Surface modification of electric hair clipper blade for increasing its lifetime

Making the angle of a hair clipper blade edge acute improves its cutting ability but causes the edge to be susceptible to wear, resulting in decreased cutting service life. An enhancement of blade edge hardness of hair clippers by various surface modifications has been studied to increase their wear resistance. Ion nitriding method formed a thick nitrided layer on the mother material surface. PVD and CVD methods formed a fine and thin hard coating at relatively low temperatures. In this study, surface modification by ion plating and plasma CVD methods was carried out to improve the cutting edge qualities of 45° angle blades, material which is used is hardened SUS420J2Mo. The effectiveness was verified by cutting performance lifetime test using artificial hair. It enhanced the cutting performance lifetime of clipper blades more than four times.     

MgSrSi-Type Compounds as a Possible New Familyof Thermoelectric Materials

We calculated electronic structures and transport properties of 33 Zintl phase compounds M¹M²X (M¹, M² = Li, Na, Mg, K, Ca, Rb, Sr, Ba; X = Si, Ge, As, Se, Sn, Sb, Te, Pb, Bi) having orthorhombic MgSrSi-type (PbCl₂-type) structure. These compounds were calculated to be narrow-gap semiconductors or semimetals. By comparison with known thermoelectric materials, our analysis showed that these compounds are promising candidate new thermoelectric materials, when heavily doped with holes or electrons. The weak chemical bonds and the variety in constituent elements indicate the possibility to achieve high thermoelectric figure of merit.     

Transmission of Force Sensation by Environment Quarrier Based on Multilateral Control

In recent years, realization of a haptic system has been strongly desired in the fields of medical treatment and expert's skill acquisition. The bandwidth of force sensing and friction compensation are very important problems for reproduction of vivid force sensation. In this paper, an environment quarrier is proposed for bilateral teleoperation instead of force sensors. The environment quarrier is a novel force-sensing method that consists of a twin robot system. Two of the same type of robot are required and they are controlled in the same position, velocity, and acceleration by bilateral acceleration control based on a disturbance observer. One robot is in contact motion and the other is unconstrained. The purity of external force is obtained by subtracting the disturbance torque in the unconstrained robot from the constrained one. The environment quarrier can observe the external force with high bandwidth and friction compensation. In this paper, the idea of multilateral control is introduced for attainment of simultaneity. Furthermore, this paper shows the controller design of the multilateral control in the modal space. The experimental results show the viability of the proposed method     

A 10 Gb/s optical heterodyne detection experiment using a 23 GHzbandwidth balanced receiver

A balanced receiver for multigigabit-per-second coherent optical transmission systems is described. A balanced optical receiver with a frequency bandwidth of 23 GHz is achieved by connecting an InGaAs twin-p-i-n photodiode to a 0.5-30.0 GHz GaAs monolithic distributed amplifier fabricated with a soldier bump flip-chip interconnection technique. An experiment which demonstrated that this receiver has the potential for use in 10-Gb/s optical CPFSK (continuous-phase frequency shift keying) heterodyne detection systems was conducted     

Colored Fluorescent Silk Made by Transgenic Silkworms

Silk is a protein fiber used to weave fabrics and as a biomaterial in medical applications. Recently, genetically modified silks have been produced from transgenic silkworms. In the present study, transgenic silkworms for the mass production of three colors of fluorescent silks, (green, red, and orange) are generated using a vector originating from the fibroin H chain gene and a classical breeding method. The suitability of the recombinant silks for making fabrics is investigated by harvesting large amounts of the cocoons, obtained from rearing over 20 thousand silkworms. The application of low temperature and a weakly alkaline solution for cooking and reeling enables the production of silk fiber without loss of color. The maximum strain tolerated and Young's modulus of the fluorescent silks are similar to those of ordinary silk, although the maximum stress value of the recombinant silk is slightly lower than that of the control. Fabrics with fluorescent color are demonstrated using the recombinant silk, with the color persisting for over two years. The results indicate that large amounts of genetically modified silk can be made by transgenic silkworms, and the silk is applicable as functional silk fiber for making fabrics and for use in medical applications.     

A highly integrated 40-MIPS (peak) 64-b RISC microprocessor

A 1-million transistor 64-b microprocessor has been fabricated using 0.8-μm double-metal CMOS technology. A 40-MIPS (million instructions per second) and 20-MFLOPS (million floating-point operations per second) peak performance at 40 MHz is realized by a self-clocked register file and two translation lookaside buffers (TLBs) with word-line transition detection circuits. The processor contains an integer unit based on the SPARC (scalable processor architecture) RISC (reduced instruction set computer) architecture, a floating-point unit (FPU) which executes IEEE-754 single- and double-precision floating-point operations a 6-KB three-way set-associative physical instruction cache, a 2-KB two-way set-associative physical data cache, a memory management unit that has two TLBs, and a bus control unit with an ECC (error-correcting code) circuit     

Analysis and experimental validation of force bandwidth for force control

Controlling robots in contact with the environment is an important problem in industry applications. In the conventional force control, much research has paid attention to develop novel force control systems and implemented force sensors to detect external force. This paper shows that narrow bandwidth of force sensor has a big influence on the force control system. Generally, to solve the instability in force control, the velocity feedback gain is enlarged. The system becomes unstable with small velocity feedback gain, and robot's response becomes slow with large one. Inasmuch as there is a tradeoff between the stability and the response, it is considered that force control by robots is difficult. This paper proposes a force control system with disturbance observer. It is possible to obtain the force information with wide bandwidth by using the disturbance observer. This paper shows that bandwidth of force sensing is very important for contact motion control. By using the wide bandwidth of force sensing, both stability and response are improved. Furthermore, force control is attainable by the construction of the easiest force control architecture. Therefore, the ideal zero-stiffness-force control is attained. The numerical and experimental results show viability of the proposed method.     

High-strength–high-modulus polyimide fibers I. One-step synthesis of spinnable polyimides

Polyimides with aromatic links are synthesized usually in two steps, but a series of aromatic polyimides with large molecular weights sufficient to produce strong fibers were prepared in one step by the reaction of 3,3′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) with various aromatic diamines. The one-step polycondensation was possible even when BPDA was replaced to some extent by pyromellitic dianhydride, which is a basic component in the conventional two-step method. The copolyimides based on BPDA and mixtures of aromatic diamines were also synthesized in similar manner. For the one-step polycondensation, phenol and some of its derivatives were found to be suitable solvents, while the typical solvent employed in the two-step method, such as N-methyl-2-pyrrolidone, could not be used because of the precipitation of low-molecular weight polyimides. p-Hydroxybenzoic acid proved to be a very efficient accelerator for the conversion of polyamic acids to polyimides.     

Characterization of human p33/41 (annexin IV), a Ca2+ dependent carbohydrate-binding protein with monoclonal anti-annexin IV antibodies, AS11 and AS17

A non-invasive method of assessing the status of the temporomandibular joint is presented. The method involves placing a computer-controlled vibrator against a lower incisor, and microphones over the temporal bones. The amplitude of the signal transmitted is shown to be a function of the input frequency, the position of the mandible and the loading on the joint.     

Process design of chondrocyte cultures with monolayer growth for cell expansion and subsequent three-dimensional growth for production of cultured cartilage

The subculture of rabbit chondrocytes with serial passaging was carried out for cell expansion on a collagen-coated surface, and the morphological transition of round-shaped cells to spindle-shaped ones was examined. The observation of cytoskeletal formation by staining F-actin and vinculin supported the view that the round-shaped cells were in the process of differentiation with immature stress fibers relating to less cellular polarity. The cellular morphology was estimated in terms of the distribution of roundness, R(C), during the subculturing on the collagen substrate. The frequency of the number of round-shaped cells, which was defined as the ratio of the number of cells with R(C) >0.9 against the total cell number, was correlated in a logarithmic formula with the number of population doublings during the subcultures. Kinetic models were adopted for the process design of the combined culture of chondrocytes with monolayer growth on the collagen substrate and subsequent three-dimensional growth in Atelocollagen gel, employing the boundary conditions based on the population balance between differentiated and dedifferentiated cells. The combined culture was performed successfully according to the process design scheduled as monolayer growth for 240 h and three-dimensional growth for 264 h, the number of seed cells being 68% of that in the conventional culture for 504 h where monolayer growth for cell expansion was not included.