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儿童带环丝圈式间隙保持器的椅旁数字化设计与制作方法初探

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华西口腔医学杂志 2024年第2期42卷 234-241页

作者：秦庆钊胡嘉陈小贤石冰清高梓翔朱玉佳温奥楠王勇赵一姣北京大学口腔医学院·口腔医院数字化研究中心国家口腔医学中心国家口腔疾病临床医学研究中心口腔生物材料和数字诊疗装备国家工程研究中心国家卫生健康委口腔数字医学重点实验室(中国医学科学院口腔数字医学重点实验室)口腔数字医学北京市重点实验室北京100081 北京大学口腔医学院·口腔医院儿童口腔科北京100081 北京大学口腔医学院·口腔医院第一门诊部儿童口腔科北京100050 北京大学医学部医学技术研究院北京100191

目的提出一种儿童带环丝圈式间隙保持器的椅旁数字化设计与制作方法,并初步验证其临床可行性。方法选取10例因乳牙早失需要进行间隙保持的患儿为研究对象,采集患儿口内扫描数据建立缺牙数字模型,使用自主研发的儿童带环丝圈式间隙保持... 详细信息

目的提出一种儿童带环丝圈式间隙保持器的椅旁数字化设计与制作方法,并初步验证其临床可行性。方法选取10例因乳牙早失需要进行间隙保持的患儿为研究对象,采集患儿口内扫描数据建立缺牙数字模型,使用自主研发的儿童带环丝圈式间隙保持器设计软件,完成个性化带环与丝圈结构的快速设计,生成一体化带环丝圈式间隙保持器的数字模型。分别采用椅旁金属数控切削工艺(试验组)和技工室金属3D打印工艺(对照组)制作间隙保持器。对保持器进行模型试戴,邀请儿童口腔高年资专家采用视觉模拟评分法(VAS)从间隙保持器的密合度、就位稳定性两个方面进行评价,并进行统计学分析。结果试验组10例间隙保持器的设计及制作总时间均小于1 h。统计分析结果表明,2.间隙保持器均满足临床使用需求,试验组间隙保持器的密合度、稳定性优于对照组。结论本研究提出的儿童带环丝圈式间隙保持器的椅旁数字化设计与制作方法,可实现初次就诊当日佩戴间隙保持器,临床可行性好,具有良好的临床应用潜力。

关键词：儿童间隙保持器计算机辅助设计与计算机辅助制作椅旁数字化金属数控切削

Penetration depth and concentration distribution for implanted heavy ions with low energies in plant seeds by SEM and EDS

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Nuclear Science and Techniques 2001年第1期12卷 26-31页

作者： wang Xin-Fu ZHOU Yun-Long ZHOU Hong-Yu LU Ting wang Chao SU Ying ZHU Guang-Hua WEN {2.-Lin LI yong-Liang (key laboratory for Beam Technology and Material Modification of Ministry of Education, institute of Low energy Nuclear physics, beijing Norm key laboratory for Beam Technology and Material Modificationof Ministry of Education Institute of Low Energy Nuclear PhysicsBeijing Normal University beijing Radiation Center Department of Biology Beijing Normal University Center for Analysis and Testing Beijing Normal University

The penetration depth and concentration distribution of implanted ions have been studied for low energy heavy ions implanted in the dry seeds of plant, such as peanut, mung beau, sunflower, wheat and radish seeds, etc. by SEM+EDS. The results .how that the maximum penetration depth is about 12.m for V+ with an energy 2.0 keV implanted in cotyledon of the peanut, 18pm, spin, 2.μm for V2. with 90 keV implanted in sunflower, wheat, radish seeds, respectively. The penetration depth of implanted Cu2. with 80 keV is about 90μm in the remainder funicle derivative of the mung beau seeds. The experimental result of the maximum penetration depth of implanted V+ in the peanut seeds was compared with the calculated value of the TRIM95.

关键词：离子移植渗透深度浓度分布植物种子

基于LCEM-GFEM方法爆炸载荷作用下含缺陷岩体损伤机理研究

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Journal of Central South University 2024年第2期31卷 496-510页

作者：陈勇王应朋杨玉贵孙文凯孟宁康 State key laboratory for Fine Exploration and Intelligent Development of Coal Resources China University of Mining and TechnologyXuzhou 221116China China Coal Consultant International Beijing 100010China State key laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou 221008China

在爆破作业过程中,岩体缺陷对裂纹扩展具有显著影响。本研究基于全局有限元方法的局部黏结单元(LCEM-GFEM)方法构建数值模拟模型,研究爆破作用下含缺陷岩体的损伤演化和裂纹扩展模式。通过引入能量传递系数,定量分析了缺陷形态对应力波... 详细信息

在爆破作业过程中,岩体缺陷对裂纹扩展具有显著影响。本研究基于全局有限元方法的局部黏结单元(LCEM-GFEM)方法构建数值模拟模型,研究爆破作用下含缺陷岩体的损伤演化和裂纹扩展模式。通过引入能量传递系数,定量分析了缺陷形态对应力波传播和衰减的影响。结果表明,缺陷形态对岩体的损伤特性和裂纹扩展具有显著影响。随着平行缺陷夹角的增加,爆破诱发的裂缝与衍生裂缝的合并路径从缺陷末端转移到了缺陷中间,能量传递系数增加,分形维度减小。随着平行缺陷之间的水平距离增加,平行缺陷之间的裂缝数目和能量传递系数相应减少。随着垂直缺陷之间的垂直距离增加,穿过缺陷C的主水平裂缝长度增加,能量传递系数和分形维度也增加。研究结果可为受到爆破荷载作用下含缺陷岩体的损伤特征提供指导。

关键词：缺陷岩体 LCEM-GFEM方法裂纹扩展 Cohesive单元分形理论

Selective lithium recovery from black powder of spent lithiumion batteries via sulfation reaction:phase conversion and impurities influence

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Rare Metals 2023年第7期42卷 2350-2360页

作者： Hao Liu jia-Liang Zhang Guo-Qiang Liang Meng wang {2.-Qiang chen cheng-Yan wang State key laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing100083China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China beijing key {2. of Green Recycling and Extraction of Metals Beijing100083China

The aim of this study is to present a new understanding for the selective lithium recovery from spent lithium-ion batteries(LIBs)via sulfation *** composition of roasting products and reaction behavior of impurity elements were analyzed through thermodynamic ***,the effects of sulfuric acid dosage,roasting temperature,roasting time,and impurity elements were assessed on the leaching efficiency of valuable *** methods such as X-ray diffraction(XRD),scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS),and X-ray photoelectron spectroscopy(XPS)were employed to analyze the phase transformation mechanism during roasting *** results indicate that after sulfation roasting(n(H_(2.SO_(4)):n(Li)=0.5,550℃,2.h),94%lithium can be selectively recovered by water leaching and more than 95%Ni,Co,and Mn can be leached through acid leaching without the addition of reduction *** the sulfation roasting process,the lithium in LiNi_(x)Mn_(y)Co_zO_(2.is mainly converted to Li_(2.SO_(4),while the Ni,Co and Mn are first transformed to sulfate and then converted into oxide *** addition,impurity elements such as Al and F will combine with lithium to form LiF and LiAlO_(2.,which will reduce the leaching rate of *** results provide a new understanding on the mechanisms of phase conversion during sulfation roasting and reveal the influence of impurity elements for the lithium recovery from spent LIBs.

关键词： Spent lithium-ion batteries(LIBs) Thermodynamic calculations Sulfation roasting Impurity elements Conversion mechanism

“溶剂剪刀”克服惰性氢键促进常压氧气下高效催化氧化芳香烃

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chinese Journal of Catalysis 2024年第6期61卷 322-330页

作者：金魁张美云车鹏华孙冬茹王永马红张巧红陈晨徐杰宁波大学材料科学与化学工程学院浙江宁波315211 中国科学院大连化学物理研究所辽宁大连116023 中国科学院大学北京100049 宁波大学新药技术研究院浙江宁波315211

氢键是调节各类催化反应体系中分子行为的重要作用力,能够有效活化分子、改变作用位置及控制反应途径,具有重要的科学意义和应用潜力.然而,氢键的利用过程存在着惰性效应难题,严重阻碍反应的顺利进行.如何有针对性地打破惰性的氢键作用... 详细信息

氢键是调节各类催化反应体系中分子行为的重要作用力,能够有效活化分子、改变作用位置及控制反应途径,具有重要的科学意义和应用潜力.然而,氢键的利用过程存在着惰性效应难题,严重阻碍反应的顺利进行.如何有针对性地打破惰性的氢键作用力,探索氢键的构建与破坏机制,成为提高反应转化效率和选择性的重要途径,有利于实现高原子经济性并减少碳足迹.芳香烃氧化制羧酸是工业上重要的催化氧化过程,但存在高能耗、副产物多以及二氧化碳排放等问题.本文以甲苯液相氧气氧化制苯甲酸为模型反应,提出了旨在克服惰性氢键的"溶剂剪刀"策略.通过利用氢键受体溶剂(如醋酸、醋酸乙酯、氯乙酸乙酯或氯乙酸甲酯)作为破坏试剂,与强氢键供体溶剂六氟异丙醇(HFIP)形成氢键,从而将关键中间体苯甲醛从惰性的氢键结合状态中释放出来,将甲苯在温和条件下高效氧化为苯甲酸.使用NHPI/金属醋酸盐/HFIP-HOAc作为催化体系,在温和的反应条件(45°C,0.1 MPa O_(2.)下反应4 h,甲苯转化率达到96.8%,苯甲酸选择性达98.7%.该方法不仅成功实现了甲苯到苯甲酸的高效转化,还可进一步拓展至邻(间,对)甲基甲苯等甲基芳烃,在2.‒45°C和常压氧气条件下高效氧化制备芳香羧酸.利用变浓度核磁共振实验,定量测定了氢键供体HFIP与不同“剪刀溶剂”形成氢键的标准吉布斯自由能变化(ΔG^(0)).结果显示,‒ΔG^(0)顺序为醋酸>醋酸乙酯>氯乙酸乙酯>氯乙酸甲酯,其中醋酸的ΔG^(0)达到‒4.319 kJ/mol,具有最强的氢键裁剪能力.实验显示,‒ΔG^(0)与周转次数(TON)值(促进苯甲醛氧化的能力)的顺序一致,表明氢键裁剪能力越强的“溶剂-剪刀”越有利于促进苯甲醛的氧化.综上,本文利用“溶剂-剪刀”重建了甲基芳烃氧化反应中的氢键平衡体系,切断了使苯甲醛惰性化的氢键,促进游离苯甲醛的释放,使甲基芳香烃能在温和条件下高效氧化为芳香酸.本研究为有机合成普遍存在的氢键惰性化效应提供了解决思路,有利于促进“氢键调控”在有机合成的应用.

关键词：氢键芳香烃选择氧化溶剂剪刀六氟异丙醇

A Deprojection Analysis of Abell 1650 with XMM-Newton

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chinese Journal of Astronomy and astrophysics 2006年第2期6卷 181-196页

作者： Shu-Mei jia yong {2. Li {2. Department of Astronomy Beijing Normal University Beijing 100875 key laboratory of Particle {2. Institute of High Energy Physics Chinese Academyof Sciences Beijing 100049

We revisit the XMM-Newton observation of the galaxy cluster Abell 1650 with a deprojection technique. We find that the radial deprojected spectra of Abell 1650 can be marginally fitted by a single-temperature model. In order to study the properties of the central gas, we fit the spectra of the central two regions with a two- temperature model. The fits then become significantly better and the cool gas about 1～2.keV can be connected with the gas cooling. Fitting the central spectrum （r≤1′） by using a cooling flow model with an isothermal component yields a small mass deposition rate of 10-7^＋11 M. yr^-1, while the standard cooling flow model can not fit this spectrum satisfactorily except that there exists a cut-off temperature having a level of about 3 keV. From the isothermal model we derive the deprojected electron density profile ne（r）, and then together with the deprojected temperature profile the total mass and gas mass fraction of cluster are also determined. We compare the properties of Abell 1650 with those of Abell 1835 （a large cooling flow cluster） and some other clusters, to explore the difference in properties between large and small cooling flow cluster, and what causes the difference in the cooling flow of different clusters. It has been shown that Abell 1835 has a steeper potential well and thus a higher electron density and a lower temperature in its center, indicating that the shape of the gravitational potential well in central region determines the cooling flow rates of clusters. We calculate the potential, internal and radiated energies of these two clusters, and find that the gas energies in both clusters are conserved during the collapsing stage.

关键词： galaxies: clusters: individual: Abell 1650 -galaxies: cooling flowsgalaxies: evolution - galaxies: intergalactic medium - X-rays: galaxies: clusters

Boosting tribo-catalytic conversion of H_(2.O and CO_(2.by Co_(3)O_(4)nanoparticles through metallic coatings in reactors

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Journal of Advanced Ceramics 2023年第10期12卷 1833-1843页

作者： Xuchao jia Hongbo wang Hua Lei {2.yue Mao Xiaodong Cui yong Liu Yanmin jia Wenqing Yao Wanping {2. School of physics and Technology Wuhan UniversityWuhan 430072China School of Science Xi’an University of Posts and TelecommunicationsXi’an 710061China Department of Chemistry Tsinghua UniversityBeijing 100084China

In recent years,more and more metal oxides have been finding critical tribo-catalytic ***,we have explored the tribo-catalytic conversion of H_(2.O and CO_(2.using Co_(3)O_(4)nanoparticles and obtained some surprising *** an as-received 150 mL glass reactor enclosed with 10 mL of H_(2.O,0.10 g of Co_(3)O_(4)nanoparticles,1 atm of CO_(2.,and a Teflon magnetic rotary disk,we observed the production of as much as 57.41μmol/L of H_(2.,0.15μmol/L of CH_(4),and 0.2.μmol/L of CO after 5 h of magnetic *** coatings of Cu,Ni,SUS316,Ti,Nb,Mo,and W were further introduced on reactor bottoms *** those coatings of Ni,SUS316,Ti,and Nb,the reduction of CO_(2.was dramatically enhanced,and C_(2.)products of C_(2.H_(6)and C_(2.H_(4)were *** for the Ti coating,the amounts of H_(2.and CH_(4)were increased by 2.and 2. times from those for the glass bottom,respectively,and the amounts of C_(2.H_(6)and C_(2.H_(4)were very *** Co_(3)O_(4)nanoparticles were proven chemically stable under magnetic stirring in water,and hydroxyl radicals and superoxide radicals have been detected for the Co_(3)O_(4)nanoparticles under magnetic stirring through fluorescence spectroscopy and electron paramagnetic resonance spectroscopy *** findings not only reveal outstanding capability of Co_(3)O_(4)to generate multicarbon products from H_(2.O and CO_(2.through tribo-catalysis but also highlight a promising potential of tribo-catalysis as a whole to harness mechanical energy for addressing energy shortages and environmental pollution.

关键词： tribo-catalysis water splitting CO_(2.reduction Co_(3)O_(4)

Facile and Cost-Efficient Synthesis of Photovoltaic Polymers via Direct Arylation Coupling

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chinese Journal of Polymer Science 2023年第11期41卷 1663-1685,I0004页

作者： Xiao-chen wang Yuan Zhang {2.-Xin Yang Jin-Jun Shao Ming-Feng wang yong-Fang Li School of Materials Science and Engineering Shaanxi Normal UniversityXi'an 710119China key laboratory of Flexible Electronics(KLOFE)&{2. of Advanced Materials(IAM) School of Flexible Electronics(Future Technologies)Nanjing Tech UniversityNanjing 211816China School of Science and Engineering The Chinese University of Hong KongShenzhen 518172China beijing National laboratory for Molecular {2. CAS Key Laboratory of Organic SolidsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China

As the high calibre candidate of lightweight and flexible solar cells,polymer solar cells(PSCs)have made tremendous progress in recent ***,the active photovoltaic materials in PSCs are mainly synthesized by metal-mediated coupling reaction requiring harsh reaction conditions,multiple-step synthesis,and cumbersome purification,which is not cost-efficient and may bring toxicity *** is not favorable to the production of photovoltaic polymers and PSC devices on a large scale,and therefore unsuitable for the PSCs *** arylation coupling reaction via aromatic C―H bonds activation enables the synthesis of conjugated polymers under mild conditions and simultaneously reduces synthetic steps,difficulty,and toxic reaction *** review provides an overview of the history of preparing representative photovoltaic polymers utilized in PSCs through direct arylation reactions and discusses the activity and selectivity of C―H bonds in typical building blocks under different reaction ***,the impact of direct arylation condition on defect formation and photovoltaic performance of the photovoltaic polymers is addressed and compared with conventional Stille coupling methods.

关键词： Photovoltaic polymers Direct arylation coupling C―H bonds activation Polymer solar cells(PSCs) Organic solar cells(OSCs) Low-cost

基于电流模分量特性的多端柔性直流配电网线路纵联保护

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现代电力 2024年第2期41卷 279-286页

作者：陈新岗邹越越马志鹏贾勇赵蕊朱磊王梅林张金京重庆理工大学重庆市巴南区400054 重庆市能源互联网工程技术研究中心重庆市巴南区400054

多端柔性直流配电网因在供电可靠性方面极具优势而受到广泛的关注,然而对于直流线路保护中故障的快速、可靠识别成为其急速发展所需解决的关键问题之一。因此,设计了一种利用电流模分量特性的直流线路纵联保护方法。该方法利用故障时正... 详细信息

多端柔性直流配电网因在供电可靠性方面极具优势而受到广泛的关注,然而对于直流线路保护中故障的快速、可靠识别成为其急速发展所需解决的关键问题之一。因此,设计了一种利用电流模分量特性的直流线路纵联保护方法。该方法利用故障时正极电流线模分量方向来判别区内外故障,以不同故障条件下故障点正极电流零模分量平均值的差异来构造保护判据,从而判别故障类型,形成保护策略。最后,在PSCAD/EMTDC4.5上搭建了多端柔性直流配电网模型,对保护判据及关键影响要素进行了仿真分析。结果表明,该保护方法能够有选择性地快速、可靠识别区内外故障及故障类型,且具有较好的耐过渡电阻与抗噪声能力。

关键词：直流配网线模分量零模分量故障识别线路纵联保护