π-Conjugated polymers containing thiophene-1,1-dioxide-2,5-diyl unit in the main chain

An alternative π-conjugated copolymer of thiophene-1,1-dioxide and thiophene has been obtained by a Pd-catalyzed reaction, and basic properties of the copolymer are described. The copolymer has a number average molecular weight of 9980 as estimated by GPC, an absorption peak at 490 nm, and an electrical conductivity of 6×10⁻⁵ S cm⁻¹ at the non-doped state. Poly(aryleneethynylene)-type polymers containing the thiophene-1,1-dioxide unit have also been prepared.     

Strong stacking behavior and large third-order nonlinear optical susceptibility χ(3) of head-to-head-type poly(3-alkynylthiophene-2,5-diyl), HH-P3(CCR)Th

The head-to-head-type poly(3-alkynylthiophene-2,5-diyl) HH-P3(CCR)Th has been shown to exhibit a strong tendency to self-assemble. The UV–vis spectrum of HH-P3(CCDec)Th (Dec = decyl) in 1,2-dichlorobenzene at 131 °C showed a peak at λ_max = 520 nm, which shifted to λ_max = 553 nm at 25 °C, with a shoulder peak at 608 nm. However, the UV–vis spectrum of an HH-P3(CCDec)Th film showed a more pronounced shift in its UV–vis absorption peak to a longer wavelength. These phenomena are the characteristics of the self-assembly of the polymer molecule. The HH-P3(CCDec)Th film had a large third-order nonlinear optical susceptibility χ⁽³⁾ of 3.6 × 10⁻¹¹ esu.     

RE_(9.33)(SiO_4)_6O_2陶瓷的制备及其热学性能

利用固相反应法制备了高纯、高致密稀土硅酸盐氧基磷灰石RE_9.33(SiO_4)_6O_2(RE=La, Nd, Sm, Gd)陶瓷材料,用XRD对所合成的RE_9.33(SiO_4)_6O_2粉末和烧结得到的块体材料进行了分析表征.系统研究了RE_9.33(SiO_4)_6O_2陶瓷材料的声子速度和弹性模量,结果表明其平均声速小、弹性模型低.另外,利用Cahill模型对其热导率进行了理论计算,其极限热导率在高温下为1.18～1.22 W/m·K.从结构等各方面推断了RE_9.33(SiO_4)_6O_2陶瓷材料的低热导可能性.     

基于2,5-二甲基三联苯-4’,4’’-二甲酸的稀土配合物及其发光调节和白光发射（英文）

制备和表征了2,5-二甲基三联苯-4’,4’’-二甲酸稀土(Tb~(3+)、Eu~(3+)、Tb~(3+)/Eu~(3+)共掺)配合物。通过荧光光谱可知,使用2,5-二甲基三联苯-4’,4’’-二甲酸作为配体时,Eu~(3+)与Tb~(3+)均能有效发出特征光,将Eu~(3+)与Tb~(3+)共掺,稀土离子发光得到增强。这是由于:1)Tb~(3+)向Eu~(3+)发生能量传递,2)Eu~(3+)猝灭效应减弱。通过调节不同浓度配比的Tb~(3+)与Eu~(3+),可以使配合物的发光从红光变化到绿光,并可以得到发出白光的配合物。发出接近白光的配合物为(Eu0.001Tb0.999)2(TDDA)3(H2O)6,样品色温达到了5199K,显色指数82%。这一稀土配合物可作为单一荧光粉应用于显示、照明等领域。     

Polymers containing alternating 1,4-bis(3-octyl-2,5-thienylene)phenylene and 2,5-pyridyl, 4,4’-biphenylene or phenylene repeating units

Two polymers based on polymer backbone modification, poly[1,4-bis(3-octyl-2,5-thienylene)phenylene-alt-2,5-pyridyl] (PBTYC₈) and poly[1,4-bis(3-octyl-2,5-thienylene)phenylene-alt-4,4’-biphenylene] (PBTBBC₈), were synthesized and characterized in comparison with other two polymers reported earlier: poly[3-octyl-2,5-thienylene-alt-1,4-phenylene] (PBTC₈) and poly[1,4-bis(3-octyl-2-thienylene)phenylene] (PBTBC₈). PBTBBC₈ shows a lower conductivity in comparison with PBTC₈ and PBTBC₈. A trend in absorption peak wavelength (λ_max) of solution samples and in emission peak wavelength (λ_em) of film samples is also noted for the polymers: PBTBBC₈<PBTC₈<PBTBC₈, with the decrease of phenylene content. The optical behavior of PBTYC₈ seems to suggest the existence of charge transfer (CT) and energy charge (ET) phenomenon due to the incorporation of electron-deficient pyridyl units. Interesting electrochemical observation is also obtained, which is supported directly by the spectral change measured in situ.     

Li_(1.3)(Al_(1-x)B_x)_(0.3)Ti_(1.7)(PO_4)_3锂离子电池的合成研究

以H_3BO_3和Al_2O_3为掺杂源,采用固相烧结法,合成了锂离子电池材料Li_(1.3)(Al_(1-x)B_x)_(0.3)Ti_(1.7)(PO_4)_3(x=0,0.2,0.4,0.6,0.8)。通过XRD、SEM和电化学性能测试,结果表明:Li_(1.3)(Al_(1-x)B_x)_(0.3)Ti_(1.7)(PO_4)_3主晶相为LiTi_2(PO_4)_3,且有Al~(3+)和B~(3+)取代了部分Ti~(4+);当掺杂量x=0.4时,材料的致密度好,且室温离子电导率最高,可达2.54×10~(-5)S/cm。     

电解珩(广石)(二)

电解电源如上所述,电解珩(广石)的加工速度或加工量几乎完全决定于电源的大小,而电源的大小由电极间隙的电阻R和电压V所决定,一般可以用下式表示。     

Photo-, and electroluminescence studies of 2,5-bis[2′-(4″-(6-hexoxy benzyl))-1′-ethenyl]-3, 4-dibutyl thiophenes

We have synthesized a thiophene-based compound 2,5-bis[2′-(4″-(6-hexoxy benzyl))-1′-ethenyl]-3, 4-dibutyl thiophene (HBDT) and a copolymer poly(2,5-bis(2′-(4″-(6-hexoxy benzyl))-1′-ethenyl)-3,4-dibutyl thiophene-1,6-diisocyanatohexane) (HBDT-PU) consisting of alternating HBDT and urethane spacer units. Absorption and photoluminescence (PL) spectra of the compounds coincide indicating that emission in HBDT-PU occurs from the thiophene containing unit. PL is emitted in the blue–green region with a maximum at 460 nm. Concentration quenching occurs in pure materials: PL efficiency is strongly enhanced when the compounds are dispersed in a polymer matrix like poly(N-vinyl carbozole) (PVK) or poly(methyl metacrylate) (PMMA). Light emitting devices were fabricated using a PVK:2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD) blend doped with HBDT as the emitter material. Efficient energy transfer from PVK:PBD to HBDT molecules takes place in blended films. The electroluminescence (EL) spectra coincided with the PL spectra of HBDT indicating that EL emission comes solely from HBDT molecules. The influence of the doping concentration on the EL efficiency was found to coincide with the concentration dependence of the PL quantum yield.     

钙钛矿型La_(0.3)(Ca_(1-x)A_x)_(0.55)-Cu_3Ti_4O_(12)(A=Sr,Mg)陶瓷的热电性能

<正>日本同志社大学功能分子和生命化学科奥村尊等人,借助聚合物复合法,在1 323K温度下合成La0.3(Ca1-xAx)0.55Cu3Ti4O12(A=Sr,O≤x0.8;A=Mg,O≤x0.1),保持时间为3.6×103 s,压力为50MPa,压制出陶瓷致密度大于97%。测试结果表明,这种陶瓷的晶格常数随x值增多而减小,其电导率随x值增     

非金刚石(夂彡)(大正)砂轮

砂轮的修整一般都是采用金刚石,不论从修整质量、效率还是从操作方便等方面来看,金刚石是理想的修整工具。 由于机械工业的飞跃发展,全国磨床迅速增加,相应修整砂轮用的金刚石消耗量也增     

电焊机产品安全认证指南(试行)(下)

二○○○年七月(上接第 11期 )4 样品的抽取与管理4 1抽样检验用样品由审核组审核人员在进行企业质量保证能力检查合格后 ,从企业的合格产品中随机抽取。抽样数量为每一申请单元中抽取同型号规格 2台 ,原则上与型式认可规格不同 ,抽取的型号规格由审核组抽样人员决定。如需委托抽样 ,由检测站办理委托抽样单 ,并在委托抽样单上指定应抽取样品的型号规格和数量。4 2抽取的样品应当场贴上封签 ,抽样单由抽样人员填写 ,并由抽样人员和企业质量保证负责人或认证联络工程师 (联络员 )签字 ,加盖公章。4 3抽取的样品由企业妥善包装 ,防止运输中…     

d-Penicillamine2,5-enkephalin作为底物考察三明治大鼠原代肝细胞的转运体功能研究

目的: 通过液相色谱-串联质谱(LC/MS/MS)法测定d-Penicillamine2,5-enkephalin (DPDPE)在肝细胞和Hank's缓冲液中的浓度,研究DPDPE作为底物用于“三明治”培养大鼠原代肝细胞(SCRH)的转运体功能。方法: 将SCRH与溶于Hank's缓冲液的DPDPE共温孵,采用LC/MS/MS法测定细胞内蓄积的和外排到缓冲液中的DPDPE浓度,用于评价模型药物α-萘异硫氰酸酯(ANIT)对参与DPDPE摄取的Oatp和负责DPDPE外排的Mrp2的转运功能的影响。结果: 建立的样品处理和测定方法能够满足体外转运实验需要的灵敏度和线性范围,在Hank's缓冲液中线性范围为0.5~50 ng/mL(r²=0.9995),在细胞基质中线性范围为 0.1~5 ng/well(r²=0.9997),样品处理操作简便。日内日间精密度(RSD)均小于15%;提取回收率大于65%。ANIT可抑制DPDPE在SCRH胆管侧的外排及基底侧的摄取,对基底侧外排无显著影响。结论: 该分析方法选择性好,灵敏度高,操作简便,并成功地用于将DPDPE作为探针底物研究SCRH模型上转运体的功能。     

Poly(2,5-dialkoxy-p-phenylenebutadiynylene)s—Novel rigid conjugated polymers with liquid crystalline property

Novel rigid conjugated poly(p-phenylenebutadiynylene)s having long alkoxy side chains, octyloxy (C8), decyloxy (C10), and dodecyloxy (C12) at 2,5-positions of a phenylene unit, are synthesized by oxidative polycondensation of corresponding 2,5-dialkoxy-1,4-diethynylbenzenes with Hay catalyst. The polymers are soluble in hot solvents such as CHCl₃ and fusible upon heating. UV–Vis spectra of the polymers show an absorption maximum (λ_max) around 420 nm due to the π-conjugation along the main chain. An intense fluorescence exhibiting the λ_max around 475 nm is observed in all of the polymers. Cyclic voltammetry of the polymer shows two Li ion-participated redox reactions occurred at the dialkoxyphenylene moiety and in the conjugated polymer chain due to an n-doping process. Electrical conductivity is an order of 10⁻⁸ S cm⁻¹ which increases to an order of 10⁻⁴ S cm⁻¹ upon vapor phase doping by H₂SO₄. Thermochemical investigations by DSC and polarized optical microscopy suggest that the polymers have a nematic liquid crystalline phase. The molecular arrangements in the phase is evaluated by XRD and a molecular dynamics simulation. A nematic phase is shown to arise from a side-by-side accretion of the rigid rodlike main chains. A lamellar structure is suggested in the crystalline phase.     

食用香料1,4-二硫-2,5-二醇环保型缓蚀剂对X70钢在0.5 mol/L H_2SO_4溶液中的缓蚀性能研究

使用实验和理论计算方法研究了食用香料1,4-二硫-2,5-二醇(DDD)对X70管线钢在0.5 mol/L硫酸溶液中的缓蚀性能。结果表明,DDD能够有效的抑制X70钢在H_2SO_4介质中的腐蚀,在温度为298 K时,DDD的缓蚀效率可以达到93.6%;随着温度的升高,DDD依然能够展现出良好的缓蚀性能。腐蚀微观形貌观察也证明了DDD能够明显抑制X70钢的腐蚀。吸附等温模型研究结果表明,DDD在X70钢表面的吸附符合Langmuir单层吸附。采用量子化学计算和分子动力学模拟从理论层面讨论了DDD在钢表面的吸附及缓蚀机理。     

管理案例困难度坐标4—4—4模型

引言案例教学需要使用大量的管理案例。每一个案例都向它的读者提出了一组特定的任务。这些任务有难有易,这一方面意味着完成案例分析任务的时间会有长有短,而学生准备分析报告、参加集体讨论的时间总是有限的。另一方面,学生的兴趣有浓有淡,能力有强有弱,层次有高有低,作为一种智力型的产品——案例也需要适应不同的要求。因此,案例的困难度成了反映不同要求的一个非常重要的概念,因而也就产生了对其困难度的估计和测量问题。我们结合企业管理的教学与科研工作,在分析比较国内外关于管理案例困难度表述的基础上,创造性地改     

关于反应扩散速度的计算(三)(续完)

一、前言气相组元 A 和金属 B 发生反应扩散时,通常包括下列步骤:组元 A 在扩散层表面上的吸附,A 解离并溶解在已形成的扩散层中;组元 A 通过已形成的扩散层向扩散层和基体金属的界面扩散;并在这个界面上与金属 B 反应形成化合物。整个过程的速度是由上述步骤中最慢的一步决定的。在[1]和[2]中,我们认为组元 A 和组元 B 通过已形成的扩散层的扩散是反应扩散的控制步骤,并且认为化学反应的自由能下降全用来推动扩散过程,这样我们得到了扩散层生长的抛物线规律。这个结论对于高温下进行的反应扩散符合的很好。因为在高温下表面吸附和界面上的化学反应进行速度很快,可以认为是在平衡条件下进行的,因而它不产生自由能下降,整个过程的自由能下降全用于     

再生资源行业涉税刑事风险报告 (2022)(续)

(上接2021年第1期33页) 五、再生资源行业虚开刑事案件的争议焦点及辩护要点 (一)再生资源行业虚开刑事案件的四大争议焦点 1、再生资源回收企业不参与货物运输,极易引起无货交易的怀疑 在废旧物资回收业务中,由于运输、仓储环节需要耗费大量的成本,而从散户处采购废旧物资的交易零散且数量众多,进行现实的运输入库、再运输出...     

SrxBa1-xBi4Ti4O15陶瓷及SrBi4Ti4O15／BaBi4Ti4O15复合材料的性能研究

采用固相烧结工艺制备了SrxBa1-xBi4Ti4O15铁电陶瓷和SrBi4Ti4O15／BaBi4Ti4O15铁电复合材料。在固相反应过程中，680℃时SrBi4Ti4O15或BaBi4Ti4O15开始生成：800℃时材料主晶相基本形成，但是还有微量焦绿石相存在；850℃时SrBi4Ti4O15或BaBi4Ti4O15的主要衍射峰全部出现。随着Ba含量的增加，SrxBa1-xBi4Ti4O15陶瓷的居里温度逐渐降低。Sr0.5Ba0.5Bi4Ti4O15，陶瓷的介电常数峰在高频时较宽，在100Hz时，介电常数峰被随温度升高而逐渐增大的介电常数所“屏蔽”，材料介电损耗随温度升高而增大，但在低频下增加得更快，这是高温下由氧空位引起的电子松弛极化造成的。将预烧后的SrBi4Ti4O15和BaBi4Ti4O15粉体分别造粒后冉均匀混合，压片成型，经烧结制得的SrBi4Ti4O15／BaBi4Ti4O15复合陶瓷其相变弥散特性明显优于SrxBa1-xBi4Ti4O15的相变弥散特性。     

In situ UV–visible spectroelectrochemical studies on electrochromic behavior of poly(2,5-dimethoxy aniline)

The electrochromic characteristics of poly(2,5-dimethoxy aniline) (PDMA), have been evaluated using cyclic voltammetry, in situ UV–visible (UV–VIS) spectroscopy, cyclic spectrovoltammetry and spectrochronoamperometry. The results from cyclic voltammetry revealed that PDMA could be easily transformed from leucoemeraldine to emeraldine state in comparison with polyaniline (PANI). The conversion of reduced PDMA form into fully oxidized state could occur at a lower positive potential for PDMA than PANI (0.70 V for PANI and 0.27 V for PDMA). UV–VIS spectrum of PDMA showed three optical transitions at λ_max=375 nm (I), 460 nm (II) and 770 nm (III). The electrochemical transitions of PDMA while cycling the potentials were simultaneously monitored through UV–VIS spectroscopy. Results of cyclic spectrovoltammetry experiments revealed that the band at λ_max^II=460 nm corresponds to intermediate state between leucoemeraldine and emeraldine forms of PDMA. Hysteresis were noticed in the absorbance-potential profile for λ_max=375, 460 and 770 nm. The derivative cyclicvoltabstogram (DCVA) deduced from spectrovoltammetry reveals the presence of residual absorbance at E=0.0 V for PDMA. A linear correlation was noticed between half intensity of absorbance (E_1/2^A) at the wavelength 375, 460 and 770 nm and scan rate (ν). Electrochromic properties of PDMA like optical contrast, columbic efficiency and electrochromic efficiency are reported.