耦合甘油高选择性转化为甲酸盐与制氢的酸碱双电解液流动电解器

氢气因其高能量密度、可持续性和燃烧后无污染等优点,被认为是取代传统化石燃料的最具前途的新兴能源载体之一。其中,电解水制氢技术因为其高效和绿色的特性而备受关注。然而电解水制氢过程通常受到阳极析氧反应(Oxygen Evolution Reaction,OER)的限制,因此这种方法的大规模应用面临重大挑战。克服这一难题的一个有前途的解决方法是在阳极上使用电催化甘油氧化反应(Glycerol Oxidation Reaction,GOR)代替OER,这种替代反应可以实现节能降耗的同时提高电解水制氢的效率,进一步推动氢气作为清洁能源的发展。然而,这一目标的实现需要高效、低成本且高选择性的GOR电催化剂。在这篇文章中,我们报告了一种新型的酸碱双电解质流电解器(AADEF-electrolyzer),用于在碱性阳极GOR耦合酸性阴极析氢反应(Hydrogen Evolution Reaction,HER)。我们通过一种简单的水热煅烧方法制备了一种在镍泡沫(NF)上原位生长的自支撑的NiCo_(2)O_(4)纳米针电极材料(NiCo_(2)O_(4)/NF)。该电极在GOR中表现出优异的电催化性能,在低电位下实现了高的电解电流密度,对甲酸盐的生产表现出优异的选择性,法拉第效率超过85%。密度泛函理论计算表明,NiCo_(2)O_(4)对GOR具有较低的反应能垒,Ni的存在有利于降低Co的电子态密度,从而实现NiCo_(2)O_(4)与中间体的高效解离,促进甲酸的生成。基于NiCo_(2)O_(4)/NF出色的GOR性能和电化学中和能(ENE)理论,我们构建了一个新型的AADEF-electrolyzer,利用NiCo_(2)O_(4)/NF作为GOR的阳极,配合酸性阴极进行析氢反应(HER)。实验结果表明,AADEF-electrolyzer对GOR具有低过电位和高选择性产甲酸的优异性能,仅需0.36 V的电压即可实现10 mA·cm^(-2)的电流密度,平均产甲酸的法拉第效率为85%。同时该电解槽表现出良好的长期稳定性和辅助产氢性能,阴极产氢的法拉第效率接近100%。这种低成本、易于制备的自支撑电极材料和新型酸碱双电解质流动电解器为促进化学品的增值转化和开发新型混合电解系统或其他相关电化学反应的混合电解装置提供了创新策略。

Deep Learning-Based Secure Transmission Strategy with Sensor-Transmission-Computing Linkage for Power Internet of Things

The automatic collection of power grid situation information, along with real-time multimedia interaction between the front and back ends during the accident handling process, has generated a massive amount of power grid data. While wireless communication offers a convenient channel for grid terminal access and data transmission, it is important to note that the bandwidth of wireless communication is limited. Additionally, the broadcast nature of wireless transmission raises concerns about the potential for unauthorized eavesdropping during data transmission. To address these challenges and achieve reliable, secure, and real-time transmission of power grid data, an intelligent security transmission strategy with sensor-transmission-computing linkage is proposed in this paper. The primary objective of this strategy is to maximize the confidentiality capacity of the system. To tackle this, an optimization problem is formulated, taking into consideration interruption probability and interception probability as constraints. To efficiently solve this optimization problem, a low-complexity algorithm rooted in deep reinforcement learning is designed, which aims to derive a suboptimal solution for the problem at hand. Ultimately, through simulation results, the validity of the proposed strategy in guaranteed communication security, stability, and timeliness is substantiated. The results confirm that the proposed intelligent security transmission strategy significantly contributes to the safeguarding of communication integrity, system stability, and timely data delivery.

Preparation of palladium-based catalyst by plasma-assisted atomic layer deposition and its applications in CO_(2) hydrogenation reduction

Supported Pd catalyst is an important noble metal material in recent years due to its high catalytic performance in CO_(2)hydrogenation.A fluidized-bed plasma assisted atomic layer deposition(FP-ALD) process is reported to fabricate Pd nanoparticle catalyst over γ-Al_(2)O_(3)or Fe_(2)O_(3)/γ-Al_(2)O_(3)support,using palladium hexafluoroacetylacetonate as the Pd precursor and H_(2)plasma as counter-reactant.Scanning transmission electron microscopy exhibits that highdensity Pd nanoparticles are uniformly dispersed over Fe_(2)O_(3)/γ-Al_(2)O_(3)support with an average diameter of 4.4 nm.The deposited Pd-Fe_(2)O_(3)/γ-Al_(2)O_(3)shows excellent catalytic performance for CO_(2)hydrogenation in a dielectric barrier discharge reactor.Under a typical condition of H_(2)to CO_(2)ratio of 4 in the feed gas,the discharge power of 19.6 W,and gas hourly space velocity of10000 h^(-1),the conversion of CO_(2)is as high as 16.3% with CH_(3)OH and CH4selectivities of 26.5%and 3.9%,respectively.

Analysis of the Heavy Rainfall Process in Mangshi City on August 8, 2023

On August 7,2023,Mangshi City,Dehong Prefecture experienced a local heavy rainstorm,and the geological disaster caused by the heavy rainfall caused casualties and property losses.Based on the real-time observation data of automatic stations,Doppler weather radar detection and meteorological risk warning products,the disaster situation,social impact,forecast and early warning service,causes of heavy precipitation and forecast and early warning inspection were summarized and analyzed.The results show that the heavy rainfall was prominent locally,lasted for a long time and accumulated a large amount of rainfall.There were biases in model products,and it was difficult for forecasters to make subjective corrections in complex terrain.The analysis ideas and focus points of heavy rainfall forecast,the improvement ideas and technical schemes of forecast deviation,and the improvement ideas and suggestions of services were summarized.It provides a reference for the forecast and early warning of severe weather in the future.

On an Invariant of Tournament Digraphs

To date, it is unknown whether it is possible to construct a complete graph invariant in polynomial time, so fast algorithms for checking non-isomorphism are important, including heuristic algorithms, and for successful implementations of such heuristics, both the tasks of some modification of previously described graph invariants and the description of new invariants remain relevant. Many of the described invariants make it possible to distinguish a larger number of graphs in the real time of a computer program. In this paper, we propose an invariant for a special kind of directed graphs, namely, for tournaments. The last ones, from our point of view, are interesting because when fixing the order of vertices, the number of different tournaments is exactly equal to the number of undirected graphs, also with fixing the order of vertices. In the invariant we are considering, all possible tournaments consisting of a subset of vertices of a given digraph with the same set of arcs are iterated over. For such subset tournaments, the places are calculated in the usual way, which are summed up to obtain the final values of the points of the vertices;these points form the proposed invariant. As we expected, calculations of the new invariant showed that it does not coincide with the most natural invariant for tournaments, in which the number of points is calculated for each participant. So far, we have conducted a small number of computational experiments, and the minimum value of the pair correlation between the sequences representing these two invariants that we found is for dimension 15.

Influence of the Randomness of Longitudinal Resistance of Ballast Bed on Track-Bridge Interaction

To get the influence of the randomness of longitudinal resistance of ballast bed (LRBB) on track-bridge interaction, the statistical law of LRBB was studied with existing test data and the Shapiro-Wilk test. Based on the principle of track-bridge interaction, a rail-sleeper-bridge-pier integrated simulation model that could consider the randomness of LRBB was established. Taking a continuous beam bridge for the heavy-haul railway as an example, the effect of the randomness of LRBB on the mechanical behavior of continuous welded rail (CWR) on bridges under typical conditions was carefully examined with a random sampling method and the simulation model. The results show that the LRBB corresponding sleeper displacement of 2 mm obeys a normal distribution. When the randomness of LRBB is considered, the amplitudes of rail expansion force, rail bending force, rail braking force and rail broken gap all follow normal distribution. As the standard deviations of the four indexes are small, which indicates the randomness of LRBB has little effect on track-bridge interaction. The distributions of the four indexes make it possible to design CWR on bridges with the limit state method.

MOF/CdS梯型光催化剂同时进行苯甲醇氧化和析氢反应及其机理研究

太阳能驱动的光催化水分解制氢是一种清洁、可持续的技术,可以减少碳排放.一般来说,光催化全解水的析氧半反应过程需要消耗四个空穴,且迟缓的反应动力学会抑制整体反应,因此光催化全解水极具挑战性.在光催化制氢中通常利用空穴牺牲剂来提升产氢半反应的效率.然而,这些过程会产生无用的氧化产物,造成光生空穴氧化能力的浪费,且增加了系统成本.因此,构建一个由光催化产氢和选择性有机合成相结合的双功能氧化还原体系,可同时利用光生电子和空穴,并且产物中氢气和高附加值的有机产品容易分离,因此具有较高的可持续经济效应.利用梯型异质结将两种带隙适合且能带结构匹配的光催化剂复合在一起,可以最大程度地利用两种光催化剂的氧化还原能力,为解决上述问题提供了一条理想途径.本文采用化学浴法将CdS纳米颗粒原位生长在锆基金属有机框架UiO-66-NH_(2)(U6N)上.在光照条件下,梯型异质结催化苯甲醇选择性氧化生成苯甲醛和氢气的性能大幅度提升,UC0.75(U6N/CdS理论质量比为0.75)复合物光照3 h产氢速率为630μmol·g^(-1)h^(-1),同时苯甲醇氧化为苯甲醛的选择性达到99%.原位辐照X射线光电子能谱结果表明,UC0.75梯型异质结界面的电子转移路径,在暗态下电子由CdS转移到U6N,在光照下电子由U6N转移到CdS.利用飞秒瞬态吸收(fs-TA)光谱进一步研究了异质结的载流子迁移的动力学信息,结果表明,复合样品中基态漂白信号衰减时间减少,梯型异质结界面处电子转移效率较高.此外,通过原位漫反射红外傅里叶变换光谱、电子顺磁共振和同位素实验揭示了苯甲醇的氧化机理,光照下,位于U6N的光生空穴与苯甲醇相互作用,先氧化苯甲醇上的α-C产生·CH(OH)Ph,然后进一步氧化产生苯甲醛,同时,CdS上的光生电子与水中产生的H+结合产生氢气.综上,本文通过飞秒瞬态吸收光谱(fs-TAS)光谱来阐述梯型异质结的电子转移机制,并为金属有机框架/无机物复合光催化剂的设计提供了借鉴.

Low-pressure-RF plasma modification of UiO-66 and its application in methylene blue adsorption

Defect engineering of metal-organic frameworks has attracted increasing attention in recent years for potential applications in gas storage and catalysis.In this study,defective UiO-66 is obtained by Ar and H_(2)plasma treatments.Compared with the pristine UiO-66,a new aperture with a size of~4 nm appears for a sample with the plasma modification,indicating the formation of mesopores within UiO-66 framework.Characterization results demonstrate that the pore volume,surface area and the number of Lewis and Br?nsted acid sites can be easily tuned by varying the discharge parameters.The adsorption performance of UiO-66 is evaluated for the adsorption of methyl blue.In comparison to the pristine UiO-66 and the sample with H_(2)plasma treatment,the Ar plasma modified sample shows excellent adsorption activity due to the suitable pore size and volume.Equilibrium adsorption capacity as high as 40.6 mg·g^(-1)is achieved for the UiO-66(Ar)sample.

经腋窝单孔充气法乳腺腔镜手术治疗乳腺疾病的临床应用分析

目的:探讨采用经腋窝单孔充气法乳腺腔镜手术在乳腺疾病中的可行性、安全性及临床应用价值。方法:回顾性分析2020年12月至2022年3月于天津医科大学肿瘤医院收治经腋窝单孔充气法乳腺腔镜手术的84例乳腺疾病患者的临床资料,包括患者基线临床特征、术中及术后恢复情况、术后满意度评分及随访情况。结果:84例患者均顺利完成手术,无中途转为开放手术病例。术后满意度评分为(8.25±1.21)分,手术效果佳。术后无切口感染、切缘坏死等重大并发症发生。随访8~23个月,未发现肿瘤局部复发及转移。结论:经腋窝单孔充气法乳腺腔镜手术安全高效、并发症少、患者满意度高,临床应用上具有推广前景。

An Evaluation Method of Human Gut Microbial Homeostasis by Testing Specific Fecal Microbiota

Research on microecology has been carried out with broad perspectives in recent decades,which has enabled a better understanding of the gut microbiota and its roles in human health and disease.It is of great significance to routinely acquire the status of the human gut microbiota;however,there is no method to evaluate the gut microbiome through small amounts of fecal microbes.In this study,we found ten predominant groups of gut bacteria that characterized the whole microbiome in the human gut from a large-sample Chinese cohort,constructed a real-time quantitative polymerase chain reaction(qPCR)method and developed a set of analytical approaches to detect these ten groups of predominant gut bacterial species with great maneuverability,efficiency,and quantitative features.Reference ranges for the ten predominant gut bacterial groups were established,and we found that the concentration and pairwise ratios of the ten predominant gut bacterial groups varied with age,indicating gut microbial dysbiosis.By comparing the detection results of liver cirrhosis(LC)patients with those of healthy control subjects,differences were then analyzed,and a classification model for the two groups was built by machine learning.Among the six established classification models,the model established by using the random forest algorithm achieved the highest area under the curve(AUC)value and sensitivity for predicting LC.This research enables easy,rapid,stable,and reliable testing and evaluation of the balance of the gut microbiota in the human body,which may contribute to clinical work.

Temperature Field in Laser Line Scanning Thermography: Analytical Calculation and Experiment

The temperature field in laser line scanning thermography is investigated comprehensively in this work,including analytical calculation and experiment.Firstly,the principle of laser line scanning thermography is analyzed.On this basis,a physical laser line scanning model is proposed.Afterwards,based on Fourier transform(FT)and segregation variablemethod(SVM),the heat conduction differential equation in laser line scanning thermography is derived in detail.The temperature field of the composite-based coatings model with defects is simulated numerically.The results show that the laser line scanning thermography can effectively detect the defects in the model.The correctness of the analytical calculation is verified by comparing the surface temperature distribution obtained by analytical calculation and numerical simulation.Additionally,an experiment is carried out and the changeable surface temperature obtained by analytical calculation is compared with the experimental results.It shows that the error of maximum temperature obtained by analytical calculation and by experiment is 8%with high accuracy,which proves the correctness of analytical calculation and enriches the theoretical foundation of laser line scanning thermography.

Single-electron transport in H_(2)O@C_(60) single-molecule transistors

Single-molecule transistors(SMTs) based on fullerenes and their derivatives have been recognized as a long-sought platform for studying the single-electron transport properties.H_(2)O@C_(60) is a combination of fullerene and H_(2)O,a typical light molecule.Here we use the 'molecular surgery' technique to synthesize the H_(2)O@C_(60) molecule and then construct the H_(2)O@C_(60) SMTs,together with the C_(60) SMTs.Evidences for single-electron transport have been obtained in our measurements,including explicit Coulomb blockade and Coulomb oscillations.We then calculate the detailed parameters of the H_(2)O@C_(60) and C_(60) SMTs using a capacitance model derived from the Coulomb diamond feature,which gives a capacitance ratio of 1:5.05:8.52 for the H_(2)O@C_(60) SMT and 1:29.5:74.8 for the C_(60) SMT.Moreover,the gate efficiency factor a turns out to be 0.0686 in the H_(2)O@C_(60) SMT,about ten times larger than that in the C_(60) SMT.We propose that the enhanced gate efficiency in H_(2)O@C_(60) SMT may be induced by the closer attachment of molecular orbital electron clouds to the gate substrate due to polarization effects of H_(2)O.

Autophagy inhibition enhances apigenin-induced apoptosis in human breast cancer cells

Apigenin （4＇,5,7-trihydroxyflavone） is a member of the flavone subclass of flavonoids present in fruits and vegetables. The involvement of autophagy in the apigenin-induced apoptotic death of human breast cancer cells was investigated. Cell proliferation and viability were assessed by 3-（4,5-dimethylthiazol- 2-yl）-2,5-diphenyltetrazolium bromide （MTT） and clonogenic assays. Flow cytometry, fluorescent staining and Western blot analysis were employed to detect apoptosis and autophagy, and the role of autophagy was assessed using autophagy inhibitors. Apigenin dose- and time-dependently repressed the proliferation and clonogenic survival of the human breast cancer T47D and MDA-MB-231 cell lines. The death of T47D and MDA-MB-231 cells was due to apoptosis associated with increased levels of Caspase3, PARP cleavage and Bax/Bcl-2 ratios. The results from flow cytometry and fluorescent staining also verified the occurrence of apoptosis. In addition, the apigenin-treated cells exhibited autophagy, as characterized by the appearance of autophagosomes under fluorescence microscopy and the accumulation of acidic vesicular organelles （AVOs） by flow cytometry. Furthermore, the results of the Western blot analysis revealed that the level of LC3-Ⅱ, the processed form of LC3-Ⅰ, was increased. Treatment with the autophagy inhibitor, 3-methyladenine （3-MA）, significantly enhanced the apoptosis induced by apigenin, which was accompanied by an increase in the level of PARP cleavage. Similar results were also confirmed by flow cytometry and fluorescence microscopy. These results indicate that apigenin has apoptosis- and autophagy-inducing effects in breast cancer cells. Autophagy plays a cyto-protective role in apigenin-induced apoptosis, and the combination of apigenin and an autophagy inhibitor may be a promising strategy for breast cancer control.

Review of low timing jitter mode-locked fiber lasers and applications in dual-comb absolute distance measurement

Passively mode-locked fiber lasers emit femtosecond pulse trains with excellent short-term stability. The quantum-limited timing jitter of a free running femtosecond erbium-doped fiber laser working at room temperature is considerably below one femtosecond at high Fourier frequency. The ultrashort pulse train with ultralow timing jitter enables absolute time-of-flight measurements based on a dual-comb implementation, which is typically composed of a pair of optical frequency combs generated by femtosecond lasers. Dead-zone-free absolute distance measurement with sub-micrometer precision and kHz update rate has been routinely achieved with a dual-comb configuration, which is promising for a number of precision manufacturing applications, from large step-structure measurements prevalent in microelectronic profilometry to three coordinate measurements in large-scale aerospace manufacturing and shipbuilding. In this paper, we first review the sub-femtosecond precision timing jitter characterization methods and approaches for ultralow timing jitter mode-locked fiber laser design. Then, we provide an overview of the state-of-the-art dual-comb absolute ranging technology in terms of working principles, experimental implementations, and measurement precisions. Finally, we discuss the impact of quantum-limited timing jitter on the dual-comb ranging precision at a high update rate. The route to highprecision dual-comb range finder design based on ultralow jitter femtosecond fiber lasers is proposed.

Enhanced atmospheric phosphorus deposition in Asia and Europe in the past two decades

磷是植物生长必需的元素,磷缺乏将限制植被生产力及碳汇功能.为厘清全球大气磷沉降的时空格局,本文收集了1959-2020年发表的396条观测资料.结果发现,全球大气磷沉降的几何均值为0.32 kg ha~(-1)yr~(-1),全球大气磷库约4.4 Tg yr~(-1).与1959-2000年相比,近20年亚洲和欧洲大气磷沉降呈现上升趋势,主要来源是农业活动,沙尘传输和燃烧源排放.碳中和背景下,清洁空气行动是否会改变磷沉降的途径和形态,进而影响到生态系统的结构和功能,是需要回答的科学问题.

Redox-sensitive micelles for targeted intracellular delivery and combination chemotherapy of paclitaxel and all-trans-retinoid acid

The application of paclitaxel(PTX) in clinic has been restricted due to its poor solubility.Several traditional nano-medicines have been developed to improve this defect,while they are still lack of tumor targeting ability and rapid drug release. In this work,an amphiphilic polymeric micelle of hyaluronic acid(HA) – all-trans-retinoid acid(ATRA) with a disulfide bond,was developed successfully for the co-delivery of PTX and ATRA. The combination chemotherapy of PTX and ATRA can strengthen the anti-tumor activity. Along with selfassembling to micelles in water,the delivery system displayed satisfying drug loading capacities for both PTX(32.62% ± 1.39%) and ATRA,due to directly using ATRA as the hydrophobic group. Rapid drug release properties of the PTX-loaded redox-sensitive micelles(HA-SS-ATRA) in vitro were confirmed under reducing condition containing GSH. Besides,HA-CD44 mediated endocytosis promoted the uptake of HA-SS-ATRA micelles by B16 F10 cells. Due to these properties,cytotoxicity assay verified that PTX-loaded HA-SS-ATRA micelles showed concentration-dependent cytotoxicity and displayed obvious combination therapy of PTX and ATRA. Importantly,HA-SS-ATRA micelles could remarkably prolong plasma circulation time after intravenously administration. Therefore,redox-sensitive HASS-ATRA micelles could be utilized and explored as a promising drug delivery system for cancer combination chemotherapy.

Phishing Detection with Image Retrieval Based on Improved Texton Correlation Descriptor

Anti-detection is becoming as an emerging challenge for anti-phishing.This paper solves the threats of anti-detection from the threshold setting condition.Enough webpages are considered to complicate threshold setting condition when the threshold is settled.According to the common visual behavior which is easily attracted by the salient region of webpages,image retrieval methods based on texton correlation descriptor(TCD)are improved to obtain enough webpages which have similarity in the salient region for the images of webpages.There are two steps for improving TCD which has advantage of recognizing the salient region of images:(1)This paper proposed Weighted Euclidean Distance based on neighborhood location(NLW-Euclidean distance)and double cross windows,and combine them to solve the problems in TCD;(2)Space structure is introduced to map the image set to Euclid space so that similarity relation among images can be used to complicate threshold setting conditions.Experimental results show that the proposed method can improve the effectiveness of anti-phishing and make the system more stable,and significantly reduce the possibilities of being hacked to be used as mining systems for blockchain.

Fabrication and characterization of iron and iron carbide thin films by plasma enhanced pulsed chemical vapor deposition

A new pulsed chemical vapor deposition (PCVD) process has been developed to fabricate iron (Fe) and iron carbide (Fe1-xCx) thin films at low temperature range from 150℃ to 230℃. The process employs bis(1,4-di-tert-butyl-1,3-diazabutadienyl)iron(II) as iron source and hydrogen gas or hydrogen plasma as the coreactant. The films deposited with hydrogen gas are demonstrated polycrystalline with body-centered cubic Fe. However, for the films deposited with hydrogen plasma, the amorphous phase of iron carbide is obtained. The influence of the deposition temperature on iron and iron carbide characteristics have been investigated.

Modeling the photon counting and photoelectron counting characteristics of quanta image sensors

A signal chain model of single-bit and multi-bit quanta image sensors(QISs)is established.Based on the proposed model,the photoresponse characteristics and signal error rates of QISs are investigated,and the effects of bit depth,quantum efficiency,dark current,and read noise on them are analyzed.When the signal error rates towards photons and photoelectrons counting are lower than 0.01,the high accuracy photon and photoelectron counting exposure ranges are determined.Furthermore,an optimization method of integration time to ensure that the QIS works in these high accuracy exposure ranges is presented.The trade-offs between pixel area,the mean value of incident photons,and integration time under different illuminance level are analyzed.For the 3-bit QIS with 0.16 e-/s dark current and 0.21 e-r.m.s.read noise,when the illuminance level and pixel area are 1 lux and 1.21μm^(2),or 10000 lux and 0.21μm^(2),the recommended integration time is 8.8 to 30 ms,or 10 to21.3μs,respectively.The proposed method can guide the design and operation of single-bit and multi-bit QISs.

Formaldehyde Free Renewable Thermosetting Foam Based on Biomass Tannin with a Lignin Additive

This study presents easily prepared free formaldehyde bio-based foam based on a prepared thermosetting resin comprising tannin–lignin–furfuryl alcohol-glyoxal(TLFG)via mechanical stirring in presence of ether as a foaming agent.The foam was developed through a co-polycondensation reaction of glyoxal and furfuryl alcohol with condensed tannin and lignin,which is a forest-derived product.Investigation using scanning electron microscopy(SEM)showed more closed-cell structure without cracks and collapse in the TLFG foam,with a higher apparent density with respect to tannin–furanic–formaldehyde(TFF)foam.Differential scanning calorimetry(DSC),dynamic thermomechanical analysis(DTMA),and thermogravimetric analysis(TGA)investigations revealed that the curing process of TLFG foam proceeds easily even at a lower temperature.Additionally,it acquired higher heat resistance than TFF foam.Moreover,TLFG has a more robust chemical network structure,which contributes efficiently to the mechanical strength and a lower pulverization degree compared with TFF-derived foam.Fourier transform infrared spectrometry(FTIR)and electrospray ionization mass spectrometry(ESI-MS)proved that the cross-inking reactions between tannin,lignin,furfuryl alcohol,and glyoxal have been proceeded efficiently.