Four-channel frequency locking using back-reflection dips of afibre-fed Fabry-Perot filter

A 4-channel frequency locking system has been demonstrated using a fibre-fed Fabry-Perot (FFP) filter with a free spectral range (FSR) of 100 GHz. A back-reflection curve from the FFP was used for the extraction of an error signal in such a way as to overcome the limitation in the number of accommodatable channels due to the saturation in a photodetector. The frequency stability and locking range of each channel were within 15 MHz and over 12 GHz, respectively     

A comparison study of 12 paradigms for developing embodied agents

We report on a study in which 12 different paradigms were used to implement agents acting in an environment which borrows elements from artificial life and multi‐player strategy games. In choosing the paradigms we strived to maintain a balance between high‐level, logic‐based approaches and low‐level, physics‐oriented models; between imperative programming, declarative approaches and ‘learning from basics’; between anthropomorphic or biologically inspired models on one hand and pragmatic, performance‐oriented approaches on the other. We have found that the choice of the paradigm determines the software development process and requires a different set of skills from the developers. In terms of raw performance, we found that the best performing paradigms were those which (a) allowed the knowledge of human experts to be explicitly transferred to the agent and (b) allowed the integration of well‐known, high‐performance algorithms. We have found that maintaining a commitment to the chosen paradigm can be difficult; there is a strong temptation to offer shallow fixes to perceived performance problems through a ‘flight into heuristics’. Our experience is that a development process without the discipline enforced by a central paradigm leads to agents which are a random collection of heuristics whose interactions are not clearly understood. Although far from providing a definitive verdict on the benefits of the different paradigms, our study provided a good insight into what kind of conceptual, technical or organizational problems would a development team face depending on their choice of agent paradigm. Copyright © 2007 John Wiley & Sons, Ltd.     

A New Method for Extracting Interface Trap Density in Short-Channel MOSFETs from Substrate-Bias-Dependent Subthreshold Slopes

Interface trap densities at gate oxide/silicon substrate (SiO₂/Si) interfaces of metal oxide semiconductor field-effect transistors (MOSFETs) were determined from the substrate bias dependence of the subthreshold slope measurement. This method enables the characterization of interface traps residing in the energy level between the midgap and that corresponding to the strong inversion of small size MOSFET. In consequence of the high accuracy of this method, the energy dependence of the interface trap density can be accurately determined. The application of this technique to a MOSFET showed good agreement with the result obtained through the high-frequency/quasi-static capacitance-voltage (C-V) technique for a MOS capacitor. Furthermore, the effective substrate dopant concentration obtained through this technique also showed good agreement with the result obtained through the body effect measurement.     

Capping interactions in isolated alpha helices: position-dependent substitution effects and structure of a serine-capped peptide helix

The influence of an amino acid on the stability of alpha-helical structure depends on the position of the residue in the helix with respect to the ends. Short alpha helices in proteins are stabilized both by H-bonding of the main-chain NH and CO groups and by capping interactions between side chains and unfulfilled peptide groups at the N and C termini. Peptide models based on consensus position-dependent helix sequences allow one to model capping effects in isolated helices and to establish a base line for these interactions in proteins. We report here an extended series of substitutions in the cap positions of our peptide models and the solution structure of peptide S3, with serine at the N-cap position defined as the N-terminal residue with partly helix and partly coil conformation. The resulting model, determined by 2D 1H NMR, is consistent with a structure at the N-cap involving H-bonding between the serine gamma oxygen and the peptide NH of the glutamic acid residue three amino acids toward the C terminus. A bifurcated H-bond of Ser O gamma with the NH of Asp5 is possible also, since this group is within interacting distance. This provides direct evidence that specific side-chain interactions with the main chain stabilize isolated alpha-helical structure.     

离子交换技术在高速连续镀锡线上的应用与研究进展

从镀锡液除铁和溶锡系统两方面阐述了离子交换技术在高速连续电镀锡生产线上的研究进展和应用,并总结了相关的行业数据,展望了离子交换技术在镀液净化和溶锡工艺中的应用前景。     

Local Crack‐Programmed Gold Nanowire Electronic Skin Tattoos for In‐Plane Multisensor Integration

Sensitive, specific, yet multifunctional tattoo‐like electronics are ideal wearable systems for “any time, any where” health monitoring because they can virtually become parts of the human skin, offering a burdenless “unfeelable” wearing experience. A skin‐like, multifunctional electronic tattoo made entirely from gold using a standing enokitake‐mushroom‐like vertically aligned nanowire membrane in conjunction with a programmable local cracking technology is reported. Unlike previous multifunctional systems, only a single material type is needed for the integrated gold circuits involved in interconnects and multiplexed specific sensors, thereby avoiding the use of complex multimaterials interfaces. This is possiblebecause the programmable local cracking technology allows for the arbitrary fine‐tuning of the properties of elastic gold conductors from strain‐insensitive to highly strain‐sensitive simply by adjusting localized crack size, shape, and orientations—a capability impossible to achieve with previous bulk cracking technology. Furthermore, in‐plane integration of strain/pressure sensors, anisotropic orientation‐specific sensors, strain‐insensitive stretchable interconnects, temperature sensors, glucose sensors, and lactate sensors without the need of soldering or gluing are demonstrated. This strategy opens a new general route for the design of next‐generation wearable electronic tattoos.     

Biomineralized Bacterial Outer Membrane Vesicles Potentiate Safe and Efficient Tumor Microenvironment Reprogramming for Anticancer Therapy

The highly immunosuppressive tumor microenvironment (TME) in solid tumors often dampens the efficacy of immunotherapy. In this study, bacterial outer membrane vesicles (OMVs) are demonstrated as powerful immunostimulants for TME reprogramming. To overcome the obstacles of antibody-dependent clearance and high toxicity induced by OMVs upon intravenous injection (a classic clinically relevant delivery mode), calcium phosphate (CaP) shells are employed to cover the surface of OMVs, which enables potent OMV-based TME reprograming without side effects. Meanwhile, the pH-sensitive CaP shells facilitate the neutralization of acidic TME, leading to highly beneficial M2-to-M1 polarization of macrophages for improved antitumor effect. Moreover, the outer shells can be integrated with functional components like folic acid or photosensitizer agents, which facilitates the use of the OMV-based platform in combination therapies for a synergic therapeutic effect.     

Reliability modeling for multistage systems subject to competing failure processes

In this paper, a novel multistage reliability model is provided as systems are often divided into many stages according to system degradation characteristics. Multistage hard failure (caused by random shock) process (MHFP) and multistage soft failure (caused by random shock and continuous degradation) process (MSFP) are introduced to describe the competing failure processes, where either the MSFP or MHFP would break down the system. The shock processes impact the system in three ways: (1) fatal load shocks cause hard failure immediately in the hard failure process; (2) time shocks cause a hard failure threshold changing; (3) damage load shocks cause degradation level increasing in the soft failure process. In this paper, a density function dispersion method is carried out to address the multistage reliability model, and the effectiveness of the proposed models is demonstrated by reliability analysis with the one-stage model. Finally, the multistage model is applied to a case study, the degradation process is divided into three stages, and the hard failure threshold can be transmitted twice. The proposed model can be applied in other multistage situations, and the calculation method can satisfy the accuracy requirements.     

Self-Limiting Sub-5 nm Nanodiamonds by Geochemistry-Inspired Synthesis

Controlling diamond structures with nanometer precision is fundamentally challenging owing to their extreme and far-from-equilibrium synthetic conditions. State-of-the-art techniques, including detonation, chemical vapor deposition, mechanical grinding, and high-pressure-high-temperature synthesis, yield nanodiamond particles with a broad distribution of sizes. Despite many efforts, the direct synthesis of nanodiamonds with precisely controlled diameters remains elusive. Here the geochemistry-inspired synthesis of sub-5 nm nanodiamonds with sub-nanometer size deviation is described. High-pressure-high-temperature treatment of uniform iron carbide nanoparticles embedded in iron oxide matrices yields nanodiamonds with tunable diameters down to 2.13 and 0.22 nm standard deviation. A self-limiting, redox-driven, and diffusion-controlled solid-state reaction mechanism is proposed and supported by in situ X-ray diffraction, ex situ characterizations, and computational modeling. This work provides a unique mechanism for the precise control of nanostructured diamonds under extreme conditions and paves the road for the full realization of their potential in emerging technologies.