Vacuum‐driven fluid manipulation by a piezoelectric diaphragm micropump for microfluidic droplet generation with a rapid system response time

Recently, we developed a convenient microfluidic droplet generation device based on vacuum‐driven fluid manipulation with a piezoelectric diaphragm micropump. In the present study built on our previous work, we investigate the influence of settings applied to the piezoelectric pump, such as peak‐to‐peak drive voltage (V_p‐p) and wave frequency, on droplet generation characteristics. Stepwise adjustments to the drive voltage in ±10‐V_p‐p increments over the range of 200?250 V_p‐p during droplet creation revealed that the droplet generation rate could be reproducibly controlled at a specific drive voltage. The droplet generation rate switched within <0.5 s after the input of a new voltage. Although the droplet generation rate depended on the drive voltage, this setting had almost no influence on droplet size. The frequency over the selected range (50?60 Hz) did not markedly influence the droplet generation rate or droplet size. We show that the current fluid manipulation system can be conveniently used for both droplet generation and for rapid droplet reading, which is required in many microfluidic‐based applications.     

Positive photosensitive polyimides with cyclobutane structure

A new family of positive photosensitive polyimide (PPI) systems composed of solvent soluble polyimides (Pls) with cyclobutane (CBDA) structures and diazonaphthoquinone compounds (DNQ) has been prepared. Heat and catalytic imidizations were carried out to obtain CBDA Pls; the former was better than the latter in controlling the molecular weight of the Pl. The ? OH groups in the Pls were easily acetylated during catalytic imidization, so ? COOH groups were selected as weak acidic groups in the Pls. The ? COOH groups were also effective in giving the Pls an alkaline solubility. Therefore, Pls having ? COOH groups were superior to those having ? OH groups for PPI systems. The photosensitive properties of various PPl systems containing ? COOH were found to vary with the fraction of ? COOH groups in the Pls, the content of DNQ in the systems, and the molecular weight of the Pls.     

双奇核188Au的准粒子带结构研究

利用在束γ谱学实验技术, 通过¹⁷³Yb(¹⁹F,4nγ)反应 布居了¹⁸⁸Au的高自旋态, 并对其准粒子带结构进行了研究. 基于实验测量结果, 对原有的双奇核¹⁸⁸Au能级纲图做了较大的修改. 通过系统性比较, 对15⁺以上的能级结构进行了讨论.     

High-throughput characterization of local conductivity of Nd0.9Ca0.1Ba2Cu3O7−δ thin film by the low-temperature scanning microwave microscope

We developed a scanning microwave microscope (SμM) designed for high-throughput electric-property screening as well as for rapid construction of electronic phase diagrams at low temperatures. As a sensor probe, we used a high-Qλ/4 coaxial cavity resonator to which a thin needle with ball-tip end was attached. The sensor module was mounted on the low-temperature XYZ stage, which allowed us to map out the change of resonance frequency and quality factor due to the local tip-sample interaction at low temperatures. From the measurements of combinatorial thin films, such as Ti_1−xCo_xO_2−δ and Nd_0.9Ca_0.1Ba₂Cu₃O_7−δ (NCBCO), it was demonstrated that this SμM system has enough performance for the high-throughput characterization of sample conductance under variable temperature conditions.     

Magneto-Optical Measurement of Organic Conductor Using Rotational Cavity System

We have developed a new magneto-optical measurement system using a rotational cavity system equipped with a millimeter vector network analyzer and a 14 T solenoid type super conducting magnet. The measurement can be performed in the transmission configuration down to 1.6 K. The results of the precise angular dependence measurement of quasi-one-dimensional organic conductor (DMET)₂I₃ using the new system are shown, and its Fermi surface will be discussed in connection with the previous reports.     

Rotational bands in 181Ta

High-spin states in ¹⁸¹Ta have been studied via the ¹⁷⁶Yb(¹¹B,α2n) reaction at 52 MeV using the PEX array and at 57 MeV using the NORDBALL array, with α-particle detection. The previously known, K^π=(7/2)⁺ ground state band and K^π=(9/2)⁻ band have been extended to spins (29/2)⁺ and (31/2)⁻, respectively. Two new one-quasiparticle bands, the K^π=(5/2)⁺ band built on the known (5/2)⁺ isomer and a K^π=((1/2)⁻) band have been observed. Two other rotational bands with three-quasiparticle structure, K^π=(15/2)⁻ and ((19/2)⁺ with π(7/2)[404]ν²(1/2)[510](9/2)[624] and π(9/2)[514]ν²(1/2)[510](9/2)[624] configurations, respectively, have been newly observed. The half-life of the K^π=((19/2)⁺) bandhead which decays to the head of the (15/2)⁻ band has been measured to be 140(36) ns. However, transitions from the ((19/2)⁺) state to the (15/2)⁻ band have not been observed. Received: 26 August 1998     

Pressure and temperature effects on the excess deuteron and proton conductance

The limiting molar conductances ° of deuterium chloride DCl in D₂O were determined as a function of pressure and temperature in order to examine the proton-jump mechanism in detail. The excess deuteron conductances °_E(D ⁺), as estimated by the equation [°_E(D ⁺) = °(DCl/D ₂ O) – °(KCl/D ₂ O)], increases with an increase in the pressure and temperature as well as the excess proton conductance [°_E(H ⁺) = °(HCl/H ₂ O) – °(KCl/H ₂ O)]. The isotope effect on the excess conductances, however, depends on the pressure and temperature contrary to the model proposed by Conway et al.: °_E(H ⁺)/°_E(D ⁺) decreases with increasing pressure and temperature. The magnitude of the decrease with pressure becomes more prominent at lower temperature. These results are discussed in terms of the pre-rotation of adjacent water molecules, the bending of hydrogen bonds with pressure, and the difference in strength of hydrogen bonds between D₂O and H₂O.