Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Single-layer metal dichalcogenides are two-dimensional semiconductors that present strong potential for electronic and sensing applications complementary to that of graphene.

/pdf/electronics-and-optoelectronics-of-two-dimensional-2jbqr1unvw.pdf

Electronics and optoelectronics of two-dimensional transition metal dichalcogenides.

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

With advances in robotic technology, the complexity of control of robot has been increasing owing to fundamental signal bottlenecks and limited expressible logic state of the von Neumann architecture. Here, we demonstrate coordinated movement by a fully parallel-processable synaptic array with reduced control complexity. The synaptic array was fabricated by connecting eight ion-gel-based synaptic transistors to an ion gel dielectric. Parallel signal processing and multi-actuation control could be achieved by modulating the ionic movement. Through the integration of the synaptic array and a robotic hand, coordinated movement of the fingers was achieved with reduced control complexity by exploiting the advantages of parallel multiplexing and analog logic. The proposed synaptic control system provides considerable scope for the advancement of robotic control systems. 

/pdf/humanlike-spontaneous-motion-coordination-of-robotic-fingers-1zlq3tom.pdf

Humanlike spontaneous motion coordination of robotic fingers through spatial multi-input spike signal multiplexing

Flexible thin film transistors (TFT) were fabricated with randomly oriented single-walled carbon nanotubes (SWNTs) synthesized selectively on a designed array of catalyst photoresists using the plasma-enhanced chemical vapor deposition (PECVD) method. The process involves SWNTs growth on SiO 2 /Si substrates, followed by transfer-printing of tubes onto thin, flexible sheets of plastic. Electrical measurements on the resulting devices reveal good characteristics. These results might be of interest for various applications of SWNTs in flexible electronics.

Flexible thin flim transistor using printed single-walled carbon nanotubes

Abstract Layered group-IV monochalcogenides, including GeS, GeSe, SnS, and SnSe, garner attention because of their anisotropic structures and properties. Here, we report on the growth of GeS microribbons via chemical vapor transport (CVT), which affords each of them with a low-symmetry orthorhombic structure and anisotropic optical and electronic properties. The single-crystalline nature of the GeS microribbon, which has a typical thickness of ~30 nm, is confirmed. Polarized Raman spectra reveal angle-dependent intensities that are attributed to the anisotropic layered structure of GeS microribbons. The photoluminescence (PL) spectra reveal a peak at ~1.66 eV. The angle-dependent PL and anisotropic absorption spectroscopy results provide evidence for a distinct anisotropic optical transition near the energy band edges; this phenomenon is also predicted by our density functional theory (DFT)-based calculations. Strong in-plane direct-current transport anisotropy is observed under dark and white illumination by using back-gate cross-shaped field effect transistors (CSFETs) fabricated with the GeS microribbon; significant gate-tunable conductivity is also confirmed. The strong anisotropy is further confirmed by the DFT-calculated effective mass ratio. Our findings not only support the application of GeS microribbons in anisotropic photoelectronic transistors but also provide more possibilities for other functional device applications. 

https://www.nature.com/articles/s41427-022-00390-8.pdf

In-plane optical and electrical anisotropy in low-symmetry layered GeS microribbons

An amorphous indium–gallium–zinc oxide based inverter (a-IGZO inverter) was fabricated. Subsequently, its mechanical characteristics were investigated. A numerical method was adopted to optimize the a-IGZO inverter design. This optimization secured mechanical stability. The curvature at the edge of the SiO2 pad and the thickness of the indium–tin-oxide (ITO) electrode were accounted for in the models. The new model improved the mechanical stability when it was stretched by a total of 5% of its length along the x-axis and did not exhibit fractures or cracks. In contrast, the referenced model fractured under the same condition. It has been verified by both experiments and simulations that newly designed models obtain mechanical stability.

https://iopscience.iop.org/article/10.1143/JJAP.51.01AG10/pdf

Numerical Design of SiO$_{2}$ Bridges in Stretchable Thin Film Transistors

The electrical characteristics of a transistor on a transferred silicon ribbon are demonstrated. The process temperature is limited to 200°C for potential use on plastic sheets. Additional hydrogen annealing reduces the threshold voltage and improves the transistor properties. A high mobility of around 160 cm 2 /V s, with a high on/off ratio and an off current of as low as < 10 11 A, is achieved. The flexibility of the device is evaluated after applying stress in the bended condition. The device shows very little change in properties with a bending radius <4 mm. Overall, good electrical and mechanical properties are demonstrated for future use on flexible device applications.

Jong Hyun Ahn

Papers

Humanlike spontaneous motion coordination of robotic fingers through spatial multi-input spike signal multiplexing

Flexible thin flim transistor using printed single-walled carbon nanotubes

In-plane optical and electrical anisotropy in low-symmetry layered GeS microribbons

Numerical Design of SiO$_{2}$ Bridges in Stretchable Thin Film Transistors

Hydrogen Defect Passivation of Silicon Transistor on Plastic for High Performance Flexible Device Application