一种基于三角数分解的可配置2-D卷积器优化方法

多尺寸2-D卷积通过特征提取在检测、分类等计算机视觉任务中发挥着重要作用。然而,目前缺少一种高效的可配置2-D卷积器设计方法,这限制了卷积神经网络(CNN)模型在边缘端的部署和应用。该文基于乘法管理以及奇平方数的三角数分解方法,提出一种高性能、高适应性的卷积核尺寸可配置的2-D卷积器。所提2-D卷积器包含一定数量的处理单元(PE)以及相应的控制单元,前者负责运算任务,后者负责管理乘法运算的组合,二者结合以实现不同尺寸的卷积。具体地,首先根据应用场景确定一个奇数列表,列表中为2-D卷积器所支持的尺寸,并利用三角数分解得到对应的三角数列表;其次,根据三角数列表和计算需求,确定PE的总数量;最后,基于以小凑大的方法,确定PE的互连方式,完成电路设计。该可配置2-D卷积器通过Verilog硬件描述语言(HDL)设计实现,由Vivado 2 022.2在XCZU7EG板卡上进行仿真和分析。实验结果表明,相比同类方法,该文所提可配置2-D卷积器,乘法资源利用率得到显著提升,由20%~50%提升至89%,并以514个逻辑单元实现1 500 MB/s的吞吐率,具有广泛的适用性。

基于离散2-D小波多级分解的电容器外观缺陷视觉检测方法

电容器外观破损、凸起等缺陷直接影响器件的生产质量。目前电容器微小外观缺陷检测难度较大,导致视觉检测效率较低。为此提出了基于离散2-D小波多层分解的电容器外观缺陷视觉检测方法。采用同态滤波处理去除光照对电容器外观视觉检测结果的影响。利用像素点灰度值确定图像边缘点位置,提取电容器外观缺陷区域。应用离散2-D小波分解的方法对其展开多级分解。再差分统计电容器图像的外观缺陷纹理特征。将特征输入Mahalanobis分类器中,完成电容器外观缺陷视觉检测。仿真结果表明,所提方法可以较好检测电容的各种缺陷,召回率最低值是94.9%,误检率最高值为9.8%,漏检率均在10%以内,电容器缺陷检测效果较好。

基于二萘并[2,3-B∶2′,3′-D]呋喃基团的高效窄发射蓝光OLED器件

高效率窄光谱蓝色有机电致发光器件(OLED)是柔性显示领域的研究重点之一。本文以二萘并[2,3-B∶2′,3′-D]呋喃为弱电子受体、N-(4-联苯基)-1-萘胺作为电子给体设计合成了一种D-A-D型蓝光分子DPF-NA,其在正己烷溶液中的发射峰位于441 nm。理论计算与光物理测试结果显示DPF-NA具有杂化局域电荷转移激发态(HLCT)特性,兼具局域态(LE)高发光效率与电荷转移态(CT)高激子利用率特征,在二氯甲烷溶液中的光致发光量子效率(PLQY)为81.2%。基于质量分数3%DPF-NA掺杂浓度的OLED器件电致发光(EL)峰位于455 nm,半峰宽(FWHM)仅为26 nm,CIE(x,y)坐标为(0.14,0.08),最大外量子效率(EQEmax)为6.76%。

New 4-imino-4H-Chromeno[2,3-d]Pyrimidin-3(5H)-Amine: Synthesis, Cytotoxic Effects on Tumoral Cell Lines and in Silico ADMET Properties

The synthesis of new 4-imino-4H-chromeno[2,3-d]pyrimidin-3(5H)-amine in four steps including one step under microwave dielectric heating is reported. The structural identity of the synthesized compounds was established according to their spectroscopic analysis, such as FT-IR, NMR and mass spectroscopy. These new compounds were tested for their antiproliferative activities on seven representative human tumoral cell lines (Huh7 D12, Caco2, MDA-MB231, MDA-MB468, HCT116, PC3 and MCF7) and also on fibroblasts. Among them, only the compounds 6c showed micromolar cytotoxic activity on tumor cell lines (1.8 50 50 > 25 μM). Finally, in silico ADMET studies ware performed to investigate the possibility of using of the identified compound 6c as potential anti-tumor compound.

2-D Modeling and Calculations of Stratospheric Ozone and Influences of Convection, Diffusion, and Time

An engineering system approach of 2-D cylindrical model of transient mass balance calculations of ozone and other concerned chemicals along with fourteen photolysis, ozone-generating and ozone-depleting chemical reaction equations was developed, validated, and used for studying the ozone concentrations, distribution and peak of the layer, ozone depletion and total ozone abundance in the stratosphere. The calculated ozone concentrations and profile at both the Equator and a 60˚N location were found to follow closely with the measured data. The calculated average ozone concentration was within 1% of the measured average, and the deviation of ozone profiles was within 14%. The monthly evolution of stratospheric ozone concentrations and distribution above the Equator was studied with results discussed in details. The influences of slow air movement in both altitudinal and radial directions on ozone concentrations and profile in the stratosphere were explored and discussed. Parametric studies of the influences of gas diffusivities of ozone DO3 and active atomic oxygen DO on ozone concentrations and distributions were also studied and delineated. Having both influences through physical diffusion and chemical reactions, the diffusivity (and diffusion) of atomic oxygen DO was found to be more sensitive and important than that of ozone DO3 on ozone concentrations and distribution. The 2-D ozone model present in this paper for stratospheric ozone and its layer and depletion is shown to be robust, convenient, efficient, and executable for analyzing the complex ozone phenomena in the stratosphere. .

设计改造羧酸还原酶合成医药中间体(S)-2-氨基丁醇

(S)-2-氨基丁醇同时具有羟基及氨基官能团,是多种重要药物分子的关键手性中间体,生物合成(S)-2-氨基丁醇尚缺少有效的酶元件。以塞格尼氏菌(Segniliparus rugosus)来源的羧酸还原酶SrCAR为研究对象,通过对实验室已有SrCAR突变文库进行筛选测试,结合活性位点共进化分析,同时利用组合活性中心饱和突变策略(Combinatorial active-site saturation test,CAST)构建新的突变体文库,经测试最终获得优势突变体XH7(G430V/E533F/A627N)。该突变体催化底物N-Boc-(S)-2-氨基丁酸到醛产物的活性(kcat/Km)较野生型SrCAR提高2.1倍,热熔值(Tm)提升2.3℃。进一步通过引入荧光假单胞菌(Pseudomonas fluorescens)来源的醇脱氢酶PfADH,可还原N-Boc-(S)-2-氨基丁醛到醇产物。XH7和PfADH的双酶共表达体系反应5 h即可将20 mmol/L底物实现几乎完全转化,转化率达到99%,并经脱Boc保护与分离纯化获得终产物(S)-2-氨基丁醇,得率为60%。通过分子动力学模拟解析最优突变体活性及热稳定性提高的分子机制,为SrCAR酶设计改造提供新的研究思路,拓展酶法合成(S)-2氨基丁醇的生物酶工具箱,可为类似高附加值医药中间体的生物合成提供理论和实践指导。

Selective arylation/annulation cascade reactions of 2-alkynylanilines with diaryliodonium salts

An efficient Cu catalyzed selective arylation/annulation cascade reaction of 2-alkynylanilines with diaryliodonium salts was developed.This reaction was selective to N-arylation instead of C-arylation,which provides a simple synthetic method for N-aryl indoles.

一种高速2-D滑动FFT的设计实现

文章介绍了采用2-D快速傅里叶变换(fast Fourier transform,FFT)算法的滑动窗FFT的基本特性原理和硬件实现过程,完成了窗长256点、步长16点的2-D滑动窗FFT的专用集成电路(application specific integrated circuit,ASIC)设计。传统FFT算法受序列完整性的制约,时滞较大,无法满足某些高实时性信号分析领域的处理速度要求。该文采用滑动FFT算法,克服了传统FFT对序列完整性的依赖,设计的滑动FFT处理器使用2-D FFT压缩新序列计算时间,以基16蝶形运算器为核心,采用系数复用和高基Booth方法优化系数编码技术压缩乘法器的数量,减少电路面积。所设计的2-D滑动FFT完成单次滑动窗长的计算时间比传统算法节约了16.1%,变换结果与MATLAB的运算结果相比,信噪比(signal-to-noise ratio,SNR)大于130 dB。在TSMC 28 nm的工艺下,工作主频为600 MHz,面积为1980μm×2060μm。

2-D distributed pose estimation of multi-agent systems using bearing measurements

This article studies distributed pose(orientation and position)estimation of leader–follower multi-agent systems over𝜅-layer graphs in 2-D plane.Only the leaders have access to their orientations and positions,while the followers can measure the relative bearings or(angular and linear)velocities in their unknown local coordinate frames.For the orientation estimation,the local relative bearings are used to obtain the relative orientations among the agents,based on which a distributed orientation estimation algorithm is proposed for each follower to estimate its orientation.For the position estimation,the local relative bearings are used to obtain the position constraints among the agents,and a distributed position estimation algorithm is proposed for each follower to estimate its position by solving its position constraints.Both the orientation and position estimation errors converge to zero asymptotically.A simulation example is given to verify the theoretical results.

具有执行器饱和的切换2-D系统事件触发控制

针对具有执行器饱和的切换2-D连续离散系统,提出了一种基于多Lyapunov函数法的事件触发控制方案;为了减少通信资源浪费和执行器的损耗,提出了一种事件触发机制;该触发机制考虑了执行器饱和特性,只有当执行器未饱和,且满足事件触发条件时,控制器才会更新;利用凸组合技术和多Lyapunov函数法,提出了一种状态依赖的切换信号与状态反馈控制器的设计方法,并对闭环系统的指数稳定性进行了分析,利用线性矩阵不等式技术导出了控制器增益矩阵存在的充分条件;利用Darboux方程的仿真算例验证了所提出的事件触发控制方案的有效性,仿真结果表明了在所设计的控制方案下,闭环系统的状态是指数收敛的,同时还能减少通信资源的浪费。

Mn对Ru/SiO_(2)催化2,5-己二酮与伯胺合成N-取代-2,5-二甲基吡咯烷的促进作用

采用共浸渍法制备了Mn掺杂的Ru/SiO_(2)催化剂,将其用于2,5-己二酮与伯胺经Paal-Knorr/加氢级联反应合成N-取代-2,5-二甲基吡咯烷,利用XRD,TEM,NH3-TPD,XPS等方法探究了Mn对催化剂结构和性质的影响,并考察了催化剂的稳定性与适用性。实验结果表明,Mn掺杂可提高催化剂中Ru纳米粒子的分散度和催化剂的酸性位,进而提高催化剂的性能。当Ru/Mn摩尔比为1∶2时,催化剂的催化活性最高,在H2O溶剂中130℃、氢气压力3 MPa下反应90 min,2,5-己二酮转化率和N-丁基-2,5-二甲基吡咯烷的收率均达到100%。催化剂重复使用9次后仍保持高活性,且催化剂具有良好的普适性,为N-取代吡咯烷类化合物的绿色合成提供了一种新思路。

In silico evidence of Remdesivir action in blood coagulation cascade modulation in COVID-19 treatment

BACKGROUND Coronavirus disease 2019(COVID-19)has demonstrated several clinical manifestations which include not only respiratory system issues but also liver,kidney,and other organ injuries.One of these abnormalities is coagulopathies,including thrombosis and disseminated intravascular coagulation.Because of this,the administration of low molecular weight heparin is required for patients that need to be hospitalized.In addition,Remdesivir is an antiviral that was used against Middle East Acute Respiratory Syndrome,Ebola,Acute Respiratory Syndrome,and other diseases,showing satisfactory results on recovery.Besides,there is evidence suggesting that this medication can provide a better prognosis for patients with COVID-19.AIM To investigate in silico the interaction between Remdesivir and clotting factors,pursuing a possibility of using it as medicine.METHODS In this in silico study,the 3D structures of angiotensin-converting enzyme 2(ACE2),Factor I(fibrinogen),Factor II(prothrombin),Factor III(thromboplastin),Factor V(proaccelerin),Factor VII(proconvertin),Factor VIII(antihemophilic factor A),Factor IX(antihemophilic factor B),Factor X(Stuart-Prower factor),and Factor XI(precursor of thromboplastin(these structures are technically called receptors)were selected from the Protein Data Bank.The structures of the antivirals Remdesivir and Osetalmivir(these structures are called ligands)were selected from the PubChem database,while the structure of Atazanavir was selected from the ZINC database.The software AutoDock Tools(ADT)was used to prepare the receptors for molecular docking.Ions,peptides,water molecules,and other ones were removed from each ligand,and then,hydrogen atoms were added to the structures.The grid box was delimited and calculated using the same software ADT.A physiological environment with pH 7.4 is needed to make the ligands interact with the receptors,and still the software Marvin sketch®(ChemAxon®)was used to forecast the protonation state.To perform molecular docking,ADT and Vina software was connected.Using PyMol®software and Discovery studio®software from BIOVIA,it was possible to analyze the amino acid residues from receptors that were involved in the interactions with the ligands.Ligand tortions,atoms that participated in the interactions,and the type,strength,and duration of the interactions were also analyzed using those software.RESULTS Molecular docking analysis showed that Remdesivir and ACE2 had an affinity energy of-8.8 kcal/moL,forming a complex with eight hydrogen bonds involving seven atoms of Remdesivir and five amino acid residues of ACE2.Remdesivir and prothrombin had an interaction with six hydrogen bonds involving atoms of the drug and five amino acid residues of the clotting factor.Similar to that,Remdesivir and thromboplastin presented interactions via seven hydrogen bonds involving five atoms of the drug and four residues of the clotting factor.While Remdesivir and Factor V established a complex with seven hydrogen bonds between six antiviral atoms and six amino acid residues from the factor,and Factor VII connected with the drug by four hydrogen bonds,which involved three atoms of the drug and three residues of amino acids of the factor.The complex between Remdesivir and Factor IX formed an interaction via 11 hydrophilic bonds with seven atoms of the drug and seven residues of the clotting factor,plus one electrostatic bond and three hydrophobic interactions.Factor X and Remdesivir had an affinity energy of-9.6 kcal/moL,and the complex presented 10 hydrogen bonds and 14 different hydrophobic interactions which involved nine atoms of the drug and 16 amino acid residues of the clotting factor.The interaction between Remdesivir and Factor XI formed five hydrogen bonds involving five amino acid residues of the clotting factor and five of the antiviral atoms.CONCLUSION Because of the in silico significant affinity,Remdesivir possibly could act in the severe acute respiratory syndrome coronavirus 2 infection blockade by interacting with ACE2 and concomitantly act in the modulation of the coagulation cascade preventing the hypercoagulable state.

“探究2,4-D对插枝生根的作用”实验中因变量的确定

“探究2,4-D对插枝生根的作用”是浙科版高中生物学教材选择性必修1教材中的重要实验,实践中一些师生对该实验中的因变量常有疑惑,本文选择常见的碰碰香作为实验材料展开探究。发现2,4-D浓度在2.5×10-4—2.5×10-14g/L浓度范围内,对根的平均长度和根的总长度作用差异不明显,但是对根的数量有显著的差异。该探究可为师生提供一定的参考。

Self-separation ionic liquid catalyst for the highly effective conversion of H_(2)S by α,β-unsaturated carboxylate esters under mild conditions

The deep-processing utility of pure hydrogen sulfide (H_(2)S) is a significant direction in natural gas chemical industry.Herein,a brand-new strategy of H_(2)S conversion by a,β-unsaturated carboxylate esters into thiols or thioethers using task-specific carboxylate ionic liquids (ILs) as catalyst has been developed,firstly accomplishing the phase separation of product and catalyst without introducing the third component.It can be considered as a cascade reaction in which the product selectivity can be controlled by adjusting the molar ratio of H_(2)S to a,β-unsaturated carboxylate esters.Also,the effects of ILs with different anions and cations,intermittent feeding operations,as well as pressure-time kinetic behaviors on cascade reaction were investigated.Furthermore,the proposed interaction mechanism of H_(2)S conversion using butyl acrylate catalyzed by[Emim][Ac]was revealed by DFT-based theoretical calculation.The approach enables the self-phase separation promotion of catalyst and product and achieves 99%quantitative conversion under mild conditions in the absence of solvent,making the entire process ecologically benign.High-efficiency reaction activity can still be maintained after ten cycles of the catalyst.Therefore,the good results,combined with its simplicity of operation and the high recyclability of the catalyst,make this green method environmentally friendly and cost-effective.It is anticipated that this self-separation method mediated by task-specific ILs will provide a feasible strategy for H_(2)S utilization,which will guide its application on an industrial scale.

Sustainable synthesis of high-density fuel via catalytic cascade cycloaddition reaction

The access to high-density hydrocarbon fuels from biomass for the reduction of dependence on fossil resources has been a research highlight in recent years. It is well known that cycloalkanes are the components of fuels with higher energy density than straight or branched alkanes. Herein, we developed a new catalytic pattern to synthesize dimethyltetradecahydroanthracenes(DMTHA), a kind of tricyclic alkane, from biomass-derived isoprene and p-benzoquinone via a cascade Diels-Alder reaction followed by a hydrodeoxygenation reaction. Vanadium supported on titanium dioxide(V-TiO_(2)) was applied to catalyze the cascade Diels-Alder reaction and it was disclosed that V with appropriate V^(4+)/V^(5+) ratio on the surface of TiO_(2) could activate quinones. Experimental tests showed that the heating value of final products was up to 45.7 MJ/kg. The development of new high-density fuel molecules is a long-term trend for the future renewable and sustainable fuel energy application.

Calculations and Sensitivity Analysis of Chlorine-,NO_(x)-,and Bromine-Depleting Cycles of Stratospheric Ozone

This paper presents an engineering system approach using a 2D model of conservation of mass to study the dynamics of ozone and concerned chemical species in the stratosphere.By considering all fourteen photolysis,ozone-generating,and-depleting chemical reactions,the model calculated the transient,spatial changes of ozone under different physical-chemical-radiative conditions.Validation against the measured data demonstrated good accuracy,close match of our model with the observed ozone concentrations at both 20°S and 90°N locations.The deviation in the average concentration was less than 1% and in ozone profiles less than 17%.The impacts of various chlorine-(Cl),nitrogen oxides-(NO_(x)),and bromine-(Br)depleting cycles on ozone concentrations and distribution were investigated.The chlorine catalytic depleting cycle was found to exhibit the most significant impact on ozone dynamics,confirming the key role of chlorine in the problem of ozone depletion.Sensitivity analysis was conducted with levels of 25%,50%,100%,200%,and 400% of the baseline value.The combined cycles(Cl+NO_(x)+Br)showed the most significant influence on ozone behavior.The total ozone abundance above the South Pole could decrease by a small 3%,from 281 DU(Dubson Units)to 273 DU for the 25% level,or by a huge thinning of 60%to 114 DU for the 400% concentration level.When the level of chlorine gases increased beyond 200%,it would cause ozone depletion to a level of ozone hole(below 220 DU).The 2D Ozone Model presented in this paper demonstrates robustness,convenience,efficiency,and executability for analyzing complex ozone phenomena in the stratosphere.

Molecular dynamics simulations of cascade damage near the Y_2Ti_2O_7 nanocluster/ferrite interface in nanostructured ferritic alloys

A comparative study of cascades in nanostructured ferritic alloys and pure Fe is performed to reveal the influence of Y_2Ti_2O_7 nanocluster on cascades by molecular dynamics simulations. The cascades with energies of primary knock-on atom（PKA） ranging from 0.5 keV to 4.0 keV and PKA＇s distances to the interface from 0 to 50 are simulated. It turns out that the Y_2Ti_2O_7 nanocluster can absorb the kinetic energy of cascade atoms, prevent the cascade from extending and reduce the defect production significantly when the cascades overlap with the nanocluster. When the cascade affects seriously the nanocluster, the weak sub-cascade collisions are rebounded by the nanocluster and thus leave more interstitials in the matrix. On the contrary, when the cascade contacts weakly the nanocluster, the interface can pin the arrived interstitials and this leaves more vacancies in the matrix. Moreover, the results indicate that the Y_2Ti_2O_7 nanocluster keeps stable upon the displacement cascade damage.

Thermodynamic Analysis and Comparison on Low Temperature CO_2-NH_3 Cascade Refrigeration Cycle

This paper is focused on the cascade refrigeration cycle using natural refrigerant CO 2-NH 3. The properties of refrigerants CO 2 and NH 3 are introduced and analyzed.CO 2 has the advantage in low stage of cascade refrigeration cycle due to its good characteristics and properties. The thermodynamic analysis results of the CO 2-NH 3 cascade refrigeration cycle demonstrates that the cycle has an optimum condensation temperature of low stage and also has an optimum flow rate ratio.By comparing with the R13-R22 and NH 3-NH 3 cascade refrigeration cycles, the mass flow rate ratio of CO 2-NH 3 is larger than those of R13-R22 and NH 3-NH 3, the theoretical COP of CO 2-NH 3 cascade refrigeration cycle is larger than that of the R13-R22 cascade cycle and smaller than that of the NH 3-NH 3 cascade cycle. But the real COP of CO 2-NH 3 cascade cycle will be higher than those of R13-R22 and NH 3-NH 3 because the specific volume of CO 2 at low temperature does not change much and its dynamic viscosity is also small.

Atmospheric N2O gas detection based on an inter-band cascade laser around 3.939 μm

N2O is a significant atmospheric greenhouse gas that contributes to global warming and climate change.In this work,the high sensitivity detection of atmospheric N2O is achieved using wavelength modulation spectroscopy(WMS)with an inter-band cascade laser operating around 3.939μm.A Lab VIEW-based software signal generator and software lock-in amplifiers are designed to simplify the system.In order to eliminate the interference from water vapor,the detection was performed at a pressure of 0.1 atm(1 atm=1.01325×10^5 Pa)and a drying tube was added to the system.To improve the system performance for long term detection,a novel frequency locking method and 2 f/1 f calibration-free method were employed to lock the laser frequency and calibrate the power fluctuations,respectively.The Allan deviation analysis of the results indicates a detection limit of^20 ppb(1 ppb=1.81205μg/m3)for a 1 s integration time,and the optimal detection limit is^5 ppb for a 40-s integration time.

2,4-D丁酯对轮叶马先蒿的防除效果及对草地植被的影响

为有效灭除草地害草轮叶马先蒿,采用2,4-D丁酯在巴音布鲁克高寒草地进行了不同时期不同剂量化学防除试验。结果表明,防除轮叶马先蒿的最佳时期为盛花期;最佳药品用量是0.066 mL/m2;喷施2,4-D丁酯后,草地植被生态环境得到明显改善,轮叶马先蒿被部分或完全灭除,优良牧草垂穗披碱草在草地群落中占据优势地位,同时杂类草新疆假龙胆受到一定的抑制,草地质量明显提高。