期刊文献+
共找到4篇文章
< 1 >
每页显示 20 50 100
Optimizing and extending ion dielectric polarizability database for microwave frequencies using machine learning methods
1
作者 Jincheng Qin Zhifu Liu +1 位作者 mingsheng ma Yongxiang Li 《npj Computational Materials》 SCIE EI CSCD 2023年第1期977-986,共10页
Permittivity at microwave frequencies determines the practical applications of microwave dielectric ceramics.The accuracy and universality of the permittivity prediction by Clausius–Mossotti equation depends on the d... Permittivity at microwave frequencies determines the practical applications of microwave dielectric ceramics.The accuracy and universality of the permittivity prediction by Clausius–Mossotti equation depends on the dielectric polarizability(αD)database.The most influentialαD database put forward by Shannon is facing three challenges in the 5 G era:(1)Few data,(2)Simplistic relation and(3)Low frequency(kHz–MHz)oriented.Here,we optimized and extended the Shannon’s database for microwave frequencies by the four-stage multiple linear regression and support vector machine model.In comparison with the conventional database,the optimized and extended databases achieved higher accuracy and expanded the amount of data from 60 to more than 900.Besides,we analyzed the relationships betweenαD and ion characteristics,including ionic radius(IR),atomic number(N),valence state(V)and coordination number(CN).We found that the positive cubic law of“αD~IR3”discussed in Shannon’s work was valid for the IR changed by the N,but invalid for the change caused by the CN. 展开更多
关键词 DATABASE MICROWAVE DIELECTRIC
原文传递
Machine learning approaches for permittivity prediction and rational design of microwave dielectric ceramics 被引量:3
2
作者 Jincheng Qin Zhifu Liu +1 位作者 mingsheng ma Yongxiang Li 《Journal of Materiomics》 SCIE EI 2021年第6期1284-1293,共10页
Low permittivity microwave dielectric ceramics(MWDCs)are attracting great interest because of their promising applications in the new era of 5G and IoT.Although theoretical rules and computational methods are of pract... Low permittivity microwave dielectric ceramics(MWDCs)are attracting great interest because of their promising applications in the new era of 5G and IoT.Although theoretical rules and computational methods are of practical use for permittivity prediction,unsatisfactory predictability and universality impede rational design of new high-performance materials.In this work,based on a dataset of 254 single-phase microwave dielectric ceramics(MWDCs),machine learning(ML)methods established a high accuracy model for permittivity prediction and gave insights of quantitative chemistry/structureproperty relationships.We employed five commonly-used algorithms,and introduced 32 intrinsic chemical,structural and thermodynamic features which have correlations with permittivity for modeling.Machine learning results help identify the permittivity decisive factors,including polarizability per unit volume,average bond length,and average cell volume per atom.The feature-property relationships were discussed.The optimal model constructed by support vector regression with radial basis function kernel was validated its superior predictability and generalization by verification dataset.Low permittivity material systems were screened from a dataset of~3300 materials without reported microwave permittivity by high-throughput prediction using optimal model.Several predicted low permittivity ceramics were synthesized,and the experimental results agree well with ML prediction,which confirmed the reliability of the prediction model. 展开更多
关键词 Microwave dielectric ceramics Low permittivity ceramics Permittivity prediction Machine learning Quantitative structure-property RELATIONSHIP
原文传递
Ⅰ型干扰素病25例临床特点分析 被引量:3
3
作者 王伟 王薇 +6 位作者 邹丽萍 何庭艳 马明圣 李文道 于仲勋 杨军 宋红梅 《中华儿科杂志》 CAS CSCD 北大核心 2021年第12期1043-1047,共5页
目的总结分析Ⅰ型干扰素病患儿的临床特点,为其早识别、早诊断提供线索。方法回顾性分析2016年1月至2021年9月北京协和医院儿科就诊的20例及深圳市儿童医院风湿免疫科就诊的5例基因确诊的Ⅰ型干扰素病患儿的临床资料,对其基因数据、临... 目的总结分析Ⅰ型干扰素病患儿的临床特点,为其早识别、早诊断提供线索。方法回顾性分析2016年1月至2021年9月北京协和医院儿科就诊的20例及深圳市儿童医院风湿免疫科就诊的5例基因确诊的Ⅰ型干扰素病患儿的临床资料,对其基因数据、临床表现及辅助检查结果进行分析。结果25例患儿中男12例、女13例。发病年龄1日龄~11岁。其中21例(84%)在3岁前起病。Aicardi-Goutières综合征(AGS)14例(3例AGS1型、1例AGS2型、4例AGS3型、1例AGS6型、5例AGS7型)、腺苷脱氨酶2缺陷(DADA2)6例、干扰素基因刺激蛋白相关婴儿期起病的血管炎(SAVI)3例、脊椎软骨发育异常伴免疫调节异常(SPENCD)2例。共18例(72%)患儿神经系统受累,其中16例(64%)表现为颅内钙化、11例(44%)为肌张力异常、10例(40%)为脑白质病变、6例(24%)为癫痫、5例(20%)脑萎缩及5例(20%)脑卒中。15例(60%)患儿皮肤受累,其中8例(32%)为冻疮样皮疹,4例(16%)为网状青斑、3例(12%)为红斑,结节性红斑及雷诺现象各有2例(8%)。12例(48%)自身免疫抗体阳性,10例(40%)生长发育落后,8例(32%)肺间质病变,7例(28%)甲状腺功能异常。1例(4%)患儿11岁死亡。结论Ⅰ型干扰素病可累及全身多个脏器,具有全身炎症及自身免疫性疾病的特点。3岁前起病、神经系统症状(脑血管事件、颅内钙化、脑白质病变、脑萎缩)、皮疹(冻疮样皮疹、网状青斑、红斑)、自身免疫抗体阳性、发育落后、肺间质病变、甲状腺功能异常等特点对Ⅰ型干扰素病有提示意义。 展开更多
关键词 遗传性自身炎症性疾病 干扰素Ⅰ型 儿童
原文传递
儿童干扰素刺激基因表达检测方法的建立与应用 被引量:3
4
作者 李文道 王薇 +2 位作者 王伟 马明圣 宋红梅 《中华检验医学杂志》 CAS CSCD 北大核心 2022年第6期603-609,共7页
目的建立儿童干扰素刺激基因(ISG)表达检测方法, 确立参考值范围, 初步探讨其临床应用价值。方法纳入2017年11月至2021年9月就诊于北京协和医院儿科的Ⅰ型干扰素病患者作为疾病组, 同时纳入健康儿童作为对照组。疾病组共纳入18例患儿, ... 目的建立儿童干扰素刺激基因(ISG)表达检测方法, 确立参考值范围, 初步探讨其临床应用价值。方法纳入2017年11月至2021年9月就诊于北京协和医院儿科的Ⅰ型干扰素病患者作为疾病组, 同时纳入健康儿童作为对照组。疾病组共纳入18例患儿, 其中男性8例, 女性10例, 共采集血液样本25份, 首次检测的中位年龄为8.5岁。对照组共纳入28名健康儿童, 年龄1~18岁, 中位年龄10.5岁, 其中男性15名, 女性13名。分别提取疾病组和对照组外周血总RNA并逆转录为互补DNA(cDNA)。以β肌动蛋白基因(β-Actin)和鸟氨酸脱羧酶抗酶基因(OAZ)为内参, 采用实时荧光定量聚合酶链反应(qPCR)检测干扰素诱导的四肽重复蛋白1基因(IFIT1)、干扰素α诱导蛋白27基因(IFI27)、干扰素诱导蛋白44样基因(IFI44L)、干扰素刺激基因15(ISG15)、唾液酸结合的免疫球蛋白样凝集素1基因(SIGLEC1)、含有S-腺苷甲硫氨酸结构域2基因(RSAD2)的相对表达量, 以6个ISG的中值为干扰素评分(IS)。去除正常对照中表达明显异常的样本, 将其他样本的cDNA混合作为参照, 重新检测各样本并计算IS, 将大于对照xˉ+2s的IS结果判断为异常。用独立样本t检验或Mann-WhitneyU检验比较组内和组间IS的差异。结果对照组IS均值为1.046, 标准差0.755, IS截断值为2.556。18例Ⅰ型干扰素病患者组IS异常的有15例(15/18), IS均值为27.010。与对照组相比, 干扰素疾病患者组IS明显升高(t=4.247, P=0.000 1)。该检测方法的准确度为91.30%(42/46), 精密度为7.47%(0.084/1.124), 敏感度为15/18, 特异度为96.43%(27/28)。结论本研究通过ISG表达的检测并计算IS, 为临床筛查以及动态监测Ⅰ型干扰素疾病变化提供了新的可靠的手段。 展开更多
关键词 干扰素Ⅰ型 干扰素刺激基因 干扰素评分 Ⅰ型干扰素病 实时荧光定量聚合酶链反应
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部