Additive Manufacturing of Stable Energy Storage Devices Using a Multinozzle Printing System

The development of the Internet of things has prompted an exponential increase in the demand for flexible, wearable devices, thereby posing new challenges to their integration and conformalization. Additive manufacturing facilitates the fabrication of complex parts via a single integrated process. Herein, the development of a multinozzle, multimaterial printing device is reported. This device accommodates the various characteristics of printing materials, ensures high-capacity printing, and can accommodate a wide range of material viscosities from 0 to 1000 Cp. Complete capacitors, inclusive of the current collector, electrode, and electrolyte, can be printed without repeated clamping to complete the preheating, printing, and sintering processes. This method addresses the poor stability issue associated with printed electrode materials. Furthermore, after the intercalation of LiFePO₄ with Na ions, X-ray photoelectron spectroscopy and X-ray diffraction results reveal that the Na ions permeate the interlayer structure of LiFePO₄, enhancing the ion migration channels by increasing the ion transmission rate. A current rate of 2.5 mAh ensures >2000 charge/discharge cycles, while retaining a charge/discharge efficiency of 96% and a discharge capacity of 91.3 mAh g⁻¹. This manufacturing process can provide conformal power modules for a diverse range of portable devices with various shapes, improving space utilization.     

Flash Lamps as Ignition and Initiation Sources of the VS-2 Pyrotechnic Composition

In the present work it is found that the pyrotechnic composition VS-2 can be initiated with flash lamps IFC-500 and EVIS. VS-2 pyrotechnic composition contains 90% of mercury（Ⅱ） 5-hydrazinotetrazolate perchlorate and 10% of optically transparent copolymer of 2-methyl-5-vinyltetrazole and methacrylic acid （PVMT）. We have found that the flash lamps make it possible to initiate combustion of VS-2 composition with its transition to detonation both in cylindrical charges placed in brass caps of 5 mm diameter and 2 mm high， and film charges with 10 mm×80 mm in size and surface weights of 60 mg·cm^-2 and 90 mg·cm^-2， showing ignition delay times 10 μs and 3 μs， respectively. We also measured detonation velocities for VS-2 composition film charges， which were 4375-4505 m·s^-1 （of the charge being surface mass 60 mg·cm^-2） and 4221-4281 m·s^-1 （of the charge being surface mass 90 mg·cm^-2） and their blasting action on the aluminum plate. The depths of the normal shock wave imprints at the charge-barrier interface were 0.6-0.7 mm （for surface mass of the film charges 60 mg·cm^-2） and 1.2-1.3 mm （for surface mass of the film charges 90 mg·cm^-2）.     

基准平面垂直断面法在爆破漏斗试验中的应用

系统阐述了基准平面垂直断面法在爆破漏斗试验中测量爆破漏斗体积的基本原理,并将隧道激光断面仪应用于金厂河矿1 750 m水平15^#采场底部切割巷道爆破漏斗试验爆破漏斗体积测量中。通过与传统体重法等计算法所得漏斗体积分析比较,结果表明基于隧道激光断面仪与3D Mine软件分析的基准平面垂直断面法实用性强、操作方便、结果直观可靠,达到试验预期目的。     

Experimental study on the propagation characteristics of hydrogen/methane/air premixed flames in a narrow channel

This work is focused on the explosion characteristics of premixed gas containing different volume fractions of hydrogen in a narrow channel (1000 mm × 50 mm × 10 mm) under the circumstance of stoichiometric ratio. The ignition positions were set in the closed end and the middle of the pipeline respectively. The results showed that when the gas was ignited at the pipeline closed end, the propagating flame was tulip structure for different premixed gas. When the hydrogen volume fraction was less than 40%, the flame propagation speed increased significantly with the rise of hydrogen volume fraction, and the overpressure peak also appeared obviously in advance. However, when the volume fraction of hydrogen was more than 40%, the increase of flame propagation speed and the overpressure peak occurrence time varied slightly. Furthermore, when the ignition position was placed in the middle of the pipeline, the flame propagation speed propagating to the opening end was much faster than that propagating to the closing end, and there was no tulip shape when the flame propagates to the opening end. The flame propagating to the closed end appeared tulip shape under the influence of airflow, and high-frequency flame oscillation occurred during the propagation. This work shows that the hydrogen volume fraction and ignition position significantly affected the flame structure, flame front speed, and explosion overpressure.     

Design of geocell reinforced roads through fragility modeling

Several studies have confirmed the geocell reinforcement system as potential road material. However, there is a wide gap between the number of research studies evaluating the geocell in the laboratory and those dealing with road design methods using the geocell. Due to this gap, the geocell system has not reached its full potential in highways. The present study proposes fragility modeling to design low volume roads by considering the geocell reinforced layer's modulus. A predictive model was developed to estimate the geocell layer's modulus using laboratory and finite element analysis results. The results indicate that geocell reinforcement reduces the stresses on the underlying road layers. The developed fragility approach is then used to examine three road designs for Texas's low volume road involving different geocell reinforced layers. The obtained fragility curves indicate the reliability of each of the three road designs against the traffic load and can thereby assist decision-makers in selecting the optimum design. By designing geocell reinforced roads via fragility modeling, highway officials will be able to integrate any uncertainties in the design inputs and check designs against road performance criteria such as rutting and fatigue cracking, and against decision criteria such as cost, emissions, etc.     

Scalable Yielding of Highly Stable Polyelectrolyte-Coated Copper Sulfide Nanoparticles by Flash Nanoprecipitation for Photothermal-Chemotherapeutics

Photothermal-chemotherapeutic nanoparticles (NPs) are attracting increasing attention and becoming more widely used for cancer therapy in the clinic due to their noninvasiveness, notable tissue penetration abilities, and low systemic adverse effects. However, functional ligands are conventionally modified onto photothermal NPs to well stabilize the inorganic particles suffering from complex chemical modifications, low productivity, and batch-to-batch inconsistencies, and thus significantly restricting their clinical applications. Herein, flash nanoprecipitation (FNP) is taken advantage of to afford rapid and uniform mixing for generating local supersaturated CuS clusters for small and highly stable CuS NPs effectively stabilized by polyacrylic acid through a continuous strategy. It greatly reduces the complexity for CuS NPs synthesis and functionalization in a facile intensified mixing process. These as-synthesized particles are high-drug loading, scalable, and most importantly, it is easy to control their sizes and charges through external conditions. Toxicity and tumor inhibition experiments confirm the high cell toxicity and good suppression of tumor growth under near-infrared irradiation indicating a promising prospect of FNP in the large-scale and continuous yielding of highly stable and high-performing photothermal-chemotherapeutic NPs for cancer therapy.     

An experimental study on the spray characteristics of pressure nozzle in a fluid bed granulation

The particles with a narrow size distribution are proper products in a fluid bed granulation and coating. As well, the process efficiency is one of the most important parameters, and the wall deposition of sprayed liquid reduces it. The modality of spray volume distribution is a key parameter in the definition of particle size distribution and process efficiency. This work is done in two steps: In the first step, an experimental study on spray characteristics including spray flux distribution, spray cone angle, and discharge coefficient is conducted. Based on the experimental data, the curves of liquid volume flux versus nozzle pressure and height are obtained. The results indicate that the flux distribution changes significantly with even small pressure and height changes. In the second step, the granulation process is carried out in a semi-industrial conical fluid bed, and the particles size distribution curves and the deposited mass on the bed wall are obtained. The results show that the precise determination of the spray flux distribution is an appropriate way to predict the well-advised nozzle pressure/height in order to achieve the narrow particle size distribution and high efficiency of the process.     

电驱液压式大截面导线压接设备自动化研究

现有的压接设备可控性差、操作复杂,导致压接质量因人而异。针对此问题,提出了基于DDVC技术的导线压接设备自动化控制方案,建立了速度控制系统数学模型,应用Simulink进行仿真,分析系统性能。建立了基于DEFORM的耐张线夹压接实验模型,获得了耐张线夹压接的最佳加载速度曲线,并以此作为压接设备速度控制系统的Simulink仿真模型输入,对压接过程进行了仿真分析。结果表明:开环控制时系统存在一定的超调,加入PID控制后可有效抑制超调;所设计的压接设备可很好地跟随最佳压接曲线,跟随误差仅为0. 904 mm·s-1。研究成果对改进压接设备、提高压接质量提供了新的解决方案。     

卡系费休法测定氯乙烯单体中水含量的影响因素

介绍了卡尔费休法的测定原理,具体分析了采用卡尔费休法测定氯乙烯单体中水含量的影响因素,指出采用闪蒸仪进样器,能有效提高分析结果的准确性和工作效率。