利用手持技术数字化实验测定中和反应化学计量比*

化学计量比在中学教学及实际生产中有着重要应用,本研究针对化学计量比概念教学存在的不足,以手持技术TQVC概念认知模型为理论依据,设计实验测定中和反应的化学计量比。基于等摩尔连续变化法,本实验借助温度传感器测定不同物质的量之比反应物反应后的温度变化数据,找出最大温度变化差值对应的反应物物质的量之比,即化学计量比,帮助学生从定量的角度理解化学计量比概念。     

Trigoxyphins O–T,six new heterodimers from Trigonostemon xyphophylloides

Phytochemical study of the twigs of Trigonostemon xyphophylloides led to the isolation of six new heterodimers, trigoxyphins O (1) and R–T (4–6) comprising of two different degraded diterpenoids, and trigoxyphins P (2) and Q (3) comprising a degraded diterpenoid and a phenylpropanoid, together with a known homodimer, neoboutomannin (7). The structures and relative configurations were elucidated on the basis of extensive spectroscopic analysis, including 1D and 2D NMR experiments. Compounds 1–6 were evaluated for their cytotoxicity against four human tumour cell lines by MTT assay.     

“化学游戏教学”的“学教评产”混合式教学模式实践

基于师范类专业认证理念与毕业要求的教学前端分析,建构“学教评产”混合式教学模式,通过整合教学内容、重构教学安排与优化教学评价,对“化学游戏教学”课程进行创新性改革,并从学生学习成果、教学目标达成与学生满意度等3个方面评价教学成效。结果表明:该教学模式有助于学生学习成果质量的提升,能够有效促进教学目标的达成,并取得较高的学生满意度。     

Syntheses,Crystal Structures and Properties of Mn(Ⅱ) and Co(Ⅱ) Coordination Complexes Based on 1,10-Phenanthroline Derivative

Two new coordination complexes[Mn(L)₂(DNSA)](1) and[Co(L)(1,4-bdc)]_n (2) have been achieved under hydrothermal conditions (H₂DNSA=3,5-dinitro-salicylic acid,1,4-bdc=1,4-benzenedicarboxylic acid and L=2-(2-fluoro-6-fluorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline).1 crystallizes in monoclinic,space group P2_1/c with a=15.871(3),b=17.274(4),c=16.078(3)A,β=113.03(3)^o,V=4056.6(16)A³,Z=4,C₄₅H₂₂Cl₂F₂Mn N₁₀O₇,M_r=978.57,D_c=1.602 g/cm³,F(000)=1980,μ(Mo Ka)=0.536 mm^–1,R=0.0437 and w R=0.1065.2 belongs to the monoclinic system,space group C2/c with a=14.665(2),b=30.856(4),c=11.237(2)A,β=111.166(2)^o,V=4742.0(12)A³,Z=8,C₂₇H₁₄Cl Co FN₄O₄,M_r=517.80,D_c=1.602 g/cm³,F(000)=2312,μ(Mo Ka)=0.889 mm^–1,R=0.0364 and w R=0.0862.The central Mn(II) ion in 1 is six-coordinated by four nitrogen atoms from two L ligands and two oxygen atoms from one DNSA anion.In 2,the two kinds of 1,4-bdc ligands link neighboring Co(II) atoms to yield a two-dimensional layer structure.The luminescence of 1 has been studied in detail.Moreover,thermal behaviors of 1 and 2 are also investigated.     

Synthesis and Crystal Structure of 3-（4-Bromobenzyloxy）-6-morpholinopyridazine

The title compound 3-(4-bromobenzyloxy)-6-morpholinopyridazine(C15H16BrN3O2) was synthesized,and its crystal structure was studied.It crystallizes in the triclinic system,space group P with a = 8.3408(17),b = 8.8620(18),c = 10.832(2) ,α = 108.09(3),β = 91.28(3),γ = 100.90(3)°,Dc = 1.562 g/cm3,Z = 2,λ = 0.71073 ,μ(MoKα) = 2.769 mm-1,Mr = 350.22,V = 744.5(3) 3,F(000) = 356,the final R = 0.0522 and wR = 0.1366 for 2016 observed reflections with I > 2σ(I).In the crystal structure,the morpholine ring adopts a chair conformation with O(2) and N(3) atoms at the flap positions-0.656(7) and 0.622(6)  out of the mean plane formed by the other four C atoms,respectively.These molecules generate centro-symmetric dimers through intermolecular π-π interaction.     

芳酰胺类大环一步高效合成及其成环机理研究进展

总结了最近发现的新型芳酰胺及芳酰肼大环一步合成反应,着重探讨了由分子内三中心氢键所引导的高效一步成环反应机理.这类反应是由未成环寡聚物前体的折叠构象所构筑,不仅高效,而且反应机理新颖,提供了传统成环反应难以得到的几类刚性大环的合成方法.这些大环化合物表现出对客体识别的高度专一性,并能形成具有高通量性的跨膜孔道.     

The higher-order lump,breather and hybrid solutions for the generalized Konopelchenko–Dubrovsky–Kaup–Kupershmidt equation in fluid mechanics

Nonlinear Dynamics - Under investigation in this paper is the (2 + 1)-dimensional generalized Konopelchenko–Dubrovsky–Kaup–Kupershmidt equation, which can be utilized to describe...     

Characteristic parameters from a human of electromagnetic signals heart system

The electromagnetic field of a human heart system is a bioelectromagnetic field. Electrocardiography （ECG） and magnetocardiography （MCG） are both carriers of electromagnetic information about the cardiac system, and they are nonstationary signals. In this study, ECG and MCG data from healthy subjects are acquired; the MCG data are captured using a high-Tc radio frequency superconducting quantum interference device （HTc rf SQUIDs） and the QRS complexes in these data are analysed by the evolutionary spectrum analysis method. The results show that the quality factor Q and the central frequency fz of the QRS complex evolutionary spectrum are the characteristic parameters （CHPs） of ECG and MCG in the time-frequency domain. The confidence intervals of the mean values of the CHPs are estimated by the Student t distribution method in mathematical statistics. We believe that there are threshold ranges of the mean values of Q and fz for healthy subjects. We have postulated the following criterion： if the mean values of CHPs are in the proper ranges, the cardiac system is in a normal condition and it possesses the capability of homeostasis. In contrast, if the mean values of the CHPs do not lie in the proper ranges, the homeostasis of the cardiac system is lacking and some cardiac disease may follow. The results and procedure of MCG CHPs in the study afford a technological route for the application of HTc rf SQUIDs in cardiology.     

流动氩气放电系统中条纹斑图形成的实验研究

采用双水电极介质阻挡放电装置, 在大气压下流动氩气中产生了稳定的条纹斑图, 并采用拍照和电学方法对其产生机理进行了研究. 研究发现, 条纹斑图仅出现在外加电压较低的情况下, 在较高电压下放电会过渡到均匀模式. 低电压下的条纹斑图是由于放电丝沿着气流方向定向移动形成的, 该定向移动速度几乎与电压无关, 主要由气体流量决定. 分析发现放电空间中活性粒子的记忆效应对条纹斑图的形成起决定作用. 电学测量发现放电电流和放电的气隙起始电压都随着气流的增加而减小, 本文对这一现象进行了定性解释. 本文结果对斑图动力学研究和介质阻挡放电的工业应用都具有很重要的意义.     

d-生物素的全合成研究

以L-胱氨酸或L-半胱氨酸的盐酸盐为起始原料, 经过10步反应, 以超过30%的产率, 得到一条新的高效的d-生物素合成路线. 从L-胱氨酸开始, 通过中间休2的酰胺烷基化得到中间体3, 再在过氧酸催化下重排开环生成中间体4, 然后经过氧化、还原和缩合等几步建立起生物素的骨架.