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’

The authors report on an in-depth statistical and parametrical investigation on the microwave performance of graphene FETs on sapphire substrate. The devices differ for the gate-drain/source distance and for the gate length, having kept instead the gate width constant. Microwave S
-parameters have been measured for the different devices. Their results demonstrate that the cut-off frequency does not monotonically increase with the scaling of the device geometry and that it exists an optimal region in the gate-drain/source and gate-length space which maximises the microwave performance.

/pdf/layout-influence-on-microwave-performance-of-graphene-field-21kqm3uf3x.pdf

Layout influence on microwave performance of graphene field effect transistors

Miniaturized neural implants for monitoring neurological disorders have been investigated as a promising alternative to the neural interface for patients. However, such implants rely on physical tethers to external hardware for data and power transmission, which not only causes tissue damage and infection, but also hinders stable in vivo recordings in freely behaving animals. To enable non-tethered implants, a key feature for the robust and high-fidelity neural interface, neural implants using various wireless technologies have been reported (Fig. 20.5.1, top-left) [1]–[3]. However, the use of an inductive link [1] imposes a stringent requirement on the alignment between coils, as well as a limited transfer range. Optical [2] and ultrasound [3] telemetry suffer from attenuation from skull absorption, which requires surgically placed sub-cranial repeater or has only been demonstrated at low data rates (tens of kb/s). Hence, they are limited to the short operation range and the susceptibility to orientation, and in most cases still need a headstage that restricts freedom of action.

A Miniaturized Wireless Neural Implant with Body-Coupled Data Transmission and Power Delivery for Freely Behaving Animals

In the past decade, passively modelocked optically pumped vertical external cavity surface emitting lasers (OPVECSELs), sometimes referred to as semiconductor disk lasers (OP-SDLs), impressively demonstrated the potential for generating femtosecond pulses at multi-Watt average output powers with gigahertz repetition rates. Passive modelocking with a semiconductor saturable absorber mirror (SESAM) is well established and offers many advantages such as a flexible design of the parameters and low non-saturable losses. Recently, graphene has emerged as an attractive wavelength-independent alternative saturable absorber for passive modelocking in various lasers such as fiber or solid-state bulk lasers because of its unique optical properties. Here, we present and discuss the modelocked VECSELs using graphene saturable absorbers. The broadband absorption due to the linear dispersion of the Dirac electrons in graphene makes this absorber interesting for wavelength tunable ultrafast VECSELs. Such widely tunable modelocked sources are in particularly interesting for bio-medical imaging applications. We present a straightforward approach to design the optical properties of single layer graphene saturable absorber mirrors (GSAMs) suitable for passive modelocking of VECSELs. We demonstrate sub-500 fs pulses from a GSAM modelocked VECSEL. The potential for broadband wavelength tuning is confirmed by covering 46 nm in modelocked operation using three different VECSEL chips and up to 21 nm tuning in pulsed operation is achieved with one single gain chip. A linear and nonlinear optical characterization of different GSAMs with different absorption properties is discussed and can be compared to SESAMs.

Graphene modelocked VECSELs

Embodiments of the invention provide a method for fabricating a magnetoresistive device. The method comprises: releasing a multi-layer magnetoresistive structure for forming the magnetoresistive device from a first substrate to relax an intrinsic stress in the multi-layer magnetoresistive structure such that the magnetic and/or magnetoresistive properties of the magnetoresistive device can be improved. The magnetic and/or magnetoresistive properties include, but are not limited to coercivity, squareness or abruptness of switching, magnetoresistance (MR) and resistance of the magnetoresistive device.

Jong Hyun Ahn

Papers

Layout influence on microwave performance of graphene field effect transistors

A Miniaturized Wireless Neural Implant with Body-Coupled Data Transmission and Power Delivery for Freely Behaving Animals

Graphene modelocked VECSELs

Method for fabricating a magnetoresistive device

Graphene Photodetectors: High–Performance Perovskite–Graphene Hybrid Photodetector (Adv. Mater. 1/2015)