer performance of semi-open heat pipe which is a new type of heat pipe. After analyzing its condensation heat transfer mechanisms theoretically, several semi-open heat pipes in dif... This paper focuses on the heat transfer performance of semi-open heat pipe which is a new type of heat pipe. After analyzing its condensation heat transfer mechanisms theoretically, several semi-open heat pipes in different length ratios and upper hole diameters are studied experimentally and compared with the same dimensions closed heat pipes. Experimental results show that the heat transfer performance of semi-open heat pipe becomes better by increasing heat transfer rate. At the first transitional point, the heat transfer performance of semi-open heat pipe approaches the level of the closed heat pipe. It is suitable to choose upper small hole about 1 mm in diameter and length ratio larger than 0.6 for the semi-open heat pipe. 展开更多
关键词 semi-open heat pipe Heat transfer performance Closed heat pipe First transitional point
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Effect of Pre-Swirling Flow on Performance and Flow Fields in Semi-Opened Axial Fan
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作者 Norimasa Shiomi Pin Liu Yoichi Kinoue 《Open Journal of Fluid Dynamics》 CAS 2023年第2期113-121,共9页
In this study, we tried to improve the performance by giving a pre-swirling flow to the radial inflow that occurred in the semi-opened axial fan. In addition, the flow fields of rotor outlet were clarified experimenta... In this study, we tried to improve the performance by giving a pre-swirling flow to the radial inflow that occurred in the semi-opened axial fan. In addition, the flow fields of rotor outlet were clarified experimentally, and the effect of pre-swirling flow was considered. The experiment was carried out using a performance test wind tunnel with a square cross section of 880 mm. Three types of casings were prepared, in which the blade tip protruded 0%, 20%, and 40% of the meridional chord length. They were called R25, R15, and R05, respectively, in the casing bellmouth model code. Guide blades for generating a pre-swirling flow were installed on the vertical wall surface of the casing. In addition, a vertical wall was installed 60% upstream of the meridional chord length as an obstacle to prevent axial inflow. The velocity fields of the rotor outlet were measured using a hot-wire anemometer. From the results, the pre-swirling flow did not significantly affect the fan performance. When there was no obstacles wall upstream, there was a partial increase in efficiency, but the difference was not so large. When there was an obstacle wall upstream, the efficiency increased overall in the case of R15, but in the case of R05, the efficiency increased only in the low flow rate region, and conversely decreased in the high flow rate region. By observing the blade outlet flow fields when the performance was improved, it was confirmed that the influence of the tip leakage vortex was weakened. 展开更多
关键词 Axial Fan semi-opened Narrow Space Pre-Swirling Flow Fan Performance
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Flow Fields with Vortex in a Small Semi-open Axial Fan 被引量:14
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作者 Norimasa. Shiomi Yoichi Kinoue +2 位作者 Ying zi Jin Toshiaki Setoguchi Kenji Kaneko 《Journal of Thermal Science》 SCIE EI CAS CSCD 2009年第4期294-300,共7页
In order to clarify the effect of tip clearance (TC) size on fan performance and the flow field at rotor outlet in a small semi-open axial fan, the experimental investigation was carried out. The tip diameter of tes... In order to clarify the effect of tip clearance (TC) size on fan performance and the flow field at rotor outlet in a small semi-open axial fan, the experimental investigation was carried out. The tip diameter of test fan rotor was 180mm and test TC sizes were lmm (TC=1mm) and 4mm (TC=4mm). Fan characteristics tests were carried out for two cases of TC size and three-dimensional velocity fields at rotor outlet were measured using a single slant hot-wire probe at four flow-rate conditions. As a result, it was found that the pressure - flow-rate characteristics curves for two cases showed almost the same tendency. However, the ensemble averaged velocity profiles along radial measurement stations of TC-4mm largely changed compared with that of TC=1mm in cases of small flow-rate condition. From the phase-locked averaging results, it was also found that the vortex existed in the rotor outlet flow field of high flow-rate condition for each TC case. Compared with the vortices for TC=1mm and TC=4mm, the vortex for TC=4mm was stronger than that for TC=1mm. 展开更多
关键词 FAN semi-open type VORTEX tip clearance
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基于数值模拟的半开式叶片垂直轴风力机气动性能
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作者 宋磊 王记 +1 位作者 杨宗霄 苏建新 《新能源进展》 北大核心 2026年第1期70-78,共9页
传统H型风力机的风能利用率高,输出性能较优,但在低风速工况下难以启动,导致其自启动性能较差。为改善其综合气动性能,针对一种半开式叶片垂直轴风力机开展研究。通过对标准翼型叶片结构进行改进,获得半开式叶片垂直轴风力机的结构及参... 传统H型风力机的风能利用率高,输出性能较优,但在低风速工况下难以启动,导致其自启动性能较差。为改善其综合气动性能,针对一种半开式叶片垂直轴风力机开展研究。通过对标准翼型叶片结构进行改进,获得半开式叶片垂直轴风力机的结构及参数,基于CFD数值模拟研究其静态性能与动态性能,并与标准翼型风力机进行对比。结果表明:半开式叶片垂直轴风力机的平均静扭矩系数高于标准翼型风力机,启动性能更好;其最大功率系数为0.345,具有良好的输出性能。研究表明半开式叶片风力机在低风速启动与风能高效输出方面具有良好的综合性能。 展开更多
关键词 垂直轴风力机 数值模拟 气动性能 半开式叶片
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Creating a semi-opened micro-cavity ovary through sacrificial microspheres as an in vitro model for discovering the potential effect of ovarian toxic agents 被引量:1
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作者 Min Ye Yiran Shan +9 位作者 Bingchuan Lu Hao Luo Binhan Li Yanmei Zhang Zixuan Wang Yuzhi Guo Liliang Ouyang Jin Gu Zhuo Xiong Ting Zhang 《Bioactive Materials》 SCIE CSCD 2023年第8期216-230,共15页
The bio-engineered ovary is an essential technology for treating female infertility.Especially the development of relevant in vitro models could be a critical step in a drug study.Herein,we develop a semi-opened cultu... The bio-engineered ovary is an essential technology for treating female infertility.Especially the development of relevant in vitro models could be a critical step in a drug study.Herein,we develop a semi-opened culturing system(SOCS)strategy that maintains a 3D structure of follicles during the culture.Based on the SOCS,we further developed micro-cavity ovary(MCO)with mouse follicles by the microsphere-templated technique,where sacrificial gelatin microspheres were mixed with photo-crosslinkable gelatin methacryloyl(GelMA)to engineer a micro-cavity niche for follicle growth.The semi-opened MCO could support the follicle growing to the antral stage,secreting hormones,and ovulating cumulus-oocyte complex out of the MCO without extra manipulation.The MCO-ovulated oocyte exhibits a highly similar transcriptome to the in vivo counterpart(correlation of 0.97)and can be fertilized.Moreover,we found that a high ROS level could affect the cumulus expansion,which may result in anovulation disorder.The damage could be rescued by melatonin,but the end of cumulus expansion was 3h earlier than anticipation,validating that MCO has the potential for investigating ovarian toxic agents in vitro.We provide a novel approach for building an in vitro ovarian model to recapitulate ovarian functions and test chemical toxicity,suggesting it has the potential for clinical research in the future. 展开更多
关键词 Bio-engineered ovary SOCS semi-opened MCO Ovarian model Drug study
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A typological,environmental and socio-cultural study of semi-open spaces in the Eastern Mediterranean vernacular architecture:The case of Cyprus 被引量:1
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作者 Maria Philokyprou Aimilios Michael Eleni Malaktou 《Frontiers of Architectural Research》 CSCD 2021年第3期483-501,共19页
Semi-open spaces-largely incorporated in vernacular dwellings in Cyprus during the 19th and 20th centuries-formed diachronically significant socio-cultural, functional and environmental features of the vernacular arch... Semi-open spaces-largely incorporated in vernacular dwellings in Cyprus during the 19th and 20th centuries-formed diachronically significant socio-cultural, functional and environmental features of the vernacular architecture of the area. The climate of the Eastern Mediterranean region, i.e., hot summers and mild winters, encouraged the use of open weather protected spaces, thus leading to the widespread incorporation of such spaces in the vernacular architecture of the region. This paper focuses on the interconnections between architectural forms and human comfort, convenience or pleasure in relation to the semiopen spaces found in the vernacular architecture of Cyprus-an island in the Eastern Mediterranean region. For the purpose of this research, characteristic traditional settlements found in the coastal, lowland and mountainous areas-which represent three different climatic regions and topographies of the island-were selected for an in-depth investigation. The findings confirm a high frequency of semi-open spaces, as well as the existence of a remarkable richness of typologies. Although semi-open spaces constitute a fundamental part of the structure of these vernacular dwellings in all climatic regions examined, they dominate in the lowland regions due to the particularly hot climate, as well as the specific activities of the inhabitants of these areas. The prevailing architectural forms and constructions of these spaces in each climatic region under investigation was found to be closely adapted to the local resources, terrain and climate, while also being related to the social, household and agricultural needs of the inhabitants, thus underlining their sustainable and locus-specific conception. Research findings can contribute towards critically re-thinking semi-open spaces and their inherent value in rehabilitation projects, as well as in contemporary residential architecture. 展开更多
关键词 semi-open spaces Vernacular residential architecture Different climatic regions and topographies TYPOLOGY Environmentally responsive design Socio-cultural aspects
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喷气涡流纺成纱气流场及纤维运动模拟分析和实验
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作者 付佳琦 吉陈湘 杨瑞华 《纺织学报》 北大核心 2026年第1期89-97,共9页
为明确喷气涡流纺纺纱过程中加捻腔内的气流变化和纤维运动规律,对引纱过程和稳定纺纱过程中的气流和纤维运动进行模拟研究。结果表明:高速旋转气流的卷吸作用使得喷嘴入口形成负压气流吸入纤维,还导致加捻腔出现向上运动的气流,在纤维... 为明确喷气涡流纺纺纱过程中加捻腔内的气流变化和纤维运动规律,对引纱过程和稳定纺纱过程中的气流和纤维运动进行模拟研究。结果表明:高速旋转气流的卷吸作用使得喷嘴入口形成负压气流吸入纤维,还导致加捻腔出现向上运动的气流,在纤维输入通道内形成回流区域。引纱纺纱过程中喷嘴加捻腔内的气流场分布规律与纺纱阶段下的分布规律相似,但是受到空心管内的气流影响,越靠近空心锭口,负压值和气流速度就越大,越靠近导引针,梯度越不明显,在引纱通道内有明显的压力、速度梯度分布。在纺纱过程中纤维在喷嘴内的运动分为4个阶段,分别对应纤维输入通道进出口、加捻腔进出口、空心锭表面停留和引纱管进出口。从纤维输入通道进口到出口纤维速度逐渐增大,进入加捻腔后加速度进一步增大,速度更快,继续向前接触空心锭表面在进入引纱管前,纤维速度逐渐降低,进入引纱管后速度提高并在引纱管出口达到最大;在引纱过程纤维速度变化与此类似。 展开更多
关键词 喷气涡流纺 数值模拟 加捻腔 气流运动 纤维运动 新型纺纱 半自由端纺纱
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基于域对抗神经网络的半监督水声目标识别方法
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作者 杜箫扬 洪峰 《声学学报》 北大核心 2026年第1期145-157,共13页
现有水声目标被动识别方法存在模型跨域泛化能力不足以及对未知目标适应性不足的问题。本文提出一种基于联合训练策略的最大平均差异域对抗网络,将最大均值差异度量融入域对抗训练框架,通过约束域分类器的优化过程实现跨域特征对齐,同时... 现有水声目标被动识别方法存在模型跨域泛化能力不足以及对未知目标适应性不足的问题。本文提出一种基于联合训练策略的最大平均差异域对抗网络,将最大均值差异度量融入域对抗训练框架,通过约束域分类器的优化过程实现跨域特征对齐,同时,通过联合训练机制学习一维频谱与二维梅尔频率倒谱系数特征所包含的信息,并设计包含特征模板构建、动态阈值确定与相似度匹配的三阶段开集识别机制。在DeepShip数据集闭集跨域任务中,算法在半监督条件下可达到73.83%的平均识别准确率,相较于原始域对抗神经网络算法提升约11%。在开集识别场景下,对未知目标的识别准确率达63.44%,较传统方法提升约35%。实验结果表明,所提方法能有效缓解域失配问题,同时可以在有限标注条件下兼顾已知类判别与未知类检测的双重需求。 展开更多
关键词 水声目标识别 半监督学习 域自适应 开集识别
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Unsteady Flow at Low Flow-rate Region in a Semi-open Propeller Fan (Velocity Fluctuation outside of Blade Tip)
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作者 Norimasa SHIOMI Yoichi KINOUE Toshiaki SETOGUCHI 《Journal of Thermal Science》 SCIE EI CAS CSCD 2011年第3期218-223,共6页
In order to clarify the unsteady flow fields at low flow-rate region with positive gradient on pressure-flow-rate curve,the experimental investigation was carried out at rotor inlet and outside of rotor blade tip with... In order to clarify the unsteady flow fields at low flow-rate region with positive gradient on pressure-flow-rate curve,the experimental investigation was carried out at rotor inlet and outside of rotor blade tip without casing in a semi-opened propeller fan using a hot-wire anemometer.A single I-type hot-wire probe was used,and the data obtained were processed by the use of phase-locked averaging,ensemble averaging and FFT analyzing.The flow fields at rotor inlet and outside of rotor blade tip were discussed mainly using the results from distributions of velocity fluctuations and power spectrum density.It was found from these results that there are the two types of different periodical fluctuations and both of those frequencies were not the same of rotor rotating frequency(RRF;15Hz).One was observed at relatively high flow-rate region at relatively downstream area in measurement and its frequency was approximately 7Hz(47% of RRF).The other was observed at relatively low flow-rate region at relatively upstream area in measurement and its frequency was approximately 10Hz(67% of RRF)".As the velocity fluctuations with the flow fields are rapidly increased by the former fluctuation,it is thought that its fluctuation is the trigger of blade stall. 展开更多
关键词 semi-opened fan Propeller fan Unsteady flow measurement and FFT analysis
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基于Hydrus-1D的半开放空间含水率热源影响分析
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作者 张晓周 徐小青 李治郡 《陕西水利》 2026年第3期5-7,共3页
为探究不同热源对成都平原半开放空间土壤含水率的影响规律,本文基于Hydrus-1D软件构建了一维水-热耦合模型,模拟水-土-气系统中土气界面含水率的动态变化过程。通过设置不同热源温度、蒸发量及土壤特性参数,分析水分在土壤中的运移规... 为探究不同热源对成都平原半开放空间土壤含水率的影响规律,本文基于Hydrus-1D软件构建了一维水-热耦合模型,模拟水-土-气系统中土气界面含水率的动态变化过程。通过设置不同热源温度、蒸发量及土壤特性参数,分析水分在土壤中的运移规律。结果表明:在恒定蒸发量条件下,当热源温度低于35℃时,半开放空间内土壤含水率变化不显著;然而,当热源温度超过35℃时,各层土壤含水率显著降低。研究结果可为半开放空间土气界面环境调控提供科学依据。 展开更多
关键词 HYDRUS-1D 水量转化 包气带 半开放空间
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基于半监督聚类的安全补丁分类方法
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作者 曹家俊 谈心 张源 《计算机应用与软件》 北大核心 2026年第1期50-58,74,共10页
由于有标签样本数量少和特征表示不佳等问题,现有方法在分类开源软件的安全补丁时准确率低。针对上述问题,提出基于半监督聚类的安全补丁分类方法。从补丁描述信息中提取特征,并结合对比学习方法编码特征表示以扩大各类型样本间区分度;... 由于有标签样本数量少和特征表示不佳等问题,现有方法在分类开源软件的安全补丁时准确率低。针对上述问题,提出基于半监督聚类的安全补丁分类方法。从补丁描述信息中提取特征,并结合对比学习方法编码特征表示以扩大各类型样本间区分度;根据特征相似性进行半监督聚类以形成数据分布更丰富的簇;通过度量样本与各簇之间的相似性来分类补丁。实验结果表明,该方法能够有效分类安全补丁,准确率优于现有最先进的补丁分类方法。 展开更多
关键词 开源软件 安全补丁分类 半监督聚类 对比学习
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叶顶间隙对半开式卫生型离心泵能量损失的影响
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作者 裴吉 王振涵 +3 位作者 陈佳 高晓飞 韩沛 王文杰 《排灌机械工程学报》 北大核心 2025年第5期433-440,共8页
为研究半开式卫生型离心泵在不同叶顶间隙下的能量特性,采用非定常数值模拟方法,通过外特性试验验证数值模拟方法的正确性,基于熵产理论对不同叶顶间隙下半开式离心泵的能量损失进行定性和定量分析,并讨论离心泵内能量损失产生的原因.... 为研究半开式卫生型离心泵在不同叶顶间隙下的能量特性,采用非定常数值模拟方法,通过外特性试验验证数值模拟方法的正确性,基于熵产理论对不同叶顶间隙下半开式离心泵的能量损失进行定性和定量分析,并讨论离心泵内能量损失产生的原因.结果表明:随着叶顶间隙的增大,泵内流动损失增大,进而导致泵外特性呈下降趋势;在较大间隙下,叶片工作面高压流体通过叶顶间隙流向叶片背面产生大量泄漏流,并与主流相互耦合形成泄漏涡,泄漏涡强度随间隙增大而变大,从而产生更大的能量损失;不同间隙下,泵内能量损失分布特征总体相似,各过流部件对应的总熵产由大到小依次为蜗壳、叶顶间隙、叶轮和进口管道,蜗壳能量损失最大,这主要是由转子与蜗壳强烈的交互耦合作用所致.研究结果可为半开式卫生型离心泵的性能改善提供一定理论支撑. 展开更多
关键词 离心泵 半开式叶轮 叶顶间隙 熵产理论 能量损失
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半开放植骨术治疗感染性骨缺损合并软组织缺损的临床疗效
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作者 李延炜 林金河 +2 位作者 薜超 陈长青 洪加源 《骨科》 2025年第4期325-330,共6页
目的 探讨半开放植骨术治疗四肢感染性骨缺损合并软组织缺损的疗效。方法 回顾性分析2020年3月至2023年4月我院采用半开放植骨术治疗的8例四肢感染性骨缺损合并软组织缺损病人的临床资料,其中男5例,女3例,年龄为(41.3±2.6)岁(14~68... 目的 探讨半开放植骨术治疗四肢感染性骨缺损合并软组织缺损的疗效。方法 回顾性分析2020年3月至2023年4月我院采用半开放植骨术治疗的8例四肢感染性骨缺损合并软组织缺损病人的临床资料,其中男5例,女3例,年龄为(41.3±2.6)岁(14~68岁);清创后骨缺损长度为(4.1±0.8)cm(2~13 cm),骨缺损体积为(24.3±2.2)cm^(3)(12~54 cm^(3)),软组织缺损面积为1.8 cm×0.7 cm~11 cm×6.5 cm。所有病例均由同一组术者进行骨清创,取自体髂骨松质骨填充骨缺损区,植骨区表面骨水泥片封闭覆盖,待植骨区表面肉芽覆盖后行植皮术等修复皮肤缺损。随访记录术后植骨区表面软组织充分覆盖时间、骨及软组织愈合时间、并发症等。结果 所有病人均获得随访,随访时间为(21.4±6.2)个月(10~47个月)。植骨区软组织膜层面充分覆盖时间为术后(7.4±2.1)周(2~16周),软组织愈合时间为(8.3±2.4)周(3~18周),骨愈合时间为(5.3±1.6)月(4~10月)。1例发生髂前上棘供区血肿积聚,通过部分拆线引流后治愈;1例植骨区表层骨缺血坏死,予浅层死骨清除,打通髓腔,延长骨水泥覆盖后治愈。结论 半开放植骨术可简便易行地处理复杂感染性骨缺损合并软组织缺损,对于符合适应证的病例是一种安全有效的选择。 展开更多
关键词 半开放植骨术 骨髓炎 骨感染 骨缺损 骨水泥
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十字轴模锻成形技术 被引量:1
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作者 程俊伟 赵创新 +1 位作者 陈喜乐 崔广鑫 《锻压技术》 北大核心 2025年第1期20-25,共6页
为了解决十字轴模锻成形时材料利用率低的问题,分析了卡压和闭式挤压两种变形方式下金属的受力和流动特征,以及这两种变形方式的难易程度,提出了半闭式预锻、开式终锻的工艺方案。在半闭式预锻过程中,轴颈处材料受到挤压、镦粗复合变形... 为了解决十字轴模锻成形时材料利用率低的问题,分析了卡压和闭式挤压两种变形方式下金属的受力和流动特征,以及这两种变形方式的难易程度,提出了半闭式预锻、开式终锻的工艺方案。在半闭式预锻过程中,轴颈处材料受到挤压、镦粗复合变形,得到4个轴颈几乎一致的坯料,且模具结构相对简单,容易实现。利用Deform软件模拟了模锻成形过程,预锻和终锻的模拟结果与理论分析一致。设计制造了锻模,并在模锻压力机上进行了工艺试验,得到了合格锻件,且飞边金属沿四周分布均匀,材料利用率提高约8%,验证了方案的可行性和合理性。 展开更多
关键词 十字轴 半闭式预锻 开式终锻 锻模 材料利用率
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面向开放世界的半监督特征选择算法
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作者 王锋 武文强 梁吉业 《计算机学报》 北大核心 2025年第6期1273-1289,共17页
现有的半监督学习方法大多遵循封闭世界假设,即在模型训练过程中类别信息保持不变,标记数据可以覆盖所有类别。然而,在实际应用中,这一假设往往难以满足,未标记数据中通常会包含大量的未知类数据样本。为此,近年来研究人员提出了一个极... 现有的半监督学习方法大多遵循封闭世界假设,即在模型训练过程中类别信息保持不变,标记数据可以覆盖所有类别。然而,在实际应用中,这一假设往往难以满足,未标记数据中通常会包含大量的未知类数据样本。为此,近年来研究人员提出了一个极具挑战性的研究方向:将半监督学习推广到不仅能够有效识别已知类的未标记数据样本,还能对未知的新类样本进行学习,从而构建面向开放世界的半监督学习机制。为应对这一挑战,本文基于符号型数据,提出了一种面向开放世界的半监督特征选择算法(OpenSSFS)。该算法将耦合学习引入到了符号型样本相似性度量以及类别关联性分析中,构建了新的样本相似性和类别相关性度量,并据此依次构建了三个核心模块:面向未标记已知类数据的自适应伪标签生成算法,面向未标记未知类数据的粒化和新类发现算法,以及基于类别相关性的特征选择算法。对给定的开放世界数据集,首先计算已知类数据样本的特征选择结果,并通过伪标签生成算法为未标记的已知类样本分配伪标签,进而基于所有已知类样本更新特征选择结果;其次,识别未知类未标记样本中的新类,并计算新类上的特征选择结果;最后,融合已知类样本和未知类样本的有效特征子集,确定最终的特征选择结果。为了有效验证所提新算法的有效性,本文在模拟的开放世界数据环境中进行了实验分析,分别测试了该算法在不同比例的已知类和未知类,以及不同比例的标记样本和未标记样本上的性能。实验结果表明,OpenSSFS算法在多种场景下均展现了较好的分类性能:首先,在包含50%已知类和50%未知类,且拥有50%标记样本的数据集上,新算法的分类精度最高提升了近70%,显著优于其他对比算法;其次,随着标记样本比例从90%降至10%,新算法的性能依然优于其他算法,且未出现明显下降,显示出较强的鲁棒性;最后,即使在已知类比例较低的情况下,OpenSSFS算法仍能保持良好的性能,适用于开放性更高的任务场景。此外,实验分析中还对算法中的参数阈值进行了详细分析和讨论。 展开更多
关键词 半监督学习 开放世界学习 特征选择 耦合学习 成对相似性
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烃源岩生烃模拟实验发展现状与研究方向
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作者 谢再波 郭子栋 +2 位作者 何卫军 张文 苏龙 《山西化工》 2025年第2期53-56,共4页
烃源岩生烃模拟实验是油气资源评价、油源对比等研究中极为重要的技术手段。根据模拟实验的体系开放程度可以分为开放体系、封闭体系和半开放体系,这三类实验方法具有各自优势和缺点。本文从生烃模拟实验的发展历程、烃源岩生烃的基本... 烃源岩生烃模拟实验是油气资源评价、油源对比等研究中极为重要的技术手段。根据模拟实验的体系开放程度可以分为开放体系、封闭体系和半开放体系,这三类实验方法具有各自优势和缺点。本文从生烃模拟实验的发展历程、烃源岩生烃的基本原理、不同体系实验装置的特点等方面进行了分析,以便在研究中根据不同的研究目的、烃源岩形成的地质背景、有机质类型和成熟度等选择不同的实验方法。探讨烃源岩生烃模拟实验的发展现状,对于提高油气勘探开发中的实验研究效率具有现实意义。 展开更多
关键词 烃源岩 生烃模拟 开放体系 封闭体系 半开放体系
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电石渣浆及清液输送系统的技术改造
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作者 王玉昌 《中国氯碱》 2025年第3期14-17,共4页
阐述了电石渣浆及清液输送系统中电石渣浆出料泵和渣浆清液输送泵在生产实践中存在的问题,结合介质特性和设备内部结构进行了技术改造,投入使用后运行效果良好。
关键词 电石渣浆 螺纹连接 闭式叶轮 半开式叶轮
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面向人脸年龄估计的开集半监督多任务学习方法
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作者 张珂 梁龙萍 +1 位作者 郭玉荣 王子念 《中国图象图形学报》 北大核心 2025年第12期3804-3823,共20页
目的人脸图像年龄估计在数字营销和人机交互等领域具有重要应用价值。然而,实现精确人脸年龄估计面临缺乏大规模有标签数据集的挑战。半监督学习方法能利用无标签数据集缓解此问题,但现有方法易引入错误伪标签,对年龄估计性能产生负面... 目的人脸图像年龄估计在数字营销和人机交互等领域具有重要应用价值。然而,实现精确人脸年龄估计面临缺乏大规模有标签数据集的挑战。半监督学习方法能利用无标签数据集缓解此问题,但现有方法易引入错误伪标签,对年龄估计性能产生负面影响。因此,提出一种面向人脸年龄估计的开集半监督多任务学习方法。方法首先,为了增强模型对局部和全局特征的处理能力,提出SwinLEDF模型,该模型以Swin Transformer作为主干网络,用于提取全局特征,并通过融合LEFF(local enhanced feed-forward)模块和DFN(dynamic filter networks)模块,进一步提升模型对局部特征的提取能力。其次,为了有效利用有标签数据和无标签数据中的有效信息,设计开集半监督多任务学习框架。在此框架中,模型通过标准闭集分类器和多类二元分类器的协同工作有效排除异常数据的干扰,采用自适应阈值方法确定性别、种族和年龄的伪标签,并引入负学习策略,以提高对无标签数据的利用率。结果在MORPH数据集上,仅使用有标签数据集时,模型的平均绝对误差为1.908;同时使用有标签数据集和无标签数据集时,MAE(mean absolute error)降至1.885。在UTKface数据集上,仅使用有标签数据集时,MAE为4.343;而结合有标签数据集和无标签数据集时,MAE降至4.246。与现有的人脸年龄估计方法相比,本文方法提高年龄估计的性能,能够有效利用无标签数据集进一步优化年龄估计性能。结论本文提出一种面向人脸年龄估计的开集半监督多任务学习方法,能够从有标签数据集和无标签数据集中有效提取人脸图像的性别、种族和年龄特征,从而提升人脸年龄估计的精度。这为实现更加精准的人脸年龄估计提供了新的思路和解决方案。 展开更多
关键词 人脸年龄估计 开集半监督学习 多任务学习 SwinLEDF模型 伪标签
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