一种测量气--液两相流的线列阵传感器设计

针对气—液两相流研究对含气率测量的需求,基于线列阵测量技术原理,设计了一种可移动式线列阵两相流测量传感器,该传感器具有较高的空间分辨率（3 mm）和极高的时间分辨率（2500 Hz）,设计了线列阵传感器标定和含气率算法,实现了瞬时二维局部含气率的测量。经过射流冲击试验验证表明：该线列阵传感器结构稳定,基于原始测量数据,采用标定和含气率求解算法,可计算气泡夹带现象在水平截面的平均含气率分布情况。     

Thin film lithium niobate for use in silicon based devices

The incorporation of a thin film of lithium niobate (LiNbO3) in a conventional MOS (metal-oxide-semiconductor) structure gives the possibility of two fundamentally different types of computer memory architectures. One, based on ferroelectric switching involves the reorganization of charge in the transistor channel to compensate for the change in polarization. Another, based on the bulk photovoltaic effect, involves a shift in the transistor threshold with exposure to differing intensities of incident light. With the use of a molybdenum liftoff process, transistors have been fabricated in which LiNbO3 replaces the usual gate oxide of an MOS transistor. Transistor parameters such as the transconductance, output conductance, and amplification for these devices are reported.     

The Comox Valley Nursing Centre

With today's emphasis on health care reform across Canada, many individuals, groups and governments are seeking new approaches to the delivery of health care. Nursing organizations have argued for approaches that make better use of nurses' experience and expertise. Thus, a project in British Columbia, the Comox Valley Nursing Centre, warrants interest from nurses and policy makers for the way it broadened the nursing role to provide high quality, effective health care in specific community.     

Scanning probe microscopy of atoms and molecules on insulating films: from imaging to molecular manipulation

Scanning tunneling microscopy (STM) and atomic force microscopy (AFM) of single atoms and molecules on ultrathin insulating films have led to a wealth of novel observations and insights. Based on the reduced electronic coupling to the metallic substrate, these techniques allow the charge state of individual atoms to be controlled, orbitals of individual molecules to be imaged and metal-molecule complexes to be built up. Near-contact AFM adds the unique capabilities of imaging and probing the chemical structure of single molecules with atomic resolution. With the help of atomic/molecular manipulation techniques, chemical binding processes and molecular switches can be studied in detail.     

Giant Magnetoelectric Effect in Thin‐Film Composites

Highly sensitive AC magnetic field sensors are presented using magnetoelectric composites consisting of magnetostrictive and piezoelectric phases. They are offering passive nature, high sensitivity, large effect enhancement at mechanical resonance, and large linear dynamic range. Thin‐film magnetoelectric 2‐2 composites benefit from perfect coupling between the piezoelectric and magnetostrictive phases and from the reduction in size which is essential for high spatial resolution. Their design uses AlN and a plate capacitor or PZT with interdigital electrodes and magnetostrictive amorphous FeCoSiB single layers or exchanged biased multilayers. At mechanical resonance and depending on the geometry, extremely high ME coefficients of up to 9.7 kV/cm Oe in air and up to 19 kV/cm Oe under vacuum were obtained. To avoid external DC magnetic bias fields, composites consisting of exchanged biased multilayers serving as the magnetostrictive component with a maximum magnetoelectric coefficient at zero magnetic bias field are employed. Furthermore, the anisotropic response of these exchanged biased composites can be utilized for three‐dimensional vector field sensing. Sensitivity and noise of the sensors revealed limits of detection as good as to 2.3 pT/Hz^1/2 at mechanical resonance. Sensitivity between 0.1 and 1000 Hz outside resonance can be enhanced through frequency conversion using AC magnetic bias fields.     

Expanding the Diversity of Plant Monoterpenoid Indole Alkaloids Employing Human Cytochrome P450 3A4

Human drug-metabolizing cytochrome P450 monooxygenases (CYPs) have enormous substrate promiscuity; this makes them promising tools for the expansion of natural product diversity. Here, we used CYP3A4 for the targeted diversification of a plant biosynthetic route leading to monoterpenoid indole alkaloids. In silico, in vitro and in planta studies proved that CYP3A4 was able to convert the indole alkaloid vinorine into vomilenine, the former being one of the central intermediates in the ajmaline pathway in the medicinal plant Rauvolfia serpentina (L.) Benth. ex Kurz. However, to a much larger extent, the investigated conversion yielded vinorine (19R,20R)-epoxide, a new metabolite with an epoxide functional group that is rare for indole alkaloids. The described work represents a successful example of combinatorial biosynthesis towards an increase in biodiversity of natural metabolites. Moreover, characterisation of the products of the in vitro and in planta transformation of potential pharmaceuticals with human CYPs might be indicative of the route of their conversion in the human organism.     

Scanning tunneling spectroscopy of molecules on insulating films

Ultrathin insulating films on metal substrates are unique systems for using a scanning tunneling microscope (STM) to study the electron transport properties in the weak-coupling limit. The electronic decoupling provided by the films allows the direct imaging of the unperturbed molecular orbitals, as will be demonstrated in the case of individual pentacene molecules. The coupling between electronic states localized on the adsorbate and optical phonons in a polar insulator has two important implications: Peaks in conductance spectra resulting from resonant tunneling into electronic states of the molecules are significantly broadened by the presence of the insulator. Second, the ionic relaxations in a polar insulator may lead to an interesting charge bistability in atoms and molecules. STM-based molecular manipulation has been used to form a metallo-organic complex as well as to switch the position of the two hydrogen atoms in the inner cavity of single free-base naphthalocyanine molecules.     

Catalytic Promiscuity of cGAS: A Facile Enzymatic Synthesis of 2′-3′-Linked Cyclic Dinucleotides

Cyclic GMP-AMP synthase (cGAS) is a cytosolic DNA sensor that catalyzes the synthesis of the cyclic GMP-AMP dinucleotide 2′3′-cGAMP. 2′3′-cGAMP functions as inducer for the production of type I interferons. Derivatives of this important second messenger are highly valuable for pharmaceutical applications. However, the production of these analogues requires complex, multistep syntheses. Herein, human cGAS is shown to react with a series of unnatural nucleotides, thus leading to novel cyclic dinucleotides. Most substrate derivatives with modifications at the nucleobase, ribose, and the α-thio phosphate were accepted. These results demonstrate the catalytic promiscuity of human cGAS and its utility for the biocatalytic synthesis of cyclic dinucleotide derivatives.