Geometry of 2×2 Hermitian matrices over any division ring

Let D be a division ring with an involution-,H2(D) be the set of 2 × 2 Hermitian matrices over D. Let ad(A,B) = rank(A-B) be the arithmetic distance between A,B ∈ H2(D) . In this paper,the fundamental theorem of the geometry of 2 × 2 Hermitian matrices over D(char(D) = 2) is proved:if  :H2(D) → H2(D) is the adjacency preserving bijective map,then  is of the form (X) = tP XσP +(0) ,where P ∈ GL2(D) ,σ is a quasi-automorphism of D. The quasi-automorphism of D is studied,and further results are obtained.     

苯在[K.Ti]ZSM-5上由H2O2氧化制苯酚的研究

由 HZSM-5与 K2 Ti F6 水热法同晶取代制备 [K.Ti]/ ZSM-5 ,并用 XRD、SEM、IR给予表征 ,其在等摩尔的苯、苯酚、H2 O2 液相反应体系中 ,常温下表现出较高催化活性 ,苯转化率达 83 % (1 6h) ,选择性≥ 98% ,苯酚产率为 2 .4m M/ h· Cat(g) ,同时探讨了有关影响因素。     

粗糙集代数与MV代数

讨论粗糙集代数与MV代数的关系以及由粗糙集代数构造MV代数的方法.粗糙集代数本身具有格结构,证明了在适当选取蕴涵及乘积运算之后,粗糙集代数就成为MV代数.     

局部域反馈神经网络的全局收敛性

本文针对具有-般投影映射的连续型局部域反馈神经网络,给出了在一可验证条件下的临界全局收敛性分析.所获得的结果极大地改进了现有典型的收敛性结论.数值试验进-步证实了所得结果的正确性和可行性.     

Preparation and Recognition Study on the Peptides in Aqueous Media of Poly(pyridine derivative‐co‐acrylamide)

Three copolymers (bearing metal ion coordinated sites) P1 , P2 and P3 were synthesized and their recognition behavior on predetermined peptide sequences was studied by isothermal titration calorimetry.     

HL-2M 主机抗扭转支撑结构计算分析

根据通电的环向场(TF)线圈在磁场作用下将产生侧向力和径向力,提出了抗扭转支撑结构方案。该方案能够降低这两种力对 TF 线圈的影响,并且保证线圈连接面的紧密接触和绝缘层不会发生相对错动。对抗扭转支撑结构进行计算分析,确定该结构的受力方式以及传力路径。结果表明,在实验运行以及极端工况下结构的应力、位移能够到达设计要求,通过疲劳计算得出抗扭转支撑结构能满足 20 年以上的实验运行,能够保证 HL-2M装置安全、平稳和可靠的运行。      

Effects of lanthanum on calcium-activated K+ currents and its kinetics in MC3T3 cells

Using the whole cell patch-clamp technique,we studied the effects of La3+ on calcium-activated K+ currents and its kinetics of activation and inactivation in non-excitable MC3T3 cells.Our results showed that the calcium-activated outward K+ currents were promoted with increasing concentration of Ca2+ in the pipette solution and a voltage- and Ca2+-dependent manner.La3+ in the bath solution inhibited the currents in a concentration-dependent manner and the inhibition EC50 was 8.23 ± 1.45 μmol/L.At the concentration of 50 μmol/L,La3+ significantly changed the Vh of the activation curve and shifted the activation curve to more positive potentials,but shifted the inactivation curve to more negative potentials.It had no effect on the slope factor k of the activation and inactivation curves.Potassium currents inhibition could induce a series of physiological and molecular biological functions,presumably because of its ability to depolarize the plasma membrane and enhance cell excitability,resulting in increasing Ca2+ influx and cytoplast Ca2+ concentration.This process may be one of the molecular mechanisms by which La3+ affects the cell growth and function of MC3T3 cells.     

同位素内标超高效液相色谱-串联质谱法检测大鼠血清中丙烯酰胺和环氧丙酰胺

建立了检测大鼠血清中丙烯酰胺和环氧丙酰胺的超高效液相色谱-串联质谱法(UPLC-MS/MS).血清样品中加入乙腈沉淀蛋白质,超高速离心取上清液,离心浓缩后,采用ACQUITY UPLC T3 C18色谱柱(50 mm×2.1 mm, 1.7 μm),以0.1%甲酸溶液和甲醇为流动相进行梯度洗脱,经UPLC分离,电喷雾离子化四级杆串联质谱以正离子多反应监测方式(MRM)检测,用同位素内标法定量.丙烯酰胺和环氧丙酰胺在0.5～20.0 mg/L浓度范围内线性良好,相关系数r均大于0.999;检出限均为0.1 mg/L;在3个浓度水平(2.0, 8.0, 和15.0 mg/L)进行添加实验,样品的加标回收率分别为98.0%～108.3%和99.6%～106.7%;日内精密度(RSD)为0.54%～5.8%和1.1%～5.8%;每个样品测试时间仅为6 min.本方法测定大鼠血清中的丙烯酰胺和环氧丙酰胺操作简单快速, 重现性好, 灵敏度高.     

碳纤维上电沉积Pd-Ag合金纳米粒子链及其氢传感性能

在碳纤维上采用三脉冲电沉积的方法制备出钯银合金纳米粒子链.把表面覆盖有Pd-Ag合金纳米粒子链的碳纤维组装成氢气传感器.采用扫描电子显微镜(SEM)和X射线能谱(EDX)表征了合金纳米粒子链的形貌和成分,应用CHI660B电化学工作站测试其氢传感性能.结果表明,在钯、银离子摩尔比为15∶1的电解液中,在-1.0--1.5 V下,成核5-40 ms;在-0.25--0.35 V,生长200-300 s的条件下,即可获得银的质量分数为16.0%-25.0%的钯银合金纳米粒子链阵列.在室温下,传感器对在0.30%-5.00%(φ,体积分数,下同)范围内的氢气有响应,最快响应时间约为300 s,灵敏度最高可达31.0%;氢在0.30%-1.20%的范围内响应电流与氢气浓度成线性关系,超过4.00%时响应电流不再随浓度的增加而变化;在低于3.50%的浓度下氢传感器的重现性良好.     

铈掺杂的介孔分子筛的水热合成与结构性能

以硅酸钠、硝酸铈铵为原料,十六烷基三甲基溴化铵为模板剂,通过水热法合成铈掺杂的介孔分子筛CeMCM-41.分别采用X射线粉末衍射(XRD)、透射电子显微镜(TEM)、红外光谱(FT-IR)、紫外-可见分光光度计(UV-Vis)和N2吸附-脱附等技术对产物的晶相、结构、形貌、比表面积和孔径进行表征.同时研究硅铈物质的量比对合成材料结构性能的影响.实验结果表明:水热条件下成功合成出铈掺杂的MCM-41介孔分子筛,其比表面积为480.5～1 295.2m2/g,平均孔径在2.70～6.29 nm之间.随着稀土元素铈的掺杂量的增加,CeMCM-41介孔分子筛的比表面积和孔体积变小,介孔有序性变差.