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Fe、Ir掺杂MoS_(2)表面对N_(2)气敏吸附与解离反应性能提升的第一性原理研究
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作者 肖香珍 胡林峰 张建伟 《原子与分子物理学报》 CAS 北大核心 2025年第1期13-19,共7页
基于第一性原理方法,采用周期性平板模型,研究了N_(2)分子在掺杂体系TM-MoS_(2)(TM=Fe、Ir)表面的吸附和解离行为.研究表明:N_(2)分子在TM-MoS_(2)(TM=Fe、Ir)表面吸附能依次为0.62和0.47 eV,而完整MoS_(2)表面的吸附能只有0.08 eV,说... 基于第一性原理方法,采用周期性平板模型,研究了N_(2)分子在掺杂体系TM-MoS_(2)(TM=Fe、Ir)表面的吸附和解离行为.研究表明:N_(2)分子在TM-MoS_(2)(TM=Fe、Ir)表面吸附能依次为0.62和0.47 eV,而完整MoS_(2)表面的吸附能只有0.08 eV,说明掺杂之后对N_(2)表现出略好的吸附性能.差分电荷密度分析表明,N_(2)吸附后,掺杂Fe、Ir原子与两个N原子之间电荷有所增加,N-N键之间的区域电荷密度减少,N-N键的强度减弱.态密度计算结果发现,N_(2)在吸附过程中,主要是N原子的2p_(y)、2p_(z)轨道与Ir的5d_(xy)和5d_(z^(2))以及Fe的3d_(xy)和3d_(z^(2))发生杂化作用.通过分析解离活化能,N_(2)在掺杂体系TM-MoS_(2)(TM=Fe、Ir)表面解离需要活化能均较高,且远大于在相应掺杂表面的吸附能,说明N_(2)在掺杂体系TM-MoS_(2)(TM=Fe、Ir)表面解离应该表现为分子吸附或脱附. 展开更多
关键词 Fe、Ir 掺杂 单层MoS_(2) N_(2) 吸附与解离 活化能 密度泛函理论
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Influence of Current Density on the Photocatalytic Activity of Nd:TiO_(2) Coatings
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作者 施渊吉 ZHANG Zhen +2 位作者 DAI Yunzhong LI Jingxiao CHEN Zeyu 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第1期32-38,共7页
The Nd:TiO_(2 )PEO coatings were formed in a phosphate-based electrolyte with the addition of Nd_(2)O_(3 )under the current density of 150,200,250 and 300 m A/cm^(2).SEM results showed that the micropores decreased on... The Nd:TiO_(2 )PEO coatings were formed in a phosphate-based electrolyte with the addition of Nd_(2)O_(3 )under the current density of 150,200,250 and 300 m A/cm^(2).SEM results showed that the micropores decreased on quantity and increased on scale with the increasing current density.AFM results revealed that the roughness of the coatings increased with the increasing current density.Phase and composition analysis showed that the Nd:TiO_(2) coatings were mainly composed of anatase and rutile phase.And the anatase phase content has reached the maximum value at the current density of 250 m A/cm^(2).XPS results indicated that Ti2p spin-orbit components of the Nd:TiO_(2) coatings are shifted towards higher binding energy,compared with the pure TiO_(2) coating,suggesting that some of the Nd^(3+)ions are combined with TiO_(2) lattice and led to dislocation.Photocatalytic test showed that the photocatalytic activity of Nd:TiO_(2) coatings varied in the same pattern with the anatase content variation in Nd:TiO_(2) coatings.The photocatalytic experiment results show that the photocatalytic activity of Nd:TiO_(2) coatings can be greatly enhanced with moderate amount of Nd^(3+).However,excessive amount of Nd^(3+)does not have an effective impact on the photoctalytic activity improvement. 展开更多
关键词 PEO current density AFM XPS Nd:TiO_(2) PHOTOCATALYTIC
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A density functional theory study of polarons on different TiO_(2)surfaces
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作者 SHI Zhiqun GONG Xueqing 《燃料化学学报(中英文)》 EI CAS CSCD 北大核心 2024年第12期1877-1888,I0011-I0013,共15页
Polarons are widely considered to play a crucial role in the charge transport and photocatalytic performance of materials,but the mechanisms of their formation and the underlying driving factors remain a matter of con... Polarons are widely considered to play a crucial role in the charge transport and photocatalytic performance of materials,but the mechanisms of their formation and the underlying driving factors remain a matter of controversy.This study delves into the formation of polarons in different crystalline forms of TiO_(2)and their connection with the materials'structure.By employing density functional theory calculations with on-site Coulomb interaction correction(DFT+U),we provide a detailed analysis of the electronic polarization behavior in the anatase and rutile forms of TiO_(2).We focus on the polarization properties of defect-induced and photoexcited excess electrons on various TiO_(2)surfaces.The results reveal that the defect electrons can form small polarons on the anatase TiO_(2)(101)surface,while on the rutile TiO_(2)(110)surface,both small and large polarons(hybrid-state polarons)are formed.Photoexcited electrons are capable of forming both small and large polarons on the surfaces of both crystal types.The analysis indicates that the differences in polaron distribution are primarily determined by the intrinsic properties of the crystals;the structural and symmetry differences between anatase and rutile TiO_(2)lead to the distinct polaron behaviors.Further investigation suggests that the polarization behavior of defect electrons is also related to the arrangement of electron orbitals around the Ti atoms,while the polarization of photoexcited electrons is mainly facilitated by the lattice distortions.These findings elucidate the formation mechanisms of different types of polarons and may contribute to understanding the performance of TiO_(2)in different fields. 展开更多
关键词 POLARON surface defect PHOTOEXCITATION TiO_(2) density functional theory
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Associations between Geriatric Nutrition Risk Index,bone mineral density and body composition in type 2 diabetes patients
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作者 Xiao-Xiao Zhu Kai-Feng Yao +1 位作者 Hai-Yan Huang Li-Hua Wang 《World Journal of Diabetes》 SCIE 2024年第3期403-417,共15页
BACKGROUND Type 2 diabetes mellitus(T2DM),a fast-growing issue in public health,is one of the most common chronic metabolic disorders in older individuals.Osteoporosis and sarcopenia are highly prevalent in T2DM patie... BACKGROUND Type 2 diabetes mellitus(T2DM),a fast-growing issue in public health,is one of the most common chronic metabolic disorders in older individuals.Osteoporosis and sarcopenia are highly prevalent in T2DM patients and may result in fractures and disabilities.In people with T2DM,the association between nutrition,sarcopenia,and osteoporosis has rarely been explored.AIM To evaluate the connections among nutrition,bone mineral density(BMD)and body composition in patients with T2DM.METHODS We enrolled 689 patients with T2DM for this cross-sectional study.All patients underwent dual energy X-ray absorptiometry(DXA)examination and were categorized according to baseline Geriatric Nutritional Risk Index(GNRI)values calculated from serum albumin levels and body weight.The GNRI was used to evaluate nutritional status,and DXA was used to investigate BMD and body composition.Multivariate forward linear regression analysis was used to identify the factors associated with BMD and skeletal muscle mass index.RESULTS Of the total patients,394 were men and 295 were women.Compared with patients in tertile 1,those in tertile 3 who had a high GNRI tended to be younger and had lower HbA1c,higher BMD at all bone sites,and higher appendicular skeletal muscle index(ASMI).These important trends persisted even when the patients were divided into younger and older subgroups.The GNRI was positively related to ASMI(men:r=0.644,P<0.001;women:r=0.649,P<0.001),total body fat(men:r=0.453,P<0.001;women:r=0.557,P<0.001),BMD at all bone sites,lumbar spine(L1-L4)BMD(men:r=0.110,P=0.029;women:r=0.256,P<0.001),FN-BMD(men:r=0.293,P<0.001;women:r=0.273,P<0.001),and hip BMD(men:r=0.358,P<0.001;women:r=0.377,P<0.001).After adjustment for other clinical parameters,the GNRI was still significantly associated with BMD at the lumbar spine and femoral neck.Additionally,a low lean mass index and higherβ-collagen special sequence were associated with low BMD at all bone sites.Age was negatively correlated with ASMI,whereas weight was positively correlated with ASMI.CONCLUSION Poor nutrition,as indicated by a low GNRI,was associated with low levels of ASMI and BMD at all bone sites in T2DM patients.Using the GNRI to evaluate nutritional status and using DXA to investigate body composition in patients with T2DM is of value in assessing bone health and physical performance. 展开更多
关键词 Geriatric Nutrition Risk Index Bone mineral density Skeletal muscle mass Type 2 diabetes
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A high-entropy-designed cathode with V^(5+)-V^(2+) multi-redox for high energy density sodium-ion batteries
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作者 Xiang Ding Xiaofen Yang +3 位作者 Yibing Yang Liangwei Liu Yi Xiao Lili Han 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第10期429-437,I0008,共10页
Na_(3)V_(2)(PO_(4))_(3)(NVP)is gifted with fast Na^(+)conductive NASICON structure.But it still suffers from low electronic conductivity and inadequate energy density.Herein,a high-entropy modification strategy is rea... Na_(3)V_(2)(PO_(4))_(3)(NVP)is gifted with fast Na^(+)conductive NASICON structure.But it still suffers from low electronic conductivity and inadequate energy density.Herein,a high-entropy modification strategy is realized by doping V^(3+)site with Ga^(3+)/Cr^(3+)/Al^(3+)/Fe^(3+)/In^(3+)simultaneously(i.e.Na_(3)V_(2-x)(GaCrAlFeIn)_x(PO_(4))_(3);x=0,0.04,0.06,and 0.08)to stimulate the V^(5+)■V^(2+)reversible multi-electron redox.Such configuration high-entropy can effectively suppress the structural collapse,enhance the redox reversibility in high working voltage(4.0 V),and optimize the electronic induced effect.The in-situ X-ray powder diffraction and in-situ electrochemical impedance spectroscopy tests efficaciously confirm the robust structu ral recovery and far lower polarization throughout an entire charge-discharge cycle during 1.6-4.3 V,respectively.Moreover,the density functional theory calculations clarify the stronger metallicity of high-entropy electrode than the bare that is derived from the more mobile free electrons surrounding the vicinity of Fermi level.By grace of high-entropy design and multi-electron transfer reactions,the optimal Na_(3)V_(1.7)(GaCrAlFeIn)_(0.06)(PO_(4))_(3)can exhibit perfect cycling/rate performances(90.97%@5000 cycles@30 C;112 mA h g^(-1)@10 C and 109 mA h g^(-1)@30 C,2.0-4.3 V).Furthermore,it can supply ultra-high185 mA h g^(-1)capacity with fa ntastic energy density(522 W h kg^(-1))in half-cells(1.4-4.3 V),and competitive capacity(121 mA h g^(-1))as well as energy density(402 W h kg^(-1))in full-cells(1.6-4.1 V),demonstrating enormous application potential for sodium-ion batteries. 展开更多
关键词 Na_(3)V_(2)(PO_(4))_(3) High-entropy V^(5+)■V^(2+)multi-redox High energy density Sodium-ion batteries
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金属二聚体和氮共掺杂石墨烯(Gra)M_(2)N_(6)-Gra(M=Cr-Cu)的NO_(2)吸附特性理论研究
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作者 张展博 余娇 +5 位作者 魏亚茹 张轩 靳鑫 张子音 杨保成 张雷雷 《原子与分子物理学报》 CAS 北大核心 2025年第5期35-42,共8页
NO_(2)是空气污染物的主要成分之一,设计和开发高效的气敏传感器对NO_(2)进行检测具有重要意义.本工作利用基于密度泛函理论(DFT)的第一性原理计算方法对不同过渡金属原子形成的金属二聚体和氮共掺杂石墨烯(Gra)M_(2)N_(6)-Gra(M=Cr-Cu)... NO_(2)是空气污染物的主要成分之一,设计和开发高效的气敏传感器对NO_(2)进行检测具有重要意义.本工作利用基于密度泛函理论(DFT)的第一性原理计算方法对不同过渡金属原子形成的金属二聚体和氮共掺杂石墨烯(Gra)M_(2)N_(6)-Gra(M=Cr-Cu)的NO_(2)吸附特性进行了研究.结果表明,NO_(2)分子与M_(2)N_(6)-Gra之间均存在明显的化学吸附作用.其中,Ni_(2)N_(6)-Gra和Cu_(2)N_(6)-Gra体系具备较为适中的恢复时间(分别约为5秒和14分钟),这意味着这两个体系是开发新型NO_(2)气敏材料的潜在候选者.其它体系(M_(2)N_(6)-Gra,M=Cr-Co)强的吸附作用导致恢复时间过长,从而使得它们不适合作为NO_(2)气敏材料.这一研究不仅有望为设计和开发性能优异的新型NO_(2)气敏材料提供有益理论指导,还将有益于人们深入认识M_(2)N_(6)-Gra材料的NO_(2)电催化合成NO或NH 3性能. 展开更多
关键词 M_(2)N_(6)-Gra NO_(2)吸附 密度泛函理论
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Association between Low-density Lipoprotein Receptor-related Protein 5 Polymorphisms and Type 2 Diabetes Mellitus in Han Chinese:a Case-control Study 被引量:4
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作者 YOU Hai Fei ZHAO Jing Zhi +11 位作者 ZHAI Yu Jia YIN Lei PANG Chao LUO Xin Ping ZHANG Ming WANG Jin Jin LI Lin Lin WANG Yan WANG Qian WANG Bing Yuan REN Yong Cheng HU Dong Sheng 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2015年第7期510-517,共8页
Objective To investigate the association between low-density lipoprotein receptor-related protein 5 (LRPS) variants (rs12363572 and rs4930588) and type 2 diabetes mellitus (T2DM) in Han Chinese. Methods A total ... Objective To investigate the association between low-density lipoprotein receptor-related protein 5 (LRPS) variants (rs12363572 and rs4930588) and type 2 diabetes mellitus (T2DM) in Han Chinese. Methods A total of 1842 T2DM cases (507 newly diagnosed cases and 1335 previously diagnosed cases) and 7777 controls were included in this case-control study. PCR-RFLP was conducted to detect the genotype of the two single nucleotide polymorphisms (SNPs). Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated to describe the strength of the association by logistic regression. Results In the study subjects, neither rs12363572 nor rs4930588 was significantly associated with T2DM, even after adjusting for relevant covariates. When stratified by body mass index (BMI), the two SNPs were also not associated with T2DM. Among the 3 common haplotypes, only haplotype ~ was associated with reduced risk of T2DM (OR 0.820, 95% CI 0.732-0.919). In addition, rs12363572 was associated with BMI (P〈0.001) and rs4930588 was associated with triglyceride levels (P=0.043) in 507 newly diagnosed T2DM cases but not in healthy controls. Conclusion No LRP5 variant was found to be associated with T2DM in Han Chinese, but haplotype TT was found to be associated with T2DM. 展开更多
关键词 Low-density lipoprotein receptor-related protein 5 Gene polymorphism Type 2 diabetes mellitus HAPLOTYPE Metabolic characteristics
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掺杂对TiC_(2)纳米片析氢反应的第一性原理研究
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作者 孙楠楠 赵翠莲 +2 位作者 潘美玲 赵志超 张宇 《原子与分子物理学报》 CAS 北大核心 2025年第3期29-34,共6页
过渡金属二碳族化物单层作为一种廉价而丰富的材料,在制氢催化剂方面的应用越来越受到人们的关注.在这项工作中,基于第一性原理计算研究了掺杂二碳化钛单层的析氢还原.我们发现掺杂元素和浓度对单分子膜的催化能力有强烈的影响.结果表明... 过渡金属二碳族化物单层作为一种廉价而丰富的材料,在制氢催化剂方面的应用越来越受到人们的关注.在这项工作中,基于第一性原理计算研究了掺杂二碳化钛单层的析氢还原.我们发现掺杂元素和浓度对单分子膜的催化能力有强烈的影响.结果表明,在高氢覆盖率内,O和V掺杂能有效的降低氢吸附的吉布斯自由能.低密度掺杂可以提高催化能力.我们进一步研究表明,由于V原子在二碳化钛(TiC_(2))单层中具有最低的负形成能,因此比其他过渡金属原子更容易取代Ti原子.期望掺钒TiC_(2)单分子膜能以更高的效率应用于水电解. 展开更多
关键词 密度泛函理论 TiC_(2)单层片 覆盖率 掺杂
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Effects of current density on preparation and performance of Al/conductive coating/α-PbO_2-Ce O_2-TiO_2/β-Pb O_2-MnO_2-WC-ZrO_2 composite electrode materials 被引量:1
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作者 杨海涛 陈步明 +5 位作者 郭忠诚 刘焕荣 张永春 黄惠 徐瑞东 付仁春 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第10期3394-3404,共11页
Al/conductive coating/α-Pb O2-Ce O2-Ti O2/β-PbO 2-MnO 2-WC-Zr O2 composite electrode material was prepared on Al/conductive coating/α-PbO 2-Ce O2-Ti O2 substrate by electrochemical oxidation co-deposition technique... Al/conductive coating/α-Pb O2-Ce O2-Ti O2/β-PbO 2-MnO 2-WC-Zr O2 composite electrode material was prepared on Al/conductive coating/α-PbO 2-Ce O2-Ti O2 substrate by electrochemical oxidation co-deposition technique. The effects of current density on the chemical composition, electrocatalytic activity, and stability of the composite anode material were investigated by energy dispersive X-ray spectroscopy(EDXS), anode polarization curves, quasi-stationary polarization(Tafel) curves, electrochemical impedance spectroscopy(EIS), scanning electron microscopy(SEM), and X-ray diffraction(XRD). Results reveal that the composite electrode obtained at 1 A/dm2 possesses the lowest overpotential(0.610 V at 500 A/m2) for oxygen evolution, the best electrocatalytic activity, the longest service life(360 h at 40 °C in 150 g/L H2SO4 solution under 2 A/cm2), and the lowest cell voltage(2.75 V at 500 A/m2). Furthermore, with increasing current density, the coating exhibits grain growth and the decrease of content of Mn O2. Only a slight effect on crystalline structure is observed. 展开更多
关键词 composite electrode material A1 substrate β-PbO2-MnO2-WC-ZrO2 electrochemical co-deposition current density
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2型糖尿病患者血清β_2-GPI/ox-LDL复合物水平 被引量:9
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作者 张春妮 訾瑞峰 +4 位作者 汪俊军 刘小传 季茳 周健 李克 《临床检验杂志》 CAS CSCD 北大核心 2011年第2期100-102,共3页
目的检测分析2型糖尿病(T2DM)患者血清β2-糖蛋白I/氧化低密度脂蛋白(β2-GPI/ox-LDL)复合物水平。方法以抗人β2-GPI抗体为包被抗体、酶标记抗apoB为检测抗体的血清β2-GPI/ox-LDLELISA检测法,对42例T2DM患者和41例年龄、性别匹配的健... 目的检测分析2型糖尿病(T2DM)患者血清β2-糖蛋白I/氧化低密度脂蛋白(β2-GPI/ox-LDL)复合物水平。方法以抗人β2-GPI抗体为包被抗体、酶标记抗apoB为检测抗体的血清β2-GPI/ox-LDLELISA检测法,对42例T2DM患者和41例年龄、性别匹配的健康对照者检测分析。用ELISA方法检测血清ox-LDL水平,同时对受检者进行常规血脂水平测定。结果 T2DM组β2-GPI/ox-LDL水平显著高于对照组[(0.89±0.15)U/mlvs(0.81±0.09)U/ml,P<0.05],ox-LDL浓度也明显升高[(48.10±60.40)mg/Lvs(27.06±12.25)mg/L,P<0.05]。相关分析显示,β2-GPI/ox-LDL水平与总胆固醇(TC)、LDL-胆固醇(LDL-C)以及ox-LDL呈显著正相关。结论 T2DM患者血清β2-GPI/ox-LDL复合物水平增高,患者高浓度的血清LDL-C、ox-LDL和机体的高氧化应激状态是β2-GPI/ox-LDL升高的主要原因。 展开更多
关键词 氧化低密度脂蛋白 复合物 β2-糖蛋白I 2型糖尿病 氧化应激
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高血压左室向心性肥厚时外周血淋巴细胞β_2受体密度变化的研究 被引量:1
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作者 王红雷 朱源生 《实用临床医药杂志》 CAS 2009年第9期37-39,共3页
目的原发性高血压左室向心性肥厚时外周血淋巴细胞β2受体密度及心功能是否较正常有显著差异。方法正常对照组(CON组)31例,二维超声筛选出原发性高血压左室向心性肥厚构型组(CCH组)28例,测定2组心功能指标。同时进行放射性配基结合试验... 目的原发性高血压左室向心性肥厚时外周血淋巴细胞β2受体密度及心功能是否较正常有显著差异。方法正常对照组(CON组)31例,二维超声筛选出原发性高血压左室向心性肥厚构型组(CCH组)28例,测定2组心功能指标。同时进行放射性配基结合试验测定两组外周血淋巴细胞β2受体的密度(β2maxL)。结果①与正常对照组相比高血压左室向心性肥厚构型组左室舒张功能下降;高血压NG组收缩功能较正常对照组无差异。②CCH组β2maxL较正常组有显著差异(519±93.02,391.65±99.86 fmol/107Cell)。结论原发性高血压左室向心性肥厚时外周血淋巴细胞β2受体密度在较正常明显上调,心肌收缩功能改变处于代偿阶段。 展开更多
关键词 原发性高血压 左室几何构型 β2受体密度 心功能
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Insights into SO_2 and H_2O co-adsorption on Cu(100) surface with calculations of density functional theory
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作者 魏薪 董超芳 +3 位作者 陈章华 黄建业 肖葵 李晓刚 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第12期4102-4109,共8页
The co-adsorption behaviors of SO2 and H2 O on face-centered cubic Cu(100) ideal surface were studied using the GGA-r PBE method of density functional theory(DFT) with slab models. The optimized structures of sing... The co-adsorption behaviors of SO2 and H2 O on face-centered cubic Cu(100) ideal surface were studied using the GGA-r PBE method of density functional theory(DFT) with slab models. The optimized structures of single H2 O and SO2 on Cu(100) surface were calculated at the coverage of 0.25 ML(molecular layer) and 0.5 ML. The results show that there was no obvious chemical adsorption of them on Cu(100) surface. The adsorbed structures, adsorption energy and electronic properties including difference charge density, valence charge density, Bader charge analysis and partial density of states(PDOS) of co-adsorbed structures of H2 O and SO2 were investigated to illustrate the interaction between adsorbates and surface. H2 O and SO2 can adsorb on surface of Cu atoms chemically via molecule form at the coverage of 0.25 ML, while H2 O dissociated into OH adsorbed on surface and H bonded with SO2 which keeps away from surface at the coverage of 0.5 ML. 展开更多
关键词 SO2 H2O Cu density functional theory CO-ADSORPTION slab model adsorption energy charge transfer
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原发性高血压左室正常构型外周血淋巴细胞β_2受体密度及心功能的研究
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作者 王红雷 李东野 +1 位作者 陈清枝 张延斌 《徐州医学院学报》 CAS 2002年第6期510-512,共3页
目的 探讨原发性高血压左室正常构型外周血淋巴细胞 β2 受体密度及心功能是否较正常有显著差异。方法 超声测定正常对照组 (CON组 ) 31例、原发性高血压正常构型组 (NG组 ) 2 4例的心功能指标 ,同时进行放射性配基结合试验测定 2组... 目的 探讨原发性高血压左室正常构型外周血淋巴细胞 β2 受体密度及心功能是否较正常有显著差异。方法 超声测定正常对照组 (CON组 ) 31例、原发性高血压正常构型组 (NG组 ) 2 4例的心功能指标 ,同时进行放射性配基结合试验测定 2组外周血淋巴细胞β2 受体的密度 (β2 maxL)。结果 ①与正常对照组相比NG组左室舒张功能下降 ;NG组收缩功能与正常对照组无差异 ;②NG组 β2 maxL与正常组无显著差异 [(391.6 5± 99.86 )vs(42 6± 87.75 )fmol 10 7Cell]。结论 原发性高血压左室正常构型时外周血淋巴细胞 β2 受体密度较正常无显著变化 。 展开更多
关键词 外周血 淋巴细胞 原发性高血压 左室几何构型 β2受体密度 心功能
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活性金属Ni d电荷密度对Ni_(2)P/Al_(2)O_(3)催化剂菲加氢性能的影响 被引量:1
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作者 荆洁颖 李泽 +1 位作者 赵泽敏 张雨 《洁净煤技术》 CAS CSCD 北大核心 2024年第2期102-113,共12页
高温煤焦油中菲含量高,将菲深度加氢饱和得到全氢菲,可提升菲利用率,且全氢菲密度大,热值高,可作为喷气燃料理想组分。然而,在菲加氢反应过程中菲与中间加氢产物的竞争吸附不利于菲在催化剂上吸附活化,且对称八氢菲进一步加氢是菲加氢... 高温煤焦油中菲含量高,将菲深度加氢饱和得到全氢菲,可提升菲利用率,且全氢菲密度大,热值高,可作为喷气燃料理想组分。然而,在菲加氢反应过程中菲与中间加氢产物的竞争吸附不利于菲在催化剂上吸附活化,且对称八氢菲进一步加氢是菲加氢饱和过程的速控步骤,其吸附活化困难不易解决,催化剂活性难以满足加氢需求。根据稠环芳烃与过渡金属间π络合吸附机理,在反应物吸附活化过程中,稠环芳烃分子和活性金属分别充当电子供体和电子受体,故Ni基催化剂中活性金属Ni处于缺电子状态时利于生成全氢菲,但关于Ni缺电子量及其电子结构如何影响催化剂菲、对称八氢菲加氢性能的原因需进一步探究。此外,基于负载型Ni_(2)P催化剂稳定性高、耐硫、耐氮性强等优势,采用次磷酸盐歧化法通过调变P/Ni物质的量比制备具有不同Ni d电荷密度的Ni2P/Al_(2)O_(3)催化剂,考察Ni d电荷密度对菲、对称八氢菲吸附和反应性能的影响规律。结果表明,在320℃、5 MPa、空速1 309 h-1反应条件下,Ni-2.5P/Al_(2)O_(3)催化剂转换频率fTO最高(44.64×10^(-3)s^(-1))。通过吸附活化熵描述菲、对称八氢菲与催化剂表面间相互作用强度,发现菲、对称八氢菲在不同Ni-xP/Al_(2)O_(3)催化剂表面吸附强度不同。通过定量计算Ni d电荷密度,明确了Ni2P/Al_(2)O_(3)催化剂用于菲加氢反应时适宜Ni d电荷密度约-0.24 e,对称八氢菲加氢反应适宜的Ni d电荷密度约-0.05 e。 展开更多
关键词 加氢饱和 Ni_(2)P/Al_(2)O_(3)催化剂 d电荷密度 全氢菲
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Au-TiO_(2)光电极界面声子热输运特性的分子动力学模拟 被引量:1
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作者 桑丽霞 李志康 《物理学报》 SCIE EI CAS CSCD 北大核心 2024年第10期116-125,共10页
为了研究光电分解水体系中具有热等离激元效应的Au-TiO_(2)电极的界面热输运特性,本文采用非平衡分子动力学方法研究了温度、界面耦合强度以及添加石墨烯层对Au-TiO_(2)界面热导的影响,并通过声子态密度对界面热导的变化进行了分析.研... 为了研究光电分解水体系中具有热等离激元效应的Au-TiO_(2)电极的界面热输运特性,本文采用非平衡分子动力学方法研究了温度、界面耦合强度以及添加石墨烯层对Au-TiO_(2)界面热导的影响,并通过声子态密度对界面热导的变化进行了分析.研究结果表明,当体系温度从300 K增加到800 K时,Au-TiO_(2)界面导热系数增加了78.55%,这与更多的低频声子参与界面热输运相关,更多的热量传递到TiO_(2)上可促进界面反应.随着Au与TiO_(2)界面耦合强度的增大,界面热导率可通过TiO_(2)和Au的声子态密度的重叠程度得到优化.添加单层石墨烯可提高Au-TiO_(2)结构的界面热导,其中0—30 THz的低频区声子对导热贡献最大,但添加2层和3层石墨烯,石墨烯层与层之间的相互作用力阻碍了界面传热,且在低频区的声子数量有所降低,不利于热量在Au和TiO_(2)之间进行传递. 展开更多
关键词 Au-TiO_(2) 界面热导 声子态密度 分子动力学
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苍柴调中方辅助改善肝郁脾虚型肥胖2型糖尿病的疗效及对胰岛素抵抗、FFA、LDL-C水平的影响 被引量:1
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作者 陆聆韵 张惟郁 刘兴静 《中国医院用药评价与分析》 2024年第9期1090-1092,1096,共4页
目的:探讨苍柴调中方辅助改善肝郁脾虚型肥胖2型糖尿病(T2DM)的疗效,并分析其对胰岛素抵抗、游离脂肪酸(FFA)、低密度脂蛋白胆固醇(LDL-C)水平的影响。方法:选取2020年4月至2023年4月该院收治的肝郁脾虚型肥胖T2DM患者100例,根据随机数... 目的:探讨苍柴调中方辅助改善肝郁脾虚型肥胖2型糖尿病(T2DM)的疗效,并分析其对胰岛素抵抗、游离脂肪酸(FFA)、低密度脂蛋白胆固醇(LDL-C)水平的影响。方法:选取2020年4月至2023年4月该院收治的肝郁脾虚型肥胖T2DM患者100例,根据随机数字表法分为两组,各50例。对照组患者使用二甲双胍治疗,观察组患者在对照组基础上联合苍柴调中方辅助治疗。观察两组患者的治疗效果,比较两组患者治疗前后中医症状积分、糖代谢指标[空腹血糖(FBG)、空腹胰岛素(FINS)、胰岛素抵抗指数(HOMA-IR)]、血清FFA、LDL-C、肿瘤坏死因子α(TNF-α)水平的差异,并对不良反应发生率进行统计。结果:观察组患者的治疗总有效率高于对照组,不良反应发生率低于对照组,差异均有统计学意义(P<0.05)。治疗后,观察组患者倦怠乏力、精神抑郁、脘腹闷胀及大便黏滞等中医症状积分均低于对照组,差异均有统计学意义(P<0.05)。与治疗前比较,两组患者治疗后的FBG、HOMA-IR、FINS水平均明显降低,其中观察组患者治疗后的FINS、FBG及HOMA-IR水平低于对照组,差异均有统计学意义(P<0.05)。观察组患者治疗后的血清LDL-C、FFA、TNF-α水平均低于对照组,差异均有统计学意义(P<0.05)。结论:苍柴调中方辅助治疗可明显提高肝郁脾虚型肥胖T2DM患者的治疗效果,改善胰岛素抵抗,下调血清FFA、LDL-C水平。 展开更多
关键词 苍柴调中方 肥胖 2型糖尿病 胰岛素抵抗 游离脂肪酸 低密度脂蛋白胆固醇
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稀土金属Y掺杂锐钛矿TiO_(2)(101)表面的改性 被引量:1
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作者 朱黎原 王志文 《人工晶体学报》 CAS 北大核心 2024年第2期286-292,共7页
为了掌握Y原子掺杂在锐钛矿TiO_(2)(101)表面的稳定吸附位置和电子结构变化,提高其表面光催化活性,本文利用基于密度泛函理论的第一性原理计算研究了Y原子掺杂在完美的、带有亚表层氧空位和带有表层氧空位的锐钛矿TiO_(2)(101)表面的结... 为了掌握Y原子掺杂在锐钛矿TiO_(2)(101)表面的稳定吸附位置和电子结构变化,提高其表面光催化活性,本文利用基于密度泛函理论的第一性原理计算研究了Y原子掺杂在完美的、带有亚表层氧空位和带有表层氧空位的锐钛矿TiO_(2)(101)表面的结构稳定性和电子性能。结构优化和电荷密度结果表明,Y原子可以稳定吸附在三种不同的表面上。在完美表面吸附时,Y原子最稳定的吸附位置是两个三配位O原子之间的空位;与完美表面类似,在带有亚表层氧空位表面吸附时,Y原子最稳定吸附位置是与氧空位邻近的两个三配位O原子之间的空位;而在带有表层氧空位表面吸附时,Y原子则停留于氧空位邻近的四配位Ti原子位置上最稳定。电荷密度计算结果也表明Y原子与这三种表面结合非常稳固。电子态密度计算结果表明,在带有表层氧空位的锐钛矿TiO_(2)(101)表面引入Y原子会在费米面附近的带隙中引入缺陷态,带隙从1.67 eV降至1.44 eV,这有可能引起电子的分级跃迁,提高表面光催化能力。本文的研究为利用单原子Y掺杂提高TiO_(2)(101)表面光催化能力提供了理论支持。 展开更多
关键词 锐钛矿TiO_(2)(101)表面 氧空位 结构稳定性 电子态密度 第一性原理
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氧化型低密度脂蛋白对2型糖尿病合并肺结核患者的风险评估价值
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作者 桂静 王峰 +2 位作者 杨慧 蔡于茂 洪创跃 《实用医学杂志》 CAS 北大核心 2024年第14期1995-2002,共8页
目的探讨氧化型低密度脂蛋白(oxLDL)对2型糖尿病(T2DM)合并肺结核(PTB)患者的风险评估潜力。方法前瞻性纳入2022年6月至2023年6月门诊就诊的单纯高脂血症组病例60例、PTB组病例100例、T2DM组病例100例和T2DM合并PTB组病例100例,其中PTB... 目的探讨氧化型低密度脂蛋白(oxLDL)对2型糖尿病(T2DM)合并肺结核(PTB)患者的风险评估潜力。方法前瞻性纳入2022年6月至2023年6月门诊就诊的单纯高脂血症组病例60例、PTB组病例100例、T2DM组病例100例和T2DM合并PTB组病例100例,其中PTB组、T2DM组和T2DM合并PTB组再二次分组为血脂正常亚组40例和高脂血症亚组60例,共计360例为病例组;健康人群60例为对照组;入组年龄段为35~70岁。各组均采集静脉血,检测血液中的HbA1C、INS、FSG、TC、TG、HDL、LDL、ApoA I和Apo B,并采用ELISA法检测oxLDL,比较各组间的水平差异。应用多元logistic回归分析oxLDL水平与PTB和T2DM合并PTB的关联。结果T2DM高脂血症亚组的BMI、血糖、血脂和胰岛素抵抗等情况与T2DM合并PTB高脂血症亚组对比差异均无统计学意义(P>0.05);T2DM高脂血症亚组oxLDL水平高于对照组2倍以上,其血脂正常亚组的oxLDL水平显著高于对照组(P<0.05);T2DM合并PTB高脂血症亚组和单纯高脂血症组的oxLDL水平均显著高于对照组2倍以上,但与PTB高脂血症亚组相比,差异均无统计学意义(P>0.05)。相关性分析显示,T2DM高脂血症亚组和T2DM合并PTB高脂血症亚组的TG和LDL均与oxLDL呈显著正线性相关(R=0.352,P<0.05),PTB高脂血症亚组人群的CHOL和LDL均与oxLDL呈显著正线性相关(R=0.441,P<0.05);多元logistic回归分析显示oxLDL高于对照组2倍以上水平均是PTB和T2DM合并PTB的独立危险因素(均P<0.05)。结论显著升高的oxLDL水平可能是T2DM和PTB共病的危险因素,建议对oxLDL高于对照组2倍以上水平作为一个有临床意义的病理水平去进一步评估。 展开更多
关键词 2型糖尿病 肺结核 氧化型低密度脂蛋白 血脂
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Er掺杂PbF_(2)晶体的局域团簇结构与光谱性能研究
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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
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青海地区2型糖尿病患者血清胱抑素C及尿酸水平与骨密度的相关性分析
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作者 谢延玲 宋康 +1 位作者 林丽君 姚勇利 《中国医药》 2024年第12期1786-1790,共5页
目的探究青海地区2型糖尿病(T_(2)DM)患者血清胱抑素C及尿酸水平与骨密度的相关性。方法选取2023年1—12月在青海省人民医院内分泌科就诊的T_(2)DM患者141例。根据骨质疏松症的诊断标准将患者分为骨量正常组(56例)、骨量减少组(53例)和... 目的探究青海地区2型糖尿病(T_(2)DM)患者血清胱抑素C及尿酸水平与骨密度的相关性。方法选取2023年1—12月在青海省人民医院内分泌科就诊的T_(2)DM患者141例。根据骨质疏松症的诊断标准将患者分为骨量正常组(56例)、骨量减少组(53例)和骨质疏松组(32例),收集患者的一般资料,测定血清胱抑素C、尿酸等生化指标及骨密度数据,分析相关指标与骨密度的相关性。结果3组性别分布、年龄及25-羟维生素D、胱抑素C、总胆固醇、高密度脂蛋白胆固醇水平比较差异均有统计学意义(均P<0.05)。将单因素分析差异有统计学意义的变量作为自变量纳入多因素有序Logistic回归分析模型,分析结果显示,年龄、胱抑素C是T_(2)DM患者骨量减少及骨质疏松的危险因素,而男性、25-羟维生素D是其保护因素(比值比=0.434、0.922、1.100、3.555,均P<0.05)。结论高水平血清胱抑素C、女性、高龄、低水平25-羟维生素D可能是青海地区T_(2)DM患者骨量减少及骨质疏松症的危险因素,血尿酸水平与T_(2)DM患者骨密度变化无显著相关性。 展开更多
关键词 2型糖尿病 胱抑素C 血尿酸 骨密度
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