检索结果-南通市图书馆

Characteristics of air pollution by polychlorinated dibenzo-p-dioxins and dibenzofurans in the typical industrial areas of Tangshan City,China

引用

Journal of Environmental Sciences 2011年第2期23卷 228-235页

作者： Zhiyuan Ren Bing Zhang Pu Lu Cheng Li Lirong gao Minghui zheng Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China.

The ambient air in vicinity of different industrial sources for PCDD/PCDFs was sampled by TSP/PM10 active samplers and passive PUF disk samplers in Tangshan City, a metropolis containing clusters of various industrial plants. The TEQ concentrations of PCDD/PCDFs ranged from 44.2 to 394.1 fg I-TEQ/m^3 with an average of 169.9 fg I-TEQ]m^3. 2,3,4,7,8-PeCDF was the dominant contributor to ∑TEQ, contributing 41% （12% to 55%）, while 1,2,3,4,6,7,8-HpCDE OCDD and OCDF were the major congeners for the total concentrations. The ratios of ∑PCDF/∑PCDD reached 2.54 on average, suggesting that de novo synthesis in thermal processes played an important role to the airborne pollution of PCDD/PCDFs. The similarities congener profiles indicated that TSP and PM10 active sampling methods are comparable for the determination of the PCDD/PCDFs in ambient air, and the ratios of concentrations determined by the two methods suggested that the PCDD/PCDFs tended to stay in fine particles. It was found that 2,3,7,8-TCDF and OCDD were the dominating congeners in the passive PUF disks samples. Through principal components analysis, the coke industry was suggested to be a relatively high potential emission source for PCDD/PCDFs in the ambient air of Tangshan, which was possibly formed by de novo synthesis mechanism. In this study, the atmospheric impacts to the environment from different industrial sources could be ranked as follows （from high to low）： coking, iron sintering, steel making, power generation and chlorinate alkali chemical production industries.

关键词： ambient air dioxins inhalable particles total suspended particles metropolis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Synthesis and Properties of Novel Luminescent Compounds Containing Triphenylamine and Bipyridine Units

引用

Chemical Research in Chinese Universities 2012年第2期28卷 313-318页

作者： LU Hai-jun LI Xiang-gao WANG Shi-rong gao Wen-zheng WANG Sha-sha School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072P.R.China College of Chemical and Pharmaceutical Engineering Hebei University of Science and TechnologyShijiazhuang 050018P.R.China

Blue luminescent compounds T1―T4 containing triphenylamine donors,bipyridine acceptors and olefinic linkers were synthesized and characterized by 1 H NMR,13 C NMR and high resolution mass spectrometry（HRMS）.Four compounds T1―T4 exhibit excellent solubility in common solvents and good film forming *** chemical calculations show that compounds T1―T4 have asymmetric linear structures and the proper highest occupied molecular orbital（HOMO） *** UV-Vis absorption and fluorescence emission spectra of the four compounds in dilute chloroform solutions and on the solid films were *** reveals that compounds T1―T4 exhibit similar spectral behavior,suggesting that these compounds can form amorphous state in solid *** calculated absorption and emission spectra of compounds T1―T4 are in good agreement with experimentally determined *** T1―T4 have absolute fluorescence quantum yield above 17% in dilute chloroform *** compounds possess high glass-transition temperature（T g） exceeding 97 ℃ and the maximum T g is 155.28 ℃ for compound *** voltammetry measurements show that these compounds have proper HOMO levels in a range of-5.01―-5.13 eV for hole *** properties of compounds T1―T4 indicate that these compounds are candidates for the application in organic light-emitting devices（OLEDs） as hole-transporting materials（HTMs）.

关键词： Luminescent compound Triphenylamine Bipyridine Hole-transporting material

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Orthogonal Combinatorial Raman Codes Enable Rapid High-Throughput-Out Library Screening of Cell-Targeting Ligands

引用

Research 2024年第1期2023卷 199-208页

作者： Yuchen Tang Xingxing zheng Tingjuan gao China Key Laboratory of Pesticide and Chemical Biology of Ministry of Education College of ChemistryCentral China Normal UniversityWuhan 430079China

High-throughput assays play an important role in the fields of drug discovery,genetic analysis,and clinical *** super-capacity coding strategies may facilitate labeling and detecting large numbers of targets in a single assay,practically,the constructed large-capacity codes have to be decoded with complicated procedures or are lack of survivability under the required reaction *** challenge results in either inaccurate or insufficient decoding ***,we identified chemical-resistant Raman compounds to build a combinatorial coding system for the high-throughput screening of cell-targeting ligands from a focused 8-mer cyclic peptide *** accurate in situ decoding results proved the signal,synthetic,and functional orthogonality for this Raman coding *** orthogonal Raman codes allowed for a rapid identification of 63 positive hits at one time,evidencing a high-throughput-out capability in the screening *** anticipate this orthogonal Raman coding strategy being generalized to enable efficient high-throughput-out screening of more useful ligands for cell targeting and drug discovery.

关键词： enable throughput allowed

来源：

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

大尺寸TC4钛合金环壳充气热气胀压弯成形工艺研究

引用

航天制造技术 2024年第4期 40-46页

作者：赵子维李德崇付坤宁曹宏东高政郑凯伦大连理工大学机械工程学院大连116024

钛合金环形燃料贮箱是运载火箭上面级的薄壳件的关键结构。新一代燃料贮箱对空间利用率的要求更高,因此采用环壳代替多个球形贮箱组合。环形贮箱具有大尺寸、超薄、材料难变形的成形难点,且传统分块拼焊结构可靠性差。基于此,本文提出... 详细信息

钛合金环形燃料贮箱是运载火箭上面级的薄壳件的关键结构。新一代燃料贮箱对空间利用率的要求更高,因此采用环壳代替多个球形贮箱组合。环形贮箱具有大尺寸、超薄、材料难变形的成形难点,且传统分块拼焊结构可靠性差。基于此,本文提出了环壳热压弯成形工艺,开发了内置VUMAT子程序嵌入材料本构模型的钛合金环壳热气胀压弯仿真模型,研究了不同工艺参数下钛合金环壳热压弯的壁厚、贴模度变化规律。以环壳壁厚减薄率与截面最大变形率为判据,建立了支撑内压与管坯温度的热压弯工艺窗口图,确定最优工艺参数。搭建了TC4钛合金环壳热压弯成形装置,制造了全尺寸钛合金环壳,环壳中径2692 mm,截面直径500 mm,壁厚2 mm,径厚比高达250,实际工件中径尺寸与目标尺寸相差11 mm,环壳弯曲内侧最大增厚率为11.5%,环壳弯曲外侧最大减薄率为8.3%,抗拉强度与平均晶粒尺寸均优于设计指标。

关键词： TC4钛合金环壳热气胀成形有限元仿真

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Changes of Cu, Zn, and Cd speciation in sewage sludge during composting

引用

Journal of Environmental Sciences 2005年第6期17卷 957-961页

作者： gao Ding zheng Guo-di CHEN Tong-bin LUO Wei gao Wei ZHANG Yi-an LI Yan-xia Center for Environmental Remediation Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China

The potential toxicity risks from heavy metals depend on their chemical speciation. The four stages of the Tessier sequential extraction method were employed to investigate changes in heavy metal speciation （Cu, Zn, and Cd） of sewage sludge during forced aeration composting, and then to identify whether the composting process would reduce or enhance their toxicities. Throughout the composting process, the exchangeable, carbonate-bound, Fe-Mn oxide-bound, and organic matter-bound fractions of Cu were converted to the residual Cu fraction. The organic matter-bound Cu fraction greatly contributed to this transformation. Residual Zn fraction was transformed to the Fe-Mn oxide-bound and organic matter-bound fractions after composting. The residual Zn fraction was a major contributor to the organic matter-bound Zn fraction. The availability of Cu and Zn was reduced by composting such that the risk of heavy metal toxicity decreased with prolonged treatment times. Additionally, attention should be paid to the increased availability of Cd in sewage sludge after composting treatment.

关键词： composting distribution heavy metal sewage sludge speciation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

汽车机油泵体压铸工艺数值模拟与优化

引用

铸造 2024年第2期73卷 208-215页

作者：刘晓龙龚海军卢红林龚琛普高正源重庆交通大学机电与车辆工程学院重庆400074 重庆东科模具制造有限公司重庆401320

为满足汽车铝合金机油泵体压铸件高气密性和高强度的要求,解决该铸件缩松、缩孔缺陷问题,进行压铸工艺设计和优化。首先对铸件进行工艺分析,根据经验分别设计浇注排溢系统并初步选取工艺参数;再运用田口正交试验法设计了5因素4水平压铸... 详细信息

为满足汽车铝合金机油泵体压铸件高气密性和高强度的要求,解决该铸件缩松、缩孔缺陷问题,进行压铸工艺设计和优化。首先对铸件进行工艺分析,根据经验分别设计浇注排溢系统并初步选取工艺参数;再运用田口正交试验法设计了5因素4水平压铸工艺参数方案,并使用Procast进行数值模拟。将16组正交试验结果基于信噪比进行极差和方差分析,结果表明,模具温度对缩松缩孔的影响最为显著,5因素的最优工艺参数为:浇注温度650℃、模具温度240℃、慢/快压射距离200 mm/60 mm、快压射速度为3.0 m/s、慢压射速度为0.2 m/s。数值模拟结果显示,该工艺参数组合下铸件缩松、缩孔体积为1.067 cm^(3),较优化前降低了26.5%。试模结果表明,铸件外观完好,关键部位X射线探伤显示无明显缩孔;采用金相显微镜(OM)和扫描电镜(SEM)对铸件进行组织观察,发现铸件各区域组织致密;力学性能测试表明,压铸件显微硬度大于HV85,同等工艺下试棒平均拉伸强度为253.36 MPa,铸件满足使用要求。

关键词：机油泵体压铸缩松缩孔数值模拟正交试验

来源：

维普期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

水性反射隔热型涂料的制备及性能影响因素探究

引用

中国涂料 2024年第2期39卷 32-37页

作者：高本正王娜齐舵于帅沈阳化工大学辽宁省特种功能材料合成与制备重点实验室沈阳110142 沈阳先进涂层材料产业技术研究院沈阳110300 辽宁顺风新材料科技有限公司沈阳110326

研究了反射隔热涂料中重要组分对其性能的影响规律。以纯丙乳胶作为成膜物,空心玻璃微珠和金红石型二氧化钛作为功能填料,在基本配方体系基础上,通过单一变量控制法研究了空心玻璃微珠、金红石型二氧化钛的尺寸及添加量等因素对反射隔... 详细信息

研究了反射隔热涂料中重要组分对其性能的影响规律。以纯丙乳胶作为成膜物,空心玻璃微珠和金红石型二氧化钛作为功能填料,在基本配方体系基础上,通过单一变量控制法研究了空心玻璃微珠、金红石型二氧化钛的尺寸及添加量等因素对反射隔热涂料透水及耐沾污性、太阳光反射性能和隔热性能的影响规律,并制备得到综合性能优异的水性反射隔热涂料。研究结果表明,反射隔热填料不仅影响涂层的太阳光反射和隔热性能,对于涂层的耐水和耐沾污性也有显著影响。

关键词：反射隔热涂料空心玻璃微珠金红石型二氧化钛太阳光反射比

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Study on Reactions of 2-Acetyl-7-methylaminotropone with Pyridinecarboxyaldehydes

引用

有机化学 2003年第Z1期23卷 51-52页

作者： gao Wen-Tao zheng Zhuo Institute of Superfine Chemicals Bohai University Jinzhou 121003 Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023

　　Cinnamoyl group is a versatile constituent because of bearing active carbonyl group and α, β-unsaturated car bon-carbon double bond. A wide variety of heterocycle-fused troponoid compounds have been derived from cinnamoyl-substituted tropones. For examples, the 3-(4-aryl-3-cyano-2- methoxypyridin-6-yl)tropones were synthesized by the reactions of 2-acetyl-7-methylaminotropone with malononitrile via michael addition and cyclization. [1] There have been some reports about the synthesis of 2-cinnamoyl-7-methylaminotropone, [2,3] herein we further report the synthesis of this kind of compounds by the reactions of 2-acetyl-7-methylaminotropone with pyridinecarboxyaldehydes.……

关键词： michael addition double bond

来源：

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

反应堆控制棒驱动系统电气性能动态参数模型研究

引用

核动力工程 2024年第4期45卷 248-254页

作者：李梦书唐诗涵郑杲何正熙李庆付国忠彭子恒陈帅君张芸中国核动力研究设计院核反应堆系统设计技术重点实验室成都610213

因缺乏反应系统动态变化过程的电气性能精准参数模型,现有核电厂控制棒驱动系统在不同环境条件下的控制效果不佳。本文建立了系统静态电磁仿真模型,通过状态分类的方式获取了系统全工况下的电气性能参数(电阻、电感)和电磁力离散数据,... 详细信息

因缺乏反应系统动态变化过程的电气性能精准参数模型,现有核电厂控制棒驱动系统在不同环境条件下的控制效果不佳。本文建立了系统静态电磁仿真模型,通过状态分类的方式获取了系统全工况下的电气性能参数(电阻、电感)和电磁力离散数据,基于数据建立了控制棒驱动系统动态过程中电流、电磁力、衔铁位移和加速度的动态参数模型及算法。该算法最终通过电磁模型、电路模型与数值仿真相结合的形式进行了验证,可以模拟实际系统的运行状态,具备了仅依靠控制指令和当前时刻电流即可预测下一时刻系统电气性能参数的能力。本文构建的动态参数模型可为制订高效率的智能控制策略奠定基础。

关键词：控制棒驱动系统电气性能动态参数模型

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Dynamic interplay between dislocations and precipitates in creep aging of an Al-Zn-Mg-Cu alloy

引用

Advances in Manufacturing 2019年第1期7卷 15-29页

作者： Heng Li Tian-Jun Bian Chao Lei gao-Wei zheng Yu-Fei Wang State Key Laboratory of Solidification Processing School of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710072 People's Republic of China

Abstract Creep age forming (CAF) is an advanced forming technology used for manufacturing large complex integrated panel components. However, in creep aging (CA), unlike in sole creep or aging procedure, the dislocation movement and the precipitation process occur simultaneously, leading to difficulty in understanding of the dynamic interplay between these two phenomena. In this work, taking 7050 Al alloy, a typical Al-Zn-Mg-Cu alloy, as the test material, an experimental scheme combining pre-deformation, artificial aging (AA), and tensile/ compressive CA is designed to decouple and reveal the dynamic interaction mechanism of both phenomena. From AA experiments, the static interaction between dislocations and precipitates is studied, and then their dynamic interactions in CA and each evolution are comparatively investigated. The research shows that both total strain and strain rate increase with the increase in pre-deformation in tensile and compressive CA. However, the total creep strain in compressive CA is larger than that in tensile CA. In additional, the more the dislocations are induced, the sparser and more heterogeneous the overall distribution of precipitates becomes. For dynamic interplay, in the first stage of CA (I), under thermal-mechanical loading, the GP zones and η phases gradually nucleate and grow, while the effect of dislocation multiplication is dominant compared with dislocation annihilation, leading to an increase in total dislocation density. Soon, the dislocation movement is gradually hindered by tangling, pile-up, and the precipitates that have grown on the dislocation lines, this decreases the mobile dislocation density and results in a significant decrease in creep rate. In the second stage (II), the precipitates grow further, especially those lying on the dislocation lines;the effects of pinning and hindrance are enhanced until the dislocation multiplication and annihilation reach a dynamic equilibrium, and the total and mobile dislocatio

关键词： Creep aging (CA) Dynamic interplay Dislocation Precipitate Pre-deformation Al-Zn-Mg-Cu alloy

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：