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维生素D3纳米喷剂在维生素D不足儿童中吸收性和安全性评估:一项前瞻性随机非劣效性对照试验
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作者 李静 乔荆 +3 位作者 罗瑛仁 单红梅 洪莉 张程辰 《临床儿科杂志》 北大核心 2025年第10期755-761,共7页
目的评估维生素D3纳米喷剂在维生素D不足儿童中的吸收性和安全性。方法纳入2023年10月至2024年9月就诊于上海儿童医学中心的维生素D不足的3~18周岁患儿47例,采用前瞻性随机非劣效性对照设计,将受试者随机分配至试验组(n=19)和对照组(n=... 目的评估维生素D3纳米喷剂在维生素D不足儿童中的吸收性和安全性。方法纳入2023年10月至2024年9月就诊于上海儿童医学中心的维生素D不足的3~18周岁患儿47例,采用前瞻性随机非劣效性对照设计,将受试者随机分配至试验组(n=19)和对照组(n=28)。试验组接受维生素D3纳米喷剂,对照组接受维生素D3滴剂(胶囊型),于基线及用药第56天测量受试者的血清维生素D水平,以评估维生素D3补充效果;检测受试者基线以及用药第56天血液肝肾功能和甲状旁腺激素水平以评估药物安全性。结果试验组和对照组分别予维生素D3纳米喷剂或维生素D3滴剂56天后,两组血清维生素D水平均较基线明显改善,但两组间维生素D上升幅度差异无统计学意义(P>0.025)。用药第56天试验组的血清25-羟维生素D3水平显著高于对照组,差异有统计学意义(P<0.025)。受试者用药56天后肝肾功能和甲状旁腺激素水平均未出现异常。结论维生素D3纳米喷剂对维生素D不足儿童的补充效果与维生素D3滴剂相比无显著性差异,研究期间未报告不良反应。 展开更多
关键词 维生素d3纳米喷剂 维生素d不足 25-羟维生素d 儿童
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Exploring the effects of angle of incidence on stabbing resistance in advanced protective textiles:Novel experimental framework and analysis
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作者 Mulat Alubel Abtew François Boussu Irina Cristian 《Defence Technology(防务技术)》 2025年第2期67-82,共16页
Despite numerous research investigations to understand the influences of various structural parameters,to the authors'knowledge,no research has been the effect of different angles of incidence on stab response and... Despite numerous research investigations to understand the influences of various structural parameters,to the authors'knowledge,no research has been the effect of different angles of incidence on stab response and performance of different types of protective textiles.Three distinct structures of 3D woven textiles and 2D plain weave fabric made with similar high-performance fiber and areal density were designed and manufactured to be tested.Two samples,one composed of a single and the other of 4-panel layers,from each fabric type structure,were prepared,and tested against stabbing at[0○],[22.5○],and[45○]angle of incidence.A new stabbing experimental setup that entertained testing of the specimens at various angles of incidence was engineered and utilized.The stabbing bench is also equipped with magnetic sensors and a UK Home Office Scientific Development Branch(HOSDB)/P1/B sharpness engineered knives to measure the impact velocity and exerted impact energy respectively.A silicon compound was utilized to imprint the Back Face Signature(BFS)on the backing material after every specimen test.Each silicon print was then scanned,digitized,and precisely measured to evaluate the stab response and performance of the specimen based on different performance variables,including Depth of Trauma(DOT),Depth of Penetration(DOP),and Length of Penetration(LOP).Besides,the post-impact surface failure modes of the fabrics were also measured using Image software and analyzed at the microscale level.The results show stab angle of incidence greatly influences the stab response and performance of protective textiles.The outcome of the study could provide not only valuable insights into understanding the stab response and capabilities of protective textiles under different angle of incidence,but also provide valuable information for protective textile manufacturer,armor developer and stab testing and standardizing organizations to consider the angle of incidence while developing,testing,optimizing,and using protective textiles in various applications. 展开更多
关键词 2d/3d woven fabrics Impact protective fabric drop tower perforation test Stab resistance testing protocol Angle of incidence Multi-layer panels Soft body armor Impact surface damage
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维生素D水平与反复呼吸道感染患儿免疫障碍的相关性 被引量:2
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作者 朱瑛 南楠 +2 位作者 李婷婷 魏丽琼 黄蕾 《中国免疫学杂志》 北大核心 2025年第3期668-674,679,共8页
目的:调查甘肃省儿童维生素D水平特征,分析维生素D水平与反复呼吸道感染(RRTIs)患儿免疫障碍的相关性。方法:回顾性选取2020年1月至2021年12月期间于甘肃省6个市州妇幼保健院及三级综合医院以上儿科行维生素D检测的9790例0~6岁儿童,分... 目的:调查甘肃省儿童维生素D水平特征,分析维生素D水平与反复呼吸道感染(RRTIs)患儿免疫障碍的相关性。方法:回顾性选取2020年1月至2021年12月期间于甘肃省6个市州妇幼保健院及三级综合医院以上儿科行维生素D检测的9790例0~6岁儿童,分析其中5000例儿童维生素D特征,以5000例中出现RRTIs的90例患儿作为研究组,以80例健康儿童作为对照组。对比两组维生素D水平与免疫功能指标(IgA、IgG、IgM、补体C3、补体C4)的相关性,分析维生素D对儿童RRTIs的诊断价值。结果:分析甘肃省5000例儿童维生素D资料发现,维生素D缺乏率、不足率、充足率分别为11.58%、41.38%、47.04%,未发现维生素D过量和中毒者。儿童维生素D水平受年龄和季节的影响,3~4岁儿童维生素D缺乏较严重,冬季儿童维生素D水平最低,且维生素D水平与儿童生长发育、罹患疾病有关。研究组25(OH)D水平、免疫功能指标均低于对照组(P<0.05)。25(OH)D水平与RRTIs患儿年龄、过敏史、被动烟草暴露、易感季节有关(P<0.05)。维生素D充足患儿免疫功能指标高于维生素D不足、缺乏患儿(P<0.05)。RRTIs患儿维生素D水平与免疫功能呈正相关(P<0.05)。低出生体重、早产、偏食、每日果蔬量、户外活动时间、钙、铁、锌、25(OH)D、IgA、IgG、IgM、补体C3、补体C4均是儿童RRTIs的独立危险因素(P<0.05),维生素D对儿童RRTIs的诊断价值较高(P<0.05)。结论:甘肃省儿童维生素D水平与年龄、季节相关,在儿童RRTIs中,维生素D水平降低与患儿机体免疫障碍有关,可用于RRTIs的诊断。 展开更多
关键词 维生素d 25-羟基维生素d 儿童反复呼吸道感染 免疫球蛋白 补体
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Infrared-NeRF:a low resolution thermal infrared light field 3D reconstruction method based on NeRF
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作者 HUANG Yi-Fan WANG Rui +2 位作者 DENG Li-Ming LI Jia-Jia LI Xi-Cai 《红外与毫米波学报》 北大核心 2025年第4期605-616,共12页
This article proposes a three-dimensional light field reconstruction method based on neural radiation field(NeRF)called Infrared NeRF for low resolution thermal infrared scenes.Based on the characteristics of the low ... This article proposes a three-dimensional light field reconstruction method based on neural radiation field(NeRF)called Infrared NeRF for low resolution thermal infrared scenes.Based on the characteristics of the low resolution thermal infrared imaging,various optimizations have been carried out to improve the speed and accuracy of thermal infrared 3D reconstruction.Firstly,inspired by Boltzmann's law of thermal radiation,distance is incorporated into the NeRF model for the first time,resulting in a nonlinear propagation of a single ray and a more accurate description of the physical property that infrared radiation intensity decreases with increasing distance.Secondly,in terms of improving inference speed,based on the phenomenon of high and low frequency distribution of foreground and background in infrared images,a multi ray non-uniform light synthesis strategy is proposed to make the model pay more attention to foreground objects in the scene,reduce the distribution of light in the background,and significantly reduce training time without reducing accuracy.In addition,compared to visible light scenes,infrared images only have a single channel,so fewer network parameters are required.Experiments using the same training data and data filtering method showed that,compared to the original NeRF,the improved network achieved an average improvement of 13.8%and 4.62%in PSNR and SSIM,respectively,while an average decreases of 46%in LPIPS.And thanks to the optimization of network layers and data filtering methods,training only takes about 25%of the original method's time to achieve convergence.Finally,for scenes with weak backgrounds,this article improves the inference speed of the model by 4-6 times compared to the original NeRF by limiting the query interval of the model. 展开更多
关键词 neural radiation field 3d reconstruction thermal infrared NeRF foreground segmentation low resolution
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供应链金融对中小企业R&D投资效率的影响:基于融资约束视角 被引量:5
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作者 胡海青 原敏倩 薛萌 《科技进步与对策》 北大核心 2025年第1期102-112,共11页
创新是中小企业保持竞争力、适应市场变化和实现可持续发展的关键。基于2016-2022年创业板中小企业相关数据,运用三阶段DEA分析、面板Tobit模型回归、二元Logistic回归等方法,探究供应链金融对中小企业R&D投资效率的影响。结果表明... 创新是中小企业保持竞争力、适应市场变化和实现可持续发展的关键。基于2016-2022年创业板中小企业相关数据,运用三阶段DEA分析、面板Tobit模型回归、二元Logistic回归等方法,探究供应链金融对中小企业R&D投资效率的影响。结果表明,供应链金融能够显著提高中小企业R&D投资效率,融资约束在二者间发挥遮掩效应。进一步分析发现,上述效应对供应链集中度较高的企业更为显著。结论可为发挥供应链金融筹资优势,促进供应链生态系统资源互补、信息共享的协同创新网络形成,进而支持中小企业创新活动提供理论支持。 展开更多
关键词 供应链金融 R&d投资效率 三阶段dEA 面板Tobit模型 遮掩效应
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Optimization of Infrared-microwave Post-processing Process for 3D Printed Raspberry Preserves Based on AHP-CRITIC Hybrid Weighting Combined with Response Surface Method
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作者 Zheng Xianzhe Song Ruonan +2 位作者 Cong Hongyue Zhang Yuhan Xue Liangliang 《Journal of Northeast Agricultural University(English Edition)》 2025年第1期27-44,共18页
In order to improve the quality of 3D printed raspberry preserves after post-processing,microwave ovens combining infrared and microwave methods were utilized.The effects of infrared heating temperature,infrared heati... In order to improve the quality of 3D printed raspberry preserves after post-processing,microwave ovens combining infrared and microwave methods were utilized.The effects of infrared heating temperature,infrared heating time,microwave power,microwave heating time on the center temperature,moisture content,the chroma(C*),the total color difference(ΔE*),shape fidelity,hardness,and the total anthocyanin content of 3D printed raspberry preserves were analyzed by response surface method(RSM).The results showed that under combining with the two methods,infrared heating improved the fidelity and quality degradation of printed products,while microwave heating enhanced the efficiency of infrared heating.Infrared-microwave combination cooking could maintain relatively stable color appearance and shape of 3D printed raspberry preserves.The AHP–CRITIC hybrid weighting method combined with the response surface test to determine the comprehensive weights of the evaluation indicators optimized the process parameters,and the optimal process parameters were obtained:infrared heating temperature of 190℃,infrared heating time of 10 min and 30 s,microwave power of 300 W,and microwave heating time of 2 min and 6 s.The 3D printed raspberry cooking methods obtained under the optimal conditions seldom had color variation,porous structure,uniform texture,and high shape fidelity,which retained the characteristics of personalized manufacturing by 3D printing.This study could provide a reference for the postprocessing and quality control of 3D cooking methods. 展开更多
关键词 3d printing RASPBERRY MICROWAVE infrared heating hybrid weighting response surface method
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Dynamic mechanical characteristics of post-peak sandstone under three-dimensional cyclic impact
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作者 ZHANG Jun-wen ZHANG Yang +7 位作者 LI Shi-fang SONG Zhi-xiang DONG Xu-kai WU Shao-kang FAN Wen-bing ZHOU Yan SANG Pei-miao LI Ning 《Journal of Central South University》 2025年第8期2958-2978,共21页
At present,the surrounding rock of the deep mine roadway is prone to post-peak stress under the action of high stress,and secondary rock burst disaster is prone to occur under complex stress disturbance.According to i... At present,the surrounding rock of the deep mine roadway is prone to post-peak stress under the action of high stress,and secondary rock burst disaster is prone to occur under complex stress disturbance.According to incomplete statistics,as of 2023,80%of coal mine rock bursts accidents in China occur in mining roadway.In view of this phenomenon,the cyclic impact test of post-peak sandstone is designed,focusing on the post-peak stress state of sandstone,and exploring the post-peak dynamic response of sandstone.The post-peak sandstone specimens were prepared by a uniaxial compressor,and then cyclic impact tests were carried out on the post-peak sandstone under different coaxial pressure conditions by an improved separated Hopkinson equipment.The results show that:1)The number of impact times required for sandstone failure after peak decreased with the increase of axial pressure,indicating that the impact tendency of sandstone after peak decreased under lower axial pressure.On the contrary,the post-peak sandstone had strong impact tendency under higher axial pressure;2)The higher the axial pressure,the lower the dynamic strength of the post-peak sandstone,indicating that the axial pressure promoted the failure process of the post peak sandstone;3)It was a nonlinear evolution of a quadratic polynomial function between the dissipation-energy release rate and axial pressure;4)Shear failure occurred mainly in post-peak impact sandstone with the increased axial pressure,and the composite failure of intergranular failure and transgranular failure changed to single intergranular failure at the microscopic level.The research shows that when the roadway surrounding rock was in the post-peak stress state,reducing the static stress was the key to prevent the secondary ground pressure disaster.The research results provide a theoretical basis for the prevention and control of roadway rock burst disaster under high ground stress environment,and promote the research and exploration of post-peak mechanical properties of coal and rock. 展开更多
关键词 post-peak impact sandstone 3d cyclic impact dynamic response energy dissipation fracture mechanism
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A Retrospective Cohort Study on the Improvement of Prognosis of Hospitalized COVID-19 Patients Using Traditional Chinese Medicine Preparations
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作者 DOU Li WANG Wei +9 位作者 YU Manshu YUAN Sicheng HU Jingyi ZHUANG Yuwen QI Minghao WANG Yuanyuan YANG Fei MENG Jiale GUO Tao WANG Xiaoxiao 《南京中医药大学学报》 北大核心 2025年第11期1585-1595,共11页
OBJECTIVE The emergence of evolving variants of Coronavirus disease 2019(COVID-19)has fostered the need for change of newer and adaptive treatments for these infections.During the COVID-19 pandemic and persists,tradit... OBJECTIVE The emergence of evolving variants of Coronavirus disease 2019(COVID-19)has fostered the need for change of newer and adaptive treatments for these infections.During the COVID-19 pandemic and persists,traditional Chinese medicine(TCM)herbs exhibit significant bioactivity and therapeutic effect.This study is aimed to evaluate the efficacy of four TCM preparations on 28-day mortality risk of patients and changes of the laboratory indicators.METHODS The retrospective cohort study included patients with COVID-19 who were admitted to the Jiangsu Province Hospital of Chinese Medicine from December 15,2022 to January 15,2023,and those died within 48 hours of admission or cannot be tracked for outcomes were excluded.The primary outcome was survival status in 28 days(death or survival)starting from the day of admission.The second outcomes were laboratory indicators,including absolute lymphocyte count,lactate dehydrogenase,creatinine,and blood urea nitrogen.Binary logistic regressions were used to estimate the effect of TCM preparations on the primary and secondary outcomes in main analysis.Meanwhile,heterogeneity and robustness of results from main analysis were assessed by subgroup analyses and multiple sensitivity analyses.RESULTS 1816 eligible patients were included in analysis dataset,including 573 patients received standard care(control group)and 1243 patients received TCM preparations(hospital preparation group).The 28-day mortality rate of hospital preparation group was lower than that of control group(4.75%vs.14.83%),and the difference was statistically significant(χ^(2)=54.666,P<0.001).The risk of 28-day mortality was 0.535 times lower in the hospital preparation group as compared with the control group(OR=0.46,95%CI:0.305-0.708,P<0.001)showed by multivariable binary logistic regressions.Subgroup analyses showed that taking TCM preparations reduced the 28-day mortality risk.Sensitivity analyses demonstrated that the results of the main analysis for primary outcomes were robust.For secondary outcomes,the risk of abnormal absolute lymphocyte counts at discharge in the hospital preparation group decreased by 0.284 times(OR=0.703,95%CI:0.515-0.961,P=0.027).CONCLUSION Compared with standard of care,taking four hospital preparations including Kanggan Heji,Feining Heji,Qishen Gubiao Keli,and Qianghuo Qushi Qingwen Heji decreased risk of 28-day mortality among hospitalized COVID-19 patients.TCM therapy achieves adequate therapeutic effects in COVID-19. 展开更多
关键词 traditional Chinese medicine preparations COVId-19 28-day mortality retrospective cohort study
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熊果酸及其衍生物调控NLRP3/GSDMD轴在急性肝损伤中的作用 被引量:1
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作者 王菲 康妍钰 +4 位作者 张昊天 董璐 白婷 未志俞 杨勇 《中国药理学通报》 北大核心 2025年第5期999-1000,共2页
急性肝损伤(acute liver injury,ALI)是一种由大量肝细胞死亡引起的疾病,期间伴随着炎症、氧化应激等的发生。持续的损伤进一步恶化可进展为急性肝衰竭[1]。NOD样受体蛋白3(NOD-like receptor protein 3,NLRP3)在激活炎症方面起着关键作... 急性肝损伤(acute liver injury,ALI)是一种由大量肝细胞死亡引起的疾病,期间伴随着炎症、氧化应激等的发生。持续的损伤进一步恶化可进展为急性肝衰竭[1]。NOD样受体蛋白3(NOD-like receptor protein 3,NLRP3)在激活炎症方面起着关键作用,通过促进caspase-1活化来切割GSDMD,在细胞膜上形成孔洞,从而诱导细胞焦亡的发生,分泌IL-1β和IL-18炎症细胞因子[2]。研究表明,细胞焦亡可释放NLRP3炎症小体并诱导细胞因子风暴及炎症反应而进一步损伤肝脏,加速ALI进程[3],因此,抑制NLRP3/GSDMD信号轴,可作为缓解ALI的有效途径。 展开更多
关键词 熊果酸 熊果酸衍生物 急性肝损伤 NOd样受体蛋白3 GSdMd 脂多糖 d-(+)-半乳糖胺
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Enhanced engineering and biocidal polypropylene filaments enabling melt reduction of AgNO_(3) through PVP agent:A scalable process for the defense industry with MEX additive manufacturing
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作者 Markos Petousis Nikolaos Michailidis +7 位作者 Vassilis Papadakis Apostolos Argyros Mariza Spiridaki Nikolaos Mountakis John Valsamos Nektarios K.Nasikas Amalia Moutsopoulou Nectarios Vidakis 《Defence Technology(防务技术)》 2025年第2期52-66,共15页
This study focused on the production of polypropylene(PP)/silver(Ag)composites via additive manufacturing.This study aimed to enhance the quality of medical-grade PP in material extrusion(MEX)three-dimensional printin... This study focused on the production of polypropylene(PP)/silver(Ag)composites via additive manufacturing.This study aimed to enhance the quality of medical-grade PP in material extrusion(MEX)three-dimensional printing(3DP)by improving its mechanical properties while simultaneously adding antibacterial properties.The latter can find extremely important and versatile properties that are applicable in defense and security domains.PP/Ag nanocomposites were prepared using a novel method based on a reaction occurring while mixing appropriate quantities of the starting polymers and additives,namely polyvinylpyrrolidone(PVP)as the matrix material and silver nitrate(AgNO_(3))as the filler.This process produced three-dimensional(3D)printed filaments,which were then used to create specimens for a series of standardized tests.It was found that the mechanical properties of the nanocomposites were enhanced in relation to pristine PP,especially for the PP matrix with various loadings of AgNO_(3)and PVP,such as 5.0 wt%and 2.5 wt%,respectively.The voids,inclusions,and actual-to-nominal dimensions also showed improved results.The 3DP specimens exhibited a more effective biocidal performance against Staphylococcus aureus than Escherichia coli,which developed an inhibition zone only in the case of PP with filler loading percentages of AgNO_(3)and PVP at 10.0 wt%and 5.0 wt%,respectively Compounds possessing such properties can be beneficial for various applications requiring increased mechanical properties and biocidal capabilities,such as in the Defence or medical industries. 展开更多
关键词 Polypropylene(PP) Polyvinyl pyrrolidone(PVP) Silver nitride(AgNO_(3)) In-situ reactive melt mixing process Material extrusion(MEX)3d printing Biocidal performance
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融合CLIP和3D高斯的多模态场景编辑算法
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作者 曹仰杰 王伟平 +2 位作者 李振强 谢俊 吕润峰 《郑州大学学报(工学版)》 北大核心 2025年第5期35-42,共8页
针对3D场景编辑算法对标注数据过度依赖和计算复杂度高的问题,提出了一种融合CLIP与3D高斯的多模态场景编辑算法(CLIP2Gaussian)。首先,利用SAM从多视角图像中提取目标掩码,并引入双向传播策略实现不同视角之间的掩码一致性;其次,将提... 针对3D场景编辑算法对标注数据过度依赖和计算复杂度高的问题,提出了一种融合CLIP与3D高斯的多模态场景编辑算法(CLIP2Gaussian)。首先,利用SAM从多视角图像中提取目标掩码,并引入双向传播策略实现不同视角之间的掩码一致性;其次,将提取的掩码通过CLIP进行语义标签分配,并映射到3D高斯点,实现3D场景的语义嵌入;最后,采用可微分渲染机制对3D高斯参数进行优化,同时引入空间一致性正则化策略,通过聚类增强语义标签在3D空间中的一致性与稳定性。实验结果表明:CLIP2Gaussian在LERF数据集上IoU达到61.23%,语义分割任务中单次文本查询响应时间为0.57 s,准确率和效率均优于LERF。消融实验进一步验证了所提算法在最小扰动原始场景的前提下对目标区域的精准编辑。 展开更多
关键词 3d重建 零样本学习 场景理解 场景编辑 3d高斯
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毛衫产品3D虚拟仿真建模研究与分析 被引量:1
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作者 黄林初 赵藏 《针织工业》 北大核心 2025年第2期5-9,共5页
基于数字化虚拟仿真技术的发展和客户对于毛衫3D仿真模拟需求量的增加,文章通过将日本岛精公司的SDS·ONE APEX服装设计系统和凌迪的3D Style建模软件相结合,对毛衫3D仿真建模进行研究和分析,包括面料的制作、2D服装结构设计和修正... 基于数字化虚拟仿真技术的发展和客户对于毛衫3D仿真模拟需求量的增加,文章通过将日本岛精公司的SDS·ONE APEX服装设计系统和凌迪的3D Style建模软件相结合,对毛衫3D仿真建模进行研究和分析,包括面料的制作、2D服装结构设计和修正、3D仿真建模的方法以及在3D仿真建模中各部位参数的设置;同时对毛衫3D建模中遇到的问题进行分析并探讨解决方案,为行业内3D虚拟仿真技术的研究应用提供参考。 展开更多
关键词 3d仿真模拟 3d建模 毛衫产品 2d结构设计
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基于家用3D打印技术的空间建构探索与实践
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作者 熊璐 罗越 林广思 《西部人居环境学刊》 北大核心 2025年第4期146-151,共6页
家用3D打印技术可满足大众的定制化需求,实现小产品的自主设计与制造,但在适合人体活动的中尺度空间营造方面,往往受到打印尺寸、打印速度、构件强度等因素限制而鲜有应用。本研究旨在设计、测试并验证一套基于家用3D打印节点的空间建... 家用3D打印技术可满足大众的定制化需求,实现小产品的自主设计与制造,但在适合人体活动的中尺度空间营造方面,往往受到打印尺寸、打印速度、构件强度等因素限制而鲜有应用。本研究旨在设计、测试并验证一套基于家用3D打印节点的空间建构系统。采用通过设计做研究的方法,通过竹构作品“自由地生长”的设计与建造过程,探索家用3D打印技术应用于空间建构的具体途径,即基于家用3D打印工艺的研发,自主设计与制造节点连接管材,研发并验证具备高自由度的空间建构系统。在不依赖工厂与大型加工机械的情况下,大众仍然可以运用家用3D打印技术自主设计并快速建造适合人体活动尺度的复杂造型构筑物。研究拓宽了家用3D打印机的应用范围,降低了参数化设计的专业门槛,为原竹建筑提供了新的节点构造方式,拓展了原竹设计的自由度。 展开更多
关键词 建构 增材制造(3d打印) 原竹构筑 装配式建造 通过设计做研究(RTd)
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基于P2D模型的航空应急电源状态评估
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作者 雷晓犇 胡新华 王浩 《空军工程大学学报》 北大核心 2025年第5期1-10,共10页
针对镍镉蓄电池在高空低温环境下工作时放电能力衰减,影响飞行应急电源可靠性的问题,建立了一种实时评估其放电状态的方法。首先,扩展应用电化学伪二维(P2D)方法构建镍镉蓄电池电化学模型,识别出能表征放电状态且对温度敏感的核心参数,... 针对镍镉蓄电池在高空低温环境下工作时放电能力衰减,影响飞行应急电源可靠性的问题,建立了一种实时评估其放电状态的方法。首先,扩展应用电化学伪二维(P2D)方法构建镍镉蓄电池电化学模型,识别出能表征放电状态且对温度敏感的核心参数,并将温度对放电状态的影响转化为对核心参数的影响;进而,构建核心参数与直流内阻(DCIR)的关系,基于此关系建立等效电路模型,并采用混合脉冲功率特性测试(HPPC)方法进行模型参数辨识。结果方面,通过分析模型参数(特别是DCIR)随温度与放电状态的关联性,成功构建了温度-内阻-放电状态之间的映射关系,设计并实现了一种能够有效检测不同温度下镍镉蓄电池放电状态的方法。该方法可同时应用于飞行实时状态监控与地面维护评估,显著提升镍镉蓄电池工作状态的评估精度,为保障飞行可靠性提供了关键技术支持。 展开更多
关键词 镍镉蓄电池 P2d模型 dCIR HPPC
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3D printed hybrid rocket fuels with μAl core-shell particles coated with polyvinylidene fluoride and polydopamine: Enhanced combustion characteristics 被引量:1
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作者 Qihang Chen Xiaolong Fu +6 位作者 Weitao Yang Suhang Chen Zhiming Guo Rui Hu Huijie Zhang Lianpeng Cui Xu Xia 《Defence Technology(防务技术)》 2025年第4期59-70,共12页
3D printing technology enhances the combustion characteristics of hybrid rocket fuels by enabling complex geometries. However, improvements in regression rates and energy properties of monotonous 3D printed fuels have... 3D printing technology enhances the combustion characteristics of hybrid rocket fuels by enabling complex geometries. However, improvements in regression rates and energy properties of monotonous 3D printed fuels have been limited. This study explores the impact of poly(vinylidene fluoride) and polydopamine-coated aluminum particles on the thermal and combustion properties of 3D printed hybrid rocket fuels. Physical self-assembly and anti-solvent methods were employed for constructing composite μAl particles. Characterization using SEM, XRD, XPS, FTIR, and μCT revealed a core-shell structure and homogeneous elemental distribution. Thermal analysis showed that PVDF coatings significantly increased the heat of combustion for aluminum particles, with maximum enhancement observed in μAl@PDA@PVDF(denoted as μAl@PF) at 6.20 k J/g. Subsequently, 3D printed fuels with varying pure and composite μAl particle contents were prepared using 3D printing. Combustion tests indicated higher regression rates for Al@PF/Resin composites compared to pure resin, positively correlating with particle content. The fluorocarbon-alumina reaction during the combustion stage intensified Al particle combustion, reducing residue size. A comprehensive model based on experiments provides insights into the combustion process of PDA and PVDF-coated droplets. This study advances the design of 3D-printed hybrid rocket fuels, offering strategies to improve regression rates and energy release, crucial for enhancing solid fuel performance for hybrid propulsion. 展开更多
关键词 Hybrid propulsion Regression rate 3d print fuels Micro aluminum CORE-SHELL mAl@PdA@PVdF
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含LCC-HVDC的交直流系统D-Q建模与潮流计算
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作者 刘闯 王锡龙 +1 位作者 任洺瑶 陈俊睿 《电力自动化设备》 北大核心 2025年第5期145-152,共8页
针对包含基于电网换相换流器的高压直流输电(LCC-HVDC)的交直流系统,提出基于D-Q电网络的统一迭代潮流算法。推导考虑交直流互联的直流网络稳态模型和D-Q电网络稳态模型;根据电网换相换流器(LCC)的相量模型和功率方程,建立基于D-Q电网络... 针对包含基于电网换相换流器的高压直流输电(LCC-HVDC)的交直流系统,提出基于D-Q电网络的统一迭代潮流算法。推导考虑交直流互联的直流网络稳态模型和D-Q电网络稳态模型;根据电网换相换流器(LCC)的相量模型和功率方程,建立基于D-Q电网络的LCC稳态模型。该算法采用网络电气量为变量,通过对PQ节点和直流节点列写基于电流关系的潮流方程使潮流方程组雅可比矩阵的非零元素大多为常数,以提升计算的速度和稳定性,降低对初值的敏感度。在改进的IEEE 14、IEEE 39节点系统中,将所提算法与传统算法进行对比,结果表明,所提算法具有良好的计算速度、稳定的收敛性及对交流电压初值较低的敏感度。 展开更多
关键词 潮流计算 统一迭代 LCC-HVdC d-Q电网络 稳态模型
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RHD*DV.5与RHD阴性基因杂合型个体的基因突变分析
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作者 吴师师 彭娟 +5 位作者 吴丽波 陈洪肖 詹冬梅 董月梅 王万琴 吴梁 《中国实验血液学杂志》 北大核心 2025年第6期1758-1764,共7页
目的:对一例血清学弱D表现的标本进行RHD基因检测。方法:对织金县人民医院收到的一例标本使用微柱凝胶法、盐水法等进行血清学鉴定,采用PCR-SSP法对标本进行RHD基因型检测,对扩增出的10个外显子进行全序列测定,测序结果参比ISBT数据库... 目的:对一例血清学弱D表现的标本进行RHD基因检测。方法:对织金县人民医院收到的一例标本使用微柱凝胶法、盐水法等进行血清学鉴定,采用PCR-SSP法对标本进行RHD基因型检测,对扩增出的10个外显子进行全序列测定,测序结果参比ISBT数据库确定基因型。利用生物信息学工具对突变蛋白的功能损伤进行预测,采用AlphaFold-3对野生型和突变型RhD蛋白进行三级结构建模,并对两种蛋白结构进行对比分析,以探讨突变导致血清学弱表现的原因。结果:该患者基因型为RHD*DV.5/RHD*01N.01杂合型,其一条染色体上缺失了全部的RHD基因,无法表达D抗原;另一条染色体第5外显子上的第697号碱基发生了G>A的突变,综合表型为部分D表型。该突变引起RhD蛋白第233位氨基酸残基内部氢键的改变,进而导致蛋白质构象发生变化,可能影响其与相应抗体的结合能力。结论:该患者属于RHD*DV.5/RHD*01N.01杂合型突变个体,血清学表现为部分D,该变异十分罕见,全球范围内鲜有报道。 展开更多
关键词 RHd变异型 RHd*dV.5 部分d
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维生素D治疗全面性发育迟缓患儿的临床疗效研究 被引量:3
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作者 牛国辉 谢加阳 +6 位作者 朱登纳 崔博 赵会玲 王明梅 冯欢欢 张萌萌 李停停 《中国全科医学》 CAS 北大核心 2025年第3期346-351,共6页
背景 除了某些有明确病因的代谢性疾病导致的全面性发育迟缓(GDD),康复治疗是GDD的主要治疗方式;维生素D通过影响神经营养因子在调节神经细胞的发育和分化方面发挥着重要的神经保护作用;但目前关于补充维生素D对GDD患儿临床疗效的研究... 背景 除了某些有明确病因的代谢性疾病导致的全面性发育迟缓(GDD),康复治疗是GDD的主要治疗方式;维生素D通过影响神经营养因子在调节神经细胞的发育和分化方面发挥着重要的神经保护作用;但目前关于补充维生素D对GDD患儿临床疗效的研究开展较少。目的 探讨补充不同剂量的维生素D对GDD患儿康复治疗的临床效果。方法 于2020年9月—2022年6月选取在郑州大学第三附属医院康复医学科首次住院就诊的120例GDD患儿为研究对象,采用随机区组化的方法将其分为常规组(38例)、400 U组(37例)和1 200 U组(35例)。常规组仅进行常规康复治疗;400 U组在常规康复治疗的基础上给予口服400 U/d维生素D;1 200 U组在常规康复训练的基础上给予口服1 200 U/d维生素D。收集3组患儿的性别、就诊年龄等基本资料;于入院时(治疗前)及第3个疗程末(治疗后)行血清25羟维生素D[25(OH)D]水平检测和Gesell发育量表评估[评估适应能力、大运动能力、精细运动能力、语言能力和社交能力5个能区的发育商(DQ)];记录发生在患儿住院期间不良事件的次数,并对上述资料进行分析比较。结果 3组患儿性别、居住地、出生季节、分娩方式、就诊年龄、出生体质量、出生胎龄、主要就诊原因比较,差异均无统计学意义(P>0.05)。治疗前,3组患儿25(OH)D水平、Gesell量表各能区DQ值比较,差异均无统计学意义(P>0.05);治疗后,1 200 U组患儿血25(OH)D水平、Gesell量表大运动能力、精细运动能力、语言能力DQ值高于常规组(P<0.05)。第1、2疗程期间,3组患儿不良事件发生率比较,差异无统计学意义(P>0.05);第3疗程期间,1 200 U组患儿不良事件发生率低于常规组及400 U组(P<0.05)。结论 补充1 200 U维生素D对GDD患儿的康复疗效有益,且能减少康复期间不良事件的发生率。 展开更多
关键词 儿童发育障碍 广泛性 全面性发育迟缓 维生素d Gesell量表 不良事件 康复治疗 神经保护
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Study on Color Difference of Color Reproduction of 3D Objects
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作者 GU Chong DENG Yi-qiang 《印刷与数字媒体技术研究》 北大核心 2025年第4期33-38,69,共7页
To investigate the applicability of four commonly used color difference formulas(CIELAB,CIE94,CMC(1:1),and CIEDE2000)in the printing field on 3D objects,as well as the impact of four standard light sources(D65,D50,A,a... To investigate the applicability of four commonly used color difference formulas(CIELAB,CIE94,CMC(1:1),and CIEDE2000)in the printing field on 3D objects,as well as the impact of four standard light sources(D65,D50,A,and TL84)on 3D color difference evaluations,50 glossy spheres with a diameter of 2cm based on the Sailner J4003D color printing device were created.These spheres were centered around the five recommended colors(gray,red,yellow,green,and blue)by CIE.Color difference was calculated according to the four formulas,and 111 pairs of experimental samples meeting the CIELAB gray scale color difference requirements(1.0-14.0)were selected.Ten observers,aged between 22 and 27 with normal color vision,were participated in this study,using the gray scale method from psychophysical experiments to conduct color difference evaluations under the four light sources,with repeated experiments for each observer.The results indicated that the overall effect of the D65 light source on 3D objects color difference was minimal.In contrast,D50 and A light sources had a significant impact within the small color difference range,while the TL84 light source influenced both large and small color difference considerably.Among the four color difference formulas,CIEDE2000 demonstrated the best predictive performance for color difference in 3D objects,followed by CMC(1:1),CIE94,and CIELAB. 展开更多
关键词 Color difference formula 3d objects Light source Gray scale Normalized residual sum of squares
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基于FDM技术的蕾丝3D打印面料开发 被引量:1
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作者 程燕婷 孟家光 +1 位作者 薛涛 刘晓巧 《针织工业》 北大核心 2025年第2期1-4,共4页
为了丰富3D打印面料的花型,增加目前市面上蕾丝面料的外观、风格及品种,通过正交试验分析,得到蕾丝3D打印面料的最佳打印参数为:分层厚度0.20 mm,打印速度90 mm/s,打印温度220℃。以柔性PLA为材料,采用FDM技术,在最佳打印参数下,对3ds ... 为了丰富3D打印面料的花型,增加目前市面上蕾丝面料的外观、风格及品种,通过正交试验分析,得到蕾丝3D打印面料的最佳打印参数为:分层厚度0.20 mm,打印速度90 mm/s,打印温度220℃。以柔性PLA为材料,采用FDM技术,在最佳打印参数下,对3ds Max软件中模拟的模型进行打印,开发出一款具有科技感和时尚感的蕾丝3D打印面料。对蕾丝3D打印面料的性能进行测试,得到蕾丝3D打印面料的横向拉伸强力为74 N,纵向拉伸强力为158 N;顶破强力为204 N;横向抗弯长度为30 mm,纵向抗弯长度为32 mm;透气率为3143 L/(m^(2)·s);透湿量为8251 g/[m^(2)·(24 h)]。该研究为3D打印面料的成形精度提升及蕾丝面料的花型开发提供了参考。 展开更多
关键词 蕾丝 3d打印 FdM技术 面料开发
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