Measurement of longitudinal distribution of solids holdup in a three-phase fluidized bed by ultrasonic technique

A method of measurement of solids holdup in a three-phase reactor by analyzing the shape and the phase lag or lead of an ultrasonic wave has been proposed. The solids holdup in a solids-dilute three-phase fluidized bed could be measured without being affected by the presence of gas bubbles. The experimental values of solids axial dispersivity measured by the ultrasonic technique are in reasonable agreement with an empirical correlation of previous data obtained by other methods. The possibility of the application of the ultrasonic technique to the measurement of solids holdup in a three-phase fluidized bed has been suggested.     

A parallel image encryption method based on compressive sensing

Recently, compressive sensing-based encryption methods which combine sampling, compression and encryption together have been proposed. However, since the quantized measurement data obtained from linear dimension reduction projection directly serve as the encrypted image, the existing compressive sensing-based encryption methods fail to resist against the chosen-plaintext attack. To enhance the security, a block cipher structure consisting of scrambling, mixing, S-box and chaotic lattice XOR is designed to further encrypt the quantized measurement data. In particular, the proposed method works efficiently in the parallel computing environment. Moreover, a communication unit exchanges data among the multiple processors without collision. This collision-free property is equivalent to optimal diffusion. The experimental results demonstrate that the proposed encryption method not only achieves the remarkable confusion, diffusion and sensitivity but also outperforms the existing parallel image encryption methods with respect to the compressibility and the encryption speed.     

Local structure and concentration in Al-Mn alloy electrodeposits

The structures of f.c.c. crystalline and amorphous phases coexisting in Al-Mn alloy electrodeposits containing 11–30 wt% were examined by using the grazing-incidence X-ray diffraction (GIXD) method, high-resolution transmission electron microscopy combined with energy dispersive X-ray spectrometry (HRTEM/EDS), and the manganese K-edge extended X-ray absorption fine-structure (EXAFS) technique. The amorphous and f.c.c. phases were homogeneously distributed in the through-thickness direction of the electrodeposits, although the amorphous phase increased and the f.c.c. phase decreased with increasing manganese total concentration. The decrease of Mn-content in the f.c.c. crystalline phases with increasing manganese total concentration was revealed by the lattice constant measurement of the f.c.c. crystalline phase. This result was also supported by the microarea elemental analysis by HRTEM/EDS. The EXAFS result has indicated that the manganese local structures in the amorphous phases are almost identical in different manganese total concentration electrodeposits. This suggests that the Mn-content in the amorphous phases hardly changes with increasing manganese total concentration. These results have revealed that a peculiar elemental partition occurs in the amorphous and crystalline phases of Al-Mn alloy electrodeposits.     

Interplane charge dynamics in high-temperature superconductors; Charge confinement and spin gap

We have studies optical and transport properties of the prototypical high-T_c system La_2–xSr_xCuO₄ in the direction perpendicular to the CuO₂ planes (c-axis direction). In the normal state, it is found that the c-axis spectral weight is suppressed over a wide energy range. This is a demonstration of charge confinement in the real material which has been proposed theoretically by Anderson. Upon reducing temperature the low-energy spectral weight of the underdoped compound is further reduced, due perhaps to spin gap effect. The suppressed spectral weight results in completely different out-of-plane charge transport in the normal state and leads to the appearance of a superconducting plasma edge within the gap region in the superconducting state.     

Revolving Vernier Mechanism Controls Size of Linear Homomultimer

A new kind of the Vernier mechanism that is able to control the size of linear assembly of DNA origami nanostructures is proposed. The mechanism is realized by mechanical design of DNA origami, which consists of a hollow cylinder and a rotatable shaft in it connected through the same scaffold. This nanostructure stacks with each other by the shape complementarity at its top and bottom surfaces of the cylinder, while the number of stacking is limited by twisting angle of the shaft. Experiments have shown that the size distribution of multimeric assembly of the origami depends on the twisting angle of the shaft; the average lengths of the multimer are decamer, hexamer, and tetramer for 0°, 10°, and 20° twist, respectively. In summary, it is possible to affect the number of polymerization by adjusting the precise shape and movability of a molecular structure.     

Detection of microspotted carcinoembryonic antigen on a glass substrate by scanning electrochemical microscopy

Microspots of carbinoembryonic antigen (CEA) on glass substrates were characterized by scanning electrochemical microscopy (SECM). CEA was immobilized via a sandiwch method using horseradish peroxidase (HRP)-labeled anti-CEA. The reduction current of the oxidized form of ferrocenylmethanol generated by the HRP reaction was monitored to view SECM images. This method detects as low as ～10(4) CEA molecules in a single 20-μm-radius spot.     

The Somatropin Reference Standard (Control 951) of the National Institute of Health Sciences

Somatropin material was examined for preparation of the "Somatropin Reference Standard". The candidate material was evaluated by a domestic collaborative study in which eight laboratories participated. The protein content was determined to be 4.5 mg/Vial based on amino acid analysis. Because of the possibility of application as a chemical reference standard for assay by the HPLC method, a physico-chemical evaluation of the candidate material was also performed. By SE-HPLC, the content of polymer, dimer were determined to be 0.54%, 0.98%, respectively. By RP-HPLC, the early peak area ascribed to desamido and sulfoxide form was 1.07% of the total peak area. And for informational data, the potency of the candidate material, being estimated by three different biological methods, weight gain assay, tibia test and adiposeconversion assay is 14.8 IU/vial. Based on the above results, the candidate was authorized as the Somatropin Reference Standard of the National Institute of Health Sciences.     

Parameter identification in dynamic systems using the homotopy optimization approach

Identifying the parameters in a mathematical model governed by a system of ordinary differential equations is considered in this work. It is assumed that only partial state measurement is available from experiments, and that the parameters appear nonlinearly in the system equations. The problem of parameter identification is often posed as an optimization problem, and when deterministic methods are used for optimization, one often converges to a local minimum rather than the global minimum. To mitigate the problem of converging to local minima, a new approach is proposed for applying the homotopy technique to the problem of parameter identification. Several examples are used to demonstrate the effectiveness of the homotopy method for obtaining global minima, thereby successfully identifying the system parameters.     

Control of three-link underactuated manipulators using a switching method of fuzzy energy regions

In general, manipulators used for industry and in academic laboratories have actuators to drive each joint. On the other hand, underactuated manipulators handled by our research have some passive or free joints without actuators and brakes. We recently developed a switching method of fuzzy energy regions to control such manipulators. In such a method, it is necessary to design parameters related to energy regions and the gains of some partly stable controllers based on the computed torque method. Here, the switching method is applied for a three-link underactuated manipulator. We optimize such design parameters related to fuzzy energy regions by a genetic algorithm. The effectiveness of the present method is illustrated with some simulations. This work was presented in part at the 12th International Symposium on Artificial Life and Robotics, Oita, Japan, January 25–27, 2007