Weak base favoring the synthesis of highly ordered V-MCM-41 with well-dispersed vanadium and the catalytic performances on selective oxidation of benzyl alcohol

The key to improve the performance of heteroatom catalysts is to ensure the orderliness of catalysts and the good dispersion of heteroatoms.The alkalinity plays the indispensable role in synthetic process of V-MCM-41 catalyst.The excessive alkalinity of synthetic system will make the MCM-41 difficult to crystallize,even to dissolve.It is easy to accumulate for heteroatomic species in the system of low alkalinity.Herein,the highly ordered VMCM-41 with high vanadic content in framework is synthesized in the condition of excessive NH3·H2 O in this paper.A series of characterization results prove the good dispersion of vanadium species,and most of vanadium gets into the framework of MCM-41 with the states of tetravalence and pentavalence.Furthermore,the modified MCM-41 by other transition metals is successful synthesized by the method of V-MCM-41 in this paper.The VMCM-41 shows well catalytic activity for the selective oxidation of benzyl alcohol,which up to 74.83%for the conversion of benzyl alcohol and 96.20%for selectivity of benzaldehyde when initial V/Si=0.10.The paper provides the possibility for industrial application of V-MCM-41 in the oxidation of benzyl alcohol for benzaldehyde.Besides,the work provides a significant idea for the synthesis of modified MCM-41 by well-dispersed transition metals.

THERMODYNAMIC STUDY ON ADSORPTION OF AROMATIC SULFONIC ACIDS ONTO MACROPOROUS WEAK BASE ANION EXCHANGER FROM AQUEOUS SOLUTIONS

The adsorption equilibrium isotherms of three aromatic sulfonic acid compounds, 2-naphthalenesulfonic acid, p-toluenesulfonic acid and p-chlorobenzenesulfonic acid, from aqueous solutions by macroporous weak base anion exchanger within the temperature range of 293 K-313 K were obtained. Several isotherm equations were correlated with the equilibrium data, and the experimental data was found to fit the three-parameter Redlich-Peterson equation best within the entire range of concentrations. The study showed that the hydrophobicity of solute has distinct influence on adsorption capacity of the anion exchanger for the aromatic sulfonic acid. Moreover, estimations of the isosteric enthalpy, free energy, and entropy change of adsorption were also reported. The positive isosteric enthalpy and entropy change for adsorption indicate an endothermic and entropy driven process in the present study.

Spaces with σ-point-discrete N_0-weak bases

It is discussed in this paper the spaces with σ-point-discrete N_0-weak bases. The main results are： （1） A space X has a σ-compact-finite N_0-weak base if and only if X is a k-space with a σ-point-discrete N_0-weak base; （2） Under （CH）, every separable space with a σ-point-discrete N_0-weak base has a countable N_0-weak base.

Vibration diagnostics of weak base embankments

In this paper the theoretical background was analyzed for vibration diagnostics method and experience in its application for weak base embankments. General schemes of survey and recommendations on hardware systems and further prospective development are outlined.

A LEAST SQUARE BASED WEAK GALERKIN FINITE ELEMENT METHOD FOR SECOND ORDER ELLIPTIC EQUATIONS IN NON-DIVERGENCE FORM

This article is devoted to establishing a least square based weak Galerkin method for second order elliptic equations in non-divergence form using a discrete weak Hessian operator.Naturally,the resulting linear system is symmetric and positive definite,and thus the algorithm is easy to implement and analyze.Convergence analysis in the H2 equivalent norm is established on an arbitrary shape regular polygonal mesh.A superconvergence result is proved when the coefficient matrix is constant or piecewise constant.Numerical examples are performed which not only verify the theoretical results but also reveal some unexpected superconvergence phenomena.

QUANTITATIVE ANALYSIS OF VERY WEAK ACID AND BASE BY pH-FIXED TITRATION METHOD

pH-fixed titration method for the determination of weak acids and bases has been studied in this paper.It is not necessary to know the ionization constant of weak acid or base and the concentration of titrant. This method had been applied to determine phenol,4-aminoantipyrine and glycine,whose ionization constants range from 10^(-10)to 10^(-12).The results were satisfactory.

两代天基红外传感器对隐身飞机尾焰探测能力分析

为了对比两代天基红外传感器对隐身飞机尾焰的探测能力,以美国SBIRS-GEO和Next-Gen OPIR星座作为研究对象,通过建立高轨红外探测模型以及构建对应的预警探测场景,对两代探测器在不同飞行状态时飞机尾焰的辐亮度响应特性和模拟成像效果进行量化对比.研究结果表明,两代天基红外探测器都可以用来探测飞机尾焰信号;飞机加力对尾焰温度和外形有显著影响,成为影响天基红外传感器探测性能的关键因素;Next-Gen OPIR搭载的新一代传感器可以在36000 km高度捕获和发现处于非加力状态的尾焰,其成像信噪比明显高于SBIRS-GEO传感器对处于加力状态尾焰的信噪比.

弱光下锑基太阳电池的光谱响应与性能优化

锑基薄膜太阳电池因其制备方法简单,原材料丰富,光电性能稳定等优点而得到了快速发展。其中锑基吸光层材料(硫化锑、硫硒化锑、硒化锑)具有高吸收系数特点,因而在室内或者水下等弱光条件下具有相当大的应用潜力。通过构造两种衰减光谱以研究新型锑基薄膜太阳电池在弱光下的光电响应。首先通过厚度调节硒化锑太阳电池的吸光能力,发现当吸光层厚度较薄时,电池的光电转换效率存在较大差值;而当吸光层厚度过厚时,电池性能又因载流子复合的增大而降低。在吸光层厚度处于合适的0.4~1.2μm之间时,硒化锑太阳电池在长波衰减光谱和短波衰减光谱下都能获得高于16%的转换效率。然后通过硒含量调节锑基太阳电池的光谱吸收范围,发现长波衰减光谱下,锑基太阳电池的器件性能显著高于标准光谱,并且在20%~40%硒含量下能够获得最佳的转换效率。而在短波衰减光谱下,锑基太阳电池的最佳性能出现在硒含量为60%的情况下。因而在弱光条件下,锑基太阳电池的最佳硒含量需要通过具体的光谱特性确定。最后研究了两种衰减光谱下,硫化锑/硒化锑双结叠层太阳电池的光谱响应特性。发现在短波衰减光谱下,叠层太阳电池效率会随着总厚度的增加而增加。而在长波衰减光谱下,叠层太阳电池的最佳性能能够一直保持在较高水平。当叠层电池总厚度为2μm,且硫化锑顶电池厚度在0.5~1.2μm之间时,器件在两种衰减光谱下都能够实现光谱能量在两个子电池中的合理分配,使得叠层电池效率能够保持在20%以上。通过该研究对锑基太阳电池器件结构的合理设计,能够保证单结和双结器件在不同弱光条件下的高性能输出,为高环境适应性的锑基薄膜太阳电池的研发提供技术支持。

硫酸乙烯酯(DTD)稳定性影响因素分析

模拟投料环境,探索温度、时间、氧化剂NaClO、弱碱NaHCO_(3)、弱酸NaHSO_(3)对DTD分解情况的影响。结果表明:温度低于15℃时DTD分解缓慢,高于15℃时DTD分解迅速,且随时间的延长分解加剧。氧化剂NaClO会造成产物的迅速分解,4 h DTD分解剩余24.53%。NaHCO_(3)、NaHSO_(3)的加入对DTD的分解影响较小。为避免长时间对收率的影响,合成结束后需迅速进行后处理,对后期工业化生产具有重要的指导意义。

某多塔连体高层结构抗震性能化分析

某多塔连体高层建筑由3栋高度不同的高层建筑和高位钢结构连接体组成,连接体与主体结构之间设置摩擦摆隔震支座,支座位移较大的位置设置黏滞阻尼器。对整体结构进行了考虑支座非线性的整体建模分析,并与单塔独立模型的模拟结果进行对比。结果表明:设计所选用的弱连接有效减小了连接体对主体结构的影响,设置摩擦摆隔震支座和黏滞阻尼器减小了各塔楼的地震响应。最后,对整体结构进行了动力弹塑性时程分析,研究了结构的位移和层剪力、摩擦摆隔震支座和阻尼器的响应以及构件的损伤变化过程。结果表明:整体结构、摩擦摆隔震支座和黏滞阻尼器、结构构件均满足预定的抗震性能设计目标,该多塔结构在罕遇地震作用下的弹塑性反应及破坏机制,符合结构工程抗震概念设计的要求。

弱连接体支座形式对非对称双塔结构的影响分析

非对称双塔连体结构在连接体位置不高时常采用弱连接形式,连接体支座的选择对两侧结构受力影响很大。对比分析连接体在不同的弱连接方式下塔楼主体结构动力特性及主体结构关键构件在罕遇地震下的抗震性能,对连接体楼板进行了舒适度分析。结果表明,即使采用弱连接方式,连接体的体量及高度与塔楼单体越接近,连接体对塔楼的约束作用越明显;连接体两侧采用双向摩擦摆支座方案优于采用一端固接铰支座、一端双向摩擦摆支座方案;在罕遇地震下,采用双向摩擦摆支座方案的塔楼在连接体及以下楼层层间位移角为不同方案中的最小值,关键构件能达到更高的性能水准;双向采用摩擦摆支座方案会带来较大的支座水平位移,需要在设计中采取措施以确保连接体在罕遇地震下不致脱落;对于具有不同建筑功能的多层连体结构,可通过增加楼板厚度更有效地降低各层楼板竖向加速度峰值,以满足楼板舒适度的要求。

Base-可数弱θ加细空间

引入了base-可数弱θ加细空间,获得了如下主要结果:(1){F_i}i∈N=∪n∈NA_n是空间X的闭覆盖,且对任意x∈X,■n∈N,使得1≤ord(x,An),若每一闭集F_i(i∈N)是相对于X的base-可数弱θ加细空间,则X是base-可数弱θ加细空间.(2)设f:X→Y是base-可数弱θ加细空间,ω(X)≥ω(Y),如果Y是正则的base-可数弱θ加细空间,那么X是base-可数弱θ加细空间.

采用弱连接的不对称连体高层办公楼结构设计探究

不对称连体结构由于其两栋塔楼体型、平面布置、刚度和层数均存在较大差异,主体结构以及两端支座形式的选型,是设计过程中的要点。为此,以泰山石化总部基地1#、2#楼不对称连体结构为例,对连接体以及支座型式进行比较,分析各水平作用工况下连接体运动状态,梳理结构设计思路并逐步计算复核。对牛腿及支座在罕遇地震作用计算满足的情况下,增设防碰撞及防坠落措施,以保证连接体安全。针对项目的超限情况及薄弱部位,采取对应措施,采用YJK、PMSAP、SAUSAGE不同设计软件,对整体结构进行计算对比,以满足各自性能目标要求。

A Note on Weak Open cs-images of Metric Spaces

在这份报纸，如果并且仅当它是一个公制的空格的一幅弱开的 cs 图象，我们空间与一个紧缩的可计算的弱底证明那。

Syntheses and Crystal Structures of Two Copper(II) Complexes Derived from Bidentate Schiff Bases

Two new Cu（Ⅱ） complexes have been synthesized with two different bidentate N2O2 donor Schiffbase ligands HL1 （2-（（E）-（4-chlorophenylimino）methyl）-6-bromo-4-chlorophenol） and HL2 （2-（（E）-（2-chlorophenylimino）methyl）-6-bromo-4-chlorophenol）, respectively. Both complexes 1 and 2 have been characterized by elemental analysis and single-crystal X-ray diffraction studies. Structural studies reveal that in both complexes the metal centers are four-coordinated with N202 donor set of Schiff base ligands. Complex 1 belongs to the tetragonal system, space group P4（3）2（1）2 with a = 10.2379（2）, b = 10.2379（2）, c = 24.9623（90） A, V = 2616.41（12） A^3, Z = 4, Dc = 1.908 g/cm^3,μ（MoKa） = 4.3327 mm^-1, F（000） = 1468, S = 0.999, the final R = 0.0345 and wR = 0.0835 for 3506 unique reflections （Rint= 0.0428） with 3249 observed ones （I 〉 2σ（I））. Complex 2 is of monoclinic system, space group P21/c with a = 11.064（3）, b = 9.437（2）, c = 13.277（4） A, fl = 108.997（3）°, V = 1310.8（6） A^3, Z = 2, Dc= 1.904 g/cm^3,μ（MoKa） = 4.319 mm^-1, F（000） = 734, S = 0.997, the final R = 0.0282 and wR = 0.0619 for 3491 unique reflections （Rint = 0.0428） with 2777 observed ones （I 〉 20（I））. The units of the complex are linked via weak interactions, such as C-H…Br hydrogen bonds together with Cl…C1 and Cu…Cl interactions, leading to the formation of one-dimensional chain and two-dimensional network and stabilizing the crystal structure.

Highly sensitive giant magnetoimpedance in a solenoid containing FeCo-based ribbon

The highly sensitive giant magneto-impedance effect in a solenoid containing a magnetic core of Fe36Co36Nb4Si4.sB19.2 （FeCo-based） ribbon under a weak magnetic field （WMF） is presented in this paper. The FeCo-based amorphous ribbon is prepared by single roller quenching and annealed with Joule heat in a flowing nitro- gen atmosphere. The giant magnetoimpedance effect in solenoid （GMIES） profiles are measured with an HP4294A impedance analyzer. The result shows that the CMIES responds to the WMF sensitively （as high as 1580 %/A.m-1）. The high sensitivity can be obtained in a moderate narrow range of annealing current density （30-34 A/mm2） and closely depends on the driven current frequency. The highest sensitivity （1580 %/A.m-1） is obtained when the FeCo- based amorphous ribbon is annealed at 32 A/mm2 for 10 min and then driven with an alterning current （AC） at the frequency of 350 kHz. The highly sensitive GMIES under the WMF may result from the multiple magnetic-anisotropic structure, which is induced by the temperature gradient produced during Joule-heating the ribbon.

聚醚脂肪酸类油基钻井液提切剂的研制与应用

针对油基钻井液切力低,易导致沉砂卡钻等严重问题的现状,合成了一种聚醚脂肪酸类油基钻井液用提切剂LQZ。利用红外光谱、热重曲线、凝胶强度和界面扩张流变参数等测试方法,分析了提切剂的结构、热稳定性、凝胶性能和作用机理,同时探究了基础油、油水比、密度和温度对其提切效果的影响。结果表明,该提切剂分子中含有羟基、酰胺基、酯基、醚键,能形成网架结构,提高悬浮能力,且具有快速弱凝胶特点;300℃无明显热分解;加量小于0.85%时有利于乳液稳定性;该提切剂对白油基、柴油基和合成基钻井液体系普遍适用,且白油基中效果最好;当钻井液油水比为8∶2、密度为2.1 g/cm^(3)、190℃时提切效率最佳,动切力、φ6及φ3读数和静切力增长约1倍;与国外同类产品相比,LQZ具有提切不增塑性黏度的优势。LQZ在现场页岩油气井应用时,动切力、φ6及φ3读数和静切力基本增加100%,塑性黏度无明显增长。LQZ能够提高油基钻井液悬浮能力,不显著增加塑性黏度,具有很好的推广应用前景。

基于弱有限元法的渗流分析

在坝、闸和堤防等水工建筑物的设计和运行管理中,渗流计算占有非常重要的地位。目前渗流分析的方法以一般有限元方法为主。在渗流分析时往往希望通过加密网格来追求更高精度的数值结果,但是由于一般有限元法属于协调有限元方法,它不适合处理混合剖分网格,加密网格容易导致计算格式不稳定、计算结果不收敛。而弱有限元方法是一种非协调有限元方法,用弱函数的弱梯度算子替代一般有限元方法变分式中的经典梯度算子,并在变分式中增加稳定子项,保证了计算格式的绝对稳定性,并且它适用于混合网格。对于同一剖分网格,弱有限元法的总体代数方程组的自由度远远比一般有限元方法的要大很多,为了降低弱有限元法的自由度,探讨根据弱有限元方法适用于混合剖分网格的特点,采用有针对性的混合剖分网格,运用弱有限元法求解渗流自由面和进行有防渗帷幕的闸基渗流分析,数值结果表明弱有限元方法能灵活处理混合剖分网格,并且计算结果具有高精度。

衰弱人群规范化管理的最佳证据在老年脑卒中病人中的应用研究

目的:总结衰弱人群规范化管理的最佳证据,探讨应用于老年脑卒中人群中的效果。方法:系统检索the Cochrane Library、PubMed、EMbase、Web of Science、Joanna Briggs Institute(JBI)循证卫生保健研究中心以及中国生物医学文献数据库、中国知网、万方数据库中的临床实践指南、最佳实践标准、证据总结、专家共识。检索时限为建库至2021年3月1日。最终获得4篇指南、2篇专家共识,根据GRADE分级系统,对纳入的证据进行等级划分,最终纳入7条证据。将证据从评估、计划、运动干预、营养干预和心理干预5个层面制订了12条审查指标。选取2021年3月—9月在青岛大学附属医院神经内科病房住院的老年脑卒中病人为研究对象,最佳证据应用前收集100例病人资料,最佳证据应用后收集96例病人资料。比较最佳证据应用前后审查指标的执行情况、脑卒中病人的衰弱程度、病人神经功能缺损程度、病人的自理能力、护士对病人进行衰弱评估与管理的知信行水平、护士循证实践能力。结果:证据应用后,护士对衰弱规范化管理的12条审查指标执行率均有提高,差异有统计学意义(P<0.05);证据应用后病人的改良Rankin量表(mRS)评分低于应用前,改良Barthel指数(ADL)评分较应用前提高,差异有统计学意义(P<0.05),衰弱筛查量表(FRAIL)评分在证据应用前后差异无统计学意义(P>0.05),但衰弱综合征(≥3分)的病人比例低于证据应用前(P<0.05)。证据应用后,护士对病人进行衰弱评估与管理的知信行水平各维度得分及总分均有提高,护士的循证实践素质与实施水平各维度得分及总分均有提升,差异有统计学意义(P<0.05)。结论:衰弱人群规范化管理最佳证据的应用,提高了护士对衰弱管理的知信行水平与循证实践能力,进一步规范临床行为,从而改善病人神经功能缺损症状与自理能力,提升临床护理质量,但短期内对病人的衰弱状态改善不明显。

Comparative Study between Traditional Approach and Physico-Chemical Approach in Acid Base Disorders Interpretation in Critically Ill Patients

Objective: The traditional approach for acid base interpretation is based on Handerson-Hasselbalch formula and includes Base Excess (BE), bicarbonate (HCO3), albumin corrected anion gap. The Physicochemical approach is centered on the Carbon Dioxide tension (PCO2), the strong ion difference (SID), strong ion gap (SIG) = SID apparent-SID effective and totally weak acids (Atot). The study aims to compare between the traditional approach and the physicochemical approach in acid base disorder interpretation. Design: Prospective observational study in an adult Intensive Care Unit (ICU) recruiting six hundred and sixty one patients. Methods: Arterial blood samples were analyzed to measure pH, PaCO2 sodium, potassium, chloride and lactate. Venous blood samples were analyzed to measure ionized calcium, magnesium, phosphorous and albumin. These samples were interpreted by both techniques. Results: Normal HCO3 and BE were detected by traditional approach in 49 cases of which SIG acidosis was detected in 22 cases (46%) and Hyperchloremic acidosis was detected in 29 cases (60%) by physicochemical method. SIG was elevated in 72 cases (58%) of 124 cases with high anion gap acidosis. SIDeff and BE were strongly correlated, r = 0.8, p 0.0001, while SIG and Albumin corrected Anion Gap (ALAG) were moderately correlated r = 0.56, p Conclusion: Both approaches are important for interpretation of the acid base status. Traditional approach identifies the diagnostic description without many calculations and detects body compensatory response to acid base disorders. Physicochemical approach is essential to identify the exact causation and the severity of the acid base disorders.