Front-end of line and middle-of-line time-dependent dielectric breakdown reliability simulator for logic circuits

This paper presents a methodology for lifetime estimation of Front-End-of-Line (FEOL) and Middle-of-Line (MOL) time dependent dielectric breakdown (TDDB) in state-of-art logic circuits. The algorithm to extract vulnerable features of MOL-TDDB has been developed and implemented. A traditional 8-bit FFT circuit and a state-of-art Leon3 microprocessor are considered for lifetime calculation. The impact of different use scenarios on circuits is also investigated.     

集成反应分离制备甘露醇的多元分流式装备开发

为优化现有生产过程中的产率、能耗与排放等综合性问题,自主提出一种将电化学还原反应与连续色谱分离相耦合的新工艺,结合机电一体化控制技术,研制出一种将反应分离耦合来制备甘露醇的多元分流式机电装备。其结构简单、操作简捷、过程绿色、节能减排、自动化程度高,可获取甘露醇纯度达93%以上,同时完全利用原料葡萄糖和甘露醇收率接近100%,具有理想的应用前景和推广价值。     

Elastic analysis of exponentially graded piezoelectric cylindrical structures as sensors and actuators

An analytical solution is obtained for functionally graded piezoelectric cylindrical structures, and the electroelastic behavior is investigated. The material properties are assumed to vary as an exponential function along the radial direction of the cylinder. The cylindrical structure acts as sensor or actuator and is subjected to mechanical and electrical loads at its inner and outer cylindrical surfaces. Based on the linear piezoelectricity theory, the governing equation in terms of the radial displacement is obtained as a second-order nonhomogeneous ordinary differential equation with variable coefficients, and its solution is obtained by the Frobenius series method. The illustrative examples show that the material nonhomogeneity has significant effect on the electroelastic fields of functionally graded piezoelectric cylindrical sensors and actuators.     

Large-area profile measurement of sinusoidal freeform surfaces using a new prototype scanning tunneling microscopy

This paper presents large-area profile measurement of ultra-precision diamond turned sinusoidal surfaces by using a specially developed scanning tunneling microscopy (STM). The new prototype of STM system employs a long stroke PZT servo actuator as the Z-directional scanner, an integrated capacitance displacement sensor to accurately measure the Z-directional profile height, a motorized stage with long traveling stroke for carrying out large-area scanning. A simple method for self-calibration of the inevitable sample tilt is proposed in order to achieve large-area measurement without tip-crashing or losing of tip-sample interaction. Several types of ultra-precision machined sinusoidal freeform surfaces with different geometrical parameters are measured by the new STM system over large scanning areas at the scale of millimeters. Specially, a sinusoidal surface with peak-valley amplitude of 22 μm and periodical wavelength of 550 μm is successfully measured and imaged by the STM system. The measurement repeatability error, repeatability standard deviation and measured profile deviation are also evaluated. It is confirmed that the new STM system is capable of carrying out large-area as well as large-amplitude measurement of the ultra-precision machined sinusoidal surfaces.     

Design,development and testing twin pulse tube cryocooler

The design and development of Twin Pulse Tube Cryocooler (TPTC) is presented. Both the coolers are driven by a single Linear Moving Magnet Synchronous Motor (LMMSM) with piston heads at both ends of the mover shaft. Magnetostatic analysis for flux line distribution was carried-out during design and development of LMMSM based pressure wave generator. Based on the performance of PWG, design of TPTC was carried out using Sage and Computational Fluid Dynamics (CFD) analysis. Detailed design, fabrication and testing of LMMSM, TPTC and their integration tests are presented in this paper.     

Reply and closure to comments on “Temperature–heat diagram analysis method for heat recovery physical adsorption refrigeration cycle – Taking multi-stage cycle as an example” by M.M. Awad

The purpose of this letter is to reply to and closure the comment paper by M.M. Awad on the present authors' article that proposed the temperature–heat (T–Q) diagram methodology for adsorption refrigeration cycle. Dr. Awad did not comment on any technical content of the commented article. The comments mainly enumerated opposing views on entransy. In this letter, the present authors reiterated the theoretical basis of T–Q diagram, and gave rebuttals to Dr. Awad's comments.     

A novel self-assembly with two acetohydrazide zinc porphyrins coordination polymer for supramolecular solar cells

Two new acetohydrazide zinc porphyrin with different donor units based Mn (Ⅱ) ion coordination polymers (CPsx, x=1,2) have been designed, synthesized, and well-characterized. Two coordination polymers and anchor porphyrin (ZnPA) self-assembly by metal-ligand axial coordination to modify the nano-structured TiO₂ electrode surface has been investigated in photoelectrochemical device. Our results reveal that the self-assemblies devices show significantly improved photocurrent conversion efficiency. Particularly, CPs1 based solar cell showed higher short circuit current density and conversion efficiency. Their optical performance, electrochemical impedance spectroscopy and transient photovoltage decay were also investigated to further understand the photoelectrochemical results. In addition, the assembled modes of the assemblies immobilized on TiO₂ electrode surfaces were also verified by transmission electron microscopy (TEM), theory calculations and energy dispersive X-ray spectroscopy (EDX).     

Pressure-assisted self-assembly technique for fabricating composite membranes consisting of highly ordered selective laminate layers of amphiphilic graphene oxide

We prepare highly ordered flexible layers of graphene oxide (GO) on modified polyacrylonitrile substrates by the pressure-assisted self-assembly technique. This composite membrane shows excellent performance during the pervaporation separation of a 70 wt.% isopropyl alcohol (IPA)/water mixture: 99.5 wt% water in permeate and 2047 g m⁻² h⁻¹ permeation flux. Despite the specific GO deposition increase from 4.3 to 43.3 × 10⁻⁵ g cm⁻² (ninefold layer thickness growth), its effect on the permeation flux is not significant, as manifested by only a little decrease in the flux. At 70 °C feed temperature, the permeate water concentration remains 99.5 wt% and the permeation flux reaches 4137 g m⁻² h⁻¹. The high selectivity may be due to the dense GO film consisting of highly ordered and packed laminates, allowing water but inhibiting IPA molecules to pass through. GO is demonstrated to be amphiphilic: water molecules adsorb first at the hydrophilic edge (hydroxides) and then rapidly diffuse through the hydrophobic core (mainly carbon), forming a water passage channel that promotes high permeation flux. When water molecules permeate through the GO layers, they accumulate and form a monolayer structure that pushes the successive layers away from each other, leading to widening of the d-spacing.     

The hydrogen flow characteristics of the multistage hydrogen Knudsen compressor based on the thermal transpiration effect

Multistage hydrogen Knudsen compressor based on the thermal transpiration effect has very exciting prospect for the hydrogen transmission in the micro devices. Understanding of the hydrogen flow characteristic is the key issue for the designs and applications of the hydrogen energy systems. Firstly, the numerical models of the multistage hydrogen Knudsen compressor are established. The distributions of the rarefaction, velocity and temperature at different stages of the hydrogen flow are calculated and presented. Moreover, the dimensional pressure increases of the hydrogen gas flow are analyzed, and the flow behaviors in the microchannel and the connection channel are discussed. Secondly, the numerical simulation at different connection channel height is implemented, and the hydrogen gas flow characteristics in the connection are analyzed. Especially, the performances of the pressure drop in the connection channel under different channel heights are studied, and the hydrogen gas compression characteristics of different cases are compared and discussed. Also, the effect of the connection channel height on the hydrogen gas pressure increase in the microchannel is investigated. The studies presented in this paper could be greatly beneficial for the hydrogen detection and transmission.     

Bioaugmentation with Thermoanaerobacterium thermosaccharolyticum W16 to enhance thermophilic hydrogen production using corn stover hydrolysate

In the present work, with corn stover hydrolysate as the substrate, an efficient hydrogen-producing thermophile, Thermoanaerobacterium thermosaccharolyticum W16, was added to three kinds of seed sludge (rotten corn stover (RCS), cow dung compost (CDC), and sludge from anaerobic digestion (SAD)) to investigate the effect of bioaugmentation on thermophilic hydrogen production. Batch test results indicate that the bioaugmentation with a small amount of the strain T. thermosaccharolyticum W16 (5% of total microbes) increased the hydrogen yield to varying degrees (RCS: from 8.78 to 9.90 mmol H₂/g utilized sugar; CDC: from 8.18 to 8.42 mmol H₂/g utilized sugar; SAD: from 8.55 to 9.17 mmol H₂/g utilized sugar). The bioaugmentation process also influenced the soluble metabolites composition towards more acetate and less butyrate production for RCS, and more acetate and less ethanol accumulation for SAD. Microbial community analysis indicates that Thermoanaerobacterium spp. and Clostridium spp. dominated microbial community in all situations and might be mainly responsible for thermophilic hydrogen generation. For RCS and SAD, the bioaugmentation obviously increased the relative abundance of the strain T. thermosaccharolyticum W16 in microbial community, which might be the main reason for the improvement of hydrogen production in these cases.