基于Na-BP-DME@C阳极的长寿命准固态钠-空气电池

钠-空气电池因其能量密度高、成本低而成为金属-空气电池领域的研究热点。然而,以金属钠为阳极的钠-空气电池存在钠枝晶生长、金属钠界面稳定性差以及金属钠的反应活性高等问题,限制了钠-空气电池的快速发展。为解决上述问题,将联苯钠与导电炭黑复合材料Na-BP-DME@C作为阳极,单壁碳纳米角(SWCHNs)作为催化剂,构建准固态钠-空气电池。基于Na-BP-DME@C阳极的准固态钠-空气电池表现出优异的电化学性能,其电压差为1.5 V,功率密度为3.32 mW/cm^(2),在0.1 mA/cm^(2)电流密度下可稳定循环459 h(约459次)。

900 MHz频段5G NR与邻频DME系统共存研究

面向900 MHz频段NR网络重耕演进,进行了该频段5G NR系统与邻频DME系统的共存分析。首先介绍了系统干扰模型,而后阐述了系统干扰仿真的实现,包括使用的仿真参数、传播模型及仿真拓扑,并给出了仿真分析结果,最后针对分析结果给出了相关建议。

Synthesis of mordenite by solvent-free method and its application in the dimethyl ether carbonylation reaction

Mordenite with different Si/Al ratios were synthesized by solvent-free method and used for dimethyl ether(DME)carbonylation reaction.The influence of Si/Al ratio in the feedstock on the structure,porosity and acid sites were systematically investigated.The characterization results showed that with the increase of Si/Al ratio in the feedstock,part of silicon species fail to enter the skeleton and the specific surface area and pore volume of the samples decreased.The amount of weak acid and medium strong acid decreased alongside with the increasing Si/Al ratio,and the amount of strong acid slightly increased.The Al atoms preferentially enter the strong acid sites in the 8 member ring(MR)channel during the crystallization process.The high Si/Al ratio sample had more acid sites located in the 8 MR channel,leading to more active sites for carbonylation reaction and higher catalytic performance.Appropriately increasing the Si/Al ratio was beneficial for the improvement of carbonylation reaction activity over the mordenite(MOR)catalyst.

Interfacial engineering through lead binding using crown ethers in perovskite solar cells

In the domain of perovskite solar cells(PSCs),the imperative to reconcile impressive photovoltaic performance with lead-related issue and environmental stability has driven innovative solutions.This study pioneers an approach that not only rectifies lead leakage but also places paramount importance on the attainment of rigorous interfacial passivation.Crown ethers,notably benzo-18-crown-6-ether(B18C6),were strategically integrated at the perovskite-hole transport material interface.Crown ethers exhibit a dual role:efficiently sequestering and immobilizing Pb^(2+)ions through host-guest complexation and simultaneously establishing a robust interfacial passivation layer.Selected crown ether candidates,guided by density functional theory(DFT)calculations,demonstrated proficiency in binding Pb2+ions and optimizing interfacial energetics.Photovoltaic devices incorporating these materials achieved exceptional power conversion efficiency(PCE),notably 21.7%for B18C6,underscoring their efficacy in lead binding and interfacial passivation.Analytical techniques,including time-of-flight secondary ion mass spectrometry(ToF-SIMS),ultraviolet photoelectron spectroscopy(UPS),time-resolved photoluminescence(TRPL),and transient absorption spectroscopy(TAS),unequivocally affirmed Pb^(2+)ion capture and suppression of non-radiative recombination.Notably,these PSCs maintained efficiency even after enduring 300 h of exposure to 85%relative humidity.This research underscores the transformative potential of crown ethers,simultaneously addressing lead binding and stringent interfacial passivation for sustainable PSCs poised to commercialize and advance renewable energy applications.

机载DME设备多台轮询技术设计与实现

针对当前地面测距机(DME)导航台的作用范围一般为200 n miles左右[3],飞机在航行过程中往往需要经过多个DME导航台,而传统的机载DME设备只能工作在单频率下,这就需要飞行员手动切换对应地面台的频率,从而增加了飞行员工作量的问题。本文从实际工程应用出发,通过对机载DME设备工作过程进行分析,提出多台轮询技术,研究并实现直接扫描和自由扫描两种模式情况,该技术可提高航路定位的精准性,减少飞行员工作量。

Compositional modeling and simulation of dimethyl ether (DME)-enhanced waterflood to investigate oil mobility improvement

Dimethyl ether （DME） is a widely used industrial compound, and Shell developed a chemical EOR technique called DME- enhanced waterflood （DEW）. DME is applied as a miscible solvent for EOR application to enhance the performance of conventional waterflood. When DME is injected into the reservoir and contacts the oil, the first-contact miscibility process occurs, which leads to oil swelling and viscosity reduction. The reduction in oil density and viscosity improves oil mobility and reduces residual oil saturation, enhancing oil production. A numerical study based on compositional simulation has been developed to describe the phase behavior in the DEW model. An accurate compositional model is imperative because DME has a unique advantage of solubility in both oil and water. For DEW, oil recovery increased by 34% and 12% compared to conventional waterflood and CO2 flood, respectively. Compositional modeling and simulation of the DEW process indicated the unique solubility effect of DME on EOR performance.

Multidimensional modeling of Dimethyl Ether(DME) spray combustion in DI diesel engine

In the present study a modified CFD code KIVA3V was used to simulate the spray combustion in a small DI diesel engine fueled with DME. The improved spray models consider more spray phenomena such as cavitation flow in nozzle hole, jet atomization, droplet second breakup and spray wall interaction. Otherwise, a reduced DME reaction mechanism is implemented in the combustion model, and a new turbulent combustion model?Partial Stirred Reactor (PaSR) model is selected to simulate the spray combustion process, the effects of turbulent mixing on the reaction rate are considered. The results of engine modeling based on those models agreed well with the experimental measurements. Study of temperature fields variation and particle traces in the combustion chamber revealed that the engine combustion system originally used for diesel fuel must be optimized for DME.

Production of dimethylether(DME) as a clean fuel using sonochemically prepared CuO and /or ZnO- modified γ- alumina catalysts

The catalytic conversion of methanol to dimethylether(DME)was studied over CuO/Al2O3,ZnO/Al2O3and ZnOCuO/Al2O3nanocatalysts prepared in presence or absence of ultrasonic irradiation.The catalysts were characterized by X-ray diffraction(XRD),surface characterization method(BET),scanning electron microscope(SEM),H2-temperature programmed reduction(H2-TPR)and temperature programmed desorption of ammonia(NH3-TPD).The experimental results show that during catalytic dehydration of methanol to dimethylether,the activities of the CuO/Al2O3,ZnO/Al2O3and ZnO-CuO/Al2O3catalysts prepared using ultrasonic treatment are much higher than those prepared in absence of ultrasonication.SEM shows that the use of ultrasonication results in much smaller nanoparticles.BET and XRD show that the ultrasonication increases the surface area and pore volume of the catalysts.H2-TPR profiles indicated that reducibility of the sonicated nanocatalysts is carried out at lower temperatures.NH3-TPD shows that ultrasound irradiation has enhanced the acidity of the nanocatalyst and hence enhanced catalytic performance for DME formation.

25G玻璃体切除联合DEX治疗PDR继发玻璃体积血伴DME

目的:评价25G玻璃体切除(PPV)联合地塞米松玻璃体内植入剂(DEX)治疗增殖性糖尿病视网膜病变(PDR)继发玻璃体积血伴糖尿病性黄斑水肿(DME)的临床效果。方法:前瞻性临床病例研究。选取2020-07/2022-01天津市眼科医院收治的PDR继发玻璃体积血伴DME的患者40例40眼,所有患者均行玻璃体切除和白内障超声乳化手术,随机分为PPV组(20眼)和PPV+DEX组(20眼)。比较两组患者术前,术后1、3、6mo最佳矫正视力(BCVA)、眼压及黄斑中心凹厚度(CMT)。结果:所有患者均完成术后6mo随访。术后1、3、6mo PPV+DEX组患者BCVA均优于PPV组(P<0.05)。术后1mo,PPV+DEX组CMT低于PPV组(P<0.05)。随访6mo,PPV组术后出现视网膜新生血管或CMT消退小于5%者8眼行补充抗VEGF治疗,PPV+DEX组仅有1眼(P<0.05)。结论:玻璃体切除手术联合应用地塞米松植入剂可以产生协同效应,为PDR继发玻璃体积血伴DME的患者提供更优的治疗效果。

康柏西普不同给药方案治疗DME的安全性和疗效评估

目的:评估康柏西普采用连续3次每月注射后改用按需治疗方案(3+PRN)和连续5次每月注射后改用按需治疗方案(5+PRN)治疗糖尿病性黄斑水肿(DME)的安全性和疗效。方法:回顾性病例对照研究。选取2019-12/2020-06期间于我院就诊的DME患者51例92眼纳入研究,据治疗方案分为3+PRN组(26例48眼)和5+PRN组(25例44眼)。治疗后至少随访12mo,观察两组患者最佳矫正视力(BCVA)和中心凹视网膜厚度(CMT)的变化情况,玻璃体腔注药次数及眼部不良事件发生率。结果:随访12mo,3+PRN组、5+PRN组患者平均注药次数无差异(7.24±0.91次vs 7.56±1.04次,P=0.117)。治疗后3、6、9、12mo,两组患者BCVA和CMT均较治疗前改善(均P<0.05),且治疗后6、9、12mo,5+PRN组患者BCVA和CMT均优于3+PRN组(均P<0.05)。随访期间,两组患者均未发生严重不良事件,两组患者眼部不良事件总发生率均为27%,所有不良事件给予对症处理后均好转。结论:康柏西普3+PRN和5+PRN治疗方案均能安全有效地治疗DME,总注射次数相当,但5+PRN治疗方案较3+PRN治疗方案视力改善更佳,CMT下降更明显。

重复抗VEGF治疗对DME患者玻璃体黄斑界面的影响及其危险因素

目的:探讨糖尿病性黄斑水肿(DME)患者重复接受玻璃体腔注射抗血管内皮生长因子(VEGF)治疗对玻璃体黄斑界面(VMI)的影响及其相关危险因素。方法:回顾性分析2018-01/2021-12于遵义市第一人民医院眼科接受玻璃体腔注射康柏西普治疗(3+PRN)的DME患者31例55眼的临床资料。比较发生VMI改变(VMI改变组,9例13眼)和未发生VMI改变(VMI无改变组,22例42眼)的患者治疗前后最佳矫正视力(BCVA)、中央视网膜厚度(CRT)、中心凹下脉络膜厚度(CCT)情况,并分析发生VMI改变的危险因素。结果:纳入患者平均随访9.58±8.32mo,平均接受抗VEGF治疗4.07±2.17次,且VMI改变组患者玻璃体腔注射次数多于VMI无改变组(5.77±2.09次vs 3.55±1.93次,P=0.001)。末次随访时,与治疗前相比,两组患者治疗后BCVA均显著改善(均P<0.05),而CCT均无明显变化(均P>0.05),VMI无改变组患者CRT显著减小(P=0.039),但VMI改变组患者CRT未见明显变化(P=0.627)。Logistic回归分析结果显示,治疗前BCVA是VMI改变的危险因素(P=0.049,OR=6.210,95%CI 1.006~38.346)。结论:DME患者反复玻璃体腔注射抗VEGF药物过程中可能发生VMI改变,治疗前BCVA越差的患者VMI发生改变的风险越高,且VMI改变的患者对抗VEGF治疗反应欠佳。

Economy, environmental assessment and energy conservation for separation of isopropanol/diisopropyl ether/water multi-azeotropes via extractive distillation coupled pervaporation process

This wok proposed the extraction distillation coupled pervaporation(ED+PV) technology process using two different solvents to separate isopropanol(IPA) and diisopropyl ether(DIPE) from DIPE/IPA/H_(2)O ternary heterogeneous azeotropes in industrial wastewater from the synthesis of isopropanol in this study.Based on strict design specifications, simulation and sequential iteration methods are used for process design and optimization. Compared to the ethylene glycol(EG)-EG+H_(2)O process and the 1,3-propanediol(PDO)-IPA+H_(2)O process, the total annual cost(TAC) of the EG-IPA+H_(2)O process decreased by 20.76% and 7.86%(PDO). Compared to the EG-EG+H_(2)O process, the TAC of the PDO-IPA+H_(2)O process reduced 14%, but the global warming potential(GWP) and human toxicity of the PDO-IPA+H_(2)O process increased 11.3% and 4.07% respectively. Compared to the PDO-IPA+H_(2)O process, the EG-IPA+H_(2)O process saves 7.86%(TAC), 9.78%(GWP) and 9.85%(human toxicity). The ED+PV process with EG is superior to PDO in factors of TAC, energy consumption, human toxicity and environment. The EG-IPA+H_(2)O process changed the separation order of the products of the multi-azeotropic system, reduced the cost and energy conservation of the system, and enhanced the environmental protection evaluation of the process, is the best process through life cycle assessment for analyzing the economy, energy conservation, environmental assessment and human toxicity, designing cleaner products, controlling waste discharge, and promoting the chemical purification industry. This work provides a new process design and optimized separation ideas, will have a good guiding significance for the research and application separation of multi-azeotropic mixture with mixed solvents in organic wastewater from the cleaner chemical production, has been up to standard wastewater discharge process, and realized the development goal of carbon peak and carbon neutrality in the sustainable development of chemical clean industry.

A Comparative Study of the Hydroxyl Value and Iodine Value in Polyoxyl Stearyl Ether in United States Pharmacopeia Specifications

The iodine value (iodine number) and hydroxyl value are important analytical characteristics of fats and oils. The iodine (I2) required saturating the fatty acids present in 100 grams of the oil or fat. Iodine value is a measure of the total number of double bonds (-C=C-) present in fats and oils. Unsaturated compounds contain molecules with double and triple bonds which are very reactive towards iodine. The iodine value has been determined according to Hanus with iodine monobromide in glacial acetic acid, and then the amount of iodine remaining unreacted is determined by titration using sodium thiosulfate volumetric standard solution. The hydroxyl value is the amount of potassium hydroxide in milligrams that is equivalent to the hydroxyl amount of 1 gram of the sample (mg KOH/g sample). Poloxyl Stearyl Ether is a mixture of the monostearyl ethers of mixed polyethylene glycols. It may contain various amounts of free stearyl alcohol and some free polyethylene glycol. In this study, the iodine value and hydroxyl value have been determined by titration in polyoxyl stearyl ether. Iodine value 1.84 g of I2 absorbed/100g sample, and hydroxyl value 162.65 mg KOH/g sample have been found in poloxyl stearyl ether. The iodine value and hydroxyl value results met the United States Pharmacopeia specifications for Polyoxyl Stearyl Ether.

Harnessing dimethyl ether and methyl formate fuels for direct electrochemical energy conversion

In this work,the oxidation of a mixture of dimethyl ether(DME) and methyl formate(MF) was studied in both an aqueous electrochemical cell and a vapor-fed polymer electrolyte membrane fuel cell(PEMFC)utilizing a multi-metallic alloy catalyst,Pt_(3)Pd_(3)Sn_(2)/C,discovered earlier by us.The current obtained during the bulk oxidation of a DME-saturated 1 M MF was higher than the summation of the currents provided by the two fuels separately,suggesting the cooperative effect of mixing these fuels.A significant increase in the anodic charge was realized during oxidative stripping of a pre-adsorbed DME+MF mixture as compared to DME or MF individually.This is ascribed to greater utilization of specific catalytic sites on account of the relatively lower adsorption energy of the dual-molecules than of the sum of the individual molecules as confirmed by the density fu nctional theory(DFT) calculations.Fuel cell polarization was also conducted using a Pt_(3)Pd_(3)Sn_(2)/C(anode) and Pt/C(cathode) catalysts-coated membrane(CCM).The enhanced surface coverage and active site utilization resulted in providing a higher peak power density by the DME+MF mixture-fed fuel cell(123 mW cm^(-2)at 0.45 V) than with DME(84mW cm^(-2)at 0.35 V) or MF(28 mW cm^(-2)at 0.2 V) at the same total anode hydrocarbon flow rate,temperature,and ambient pressure.

Butyl ether as Co-diluent in medium-concentrated electrolyte for Li-S battery

1. Introduction The Lithium-sulfur battery(LSB) shows promise as a highdensity energy source, with a theoretical energy density of approximately 2600 W h kg^(-1)[1]. However, practical application of the LSB has been hindered by the “shuttle effect” and Li anode corrosion [2,3]. Highly concentrated electrolytes(HCEs) have been proposed as a solution, as they can inhibit the dissolution of lithium polysulfide and promote homogeneous lithium deposition [4].

抗VEGF治疗对不同类型DME患者黄斑中心凹无血管区的影响

目的基于糖尿病性黄斑水肿(DME)的不同影像类型,采用OCTA探讨DME患者抗血管内皮生长因子(VEGF)治疗前后黄斑中心凹无血管区(FAZ)结构的变化。方法回顾性分析2019年10月至2021年10月来我院就诊的经3+PRN抗VEGF治疗的51例62眼DME患者资料。根据黄斑水肿类型分为弥漫增厚型DME(DRT-DME)组30例(36眼)和黄斑囊样水肿型DME(CME-DME)组21例(26眼)。分别收集两组患者抗VEGF治疗前、治疗后3个月及治疗后6个月的临床资料和OCTA指标,包括最佳矫正视力(BCVA)、黄斑中心凹视网膜厚度(CRT)、FAZ面积、黄斑中心凹旁300μm范围内的视网膜血流密度(FD)和FAZ非圆度指数(AI),并对其进行比较分析。对CME-DME组患者抗VEGF治疗前后OCTA指标差值(治疗前与治疗后6个月差值)之间的相关性采用Spearman相关性分析。结果与治疗前相比,DRT-DME组患者治疗后3个月和治疗后6个月各方位的CRT均下降、BCVA均改善(均为P<0.05),但FAZ面积、FD和AI的差异均无统计学意义(均为P>0.05)。与治疗前相比,CME-DME组患者治疗后3个月和治疗后6个月各方位的CRT均下降、BCVA均改善、FAZ面积均减小、FD均增加和AI均减小(均为P<0.05)。而DRT-DME组和CME-DME组患者治疗后3个月、6个月之间相比,上述各指标间的差异均无统计学意义(均为P>0.05)。对CME-DME组患者抗VEGF治疗前后OCTA指标差值(△=治疗前-治疗后6个月)的Spearman相关性分析结果显示:△FAZ面积与△AI呈正相关(P<0.05);△FD与△FAZ面积、△AI均呈负相关(均为P<0.05);△CRT与△FAZ面积、△AI均呈正相关,与△FD呈负相关(均为P<0.05)。结论抗VEGF治疗对不同影像类型DME患者FAZ结构的影响不同,有助于改善CME-DME患者黄斑区血供,促进FAZ结构的修复,而对DRT-DME患者无明显影响,但随访期内未加重中心凹旁视网膜缺血。

CO_(2)utilization in syngas conversion to dimethyl ether and aromatics:Roles and challenges of zeolites-based catalysts

Several studies have proven a strong correlation between global warming and CO_(2)emissions.Annually,38 billion tons of CO_(2)are approximately emitted into the atmosphere.Utilizing CO_(2)via chemical conversion to clean fuels and value-added aromatics can substantially contribute to controlling the problem.Considering the thermodynamic and environmental limitations of hydrogenation of CO_(2)alone to value-added aromatics and fuels,CO_(2)utilization has currently emerged as a promising and practical approach for the production of fuels and aromatics with simultaneous utilization of both CO and CO_(2)wastes.As such,the approach is economically preferable.CO_(2)could be converted directly to fuels by the hydrogenation process or as a part of a syngas mixture.Dimethyl ether(DME)is a clean fuel with a higher energy density,which could be used as a substituent for several fuels such as diesel.In the same vein,value-added aromatics such as benzene,toluene,and xylene(BTX)can be produced from a similar process.Herein,we report a review that collects the most recent studies for the conversion of CO_(2)to DME and aromatics via zeolite-based bifunctional catalysts.We highlighted the main routes for producing DME and aromatics,as well as thoroughly discussed the conducted studies on CO_(2)hydrogenation and CO_(2)-rich syngas utilized as feedstock for conversion to DME and aromatics.The CO_(2)hydrogenation mostly occurs through the methanol-mediated reaction route but is most often limited by low selectivity and catalyst deactivation,particularly in the utilization of CO_(2)alone for the reduction reaction.The review takes an overview of the progress made so far and concluded by identifying the roles and challenges of zeolite-based catalysts for CO_(2)utilization and conversion to DME and aromatics.Accordingly,despite the incredible growth the field received in the last couple of years,however,many research challenges and opportunities associated with this process are still abounded and required to be addressed.Special attention is required for the development of approaches to block diffusion of H2O through zeolite to suppress the excess formation of CO_(2)in CO_(2)-rich syngas hydrogenation to DME and aromatics,exceed the product distribution limits,and suppress catalysts deactivation.

Li^(+)-ion bound crown ether functionalization enables dual promotion of dynamics and thermodynamics for ambient ammonia synthesis

Electrosynthesis of ammonia from the reduction of nitrogen is still confronted with the limited supply of gas reactant in dynamics as well as high activation barrier in thermodynamics.Unfortunately,despite tremendous efforts devoted to electrocatalysts themselves,they still fail to tackle the above two challenges simultaneously.Herein,we employ a heterogeneous catalyst adlayer-composed of crown ethers associated with Li^(+)ions-to achieve the dual promotion of dynamics and thermodynamics for ambient ammonia synthesis.Dynamically,the bound Li^(+)ions interact with the strong quadrupole moment of nitrogen,and trigger considerable reactant flux toward the catalyst.Thermodynamically,Li^(+)associated with the oxygen of crown ether achieves a higher density of states at the Fermi level for the catalyst,enabling effortless electron transfer from the catalysts to nitrogen and thus greatly reducing the activation barrier.As expected,the proof-of-concept system achieves an ammonia yield rate of 168.5μg h^(-1)mg^(-1)and a Faradaic efficiency of 75.3%at-0.3 V vs.RHE.This system-level approach opens up pathways for tackling the two key challenges that have limited the field of ammonia synthesis.

Durable semi-crystalline interphase engineering to stabilize high voltage Ni-rich cathode in dilute ether electrolyte

Ethers are promising electrolyte solvents for secondary Li metal batteries because of their excellent reduction stability.However,their oxidation stability has been mostly relying on the high concentration approach,and limited progress has been made on building effective interphase to protect the cathode from the corrosion of the electrolyte.In this work,we construct a semi-crystalline interfacial layer on the surface of Li(Ni_(0.8)Co_(0.1)Mn_(0.1))O_(2)cathode that can achieve improved electrochemical stability in the highly corrosive chemical environment formed by the decomposition of ether molecules.Different from traditional brittle crystalline interphases,the optimized semi-crystalline layer with low modulus and high ionic conductivity can effectively relieve electrode strain and maintain the integrity of the interface layer.Due to this design,the continuous oxidation decomposition of ether-based electrolytes could be significantly suppressed and the battery shows outstanding cycling stability(84%capacity retention after 300 cycles).This article provides a solution to address the oxidation instability issue of ether-based electrolytes.

Functional zirconium phosphate nanosheets enabled transfer hydrogenolysis of aromatic ether bonds over a low usage of Ru nanocatalysts

Catalytic hydrogenolysis of aromatic ether bonds is a highly promising strategy for upgrading lignin into small-molecule chemicals,which relies on developing innovative heterogeneous catalysts with high activity.Herein,we designed porous zirconium phosphate nanosheet-supported Ru nanocatalysts(Ru/ZrPsheet)as the heterogeneous catalyst by a process combining ball milling and molten-salt(KNO_(3)).Very interestingly,the fabricated Ru/ZrPsheetshowed good catalytic performance on the transfer hydrogenolysis of various types of aromatic ether bonds contained in lignin,i.e.,4-O-5,a-O-4,β-O-4,and aryl-O-CH3,over a low Ru usage(<0.5 mol%)without using any acidic/basic additive.Detailed investigations indicated that the properties of Ru and the support were indispensable.The excellent activity of Ru/ZZrPsheetoriginated from the strong acidity and basicity of ZrPsheetand the higher electron density of metallic Ru0as well as the nanosheet structure of ZrPsheet.