检索结果-南通市图书馆

Viscosity and structure relationship with equimolar substitution of CaO with MgO in the CaO–MgO–Al_(2)O_(3)–SiO_(2)slag melts

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 70-79页

作者： Yong Hou Shuo Zhang Jie dang Jia Guo Hanghang zhou Xuewei Lü College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New Materials Chongqing UniversityChongqing 400044China

Currently,the Al_(2)O_(3)content in the high-alumina slag systems within blast furnaces is generally limited to 16wt%–18.5wt%,making it challenging to overcome this *** most studies that concentrated on managing the MgO/Al_(2)O_(3)ratio or basicity,this paper explored the effect of equimolar substitution of MgO for CaO on the viscosity and structure of a high-alumina CaO-MgO-Al_(2)O_(3)-SiO_(2)slag system,providing theoretical guidance and data to facilitate the application of high-alumina *** results revealed that the viscosity first decreased and then increased with higher MgO substitution,reaching a minimum at 15mol%MgO *** transform infrared spectroscopy(FTIR)results found that the depths of the troughs representing[SiO_(4)]tetrahedra,[AlO_(4)]tetrahedra,and Si-O-Al bending became progressively deeper with increased MgO *** of the Raman spectra showed that the average number of bridging oxygens per Si atom and the X_(Q^(3))/X_(Q^(2))(X_(Q^(i))is the molar fraction of Q^(i) unit,and i is the number of bridging oxygens in a[SiO_(4)]tetrahedral unit)ratio increased from 2.30 and 1.02 to 2.52 and 2.14,respectively,indicating a progressive polymerization of the silicate structure.X-ray photoelectron spectroscopy(XPS)results highlighted that non-bridging oxygen content decreased from 77.97mol% to 63.41mol% with increasing MgO concentration,whereas bridging oxygen and free oxygen contents *** analysis demonstrated a gradual increase in the polymerization degree of the tetrahedral structure with the increase in MgO ***,bond strength is another important factor affecting the slag *** occurrence of a viscosity minimum can be attributed to the complex evolution of bond strengths of non-bridging oxygens generated during depolymerization of the[SiO_(4)]and[AlO_(4)]tetrahedral structures by CaO and MgO.

关键词： aluminosilicate viscosity structure spectroscopy

Statistical characteristics and classification of ionospheric mid-latitude trough as revealed by the observations of DMSP-F18

在线全文

学校读者我要写书评

暂无评论

Earth and Planetary Physics 2025年第1期9卷 137-147页

作者： Yi Liu JiuHou lei FuQing Huang Su zhou School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China School of Science Guiyang UniversityGuiyang 550005China

Statistical characteristics and the classification of the topside ionospheric mid-latitude trough are systemically analyzed,using observations from the Defense Meteorological Satellite Program F18(DMSP-F18)*** data was obtained at an altitude of around 860 km in near polar orbit,throughout *** study identified the auroral boundary based on the in-situ electron density and electron spectrum,allowing us to precisely determine the location of the mid-latitude *** differs from most previous works,which only use Total Electron Content(TEC)or in-situ electron *** our study,the troughs exhibited a higher occurrence rate in local winter than in summer,and extended to lower latitudes with increasing geomagnetic *** was found that the ionospheric mid-latitude trough,which is associated with temperature changes or enhanced ion drift,exhibited distinct ***,the ionospheric mid-latitude troughs related to electron temperature(Te)peak were located more equatorward of auroral oval boundary in winter than in *** ionospheric mid-latitude troughs related to Te-maximum were less frequently observed at 60−70°S magnetic latitude and 90−240°E ***,the troughs related to ion temperature(Ti)maximums were observed at relatively higher latitudes,occurring more frequently in *** addition,the troughs related to ion velocity(Vi)maximums could be observed in all *** troughs with the maximum-Ti and maximum-Vi were located closer to the equatorward boundary of the auroral oval at the nightside,and in both *** implies that enhanced ion drift velocity contributes to increased collisional frictional heating and enhanced ion temperatures,resulting in a density depletion within the trough region.

关键词： topside ionosphere mid-latitude trough ionospheric main trough auroral oval boundary temperature maximum

Dative B–N bonds weaven toward two-dimensional purely organic materials for single crystals

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2025年第01期 12-14页

作者： Wei-lei zhou Siwei Wang Yong Chen College of Chemistry and Materials Science Inner Mongolia Key Laboratory of Chemistry for Nature Products and Synthesis for Functional Molecules Innovation Team of Optical Functional Molecular Devices Inner Mongolia Minzu University College of Chemistry Nankai University

Molecular topology is one of the important topics to study and understand the relationship between molecular structure and properties [1]. Particularly, two-dimensional (2D) materials with extremely high surface area and ultra-thin morphology have attracted considerable attention due to their unexpected properties in materials and chemistry [2,3].

关键词：

同方期刊数据库

Transforming waste particles into valuable adsorbents via amyloid-mediated molecular engineering

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2025年第01期 317-328页

作者： Qingmin Yang Jian Zhao Yujia Zhang Xingyu zhou Hao Ren Bowen Hu Zhongli lei Lixin Chen Peng Yang School of Material and Chemical Engineering Bengbu University Anhui Provincial Engineering Laboratory of Silicon-Based Materials School of Chemistry and Chemical Engineering Northwestern Polytechnical University Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education School of Chemistry and Chemical EngineeringShaanxi Normal University Xi'an Key Laboratory of Polymeric Soft Matter School of Chemistry and Chemical Engineering Shaanxi Normal University International Joint Research Center on Functional Fiber and Soft Smart Textile School of Chemistry and Chemical EngineeringShaanxi Normal University

The high-value utilization of industrial solid waste using a facile and eco-friendly process is of great interest and significance in reducing environmental pollution and developing a green circular economy. Herein, we propose an amyloid-mediated molecular engineering strategy to transform particulate waste into valuable adsorbents for metal ions. Our method has the advantage of aqueous solution fabrication under mild conditions without the use of high-temperature hydrothermal methods and toxic chemical reagents. Amyloid-mediated molecular engineering manipulates the phase transition of bovine serum albumin(BSA)on particulate waste surfaces, resulting in a remarkable ～3.1 times improvement in the adsorption capacity of fly ash, a typical industrial solid waste for gold ions after modification with the phase-transitioned BSA(PTB). The resultant adsorption ability was 69–1,980 times higher than those of conventional and emerging adsorbent materials such as ion exchange resins, activated carbon(AC), covalent organic frameworks(COFs), and metal-organic frameworks(MOFs). We further demonstrated the application of our PTB-modified materials in the recovery of precious metals from low-grade gold ore and electronic waste leachates. Consequently, this strategy could increase the value of waste materials nearly 27 times. In addition, this method is generally extendable to other conventional industrial adsorbents such as resin, clay, and Al2O3, and enhances their adsorption capabilities at least twofold. Overall, this work provides a simple and green approach for improving the adsorption performance of solid particles, and is expected to develop into a universal strategy for transforming waste particles into high-value-added products.

关键词：

同方期刊数据库

Acceptor concentration dependent Fo?rster resonance energy transfer in nanocrystal-molecule complexes revealed by spectral analysis

在线全文

学校读者我要写书评

暂无评论

Optoelectronics Letters 2025年

作者： Rongxin ZHANG Zixiang zhou lei WANG Xin ZHANG Ying LIANG Guijie LIANG Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices， Hubei University of Arts and Science

A nanocrystal-molecule complex composed of CdSe donor and Rhodamine B (RhB) acceptor is prepared to investigate the effect of accepter-donor ratio on the Fo?rster resonance energy transfer (FRET) process. To highlight the FRET process， the energy level alignment between CdSe and RhB is purposefully designed and CdSe nanocrystal is coated with a wide band-gap ZnS shell. The carrier dynamics is observed via combined spectral analysis. The results reveal clear FRET process between the CdSe donor and RhB acceptor. The FRET is enhanced by increasing RhB/CdSe ratio and a gradual saturation will be present at high RhB concentration.

关键词：

胸椎管狭窄症术后脑脊液漏继发皮下积液的治疗

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

北京大学学报（医学版） 2018年第4期50卷 657-661页

作者：王永强刘晓光姜亮韦峰于淼吴奉梁党礌周华刘忠军北京大学第三医院骨科北京100191

目的:探讨胸椎管狭窄症术后脑脊液漏继发皮下积液的治疗方法。方法:回顾分析2005年1月至2014年12月北京大学第三医院骨科脊柱组完成手术的胸椎管狭窄症患者,其中术中、术后发生脑脊液漏者186例,选取其中继发皮下积液且规律随访的11例患... 详细信息

目的:探讨胸椎管狭窄症术后脑脊液漏继发皮下积液的治疗方法。方法:回顾分析2005年1月至2014年12月北京大学第三医院骨科脊柱组完成手术的胸椎管狭窄症患者,其中术中、术后发生脑脊液漏者186例,选取其中继发皮下积液且规律随访的11例患者作为研究对象,治疗方法依据患者脑脊液漏严重程度以及胸脊髓病恢复情况决定。采取日本骨科协会(Japanese Orthopedic Association,JOA)改良11分评分评价患者术前及术后的脊髓功能,将手术前后的JOA评分进行统计学分析。结果:11例患者均获得随访,其中后纵韧带骨化合并黄韧带骨化者6例,均接受椎管后壁切除及"涵洞塌陷法"360°脊髓环形减压术,单纯黄韧带骨化行椎管后壁切除术者5例。随访时间30~131个月,平均(85±34)个月。术前症状持续时间3个月至8年,中位数18个月;术后引流管拔出时间2~6 d,平均(4.2±1.1)d;围手术期出现发热患者10例,最高体温(37.3~39.7)℃,其中高热患者2例,延长抗生素使用时间。10例患者采取保守治疗,随访发现脑脊液漏全部吸收,其中拔出引流管后加压包扎伤口者8例,局部穿刺抽液后加压包扎伤口者2例;1例患者因保守治疗无效,继发脑脊液假性囊肿而接受再次手术治疗。11例患者的JOA评分从术前的(3.8±1.6)分升高到末次随访时的(8.9±1.2)分,神经功能改善率为70.8%。没有患者出现切口感染、切口不愈合及颅内感染等并发症。结论:胸椎管狭窄症术后脑脊液漏继发皮下积液者多数可以采取保守治疗,只有出现脑脊液假性囊肿压迫脊髓时需要采取手术治疗。

关键词：后纵韧带骨化黄韧带骨化胸椎脑脊液漏皮下积液

Improved stability of superelasticity and elastocaloric effect in Ti-Ni alloys by suppressing Lüders-like deformation under tensile load

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第15期146卷 154-167页

作者： Pengfei dang Jianbo Pang Yumei zhou lei Ding lei Zhang Xiangdong Ding Turab Lookman Jun Sun Dezhen Xue State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China AiMaterials Research LLC Santa FeNM 87501USA

Functional stability of superelasticity is crucial for practical applications of shape memory *** is degraded by a Lüders-like deformation with elevated local stress concentration under tensile *** increasing the degree of solute supersaturation and applying appropriate thermomechanical treatments,a Ti-Ni alloy with nanocrystallinity and dispersed nanoprecipitates is *** contrast to conventional Ti-Ni alloys,the superelasticity in the target alloy is accompanied by homogeneous deformation due to the sluggish stress-induced martensitic *** alloy thus shows a fully recoverable strain of 6%under tensile stress over 1 GPa and a large adiabatic temperature decrease of 13.1 K under tensile strain of 4.5%at room ***,both superelasticity and elastocaloric effect exhibit negligible degradation in response to applied strain of 4%during *** attribute the improved functional stability to low dislocation activity resulting from the suppression of localized deformation and the combined strengthening effect of nanocrystalline structure and ***,the design of such a microstructure enabling homogeneous deformation provides a recipe for stable superelasticity and elastocaloric effect.

关键词： Ti-Ni alloys Superelasticity Elastocaloric effect Martensite band Functional stability

应用谷歌地球引擎和多维特征集构建的艾比湖流域长时序景观分类模型

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

东北林业大学学报 2025年第2期53卷 97-104页

作者：雷焯越蒲智周军新疆农业大学乌鲁木齐830000

以新疆艾比湖流域为研究区域,整合历史遥感影像数据与现场地表特征考察,将艾比湖流域景观类型划分为6类(耕地、林地、草地、水域、建设用地、未利用地);以谷歌地球引擎(GEE)平台提供的艾比湖流域2002—2023年(2002、2008、2013、2018、2... 详细信息

以新疆艾比湖流域为研究区域,整合历史遥感影像数据与现场地表特征考察,将艾比湖流域景观类型划分为6类(耕地、林地、草地、水域、建设用地、未利用地);以谷歌地球引擎(GEE)平台提供的艾比湖流域2002—2023年(2002、2008、2013、2018、2023年)的陆地卫星(Landsat)影像为基础数据源,以艾比湖流域长时序景观分类为评价指标,光谱指数(归一化植被指数、增强植被指数、归一化水体指数、归一化建筑指数)、地形特征(海拔、坡度、坡向)、纹理特征(角二阶矩阵、对比度、相关性、熵、协方差、逆方差、总和平均值)为影响因素,从光谱指数、地形特征、纹理特征三个角度构建并筛选最优多维特征模型;分别运用分类回归树(CART)、随机森林(RF)、梯度提升树(GBT)、支持向量机(SVM)机器学习算法,对艾比湖流域长时序景观信息进行自动分类,对比4种机器学习算法的分类精度,遴选最适用于艾比湖流域的景观分类模型。结果表明:(1)应用谷歌地球引擎云计算平台,能够高效处理、分析及可视化研究区近22 a的景观分类结果。(2)3类特征重要性,由大到小依次为光谱指数(31.52%)、地形特征(17.18%)、纹理特征(3.83%)。地形特征在单一特征中分类精度最高;光谱特征联合纹理特征,在双特征配置中对提高研究区景观分类精度呈现出较好效果;而整合光谱指数、地形特征、纹理特征的模型,能够在任一特征组合的基础上有效提高研究区景观分类模型精度。(3)4种分类算法融合光谱、地形、纹理特征,分类精度由高到低依次为随机森林、梯度提升树、分类回归树、支持向量机;随机森林在5期(2002、2008、2013、2018、2023年)影像中的总体分类精度不低于93%,卡帕系数(Kappa)不低于0.92,最适用于艾比湖流域景观分类。

关键词：景观分类生态系统生态环境艾比湖流域

The Stable Carbon Isotopic Compositions of n-Alkanes in Sediments of the Bohai and North Yellow Seas: Implications for Sources of Sedimentary Organic Matter

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2021年第2期20卷 340-348页

作者： dang Tianxiang CAO Yunyun XING lei Key Laboratory of Marine Chemistry Theory and Technology Ministry of EducationOcean University of ChinaQingdao 266100China Laboratory for Marine Ecology and Environmental Science Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China

Stable carbon isotopic compositions of n-alkanes in surface sediments of the Bohai and North Yellow Seas were investigated to elucidate sources of sedimentary organic matter in these seas. The long-chain n-alkanes in surface sediments are predominantly long-chain C27, C29, and C31 types, with obvious odd carbon predominance. The δ13 C values of long-chain n-C27, n-C29, and n-C31 alkanes are-30.8% ± 0.5‰,-31.9% ± 0.6‰, and-32.1% ± 1.0‰, respectively, within the range of n-alkanes of C3 terrestrial higher plants. This suggests that sedimentary n-alkanes are derived mainly from terrestrial higher plants. Compound-specific carbon isotopic analysis of long-chain n-alkanes indicates that C3 terrestrial higher plants predominate(64%–79%), with angiosperms being the main contributors. The n-alkane δ13 C values indicate that mid-chain n-alkanes in sediments are derived mainly from aquatic emergent macrophytes, with significant petroleum pollution and bacterial degradation sources for short-chain n-alkanes.

关键词： biomarker carbon isotopes n-alkanes Bohai Sea North Yellow Sea