353 research outputs found

    Counter operation in nonlinear micro-electro-mechanical resonators

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    This paper discusses a logical operation of multi-memories that consist of coupled nonlinear micro-electro-mechanical systems (MEMS) resonators. A MEMS resonator shows two coexisting stable states when nonlinear responses appear. Previous studies addressed that a micro- or nano-electrical-mechanical resonator can be utilized as a mechanical 1-bit memory or mechanical logic gates. The next phase is the development of logic system with coupled multi-resonators. From the viewpoint of application of nonlinear dynamics in coupled MEMS resonators, we show the first experimental success of the controlling nonlinear behavior as a 2-bit binary counter.Comment: 5 pages, 13 figure

    Visualization of Au Nanoparticles Buried in a Polymer Matrix by Scanning Thermal Noise Microscopy

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    We demonstrated visualization of Au nanoparticles buried 300 nm into a polymer matrix by measurement of the thermal noise spectrum of a microcantilever with a tip in contact to the polymer surface. The subsurface Au nanoparticles were detected as the variation in the contact stiffness and damping reflecting the viscoelastic properties of the polymer surface. The variation in the contact stiffness well agreed with the effective stiffness of a simple one-dimensional model, which is consistent with the fact that the maximum depth range of the technique is far beyond the extent of the contact stress field.Comment: 13 pages, 4 figures in main text; 7 pages, 5 figures in supplementary informatio

    Electrodeposition of an iron thin film with compact and smooth morphology using an ethereal electrolyte

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    Electrodeposition of iron (Fe) from an ethereal solution was investigated. The bath consisted of ferrous chloride (FeCl₂), diglyme (G2), and aluminum chloride (AlCl₃), in which iron species were estimated to be [Fe(G2)₂]²⁺ complex cations. The effect of hydrogen gas evolution on the morphology of iron deposits was determined by comparing common aqueous electrolytes. An Fe thin film was fabricated using the FeCl₂–G2–AlCl₃ bath without the influence of hydrogen gas evolution, and the nucleation of Fe was explained by an instantaneous nucleation mechanism. As a result, the surface morphology of the Fe thin film was compact and smooth compared with the cases of aqueous and other nonaqueous electrolytes

    TRIM28-Regulated Transposon Repression Is Required for Human Germline Competency and Not Primed or Naive Human Pluripotency.

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    Transition from primed to naive pluripotency is associated with dynamic changes in transposable element (TE) expression and demethylation of imprinting control regions (ICRs). In mouse, ICR methylation and TE expression are each regulated by TRIM28; however, the role of TRIM28 in humans is less clear. Here, we show that a null mutation in TRIM28 causes significant alterations in TE expression in both the naive and primed states of human pluripotency, and phenotypically this has limited effects on self-renewal, instead causing a loss of germline competency. Furthermore, we discovered that TRIM28 regulates paternal ICR methylation and chromatin accessibility in the primed state, with no effects on maternal ICRs. Taken together, our study shows that abnormal TE expression is tolerated by self-renewing human pluripotent cells, whereas germline competency is not

    Small CRT-Exponent RSA Revisited

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    Since May (Crypto\u2702) revealed the vulnerability of the small CRT-exponent RSA using Coppersmith\u27s lattice-based method, several papers have studied the problem and two major improvements have been made. (1) Bleichenbacher and May (PKC\u2706) proposed an attack for small dqd_q when the prime factor pp is significantly smaller than the other prime factor qq; the attack works for p<N0.468p<N^{0.468}. (2) Jochemsz and May (Crypto\u2707) proposed an attack for small dpd_p and dqd_q when the prime factors pp and qq are balanced; the attack works for dp,dq<N0.073d_p, d_q<N^{0.073}. Even a decade has passed since their proposals, the above two attacks are still considered as the state-of-the-art, and no improvements have been made thus far. A novel technique seems to be required for further improvements since it seems that the attacks have been studied with all the applicable techniques for Coppersmith\u27s methods proposed by Durfee-Nguyen (Asiacrypt\u2700), Jochemsz-May (Asiacrypt\u2706), and Herrmann-May (Asiacrypt\u2709, PKC\u2710). In this paper, we propose two improved attacks on the small CRT-exponent RSA: a small dqd_q attack for p<N0.5p<N^{0.5} (an improvement of Bleichenbacher-May\u27s) and a small dpd_p and dqd_q attack for dp,dq<N0.122d_p, d_q < N^{0.122} (an improvement of Jochemsz-May\u27s). The latter result is also an improvement of our result in the proceeding version (Eurocrypt \u2717); dp,dq<N0.091d_p, d_q < N^{0.091}. We use Coppersmith\u27s lattice-based method to solve modular equations and obtain the improvements from a novel lattice construction by exploiting useful algebraic structures of the CRT-RSA key generation equation. We explicitly show proofs of our attacks and verify the validities by computer experiments. In addition to the two main attacks, we also propose small dqd_q attacks on several variants of RSA

    QCD Sum Rule Study of the Masses of Light Tetraquark Scalar Mesons

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    We study the low-lying scalar mesons of light u, d, s flavors in the QCD sum rule. Having all possible combinations of tetraquark currents in the local form, QCD sum rule analysis has been carefully performed. We found that using the appropriate tetraquark currents, the masses of sigma, kappa, f_0 and a_0 mesons appear in the region of 0.6 -- 1 GeV with the expected ordering. The results are compared with that of the conventional \bar{q} q currents, where the masses are considerably larger.Comment: 4 pages, 2 figures; reference added, minor corrections; version to appear in Physics Letters