期刊文献+
共找到17,909篇文章
< 1 2 250 >
每页显示 20 50 100
Bioactive compounds in Hericium erinaceus and their biological properties:a review
1
作者 Yue Qiu Genglan Lin +4 位作者 Weiming Liu Fuming Zhang Robert J.Linhardt Xingli Wang Anqiang Zhang 《Food Science and Human Wellness》 SCIE CAS CSCD 2024年第4期1825-1844,共20页
Hericium erinaceus is a nutritious edible and medicinal fungi,rich in a variety of functional active ingredients,with various physiological functions such as antioxidation,anticancer,and enhancing immunity.It is also ... Hericium erinaceus is a nutritious edible and medicinal fungi,rich in a variety of functional active ingredients,with various physiological functions such as antioxidation,anticancer,and enhancing immunity.It is also effective in protecting the digestive system and preventing neurodegenerative diseases.In this review paper,we summarize the sources,structures and efficacies of the main active components in H.erinaceus fruiting body,mycelium,and culture media,and update the latest research progress on their biological activities and the related molecular mechanisms.Based on this information,we provide detailed challenges in current research,industrialization and information on the active ingredients of H.erinaceus.Perspectives for future studies and new applications of H.erinaceus are proposed. 展开更多
关键词 Hericium erinaceus bioactive compounds Biological activities ANTIOXIDATION NEUROPROTECTION IMMUNOREGULATION
下载PDF
Extraction,chemical components,bioactive functions and adulteration identification of walnut oils:A review
2
作者 Yuan Gao Jia Hu +6 位作者 Xia Su Qi Li Caihong Su Yongling Li Gaiqin Ma Siyu Zhang Xiuzhu Yu 《Grain & Oil Science and Technology》 CAS 2024年第1期30-41,共12页
Walnut oil is a functional wood oil known to researchers that may potentially be a large source of Chinese edible oils.There are various extraction methods for walnut oil,including traditional(pressing,solvent-and enz... Walnut oil is a functional wood oil known to researchers that may potentially be a large source of Chinese edible oils.There are various extraction methods for walnut oil,including traditional(pressing,solvent-and enzymeassisted extraction)and novel methods(microwave,ultrasound,supercritical CO_(2),subcritical and other extraction technologies).Walnut oil is rich in nutrients,including phytosterols,tocopherols,polyphenols,squalene and minerals.It provides many health benefits,such as antioxidant,antitumor,anti-inflammatory,antidiabetic and lipid metabolism-related functions.In addition,the authentication of walnut oil has received much research attention.The present review provides detailed research on walnut oil extraction,composition,health benefits and adulteration identification methods.The path toward further walnut oil improvement in the context of the market value of walnut oil is also discussed. 展开更多
关键词 Extraction technology Chemical composition bioactive AUTHENTICATION
下载PDF
Effects of friction stir processing and nano-hydroxyapatite on the microstructure,hardness,degradation rate and in-vitro bioactivity of WE43 alloy for biomedical applications
3
作者 Bo Wu Farazila Yusof +5 位作者 Fuguo Li Huan Miao A.R.Bushroa Mohd Ridha Bin Muhamad Irfan Anjum Badruddin Mahmoud Z.Ibrahim 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第1期209-224,共16页
Nowadays,magnesium alloys are emerging in biomedical implants for their similar properties to natural bones.However,the rapid degradation of magnesium alloys in biological media hinders successful implantation.Refinem... Nowadays,magnesium alloys are emerging in biomedical implants for their similar properties to natural bones.However,the rapid degradation of magnesium alloys in biological media hinders successful implantation.Refinement of microstructure,as well as reinforcement particles can significantly improve the degradation rate.In this work,multi-pass friction stir processing(FSP)was proposed to synthesize WE43/nano-hydroxyapatite(n HA)surface composite,the microstructure,reinforced particle distribution,micro-hardness,corrosion behavior and in-vitro bioactivity were studied.The subsequent FSP passes of WE43 alloy and WE43/n HA composite refined the grain size which was reduced by 94.29%and 95.92%(2.63 and 1.88μm,respectively)compared to base metal after three passes.This resulted in increasing the microhardness by 120%(90.86 HV0.1)and 135%(105.59 HV0.1)for the WE43 and WE43-n HA,respectively.It is found that increasing FSP passes improved the uniform distribution of n HA particles within the composite matrix which led to improved corrosion resistance and less degradation rate.The corrosion rate of the FSPed WE43/n HA composite after three passes was reduced by 38.2%(4.13 mm/year)and the degradation rate was reduced by 69.7%(2.87 mm/y).This is attributed to secondary phase(Mg24Y5and Mg41Nd5)particle fragmentation and redistribution,as well as a homogeneous distribution of n HA.Additionally,the growing Ca-P and Mg(OH)2layer formed on the surface represented a protective layer that reduced the degradation rate.The wettability test revealed a relatively hydrophilic surface with water contact angle of 49.1±2.2°compared to 71.2±2.1°for base metal.Also,biomineralization test showed that apatite layer grew after immersion 7d in simulated body fluid with atomic ratio of Ca/P 1.60 approaching the stoichiometric ratio(1.67)indicating superior bioactivity of FSPed WE43/n HA composite after three passes.These results raise that the grain refinement by FSP and introduction of n HA particles significantly improved the degradation rate and in-vitro bioactivity of WE43 alloy for biomedical applications. 展开更多
关键词 Friction stir processing Magnesium-based composite NANO-HYDROXYAPATITE Corrosion behavior In-vitro bioactivity
下载PDF
Transcriptomic analysis of Andrias davidianus meat and experimental validation for exploring its bioactive components as functional foods
4
作者 Changge Guan Zhenglin Tan +6 位作者 Shucheng Li Yi Wang Naoyuki Yamamoto Chong Zhang Songjun Wang Junjie Chen Xinhui Xing 《Food Science and Human Wellness》 SCIE CSCD 2024年第1期166-172,共7页
Andrias davidianus(Chinese giant salamander,CGS)is the largest and oldest extant amphibian species in the world and is a source of prospective functional food in China.However,the progress of functional peptides minin... Andrias davidianus(Chinese giant salamander,CGS)is the largest and oldest extant amphibian species in the world and is a source of prospective functional food in China.However,the progress of functional peptides mining was slow due to lack of reference genome and protein sequence data.In this study,we illustrated full-length transcriptome sequencing to interpret the proteome of CGS meat and obtain 10703 coding DNA sequences.By functional annotation and amino acid composition analysis,we have discovered various genes related to signal transduction,and 16 genes related to longevity.We have also found vast variety of functional peptides through protein coding sequence(CDS)analysis by comparing the data obtained with the functional peptide database.Val-Pro-Ile predicted by the CDS analysis was released from the CGS meat through enzymatic hydrolysis,suggesting that our approach is reliable.This study suggested that transcriptomic analysis can be used as a reference to guide polypeptide mining in CGS meat,thereby providing a powerful mining strategy for the bioresources with unknown genomic and proteomic sequences. 展开更多
关键词 Chinese giant salamander Transcriptomic analysis bioactive components Functional peptides mining
下载PDF
Effect of Ta_(2)O_(5)nanoparticles on bioactivity,composition,structure,in vitro and in vivo behavior of PEO coatings on Mg-alloy
5
作者 D.V.Mashtalyar I.M.Imshinetskiy +7 位作者 V.V.Kashepa K.V.Nadaraia M.A.Piatkova A.I.Pleshkova K.A.Fomenko A.Yu.Ustinov S.L.Sinebryukhov S.V.Gnedenkov 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第6期2360-2379,共20页
The present study investigates the physical and chemical characteristics,behavior in vitro and in vivo,and biocompatibility of coatings containing Ta_(2)O_(5),which are obtained by plasma electrolytic oxidation(PEO)on... The present study investigates the physical and chemical characteristics,behavior in vitro and in vivo,and biocompatibility of coatings containing Ta_(2)O_(5),which are obtained by plasma electrolytic oxidation(PEO)on MA8 magnesium alloy.The obtained coatings demonstrate in vivo biocompatibility and in vitro bioactivity.Compared to the base PEO coating,the layers containing Ta_(2)O_(5)facilitate the development of apatite in simulated body fluid,suggesting that the inclusion of nanoparticles improves bioactivity of the coatings.It was found that incorporation of Ta_(2)O_(5)nanoparticles increases roughness and porosity of the formed layers by increasing particle concentration in electrolytes for the PEO process contributing to sufficient soft tissue ingrowth in vivo.Based on in vivo studies,these coatings also provide favorable tissue response and minimal inflammatory reaction in comparison with the bare magnesium alloy due to protection of living tissues from deleterious corrosion events of magnesium implant such as local alkalization and intense hydrogen evolution.The results obtained in the present study concluded biocompatibility,tissue integration of the PEO coatings containing Ta_(2)O_(5)nanoparticles making them a promising protective layer for biodegradable magnesium implants. 展开更多
关键词 Plasma electrolytic oxidation bioactive coatings Tantalum pentoxide Simulated body fluid(SBF) Apatite formation HISTOLOGY
下载PDF
Characterization and Performance of Magnesium Doped Bioactive Glass Nanoparticles
6
作者 Anteneh Tilahun Awoke Lingqi Zhu Xinbo Ding 《Open Journal of Polymer Chemistry》 2024年第2期95-111,共17页
The bioactive glass and related biomaterials have become increasingly popular, and have also attracted the research interest of many researchers in recent years due its special performance and tissue engineering appli... The bioactive glass and related biomaterials have become increasingly popular, and have also attracted the research interest of many researchers in recent years due its special performance and tissue engineering application. In this study, to create a material with a variety of properties Mg doped hollow bioactive glass (Mg-HBG) of 80SiO2-5P2O5-10CaO-5MgO system had been produced by using a sol-gel method. The porous structure nanoparticles were specifically made by employing the cetyltrimethylammonium bromide (CTAB) as a surfactant. Magnesium was selected as a doped material with HBG, because it is the most existing cations in the human body which helps for bone metabolism as well as it has antibacterial property. Based on different investigations resulted nanoparticle with the inclusion of the lower molar fractions magnesium has good tested result. For a drug model vancomycin hydrochloride (VAN) was used in this study and it has also good antibacterial activity effect. These findings help the possibility of using Mg-HBG nanoparticles to treat infectious bone abnormalities by demonstrating their compatibility with antibiotics, drug loading and release behavior. 展开更多
关键词 Tissue Engineering bioactive Glass Sol-Gel Process Drug Loading and Release
下载PDF
Predicting bioactive compounds and cancer-related molecular targets of lotus seedpod (Receptaculum Nelumbinis) based on network pharmacology and molecular docking
7
作者 Jian-Lin Shen Meng-Tong Zhang +8 位作者 Fei Li Jia-Yu Huang Quan-Sheng Xu Han-Yue Zhang Jun Zhang Jing Li Yan-Ping Li Qi Zou Xiao-Yin Wang 《Food and Health》 2024年第2期14-41,共28页
Background:Lotus seedpod(Receptaculum Nelumbinis)is the abundant by-products produced during lotus seed processing,and the sources are usually considered to be wastes and are abandoned outdoors or incinerated.This stu... Background:Lotus seedpod(Receptaculum Nelumbinis)is the abundant by-products produced during lotus seed processing,and the sources are usually considered to be wastes and are abandoned outdoors or incinerated.This study aims at predicting its bioactive compounds and cancer-related molecular targets against six cancers,including lung cancer,gastric cancer,liver cancer,breast cancer,ovarian cancer and cervical cancer.Methods:Network pharmacology and molecular docking methods were performed.Results:Network pharmacology results indicated that 14 core compounds(liensinine,tetrandrine,lysicamine,tricin,sanleng acid,cireneol G,ricinoleic acid,linolenic acid,5,7-dihydroxycoumarin,apigenin,luteolin,morin,quercetin and isorhamnetin)and 10 core targets(AKT1,ESR1,HSP90AA1,JUN,MAPK1,MAPK3,PIK3CA,PIK3R1,SRC and STAT3)were screened for lotus seedpod against the six cancers.Molecular docking analysis suggested that the binding abilities between the core compounds and the core targets were mostly strong.GO analysis revealed that the intersected targets between the bioactive compounds of lotus seedpod and the six cancers were significantly related to biological processes,cell compositions and molecular functions.KEGG analysis showed that PI3K-Akt,TNF,Ras,MAPK,HIF-1 and C-type lectin receptor signaling pathways were notably involved in the anti-cancer activities of lotus seedpod against the six cancers.Conclusions:14 core compounds and 10 core targets were screened for lotus seedpod against lung cancer,gastric cancer,liver cancer,breast cancer,ovarian cancer and cervical cancer.This study supports the application of lotus seedpod in treating cancers,and promotes the recycling and the high-value utilization. 展开更多
关键词 Lotus seedpod ANTI-CANCer bioactive compounds Molecular targets Network pharmacology Molecular docking.
下载PDF
Er掺杂PbF_(2)晶体的局域团簇结构与光谱性能研究
8
作者 李琳 张沛雄 +4 位作者 谭俊成 朱思祁 尹浩 李真 陈振强 《人工晶体学报》 CAS 北大核心 2024年第7期1112-1120,共9页
本文采用Bridgman法成功生长了一系列Er∶PbF_(2)晶体。利用基于密度泛函理论的第一性原理计算详细研究了Er^(3+)在PbF_(2)晶体中的团簇效应。首次获得了Er∶PbF_(2)晶体的上转换发光特性(发光强度、颜色变化)与团簇结构之间的关系。研... 本文采用Bridgman法成功生长了一系列Er∶PbF_(2)晶体。利用基于密度泛函理论的第一性原理计算详细研究了Er^(3+)在PbF_(2)晶体中的团簇效应。首次获得了Er∶PbF_(2)晶体的上转换发光特性(发光强度、颜色变化)与团簇结构之间的关系。研究发现,随着Er^(3+)浓度增加,团簇从单聚体向高阶构型演化,Er^(3+)离子之间的距离先减小后增大,这使得上转换发光中的红色发射强度先增大后减小,红绿发光比也在Er^(3+)浓度高于6.5%(摩尔分数)后逐渐减小,即发光颜色可以从红色调整为黄绿色。该研究证明了稀土离子团簇的结构演化可以调控Er∶PbF_(2)的光谱特性,为多色发光材料的设计提供一种新方法。 展开更多
关键词 er∶PbF_(2)晶体 上转换发光 密度泛函理论 铒离子团簇 光谱性能
下载PDF
不同雌激素水平大鼠舌下神经核中ERα的表达
9
作者 李环 梁军 侯玉霞 《山西医科大学学报》 CAS 2024年第6期735-739,共5页
目的 研究雌性大鼠去卵巢对雌激素受体ERα在舌下神经核表达的影响。方法 选取90只8周龄雌性SD大鼠,体质量(250±25)g,随机等量分为假手术组(sham组)、去卵巢组(OVX组)、去卵巢+雌二醇组(OVX+E2组),建立不同雌激素水平大鼠模型。sha... 目的 研究雌性大鼠去卵巢对雌激素受体ERα在舌下神经核表达的影响。方法 选取90只8周龄雌性SD大鼠,体质量(250±25)g,随机等量分为假手术组(sham组)、去卵巢组(OVX组)、去卵巢+雌二醇组(OVX+E2组),建立不同雌激素水平大鼠模型。sham组去除大鼠卵巢周围少量脂肪,OVX组去除卵巢,OVX+E2组去除卵巢后皮下注射雌二醇;使用免疫组织化学检测ERα在舌下神经核表达;real-time PCR、Western blot检测ERα mRNA、蛋白表达。结果 三组大鼠舌下神经核均存在ERα阳性表达。与sham组比较,OVX组ERα mRNA及蛋白含量明显降低(P<0.01);与OVX组比较,OVX+E2组ERα mRNA及蛋白含量明显升高(P<0.01);sham组和OVX+E2组间差异无统计学意义(P>0.05)。结论 雌激素受体ERα在不同雌激素水平雌性大鼠舌下神经核均存在表达,ERα mRNA及蛋白的表达均受雌激素水平调节。 展开更多
关键词 去卵巢 雌激素 舌下神经核 erα 大鼠
下载PDF
ER50-6焊丝激光焊接Q345B/304异种钢接头组织与性能
10
作者 刘海 陈辉 《精密成形工程》 北大核心 2024年第6期129-137,共9页
目的研究异种钢激光填丝焊接工艺对焊接组织与性能的影响规律,以降低Q345B/304异种钢激光焊接的成本,扩大异种钢激光焊接的应用范围,使其能够满足使用要求,实现Q345B/304异种钢激光焊接低成本的产业化应用。方法采用便宜的ER50-6碳钢焊... 目的研究异种钢激光填丝焊接工艺对焊接组织与性能的影响规律,以降低Q345B/304异种钢激光焊接的成本,扩大异种钢激光焊接的应用范围,使其能够满足使用要求,实现Q345B/304异种钢激光焊接低成本的产业化应用。方法采用便宜的ER50-6碳钢焊丝代替价格高昂的ER308L不锈钢焊丝以及不锈钢药芯焊丝对Q345B/304异种钢进行激光焊接,主要采用填丝ER50-6焊丝对5 mm厚的Q345B/304异种钢板进行激光焊接,再结合焊缝区、熔合区及热影响区的纳观-微观-宏观多尺度表征和测试结果,研究不同工艺参数下焊接接头的组织与结构,同时结合焊接工艺参数和多尺度的表征结果,研究焊接接头硬度、焊缝中元素分布、物相特征、力学性能的变化规律。结果当激光功率为4.5 kW、焊接速度为6 mm/s、焊丝直径为1.2 mm、装配间隙为1 mm、送丝速度为2.5 m/min时,焊缝成形最好,且在焊缝中没有出现大量的M_(23)C_(6)和σ等有害相,焊接接头的力学性能等也完全满足使用要求。结论采用ER50-6焊丝对Q345B/304异种钢进行激光焊接,能够得到完全符合质量要求的焊接接头,且降低了焊接成本。 展开更多
关键词 异种钢 激光焊接 er50-6 焊接质量 成本控制
下载PDF
Er:YAG激光和传统车针去龋后牙本质粘接强度的比较
11
作者 黄莉莉 张佳钰 《医疗卫生装备》 CAS 2024年第4期56-60,共5页
目的:比较使用不同模式Er:YAG激光以及传统车针去龋后牙本质与复合树脂的粘接强度。方法:选用人类离体磨牙模拟龋坏,分别采用Er:YAG激光中短脉冲(medium short pulse,MSP)模式、Er:YAG激光超短脉冲(super short pulse,SSP)模式和传统车... 目的:比较使用不同模式Er:YAG激光以及传统车针去龋后牙本质与复合树脂的粘接强度。方法:选用人类离体磨牙模拟龋坏,分别采用Er:YAG激光中短脉冲(medium short pulse,MSP)模式、Er:YAG激光超短脉冲(super short pulse,SSP)模式和传统车针去除模拟的龋坏后,采用自酸蚀粘接剂将牙体标本与复合树脂粘接制成试件。使用万能试验机对试件进行拉伸试验,测得断裂负荷和粘接强度,并采用单因素方差分析和Tukey多重比较进行统计学分析。采用扫描电子显微镜观察3种不同去龋方式处理后的牙本质表面形态,以及涂布自酸蚀粘接剂并固化后试件的横截面形态。结果:使用Er:YAG激光MSP模式处理后牙本质与复合树脂的粘接强度最高,SSP模式处理后次之,传统车针处理后最低,但差异无统计学意义(P>0.05)。扫描电子显微镜图像显示,Er:YAG激光MSP模式处理后的牙本质表面较平坦,牙本质小管内几乎没有残屑;Er:YAG激光SSP模式处理后的牙本质表面呈现鳞片状,牙本质小管内可见少量碎屑;而传统车针处理后牙本质小管大部分处于被表面牙本质部分甚至完全遮盖的状态,牙本质小管内充满残屑。结论:使用Er:YAG激光去龋相比传统车针去龋可以获得较好的牙本质粘接强度,且对牙本质小管的处理深度和洁净度明显优于传统车针去龋,其中MSP模式更佳。 展开更多
关键词 er:YAG激光 传统车针 去龋 牙本质 粘接强度
下载PDF
Nd:YAG激光和Er:YAG激光治疗牙本质敏感的临床对比研究
12
作者 张子旋 周璇 刘立访 《口腔材料器械杂志》 2024年第1期60-64,共5页
目的探讨Nd:YAG激光和Er:YAG激光治疗牙本质敏感(Dentin Hypersensitivity,DH)的效果。方法收治佛山市第一人民医院2021年3月至2022年12月期间就诊的牙本质敏感93例患者共259颗牙,患者均在受到冷、酸、甜及刷牙等刺激后存在酸痛感,诊断... 目的探讨Nd:YAG激光和Er:YAG激光治疗牙本质敏感(Dentin Hypersensitivity,DH)的效果。方法收治佛山市第一人民医院2021年3月至2022年12月期间就诊的牙本质敏感93例患者共259颗牙,患者均在受到冷、酸、甜及刷牙等刺激后存在酸痛感,诊断为DH。随机分为3组,分别给予常规脱敏剂治疗组(31例患者,86颗患牙)、Nd:YAG激光治疗组(31例患者,90颗患牙)、Er:YAG激光治疗组(31例患者,83颗患牙)3种方法,其中激光组尝试改变激光照射参数及时间,寻求最好的治疗参数。对比3种脱敏方法的即刻效果、1周效果、1个月效果及3个月效果。结果治疗前3组对冷空气及机械刺激反应的VAS评分无明显差异(P>0.05);治疗后各个时间段Nd:YAG激光组和Er:YAG激光组对冷空气刺激反应均明显轻于对照组(P<0.05)。治疗后各个时间段Nd:YAG激光组和Er:YAG激光组对机械刺激反应均明显轻于对照组(P<0.05)。3组经治疗后均获得一定疗效,Nd:YAG激光组和Er:YAG激光组的效果好于常规组,但差异无统计学意义(P>0.05)。结论Nd:YAG激光、Er:YAG激光治疗DH与常规脱敏方法相比,明显降低患者的冷空气和机械刺激反应,在一定程度上提升了治疗效果。 展开更多
关键词 牙本质敏感 ND:YAG激光 er:YAG激光 Bifluorid 12 脱敏剂量疗效
下载PDF
基于ER Rule的多分类器汽车评论情感分类研究
13
作者 周谧 周雅婧 +1 位作者 贺洋 方必和 《运筹与管理》 CSCD 北大核心 2024年第5期161-168,共8页
该文针对汽车评论语料的情感二分类问题,提出一种基于证据推理规则的多分类器融合的情感分类方法。在情感特征构建方面,通过实验对比不同特征模型对分类结果的影响,并改进传统的TFIDF权重计算方法。同时,在此基础上使用ER Rule融合不同... 该文针对汽车评论语料的情感二分类问题,提出一种基于证据推理规则的多分类器融合的情感分类方法。在情感特征构建方面,通过实验对比不同特征模型对分类结果的影响,并改进传统的TFIDF权重计算方法。同时,在此基础上使用ER Rule融合不同分类器进行文本情感极性分析,并考虑各分类器的权重和可靠度。最后,爬取汽车网站上的评论数据对上述方法进行测试,并用公开的中文酒店评论语料数据进行了验证,结果表明该方法能够有效集成不同分类器的优点,与传统机器学习分类算法相比,其结果在Recall,F1值和Accuracy三个指标上得到了提高,与目前流行的深度学习算法和集成学习算法相比,其结果总体占优。 展开更多
关键词 证据推理规则 多分类器融合 TFIDF权重 深度学习算法 集成学习算法
下载PDF
高速拉拔ER70S-6焊丝钢生产工艺优化
14
作者 赵晓敏 罗海炯 +2 位作者 王刚 李学东 白彬亨 《包钢科技》 2024年第1期65-69,共5页
通过总结分析ER70S-6焊丝钢存在的质量问题,提出了有针对性的优化改进措施,重点对ER70S-6焊丝钢的化学成分范围、气体氮含量、尺寸精度、显微组织等关键指标严格控制,攻关后C、Si、Mn、N含量内控达标率提高,尺寸偏差C级精度得到改善,而... 通过总结分析ER70S-6焊丝钢存在的质量问题,提出了有针对性的优化改进措施,重点对ER70S-6焊丝钢的化学成分范围、气体氮含量、尺寸精度、显微组织等关键指标严格控制,攻关后C、Si、Mn、N含量内控达标率提高,尺寸偏差C级精度得到改善,而且消除了混晶异常组织。用户拉拔使用结果表明,优化后的焊丝钢质量得到进一步的提高,可满足用户拉拔速度28 m/s以上高速拉拔的要求。 展开更多
关键词 er70S-6焊丝钢 氮含量 尺寸精度 高速拉拔
下载PDF
2.79μm高速转镜调Q Er,Cr:YSGG纳秒窄脉冲激光器
15
作者 朱永斌 马圣洁 +3 位作者 程庭清 王礼 陈月明 江海河 《光学精密工程》 EI CAS CSCD 北大核心 2024年第8期1122-1129,共8页
转镜调Q无插入损耗,是获得窄脉冲、高峰值功率输出激光的直接方式。纳秒脉冲需要使用高速转镜调Q,并精准控制电机转速与氙灯放电延时,以使激光介质上能级粒子数反转最大,获得最大激光能量输出。本文设计了以Arduino mega 2560单片机为... 转镜调Q无插入损耗,是获得窄脉冲、高峰值功率输出激光的直接方式。纳秒脉冲需要使用高速转镜调Q,并精准控制电机转速与氙灯放电延时,以使激光介质上能级粒子数反转最大,获得最大激光能量输出。本文设计了以Arduino mega 2560单片机为核心的高速转镜调Q控制系统,通过精确单片机解析串口屏指令控制激光电源的充放电和高速电机启停,同时通过对转镜脉冲信号整合降频控制氙灯放电时刻,实现对延迟时间的精准控制,实现了灯泵Er,Cr:YSGG激光纳秒窄脉冲调Q输出。在5 Hz重复频率下,转镜转速为650 r/s时,获得的最高单脉冲激光能量为45.7 mJ、脉冲宽度为86.2 ns,相应的峰值功率为530.2 kW。 展开更多
关键词 转镜调Q 固体激光器 er Cr:YSGG激光 ARDUINO 氙灯泵浦
下载PDF
基于石墨烯可饱和吸收体的Er∶YAG被动调Q激光器
16
作者 陈言 张沛雄 +3 位作者 权聪 孙敦陆 李真 陈振强 《人工晶体学报》 CAS 北大核心 2024年第7期1127-1135,共9页
本文研究了一种采用氙灯侧泵方式,并基于石墨烯可饱和吸收体的Er∶YAG被动调Q激光器。首先成功将石墨烯转移至Al_(2)O_(3)衬底制备得到石墨烯可饱和吸收体,并对其进行了形貌、结构及化学状态等性能表征。此外,对基于石墨烯可饱和吸收体... 本文研究了一种采用氙灯侧泵方式,并基于石墨烯可饱和吸收体的Er∶YAG被动调Q激光器。首先成功将石墨烯转移至Al_(2)O_(3)衬底制备得到石墨烯可饱和吸收体,并对其进行了形貌、结构及化学状态等性能表征。此外,对基于石墨烯可饱和吸收体的Er∶YAG被动调Q激光特性进行了研究,结果表明单脉冲能量从0.4 mJ增加至7 mJ,输出激光单脉冲宽度从761.2 ns下降至510 ns,最大峰值功率为13.7 kW。激光中心波长位于2935和2945 nm,且主波长在2935 nm处对应的半峰全宽(FWHM)为1.535 nm。沿x和y方向的光束质量因子分别为4.45和5.76。实验结果表明,该研究为推进更低成本、谐振腔设计简单且紧凑的2.94μm波段Er∶YAG激光器的发展提供了有效的参考依据。 展开更多
关键词 石墨烯可饱和吸收体 氙灯侧泵 被动调Q er∶YAG ~3μm激光
下载PDF
基于ERS信号蛋白异常表达探讨清肝降浊方治疗NAFLD的机制研究
17
作者 丁云录 薄天儒 +4 位作者 王铁成 李驰坤 李晓兵 欧喜燕 刘彦晶 《吉林中医药》 2024年第2期206-210,共5页
目的通过试验研究探讨清肝降浊方基于ERS信号蛋白异常表达治疗非酒精性脂肪肝病的作用机制。方法采用高脂饮食饲喂的方法,诱导建立非酒精性脂肪肝病大鼠动物模型。给药8周后,进行肝功能指标AST、ALT、AKP检测、血清中TC、TG、NEFA及肝... 目的通过试验研究探讨清肝降浊方基于ERS信号蛋白异常表达治疗非酒精性脂肪肝病的作用机制。方法采用高脂饮食饲喂的方法,诱导建立非酒精性脂肪肝病大鼠动物模型。给药8周后,进行肝功能指标AST、ALT、AKP检测、血清中TC、TG、NEFA及肝组织匀浆中TC、TG检测、肝组织匀浆中SOD、MDA检测,检测信号通路相关蛋白ATF4、eIF2a、CHOP的表达水平。结果清肝降浊方865.1 mg/kg、432.6 mg/kg和216.3 mg/kg给药组动物血清AST、ALT、AKP活性及肝组织中ATF4、CHOP表达量、TG含量均明显的低于模型组,而肝组织中SOD活性显著高于模型组(P<0.01或P<0.05);865.1 mg/kg和432.6 mg/kg 2个给药组动物血清TC、TG、NEFA含量及肝组织中TC、TG、MDA含量、eIF2a表达量均低于模型组(P<0.01或P<0.05)。结论清肝降浊方治疗NAFLD作用机制可能是通过调节ERS信号蛋白异常表达,从而达到防治非酒精性脂肪肝病。 展开更多
关键词 清肝降浊方 SD大鼠 NAFLD erS信号蛋白
下载PDF
Er∶YAG激光SWEEPS双脉冲模式激活荡洗在自由水域中的气泡动力学观测
18
作者 何新宇 李依洲 +4 位作者 聂铭远 于悦 陈浩天 潘翀 赵继志 《实用口腔医学杂志》 CAS CSCD 北大核心 2024年第1期64-70,共7页
目的:探究Er∶YAG激光光子增强的光声流(SWEEPS)技术在不同脉冲间隔参数条件下的蒸汽气泡动力学效应。方法:Er∶YAG激光手具连接工作尖放置于自由水域模型中,设置SWEEPS模式,150~600μs脉冲间隔激活。高速摄像机(200 000 Hz)摄录Er∶YA... 目的:探究Er∶YAG激光光子增强的光声流(SWEEPS)技术在不同脉冲间隔参数条件下的蒸汽气泡动力学效应。方法:Er∶YAG激光手具连接工作尖放置于自由水域模型中,设置SWEEPS模式,150~600μs脉冲间隔激活。高速摄像机(200 000 Hz)摄录Er∶YAG激光激活荡洗引起空穴效应的过程,matlab逐帧分析蒸汽气泡间的相互作用关系,及蒸汽气泡消失时刻气泡残余与激光工作尖之间的距离。实验数据经SPSS 19.0统计软件进行统计分析。结果:在自由水域中,Er∶YAG激光SWEEPS模式下,脉冲间隔设置的改变会引起两次脉冲激发的蒸汽气泡形成不同的相互作用关系,包括双气泡融合、双气泡撞击及双气泡脱离。其中,脉冲间隔设置为360~440μs时,双气泡撞击现象会使蒸汽气泡消失时气泡残余与激光工作尖之间达到最远距离。结论:在自由水域中,Er∶YAG激光双脉冲SWEEPS模式在不同的脉冲间隔设置下引起双气泡间形成不同的作用关系,该现象可能可以增强Er∶YAG激光空穴效应,强化激光激活荡洗的临床应用效果。 展开更多
关键词 er∶YAG激光 激光激活荡洗 气泡动力学 SWEEPS
下载PDF
Synthesis, Characterization and Bioactivity of Complexes of Rare Earth with Bis-Schiff Base from Furoylpyrazolone 被引量:4
19
作者 李锦州 李刚 于文锦 《Journal of Rare Earths》 SCIE EI CAS CSCD 2000年第3期233-236,共4页
Eleven new complexes of rare earths with bis-Schiff base derived from N,N'-bis[(1-phenyl-3-methyl-5-oxo-4-pyrazolinyl) alpha-furylmethylidyne] ethylenediimine ((HPM alpha FP)(2)en) were synthesized. On the basis o... Eleven new complexes of rare earths with bis-Schiff base derived from N,N'-bis[(1-phenyl-3-methyl-5-oxo-4-pyrazolinyl) alpha-furylmethylidyne] ethylenediimine ((HPM alpha FP)(2)en) were synthesized. On the basis of elemental analysis and molar conductance, a general formula of the complexes, [RE(HPM alpha FP)(2)en(NO3)(2)]NO3(RE = La, Pr, Nd, Sm, Eu, Th, Dy, Ho, Er, Yb,Y), was given. The complexes were characterized by IR, UV-visible, H-1 NMR, C-13 NMR and fluorescence. The results show that the bis-Schiff base is a quadridentate ligand and the rare earth ions exhibit coordination of eight in the complexes. The antibacterial experiments indicate that they have high antibacterial activities against S. aureus, B. subtillis, E. coli, E. carotovora, C. flaccumfaciens. 展开更多
关键词 rare earths FUROYLPYRAZOLONE bis-Schiff base bioactivity
下载PDF
热键合、凹端面及晶体棒直径对Er∶YSGG中红外激光性能的影响
20
作者 程毛杰 董昆鹏 +5 位作者 胡伦珍 张会丽 罗建乔 权聪 韩志远 孙敦陆 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2024年第2期571-579,共9页
对热键合、凹端面及不同直径Er∶YSGG晶体棒的中红外激光性能进行了系统对比研究。晶体经高温退火、定向切割、端面精密抛光后,测量得到其平面度和表面粗糙度分别小于0.1λ@633 nm和0.5 nm。通过精密加工实现了YSGG与Er∶YSGG室温光胶,... 对热键合、凹端面及不同直径Er∶YSGG晶体棒的中红外激光性能进行了系统对比研究。晶体经高温退火、定向切割、端面精密抛光后,测量得到其平面度和表面粗糙度分别小于0.1λ@633 nm和0.5 nm。通过精密加工实现了YSGG与Er∶YSGG室温光胶,然后进行了高温热键合,透过谱表明键合界面基本无损耗,达到了一体化。热焦距结果表明,热键合、凹端面能够有效改善和补偿高功率泵浦条件下晶体的热透镜效应,有利于提高晶体的激光性能。对比未键合、热键合及凹面热键合Er∶YSGG晶体在968 nm LD侧面泵浦条件下的激光性能发现,低频150 Hz以下,键合与凹面并未表现出优势,三种棒的最大输出功率和斜效率分别均在24 W和28%附近;但随重频增加,热效应逐渐加重,键合晶体良好散热能力和凹面热补偿效应使激光性能得到提高。在重频300 Hz下,未键合、热键合及凹面热键合三种棒的最大输出功率分别为15.54,17.85和18.33 W、斜效率分别为16.6%,18.3%和18.4%;重频600 Hz条件下,三种棒的最大输出功率分别为9.4,13.32和13.18 W、斜效率分别为6.7%,8.6%和9%。此外,对比研究了不同直径Er∶YSGG晶体的激光性能,在低于100 Hz的低频下,三种晶体的激光性能接近。但相比于3和4 mm键合凹面棒,直径2 mm棒有大的比表面积,拥有更好的热管理能力,使其在高重频条件下具有更好的激光性能。如在150 Hz条件下,2 mm凹面键合Er∶YSGG晶体棒获得了功率23.82 W、斜效率27.7%的中红外激光输出,大大高于直径3和4 mm棒的18 W和23%。在600 Hz,直径2 mm键合凹面棒中实现了功率13.18 W,斜效率9%的激光输出,相比于直径3和4 mm键合凹面棒的9 W,7%具有较大的改善。测量得到2 mm凹面键合Er∶YSGG晶体棒在150 Hz,200μs条件下的光束质量因子M_(x)^(2)/M_(y)^(2)=6.28/6.30,表明该激光具有良好的光束质量。综上,选择合适晶体棒直径,并将键合与凹面相结合是实现高性能2.79μm激光的有效方法。 展开更多
关键词 热键合 er∶YSGG激光晶体 凹端面 LD侧面泵浦 2.79μm中红外激光 斜效率 光束质量因子
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部