Phosphotungstic acid immobilized on amino-functionalized TS-1 zeolite as a solid acid catalyst for the synthesis of tributyl citrate

The amino-functionalization of TS-1 zeolite followed by immobilization of phosphotungstic acid(HPW)was presented to prepare a strong solid acid catalyst for the synthesis of bio-based tributyl citrate from the esterification of citric acid and n-butanol.γ-Aminopropyltriethoxysilane(APTES)was first grafted on the TS-1 zeolite via the condensation reactions with surface hydroxyl groups,and subsequently the HPW was immobilized via the reaction between the amino groups and the protons from HPW-forming strong ionic bonding.The Keggin structure of HPW and MFI topology of TS-1 zeolite were well maintained after the modifications.The amino-functionalization generated abundant uniformly distributed active sites on TS-1 for HPW immobilization,which promoted the dispersity,abundance,as well as the stability of the acid sites.The tetrahedrally coordinated framework titanium and non-framework titania behaved as weak Lewis acid sites,and the protons from the immobilized HPW acted as the moderate or strong Brønsted acid sites.An optimized TBC yield of 96.2%(mol)with a conversion of-COOH of 98.1%(mol)was achieved at 150℃for 6 h over the HPW immobilized on amino-functionalized TS-1.The catalyst exhibited good stability after four consecutive reaction runs,where the activity leveled off at still a relatively high level after somewhat deactivation possibly caused by the leaching of a small portion of weakly anchored APTES or HPW.

Graph neural network-based scheduling for multi-UAV-enabled communications in D2D networks

In this paper,we jointly design the power control and position dispatch for Multi-Unmanned Aerial Vehicle(UAV)-enabled communication in Device-to-Device(D2D)networks.Our objective is to maximize the total transmission rate of Downlink Users(DUs).Meanwhile,the Quality of Service(QoS)of all D2D users must be satisfied.We comprehensively considered the interference among D2D communications and downlink transmissions.The original problem is strongly non-convex,which requires high computational complexity for traditional optimization methods.And to make matters worse,the results are not necessarily globally optimal.In this paper,we propose a novel Graph Neural Networks(GNN)based approach that can map the considered system into a specific graph structure and achieve the optimal solution in a low complexity manner.Particularly,we first construct a GNN-based model for the proposed network,in which the transmission links and interference links are formulated as vertexes and edges,respectively.Then,by taking the channel state information and the coordinates of ground users as the inputs,as well as the location of UAVs and the transmission power of all transmitters as outputs,we obtain the mapping from inputs to outputs through training the parameters of GNN.Simulation results verified that the way to maximize the total transmission rate of DUs can be extracted effectively via the training on samples.Moreover,it also shows that the performance of proposed GNN-based method is better than that of traditional means.

光储备池通感一体通信噪声抑制方案(封面文章·特邀)

通感一体技术可利用已大范围铺设的光纤网实现智能传感,具备智能识别、信息融合优势。在同波长通感共传信道中,通感信号串扰及光纤传输噪声严重影响通信信号质量,需提升发射功率来保证低误码率,但增大了非线性噪声和功耗。提出了基于光储备池计算神经网络的通感共传信道通信失真均衡方法,搭建了信道均衡仿真系统,实现了低发射功率下前向通信信号噪声均衡。周期线性调频光和56 Gb/s四电平脉冲幅度调制信号分别用于分布式瑞利散射传感和数据通信。仿真结果表明,在5~14 dBm入纤功率时,与未均衡信号相比该方法可提供高于3个数量级以上的误码率优化。此方法在短距离模块间15~24 km光纤传输和0.5~2.0 GHz带宽线性调频感测脉冲下均实现了2个数量级以上的误码率下降。依托光储备池计算芯片的低能耗和低延时优势,该方法可为进一步提升通感一体系统中噪声抑制能力提供理论支撑。

Synthesis of Branched Polyethylene via Bulky α-Diimine Nickel(II)-Catalyzed Ethylene Chain-Walking Polymerization

The catalysis of olefin polymerization through the chain-walking process is a subject of great interest. In this contribution, the successful synthesis of a Brookhart-type unsymmetrical α-diimine nickel catalyst Ni, which contains both dibenzhydryl and phenyl groups, was determined by X-ray crystallography. The compound has a pseudo-tetrahedral geometry at the Ni center, showing pseudo-C2-symmetry. Upon activation with modified methylaluminoxane (MMAO), Ni1 exhibits high catalytic activity up to 1.02 × 107 g PE (mol Ni h)−1 toward ethylene polymerization, enabling the synthesis of high molecular weight branched polyethylene. The molecular weights and branching densities could be tuned over a very wide range. The polymerization results indicated the possibility of precise microstructure control, depending on the polymerization temperature. The branching densities were decreased with increasing the polymerization temperature.

欧盟《数据治理法》的解读及对我国智慧图书馆数据治理的启示

数据治理是智慧图书馆管理和利用数据的有效手段,现阶段,国内图书馆在数据开放共享和数据价值利用等方面仍存在许多不足。欧盟《数据治理法》在数据共享和数据再利用上具有一定的优势,基于此,文章通过深入分析欧盟《数据治理法》的主要内容,借鉴其成功经验,以为我国智慧图书馆数据治理提供参考。

PHENIX—USB4电刺激联合产后康复综合治疗仪治疗腹直肌分离的临床价值

目的 探讨PHENIX—USB4电刺激联合产后康复综合治疗仪治疗腹直肌分离的临床价值。方法 选取62例产后腹直肌分离患者为研究对象,根据随机数字表法分为两组,各31例。对照组接受PHENIX—USB4电刺激治疗,试验组接受PHENIX—USB4电刺激联合产后康复综合治疗仪治疗,比较两组的治疗效果。结果 治疗8周后,试验组腹围、脐上腹直肌分离间距、脐下腹直肌分离间距均小于对照组,差异有统计学意义(P<0.05);剖宫产次数、胎儿大小是腹直肌分离治疗有效性的影响因素(P<0.05)。结论 与单纯PHENIX—USB4电刺激相比,联合产后康复综合治疗仪治疗对产后腹直肌分离患者的应用效果更好,能有效缩小腹围及腹直肌间距,临床应用价值较高。

多芯超模光纤放大器增益均衡设计(内封底文章)

多芯超模光纤(MCSMF)的芯间距较小,多个芯子共同形成芯区支持多个超模传输,与普通单芯少模光纤相比,其具有较大的有效模场面积和较小的模式串扰,备受关注。MCSMF用于长距离传输时,与其相匹配的新型增益均衡放大器是实现信号中继并保持信号稳定传输的必要器件。文中提出了一种基于粒子群优化算法的19芯超模光纤增益均衡放大器,该光纤支持10个超模共同传输。通过粒子群算法分别优化各纤芯内掺铒浓度来降低不同超模的交叠积分因子,从而减小模式增益差(DMG)。结果表明,在包层泵浦条件下,最大DMG从1.33 dB (各纤芯均匀掺杂)降低至0.20 dB,在1 550 nm信号波长处10模式的平均增益为27.79 dB,且该放大器在整个C波段的增益平坦度低于1 dB。

基于偏振复用调制的周期性光学任意波形生成方案

针对复杂波形生成的需求,提出了一种基于偏振复用调制的周期性光学任意波形信号生成方案。通过精心调控正交相移键控(QPSK)调制器的调制指数、射频偏移及偏置相移等关键参数,使得2个正交偏振态上的调制器能够分别输出傅里叶级数中的正弦和余弦谐波叠加形式的光强。当这些光强合束后,就能得到幅度和相位均可精确控制的函数波形,而且还具备可调谐函数波形信号输出的特性。仿真结果表明:当均方根误差小于等于0.05时,该方案可生成对称因子可调(20%~80%)斜坡波、占空比可调(30%~100%)三角波和半占空比可调(20%~80%)斜坡波3种典型波形,验证了该方案的可行性。

妊娠晚期孕妇症状群的范围综述

目的 对妊娠晚期孕妇症状群相关研究进行范围综述,确定症状群特点及研究现状,为完善孕妇妊娠晚期症状群管理提供参考。方法 检索PubMed、Embase、CINAHL、PsycINFO、Scopus、中国知网、中国生物医学文献库、维普网、万方数据库中妊娠晚期孕妇症状群的相关研究。检索时限为建库至2023年3月21日。结果 共纳入17篇文献,症状群的识别要素涵盖症状评估及分析方法。妊娠晚期孕妇症状群类型可划分为3大类,焦虑症状群、抑郁症状群是妊娠晚期孕妇最常见的症状群。结论 妊娠晚期孕妇存在多种类型症状群,未来研究应进一步检查症状群内部一致性,开发统一系统评估妊娠晚期孕妇症状特异性工具及新的分析方法,优化症状群的识别,探究规范化症状群管理方案的构建。

High Density 3D Carbon Tube Nanoarray Electrode Boosting the Capacitance of Filter Capacitor

Electric double-layer capacitors(EDLCs)with fast frequency response are regarded as small-scale alternatives to the commercial bulky aluminum electrolytic capacitors.Creating carbon-based nanoarray electrodes with precise alignment and smooth ion channels is crucial for enhancing EDLCs’performance.However,controlling the density of macropore-dominated nanoarray electrodes poses challenges in boosting the capacitance of line-filtering EDLCs.Herein,a simple technique to finely adjust the vertical-pore diameter and inter-spacing in three-dimensional nanoporous anodic aluminum oxide(3D-AAO)template is achieved,and 3D compactly arranged carbon tube(3D-CACT)nanoarrays are created as electrodes for symmetrical EDLCs using nanoporous 3D-AAO template-assisted chemical vapor deposition of carbon.The 3D-CACT electrodes demonstrate a high surface area of 253.0 m^(2) g^(−1),a D/G band intensity ratio of 0.94,and a C/O atomic ratio of 8.As a result,the high-density 3D-CT nanoarray-based sandwich-type EDLCs demonstrate a record high specific areal capacitance of 3.23 mF cm^(-2) at 120 Hz and exceptional fast frequency response due to the vertically aligned and highly ordered nanoarray of closely packed CT units.The 3D-CT nanoarray electrode-based EDLCs could serve as line filters in integrated circuits,aiding power system miniaturization.

芪灯明目胶囊对氧诱导视网膜病变小鼠视网膜血管的保护作用

目的研究芪灯明目胶囊对氧诱导视网膜病变(OIR)小鼠视网膜新生血管形成及重塑的影响。方法将36只出生后第7天的(P7)SPF级C57BL/6J幼鼠采用随机数字表法分为正常组、OIR组、芪灯明目胶囊组和阿帕替尼组,每组9只。正常组小鼠于正常环境下饲养,其余小鼠均在高氧环境中[氧浓度为(75±2)%]饲养5 d(P7~P12)后再在正常环境中饲养5 d(P12~P17)建立OIR模型。芪灯明目胶囊组和阿帕替尼组从P12开始分别给予芪灯明目胶囊(900 mg/kg)与血管内皮生长因子受体2抑制剂阿帕替尼(70 mg/kg)灌胃,1次/d,连续5 d。P17时,摘取小鼠眼球,制作眼球石蜡切片并行苏木精-伊红染色,计数各组小鼠突破内界膜的血管内皮细胞数目;制作视网膜铺片并行FITC-dextran荧光染色,计算视网膜无灌注区面积比、新生血管密度与总血管密度;采用免疫荧光染色法检测视网膜血管内皮细胞标志物CD31与周细胞标志物α-平滑肌肌动蛋白(α-SMA)的分布和荧光强度;采用免疫组织化学染色法检测视网膜缺氧诱导因子1α(HIF-1α)与血管内皮钙黏蛋白(VE-cadherin)的表达分布。结果正常组、OIR组、芪灯明目胶囊组和阿帕替尼组突破内界膜的血管内皮细胞数目分别为(2.83±4.40)、(37.33±5.43)、(23.83±6.79)和(14.00±9.34)个,总体比较差异有统计学意义(F=28.313,P<0.001),其中OIR组突破内界膜血管内皮细胞数明显多于正常组、芪灯明目胶囊组和阿帕替尼组,差异均有统计学意义(均P<0.05)。视网膜铺片结果显示,OIR组视网膜存在大片无灌注区域与新生血管芽,血管迂曲,分布紊乱,芪灯明目胶囊组和阿帕替尼组血管分布较OIR组更均匀,无灌注区面积和新生血管较OIR组减少。正常组、芪灯明目胶囊组和阿帕替尼组视网膜无灌注区面积比和新生血管密度均较OIR组降低,差异均有统计学意义(均P<0.05)。正常组、芪灯明目胶囊组和阿帕替尼组CD31免疫荧光强度和HIF-1α吸光度值明显低于OIR组,α-SMA免疫荧光强度和VE-cadherin吸光度值明显高于OIR组,差异均有统计学意义(均P<0.05)。结论芪灯明目胶囊能够抑制OIR小鼠视网膜新生血管形成,增加血管周细胞覆盖,缓解视网膜缺氧以及增加血管完整性,对OIR小鼠视网膜血管起到保护作用。

High performance columnar-like Fe2O3@carbon composite anode via yolk@shell structural design

Conversion-type reaction anode materials with high specific capacity are attractive candidates to improve lithium ion batteries(LIBs), yet the rapid capacity fading and poor rate capability caused by drastic volume change and low electronic conductivity greatly hinder their practical applications. To circumvent these issues, the successful design of yolk@shell Fe2 O3@C hybrid composed of a columnar-like Fe2O3 core within a hollow cavity completely surrounded by a thin, self-supported carbon(C) shell is presented as an anode for high-performance LIBs. This yolk@shell structure allows each Fe2O3 core to swell upon lithiation without deforming the carbon shell. This preserves the structural and electrical integrity against pulverization, as revealed by in situ transmission electron microscopy(TEM) measurement. Benefiting from these structural advantages, the resulting electrode exhibits a high reversible capacity(1013 m Ah g-1 after80 cycles at 0.2 A g-1), outstanding rate capability(710 m Ah g-1 at 8 A g-1) and superior cycling stability(800 m Ah g-1 after 300 cycles at 4 A g-1). A Li-ion full cell using prelithiated yolk@shell Fe2 O3@C hybrid as the anode and commercial Li CoO2(LCO) as the cathode demonstrates impressive cycling stability with a capacity retention of 84.5% after 100 cycles at 1 C rate, holding great promise for future practical applications.

成都市中小学生近视情况及防控措施应用现状调查

目的调查中小学生近视及防控措施应用现状。方法随机抽取1624名中小学生家长为调查对象,利用问卷调查表收集学生性别、年龄、屈光状态及防控措施应用情况等信息进行分析。结果1624名学生中,近视率48.09%,随年龄增长近视率呈上升趋势。家长对近视健康风险意识淡薄,68.04%的学生未采取任何预防措施,学生近视后,33.42%的学生未采取任何控制措施。各类预防及控制措施均未取得满意效果,安全性及效果是影响选择的主要因素。结论中小学生近视率较高,近视防控措施应用情况较差,目前防控措施效果未达到近视防控预期目标。

Impaired SWEET-mediated sugar transportation impacts starch metabolism in developing rice seeds

Sugar transportation and sugar-to-starch metabolism are considered important processes in seed development and embryo viability.A few plant SWEET proteins acting as sugar transporters have been reported to function in inflorescence and/or seed development.Here,we identified seven members of the 21 Os SWEET genes in rice that play essential roles in sugar transportation and sugar-to-starch conversion in seed development.Nineteen Os SWEET genes exhibiting different expression patterns during inflorescence and seed development were knocked out individually by CRISPR/Cas9.One third of the mutants showed decreased fertile pollen viability and shriveled mature caryopses,resulting in weakened seed traits.Grain fill-related genes but not representative grain shape-regulating genes showed attenuated expression in the mutants.Seed of each of these mutants accumulated more sucrose,glucose or fructose but less starch.Among all Os SWEET genes,Os SWEET4 and Os SWEET11 had major effects on caryopsis development.The sugar-to-starch metabolic pathway was significantly altered in ossweet11 mutants based on differential expression analysis in RNA sequencing assays,confirming that Os SWEET11 functions as a sugar transporter with a key role in seed development.These results help to decipher the multiple functions of Os SWEET genes and to show how they might be used in genetic improvement of rice.

Fabrication of high-performance PVA/PAN composite pervaporation membranes crosslinked by PMDA for wastewater desalination

The pyromellitic dianhydride（PMDA） crosslinked poly（vinyl alcohol）（PVA） was coated on top of the PAN ultrafiltration membrane to form a PVA/PAN composite PV membranes for wastewater desalination. The composite membranes have high application value in industrial wastewater treatment. By varying the membrane fabrication parameters including the weight percent（wt%） of the PMDA, the crosslink temperature and duration, membrane with the best desalination performance was obtained. The composite membrane with a 2-lm-thick PVA selective layer containing 20 wt% of PMDA and being crosslinked at 100 °C for 2 h showed the highest Na Cl rejection of 99.98% with a water flux of 32.26 L/（m^2 h）at 70 °C using the 35,000 ppm Na Cl aqueous solution as feed. FTIR spectroscopy, wide-angle X-ray diffraction, thermogravimetric analysis and scanning electron microscope have been used to characterize the structures and properties of both the crosslinked PVA dense films and PVA/PAN composite membranes. The effects of the concentrations of PMDA,the crosslinking time and temperature to the membrane water contact angle, swelling degree, salt rejection and water flux were systematically studied.

Ultrasonic diagnosis of patients with clonorchiasis and preliminary study of pathogenic mechanism

Objective:To discuss the liver function damage mechanism of patients with clonorchiasis by analyzing the ultrasound characteristics,liver function,change of the serum inflammatory factors and cell apoptosis factors.Methods:Color Doppler ultrasound technique was adopted to detect the portal vein and blood flow change of patients with clonorchiasis;ELISA was used to determine the level of different serum inflammatory factors.The levels of serum total bilirubin,serum albumin and glutamic-pyruvic transaminase were detected by automatic biochemical analyzer.Western blot was used to determine the expression of proteins relevant to apoptosis.Results:Compared with the health control group,the trunk diameter of portal vein and the thickness of spleen,as well as the hepatic artery pulsation index of clonorchiasis patients increased obviously,the mean blood flow velocity of portal vein(P<0.05 or P<0.01) decreased.The content of total bilirubin and transaminase in plasma increased significantly,but albumin decreased(P<0.05).Levels of TNF-α,IL-6 and IFN-γ increased remarkably,and the level of every factor was significantly different among patients with Child-Pugh Ⅰ,Child-Pugh Ⅱ and Child-Pugh Ⅲ classification of liver function(P<0.05 or P<0.01).With the exacerbation of liver dysfunction,levels of TNF-α,IL-6 and IFN-γ gradually increased(P<0.05).Compared with the healthy control group,the expression quantity of apoptosis protein Fas,FasL,Bax and Caspase-3 increased significantly(P<0.05 or P<0.01),but Bcl-2 decreased(P<0.05).Conclusions:Changes of ultrasonic characteristics and liver dysfunction,caused by liver fluke infection,may be related to that both inflammatory response and apoptosis response have participated in the pathogenic process and liver damage course of clonorchiasis.

Pore-scale mechanisms and characterization of light oil storage in shale nanopores:New method and insights

A new method is proposed to analyze the pore-scale mechanisms and characterization of light oil storage in shale nanopores,which is based on the Hydrocarbon Vapor Adsorption(HVA)and Pore Calculation Model(PCM).First,the basic principle of the HVA-PCM method is introduced,and the experimental/mathematical analysis processes are given.Then,the HVA-PCM method is applied to shale samples to analyze the mechanisms and characterization of light oil storage in shale nanopores.The results provide insights into the pore-scale oil storage mechanisms,oil storage structure,oil film thickness,oil distribution within different sized pores,and the oil storage state.Finally,the advantages and limitations of the HVA-PCM method are discussed,and suggestions for further improvement are proposed.Overall,the HVA-PCM method is a powerful tool for extracting quantitative information on the light oil storage in shale nanopores.

Effect of temper rolling on the bake-hardening behavior of low carbon steel

In a typical process, low carbon steel was annealed at two different temperatures （660℃ and 750℃）, and then was temper rolled to improve the mechanical properties. Pre-straining and baking treatments were subsequently carried out to measure the bake-hardening （BH） values. The influences of annealing temperature and temper rolling on the BH behavior of the steel were investigated. The results indicated that the microstructure evolution during temper rolling was related to carbon atoms and dislocations. After an apparent increase, the BH value of the steel significantly decreased when the temper rolling reduction was increased from 0%to 5%. This was attributed to the increase in solute carbon concentration and dislocation density. The maximum BH values of the steel annealed at 660℃ and 750℃ were 80 MPa and 89 MPa at the reductions of 3%and 4%, respectively. Moreover, increasing the annealing temperature from 660 to 750℃ resulted in an ob-vious increase in the BH value due to carbide dissolution.

A regeneration system using cotyledons and cotyledonary node explants of Toona ciliata

We used the cotyledons and cotyledonary nodes of Toona ciliata(Chinese mahogany)as explants to examine callus and adventitious shoot induction when exposed to different ratios of hormones.We also investigated the effects of seedling age,inoculation method,and genotype on the efficient regeneration of T.ciliata.The results showed that different genotypes exhibited significantly different callus induction efficiency.The cotyledons and cotyledonary nodes of 20-day seedlings inoculated onto MS medium with 0.5 mg/L 6-benzylaminopurine(6-BA),0.5 mg/L kinetin(KT)and 0.05 mg/L 1-naphthylacetic acid(NAA)achieved a greater regeneration rate than did other concentrations of cytokinin and auxin.The numbers of shoots per cotyledon and cotyledonary node explant were 7.33 and 6.67.The optimal inoculation method for cotyledons was that the distal end of the explants was placed in contact with the medium.The optimal adventitious shoot differentiation medium for cotyledon explants was MS medium containing 0.3 mg/L 6-BA and 0.2 mg/L NAA,producing a 3.4 cm height of shoot on average.This study established an efficient regeneration system for T.ciliata with cotyledons and cotyledonary nodes as explants.

中医药科技查新技术规范

《中医药科技查新技术规范》的发布可为中医药查新机构的查新工作提供技术指导。通过实地调研及文献研究,按照GB/T 32003的要求,结合中医药行业的特点,在征求专家意见的基础上,制定本规范。本规范界定了中医药科技查新的基本术语,规定了中医药科技查新的原则、资质、工作流程和质量控制要求,给出了中医药科技查新报告的基本内容、要求以及撰写方法与格式。