水坝在水流作用下动力响应的一种分析方法

以广东某水坝为研究对象,给出一种基于Fluent平台和Ansys平台进行结构动力响应分析的方法。首先采用基于YOUNGS界面重构技术的VOF模型,对流动进行数值模拟,成功捕捉了闸门开启过程中自由面的变化,比较了在三种落差情况下水坝的受力差异。计算表明,即使在上游平稳的入流条件下,水坝所受到的湍流水压力也会出现波动现象,水压力对坝体的冲击为低频作用,下游水位的升高会减缓水压力的波动,这些特点都与现场观察的相符。然后将水动力作为激励条件导入结构动力分析平台Ansys后,进一步对坝体结构进行动力分析。结构的模态分析结果与实测结果一致。因此,方法可以应用于实际。     

Fluorescence energy transfer-based multiplexed hybridization assay using gold nanoparticles and quantum dot conjugates on photonic crystal beads

A multiplexed assay strategy was developed for the detection of nucleic acid hybridization. It is based on fluorescence resonance energy transfer (FRET) between gold nanoparticles (AuNPs) and multi-sized quantum dots (QDs) deposited on the surface of silica photonic crystal beads (SPCBs). The SPCBs were first coated with a three-layer primer film formed by the alternating adsorption of poly(allylamine hydrochloride) and poly(sodium 4-styrensulfonate). Probe DNA sequences were then covalently attached to the carboxy groups at the surface of the QD-coated SPCBs. On addition of DNA-AuNPs and hybridization, the fluorescence of the donor QDs is quenched because of the close proximity of the AuNPs. However, the addition of target DNA causes a recovery of the fluorescence of the QD-coated SPCBs, thus enabling the quantitative assay of hybridized DNA. Compared to fluorescent dyes acting as acceptors, the use of AuNPs results in much higher quenching efficiency. The multiplexed assay displays a wide linear range, high sensitivity, and very little cross-reactivity. This work, where such SPCBs are used for the first time in a FRET assay, is deemed to present a new and viable approach towards high-throughput multiplexed gene assays.

A 0.5–2.5 GHz 910 uW complementary LNA employing positive–negative feedback

A 0.5–2.5 GHz ultra low power differential resistive feedback common gate low noise amplifier (RFCGLNA) without the use of inductor is presented. The proposed RFCGLNA adopts the NMOS and PMOS complementary topology to reduce the power consumption by half. Based on common-gate topology, the proposed RFCGLNA employs capacitive cross-coupling (CCC) and resistive feedback techniques. The CCC technique can further reduce the power consumption by half. The resistive feedback technique can constrain the common mode voltages of the proposed RFCGLNA and meanwhile, improve the third-order input intercept point (IIP3). The DC path is supplied by the current source transistor which forms a positive feedback loop to improve the gain at low frequency. Implemented with 65 nm standard complementary metal oxide semiconductor (CMOS) technology, the measured performance achieves 15 dB gain with S₁₁ < ?10 dB in the 0.5–2.5 GHz band. The noise figure (NF) is 3.9–5.0 dB and the IIP3 is 3.1–3.6 dBm. The power consumption is only 910 uW.     

Hydrogen-bonding interaction of urea with DNA bases: A density functional theory study

This work deals with the interaction between urea and DNA bases (adenine, thymine, guanine, and cytosine). The optimized geometries, binding energies, and harmonic vibrational frequencies are calculated using the DFT/B3LYP functional combined with the 6–31+G(d,p) basis set. Their interactions are studied aiming to understand more about the nature of the intercalation binding forces between urea and DNA. Fourteen stable complexes are found on the potential energy surface. The structures are cyclic; they are stabilized by NH...O/N and CH...O interactions. The binding energies range from −19.9 kJ·mol⁻¹ to −74.0 kJ·mol⁻¹. The obtained formation energies indicate that Urea:G and Urea:C are more favorable than Urea:T and Urea:A. In addition, the Atoms in Molecules theory is performed to study the hydrogen bonds in the complexes.     

无溶剂合成1,3,5-三芳基-2-芳酰基环己醇衍生物和晶体结构

在NaOH存在下室温研磨查尔酮与丙二腈,可以有效地得到1,3,5-三芳基-2-芳酰基环己醇衍生物,本合成方法反应时间短、操作简单、产率高,符合绿色化学特点.产物结构经过红外、核磁、元素分析和高分辨质谱确证,并对3b做了单晶衍射测定.     

On <Emphasis Type="Italic">s</Emphasis>-Elementary Super Frame Wavelets and Their Path-Connectedness

A super wavelet of length n is an n-tuple (ψ ₁,ψ ₂,…,ψ _n ) in the product space \(\prod_{j=1}^{n} L^{2}(\mathbb{R})\), such that the coordinated dilates of all its coordinated translates form an orthonormal basis for \(\prod_{j=1}^{n} L^{2} (\mathbb{R})\). This concept is generalized to the so-called super frame wavelets, super tight frame wavelets and super normalized tight frame wavelets (or super Parseval frame wavelets), namely an n-tuple (η ₁,η ₂,…,η _n ) in \(\prod_{j=1}^{n}L^{2} (\mathbb{R})\) such that the coordinated dilates of all its coordinated translates form a frame, a tight frame, or a normalized tight frame for \(\prod_{j=1}^{n} L^{2}(\mathbb{R})\). In this paper, we study the super frame wavelets and the super tight frame wavelets whose Fourier transforms are defined by set theoretical functions (called s-elementary frame wavelets). An m-tuple of sets (E ₁,E ₂,…,E _m ) is said to be τ-disjoint if the E _j ’s are pair-wise disjoint under the 2π-translations. We prove that a τ-disjoint m-tuple (E ₁,E ₂,…,E _m ) of frame sets (i.e., η _j defined by \(\widehat{\eta_{j}}=\frac{1}{\sqrt{2\pi}}\chi_{E_{j}}\) is a frame wavelet for L ²(?) for each j) lead to a super frame wavelet (η ₁,η ₂,…,η _m ) for \(\prod_{j=1}^{m} L^{2} (\mathbb{R})\) where \(\widehat{\eta_{j}}=\frac{1}{\sqrt{2\pi}}\chi_{E_{j}}\). In the case of super tight frame wavelets, we prove that (η ₁,η ₂,…,η _m ), defined by \(\widehat{\eta_{j}}=\frac{1}{\sqrt{2\pi}}\chi_{E_{j}}\), is a super tight frame wavelet for ∏_1≤j≤m L ²(?) with frame bound k ₀ if and only if each η _j is a tight frame wavelet for L ²(?) with frame bound k ₀ and that (E ₁,E ₂,…,E _m ) is τ-disjoint. Denote the set of all τ-disjoint s-elementary super frame wavelets for ∏_1≤j≤m L ²(?) by \(\mathfrak{S}(m)\) and the set of all s-elementary super tight frame wavelets (with the same frame bound k ₀) for ∏_1≤j≤m L ²(?) by \(\mathfrak{S}^{k_{0}}(m)\). We further prove that \(\mathfrak{S}(m)\) and \(\mathfrak{S}^{k_{0}}(m)\) are both path-connected under the ∏_1≤j≤m L ²(?) norm, for any given positive integers m and k ₀.     

Optical and electrical properties of porous silicon layer formed on the textured surface by electrochemical etching

Porous silicon(PS) layers were formed on textured crystalline silicon by electrochemical etching in HF-based electrolyte.Optical and electrical properties of the TMAH textured surfaces with PS formation are studied. Moreover,the influences of the initial structures and the anodizing time on the optical and electrical properties of the surfaces after PS formation are investigated.The results show that the TMAH textured surfaces with PS formation present a dramatic decrease in reflectance.The longer the anodizing time is,the lower the reflectance.Moreover,an initial surface with bigger pyramids achieved lower reflectance in a short wavelength range.A minimum reflectance of 3.86%at 460 nm is achieved for a short anodizing time of 2 min.Furthermore,the reflectance spectrum of the sample,which was etched in 3 vol.%TMAH for 25 min and then anodized for 20 min,is extremely flat and lies between 3.67%and 6.15%in the wavelength range from 400 to 1040 nm.In addition,for a short anodizing time,a slight increase in the effective carrier lifetime is observed.Our results indicate that PS layers formed on a TMAH textured surface for a short anodization treatment can be used as both broadband antireflection coatings and passivation layers for the application in solar cells.     

一款应用于生物传感器的1.2V-600nW 12bit 2kS/s的增量型模数转换器

This paper presents an ultra-low power incremental ADC for biosensor interface circuits.The ADC consists of a resettable second-order delta–sigma(°/ modulator core and a resettable decimation filter.Several techniques are adopted to minimize its power consumption.A feedforward path is introduced to the modulator core to relax the signal swing and linearity requirement of the integrators.A correlated-double-sampling(CDS)technique is applied to reject the offset and 1/f noise,thereby removing the integrator leakage and relaxing the gain requirement of the OTA.A simple double-tailed inverter-based fully differential OTA using a thick-oxide CMOS is proposed to operate in the subthreshold region to fulfill both an ultra-low power and a large output swing at 1.2 V supply.The signal addition before the comparator in the feedforward architecture is performed in the current domain instead of the voltage domain to minimize the capacitive load to the integrators.The capacitors used in this design are of customized metal–oxide–metal(MOM) type to reach the minimum capacitance set by the k T =C noise limit.Fabricated with a 1P6 M 0.18 m CMOS technology,the presented incremental ADC consumes600 n W at 2 k S/s from a 1.2 V supply,and achieves 68.3 d B signal to noise and distortion ratio(SNDR) at the Nyquist frequency and an FOM of 0.14 p J/conversion step.The core area is 100120 m2.     

重组家蚕核多角体病毒（rBmNPV）的复制及所载HuIFN－α基因的表达

报道了重组家蚕核多角体病毒（ＢｏｍｂｙｘｍｏｒｉｎｕｃｌｅａｒＰｏｌｙｈｅｄｒｏｓｉｓＶｉｒｕｓＢｍＮＰＶ）在家蚕细胞ＢｍＮ中复制的细胞病理学变化，除了不形成多角体以外，与野生型病毒相同．研究了病毒感染复数、细胞接种密度和细胞生长阶段对重组病毒复制和α－干扰素（ＩＦＮ－α）表达量的影响．在一定低感染复数时，α－干扰素的产量较高．对于重组病毒的复制，最适的细胞接种密度为３．６～７．０×１０５细胞／瓶．在细胞指数生长前期（４８～６０ｈ）接种重组病毒，对于获得较高的重组病毒复制效价和α－干扰素的产量都是有利的．