X-ray line profile analysis of silver base Ag-Cd-In alloys

X-ray diffraction line profiles of five silver base ternary alloys in α-phase with varying atomic percentages of cadmium and indium were recorded in both cold-worked and annealed states of the samples. Detailed studies on the profiles involving peak shift, peak asymmetry and Fourier analysis of line shapes have been carried out to evaluate microstructural parameters such as deformation fault probabilities,rms strains and dislocation densities. It was found that the addition of indium has a marked effect in producing deformation fault probabilities in comparison to that of adding cadmium in ternary silver base alloys. Compound fault probability was found to be maximum for the alloy Ag-10Cd-15In.     

低温奥氏体钢的层错能

根据层错及层错能的物理本质和测试层错的依据，明确了层错能和层错形核能的定义。借助计算机处理大量试验结果得到了计算机层错能的表达式。     

高分辨率层序地层学的应用——以鄂尔多斯盆地榆林长北气田山西组2段为例

以高分辨率层序地层学原理为指导,利用测井、钻井和野外露头剖面等资料,对鄂尔多斯盆地榆林长北气田山西组2段不同级次基准面旋回进行了详细划分,将山西组2段划分为1个长期、2个中期和5个短期基准面旋回.短期基准面旋回细分为两大类5种结构;中期基准面细分为两大类3种结构;长期基准面旋回为不完全对称型结构,区域分布较稳定.分析了不同级别的基准面旋回叠加式样与沉积相展布、演化规律之间的关系,中期基准面旋回上升半旋回开始阶段是辫状河三角洲河道砂体连续叠置形成巨厚砂体时期,洪泛面期及下降半旋回为细粒沉积物发育期.连续叠置的主水道和分支水道砂体形成了有利储层发育区,水下分流河道砂体与河口坝砂体构成了较好储层发育区.     

Ultra‐small Form‐Factor Helix on Pad‐Type Stage‐Bypass WCDMA Tx Power Amplifier Using a Chip‐Stacking Technique and a Multilayer Substrate

A fully integrated small form‐factor HBT power amplifier (PA) was developed for UMTS Tx applications. For practical use, the PA was implemented with a well configured bottom dimension, and a CMOS control IC was added to enable/disable the HBT PA. By using helix‐on‐pad integrated passive device output matching, a chip‐stacking technique in the assembly of the CMOS IC, and embedding of the bulky inductive lines in a multilayer substrate, the module size was greatly reduced to 2 mm × 2.2 mm. A stage‐bypass technique was used to enhance the efficiency of the PA. The PA showed a low idle current of about 20 mA and a PAE of about15% at an output power of 16 dBm, while showing good linearity over the entire operating power range.     

无Cr腐蚀液显示直拉Si单晶中的氧化诱生层错

Si抛光片的氧化诱生层错(OSF)是一种重要的工艺诱生缺陷,为提高Si抛光片质量,应对氧化诱生层错的产生有充分的认识和了解,并加以克服,而简单、快捷、准确地显示缺陷是首要条件.介绍了采用环保的无Cr腐蚀液显示氧化诱生层错,实验发现无Cr腐蚀液能很好地显示氧化诱生层错,比较了无Cr腐蚀液和其他常用腐蚀液的缺陷腐蚀形貌,探讨了无Cr腐蚀液的腐蚀机理及腐蚀条件.实验发现环保的无Cr腐蚀液能很好地显示直拉Si单晶中的氧化诱生层错,能应用于生产.     

Partial dislocations and stacking faults in 4H-SiC PiN diodes

Using plan-view transmission electron microscopy (TEM), we have identified stacking faults (SFs) in 4H-SiC PiN diodes subjected to both light and heavy electrical bias. Our observations suggest that the widely expanded SFs seen after heavy bias are faulted dislocation loops that have expanded in response to strain of the 4H-SiC film, while faulted screw or 60° threading dislocations do not give rise to widely expanded SFs. Theoretical calculations show that the expansion of SFs depends on the Peach-Koehler (PK) forces on the partial dislocations bounding the SFs, indicating that strain plays a critical role in SF expansion.     

Optimizing the Optoelectronic Properties of Face-On Oriented Poly(3,4-Ethylenedioxythiophene) via Water-Assisted Oxidative Chemical Vapor Deposition

Engineering the texture and nanostructure to improve the electrical conductivity of semicrystalline conjugated polymers must address the rate-limiting step for charge carrier transport. In highly face-on orientation, the charge transport between chains within a crystallite becomes rate-limiting, which is highly sensitive to the π–π stacking distance and interchain charge transfer integral. Here, face-on oriented semicrystalline poly(3,4-ethylenedioxythiophene) (PEDOT) thin films are grown via water-assisted (W-A) oxidative chemical vapor deposition (oCVD). Combining W-A with the volatile oxidant, antimony pentachloride, yields an optimized electrical conductivity of 7520  ±  240 S cm⁻¹, a record for PEDOT thin films. Systematic control of π–π stacking distance from 3.50 Å down to 3.43 Å yields an electrical conductivity enhancement of ≈ 1140%. The highest electrical conductivity also corresponds to minimum in Urbach energy of 205 meV, indicating superior morphological order. The figure of merit for transparent conductors, σ_dc/σ_op, reaches a maximum value of 94, which is 1.9 × and 6.7 × higher than oCVD PEDOT grown without W-A and utilizing vanadium oxytrichloride and iron chloride oxidizing agents, respectively. The W-A oCVD is single-step all-dry process and provides conformal coverage, allowing direct growth on mechanical flexible, rough, and structured surfaces without the need for complex and costly transfer steps.     

Modulating the Interlayer Stacking of Covalent Organic Frameworks for Efficient Acetylene Separation

Controllable modulation of the stacking modes of 2D (two-dimensional) materials can significantly influence their properties and functionalities but remains a formidable synthetic challenge. Here, an effective strategy is proposed to control the layer stacking of imide-linked 2D covalent organic frameworks (COFs) by altering the synthetic methods. Specifically, a modulator-assisted method can afford a COF with rare ABC stacking without the need for any additives, while solvothermal synthesis leads to AA stacking. The variation of interlayer stacking significantly influences their chemical and physical properties, including morphology, porosity, and gas adsorption performance. The resultant COF with ABC stacking shows much higher C₂H₂ capacity and selectivity over CO₂ and C₂H₄ than the COF with AA stacking, which is not demonstrated in the COF field yet. Furthermore, the outstanding practical separation ability of ABC stacking COF is confirmed by breakthrough experiments of C₂H₂/CO₂ (50/50, v/v) and C₂H₂/C₂H₄ (1/99, v/v), which can selectively remove C₂H₂ with good recyclability. This work provides a new direction to produce COFs with controllable interlayer stacking modes.     

Controllable Preparation of 2D V2O5 Peroxidase-Mimetic Nanozyme to Develop Portable Paper-Based Analytical Device for Intelligent Pesticide Assay

Given severe harmfulness of pesticides, unique characteristics of peroxidase-mimetic nanozymes, and favorable prospects of paper-based analytical devices (PADs), it is highly desirable to construct a nanozyme-based PAD for intelligent analysis of pesticide without enzyme/aptamer/antibody and interference of O₂. Herein, 2D nanosheet-like V₂O₅ (2D-VONz) with exclusive peroxidase-mimetic activity is controllably prepared under the optimal reactants concentration and reaction temperature. Experimental characterizations demonstrate that 2D-VONz exhibits high affinity and catalytic rate, and catalytic oxidation is dependent on •OH yielded from the decomposition of H₂O₂ catalyzed by 2D-VONz, and the catalytic performance is relevant to π–π stacking force-controlled surface zeta potential of 2D-VONz changed by substrates, giving a comprehensive understand of the inherent mechanism. Interestingly, 2D-VONz activity is inhibited by pesticide glyphosate (Gly), and then is exploited to develop a PAD, on which, Gly declines 2D-VONz activity to prevent it from catalyzing the oxidation of 3,3′,5,5′-tetramethylbenzidine, contributing to rapid, naked-eye, and portable analysis of pesticide using a smartphone. The current strategy on preparing exclusive peroxidase-mimetic 2D nanozyme, investigating catalytic mechanism, developing nanozyme-based PAD, and achieving direct pesticide sensing will set up new avenues to improve the analytical performance, strengthen the practicability, and broaden the application scope of nanozymes.