诊断仪嵌入式软件测试方法研究

嵌入式软件在工程机械中应用越来越广泛,为保证软件产品高质量和可靠性,需进行软件测试以最小化软件缺陷;嵌入式软件的开发环境和运行环境不一致,增加了软件测试难度;文章以某型诊断仪嵌入式软件为对象,对被测件进行需求分析,基于需求分析将测试类型划分为人机界面测试、功能测试、接口测试、边界测试及性能测试;基于诊断仪软件运行环境特点,分析并搭建了模拟测试环境;然后针对各测试类型,提出对应的测试方法并进行了阐述;最后利用所述测试方法执行测试用例;通过测试结果可见,提出的测试方法能有效发现软件问题,具有一定的实用价值。     

Space Charge Induced Nonlinear Effects in Quadrupole Ion Traps

A theoretical method was proposed in this work to study space charge effects in quadrupole ion traps, including ion trapping, ion motion frequency shift, and nonlinear effects on ion trajectories. The spatial distributions of ion clouds within quadrupole ion traps were first modeled for both 3D and linear ion traps. It is found that the electric field generated by space charge can be expressed as a summation of even-order fields, such as quadrupole field, octopole field, etc. Ion trajectories were then solved using the harmonic balance method. Similar to high-order field effects, space charge will result in an “ocean wave” shape nonlinear resonance curve for an ion under a dipolar excitation. However, the nonlinear resonance curve will be totally shifted to lower frequencies and bend towards ion secular frequency as ion motion amplitude increases, which is just the opposite effect of any even-order field. Based on theoretical derivations, methods to reduce space charge effects were proposed.

Enantioselective Radical-Polar Crossover Reactions of Indanonecarboxamides with Alkenes

Highly efficient asymmetric intermolecular radical-polar crossover reactions were realized by combining a chiral N,N′-dioxide/Ni^II complex catalyst with Ag₂O under mild reaction conditions. Various terminal alkenes and indanonecarboxamides/esters underwent radical addition/cyclization reactions to afford spiro-iminolactones and spirolactones with good to excellent yields (up to 99 %) and enantioselectivities (up to 97 % ee). Furthermore, a range of different radical-mediated oxidation/elimination or epoxide ring-opening products were obtained under mild reaction conditions. The Lewis acid catalysts exhibited excellent performance and precluded the strong background reaction.     

心形图的匹配能序及Hosoya指标排序

以G(a, 4, b)(a 1, b 1)表示a+b+4个点的心形图.从匹配多项式的定义出发,通过递推关系式刻画出了这类心形图的匹配能级和它们的Hosoya指标的全排序.     

Recent advances in sample preparation techniques in China

Sample preparation is the procedure before instrumental analysis and significant to its effectiveness and efficiency. However, this procedure is usually time‐consuming, labor intensive, and prone to error. In the last decade, the development of sample preparation techniques has received increasing attention, especially in complex sample application. To pretreat samples faster and more effectively, advanced materials, instrumentation, and methods have been combined with typical techniques, including extraction, membrane separation, and chemical conversion techniques. Researchers in China focused on the development of simple, efficient sample preparation methods with selective enrichment and rapid separation capabilities for target analysis in complicated sample matrix and contribute almost a half of the publications in this specific field. In this review, a panorama of sample preparation techniques in China has been composed from more than 140 references, and we highlight some promising methods developed during recent years and introduce different separation materials with respect to these methods.     

石墨型氮化碳对氨硼烷放氢性能的影响

利用石墨型氮化碳(C₃N₄)和氨硼烷(NH₃BH₃,AB)球磨制备了AB-C₃N₄体系,发现C₃N₄的加入使AB放氢反应温度明显降低,但是副产物氨气浓度有所升高. 因此,利用LiBH₄改性的C₃N₄(LC₃N₄)同AB球磨合成出了AB-LC₃N₄体系,并采用X射线衍射、程序升温脱附-质谱联用、热重-差热分析及核磁共振等技术考察了该体系的脱氢性能. 结果表明,由于LC₃N₄的加入,AB的放氢反应温度明显降低,放氢反应速率加快,放氢诱导期缩短,同时抑制了副产物无机苯的生成. 另外,C₃N₄的化学修饰也降低了AB-LC₃N₄放氢过程中生成氨气的浓度. 动力学分析和核磁共振结果表明,AB-LC₃N₄分解过程依然遵循NH₃BH₂NH₃BH₄诱导的氨硼烷自分解机理.     

A Chemiluminescence Microarray Based on Catalysis by CeO2 Nanoparticles and Its Application to Determine the Rate of Removal of Hydrogen Peroxide by Human Erythrocytes

In this work, cerium oxide nanoparticles are capable of strongly enhancing the chemiluminescence (CL) of the luminol–hydrogen peroxide (H₂O₂) system. Based on this, a microarray CL method for the determination of the removal rate constant of H₂O₂ by human erythrocytes has been developed. It is providing direct evidence for a H₂O₂-removing enzyme in human erythrocytes that acts as the predominant catalyst. A reaction mechanism is discussed. The proposed microarray CL method is sensitive, selective, simple and time-saving, and has good reproducibility and high throughput. Relative CL intensity is linearly related to the concentration of H₂O₂ in the range from 0.01 to 50 μM. The limit of detection is as low as 6.5?×?10^?11 M (3σ), and the relative standard deviation is 2. 1 % at 1 μM levels of H₂O₂ (for n?=?11).     

Hierarchically Structure SnO2/ZnO Nanocomposites: Preparation,Growth Mechanism and Gas Sensing Property

SnO₂/ZnO nanocomposite was synthesized from mixed ethanol and water systems and the ethanol-sensing properties of sensors based on SnO₂/ZnO were investigated. The structure and morphology of the products was characterized by x-ray diffraction (XRD) and a field emission scanning electron microscope (FE-SEM). The results showed that the diameter of the liked pine needle SnO₂ was about 40 nm with a length about 300 nm, which are uniformly dispersed on the surface of the ZnO nanosheets. The growth process of the SnO₂/ZnO nanocomposite was discussed. The results of gas sensing properties of SnO₂/ZnO nanocomposite sensor showed high and quick response to ethanol vapor at 5.0 v. This sensor showed the advantages of high selectivity, strong stability, and prompt response/recovery characteristics in detecting ethanol vapor at 5.0 v.