This study adopted a semi‑analytical CFD‑DEM coupling method to simulate the movement and deposition of lignin particles in ceramic membrane pores, with the aim of elucidating the microscopic mechanisms of membrane fouling. The movement of lignin particles is predicted to be primarily governed by local hydrodynamic forces and, for sub‑micron particles, by Brownian motion, whereas van der Waals forces determine the strength of particle–particle and particle–surface adhesion during deposition. Because the magnitude of this adhesive interaction was modeled as being controlled by the ‘surface energy’ parameter in the JKR model, calibration of this parameter was essential for reliable simulation results. Accordingly, this study concentrated on systematically analyzing how ‘surface energy’ could influence coordination number, filter‑cake porosity, and deposition morphology during particle sedimentation. The analysis identified a reasonable and physically consistent range for the ‘surface energy’ parameter. The results indicated that setting the particle ‘surface energy’ between 0.2 and 1.0 J/m² yielded deposition behavior that could closely resemble experimental trends reported for lignin filtration, thereby providing a theoretical basis for more accurate prediction and regulation of membrane‑fouling behavior.

Marine heavy metal pollution poses a severe threat to ecosystems and human health. Conventional detection methods can hardly meet the demand for on-site rapid monitoring, while micro-mixing technologies in microfluidic chips provide a novel approach for in-situ detection of heavy metals in seawater. This paper systematically reviews the research progress of active and passive micro-mixing technologies, analyzes their current applications in electrochemical and optical detection platforms, and discusses the adaptability of chip materials in seawater environments. The review indicates that passive micro-mixing technologies show greater potential for field applications due to their advantages of no external energy required and low cost. However, both electrochemical and optical detection methods still face common challenges in seawater applications, such as electrode corrosion, optical interference, and insufficient long-term stability. In the future, priority should be given to the development of seawater-adapted micro-mixers, anti-fouling sensing interfaces, and fully automatic integrated systems, so as to promote the translation of microfluidic technologies from the laboratory to practical marine monitoring applications.

Label-free cell sorting technology holds significant value in fundamental biomedical research and clinical precision diagnostics. However, existing dielectrophoresis sorting chips generally face the challenge of balancing high throughput with high resolution, while traditional metal electrodes are prone to bubble formation and sample contamination. To address these issues, this study proposes a ring-array dielectrophoresis microfluidic chip based on liquid electrodes. Through the synergistic design of semicircular flow channels and 36 circumferentially arranged liquid electrodes, the effective selection region of the electric field is significantly extended within the limited chip area, while a gradient electric field is formed along the flow direction, enabling continuous and dynamic deflection separation of particles of similar size. Key parameters such as voltage, frequency, and flow rate were optimized using a multiphysics simulation system, and the chip was fabricated via 3D printing. Fluorescent polystyrene microspheres of 5 μm and 15 μm were used to simulate non-target and target cells, respectively, and sorting experiments were conducted under various optimized parameter conditions. Compared to existing dielectrophoresis chips, this design maintains excellent resolution during high-throughput operations while fundamentally eliminating bubble formation and sample contamination caused by liquid electrodes, featuring a simple structure and convenient fabrication. This study provides a novel solution that balances performance and practicality for label-free, high-activity cell sorting, with subsequent efforts focused on validation with real-cell samples and exploration of integration with point-of-care diagnostic systems.

At the micro-scale channel dimensions and relatively low Reynolds numbers, fluids can only mix through diffusion in a laminar flow state. This dependence on molecular diffusion significantly hinders the mixing performance of microfluidic chips. To address this issue and promote the application of microfluidic technology in the detection of heavy metal ions, we propose a high-performance microfluidic chip with variable cross-sectional channels based on passive mixing. By setting bias centrifugal bends and linear flow channels with periodic diameter changes, the mixing efficiency of the microfluidic chip has been significantly improved. To verify the theoretical mixing effect, we set up eight groups of different Reynolds number conditions for the microfluidic chip and simulated the fluid flow in laminar state. Through analyzing the simulation cloud diagrams and the mass fraction mixing index, it was found that when the Reynolds number was 0.5, the mixing efficiency of the microfluidic chip reached the optimal state, with a mass fraction mixing index of 0.9998, and the pressure drop was only 0.1502 Pa, which was higher than the mixing efficiency of similar chips under the same conditions. Using 3D printing technology to fabricate the microfluidic chip and conducting characterization analysis. To verify the actual mixing effect, a colorimetric mixing experiment was set up, and a visual mixing effect analysis of the chip was conducted. Through ICP-MS for copper ion detection experiments, three control experiments were set up to conduct a data-driven mixed effect comparison analysis of the chip. After verification, the overall and local mixing effects of the microfluidic chip were highly consistent with the simulation results under the same conditions, and the detection value of the mixed solution was 101.99% of the completely mixed solution, showing good consistency. Therefore, this chip has excellent mixing performance and is conducive to promoting the application of passive microfluidic chips in fields such as heavy metal detection.

In ceramic digital light processing (DLP) additive manufacturing, the photosensitive resin, which acts as a carrier for ceramic particles, must exhibit suitable curing performance, curing strength, and viscosity. This ensures both the bonding strength of the fabricated ceramic parts and the dimensional accuracy of the ceramic green body. In this study, various photosensitive resin monomers were investigated in depth to formulate resins containing monofunctional, bifunctional, and multifunctional groups. Their rheological and curing properties were analyzed theoretically and experimentally. Different resin slurry systems were prepared and printed using DLP technology, and their mechanical properties were tested and compared. The effect of photoinitiator content on the curing behavior of the resin was examined, and the optimal photoinitiator concentration was identified. Based on the optimized resin, a zirconia ceramic slurry with 56 vol% solid content was prepared. After DLP printing, debinding, and sintering, dense zirconia ceramic samples with a relatively uniform grain structure were obtained, exhibiting a bending strength of 766.85 MPa. These results significantly expand the potential applications for zirconia ceramic components with complex geometries.

Digital light processing (DLP) is widely recognized as one of the most promising additive manufacturing technologies for ceramic fabrication. Nevertheless, during the additive manufacturing of zirconia ceramics, debinding and sintering often lead to structural defects, which severely deteriorate the material properties and hinder their broader application. In this study, we added an oligomer into the photosensitive resin and systematically investigated the effects of oligomer content on the viscosity and curing properties of ceramic suspensions. The results demonstrated that the introduction of oligomers is conducive to enhancing the crosslinking density and reducing defects. Finally, a 45 vol% solid content zirconia ceramic slurry was prepared by adding 20 wt% oligomers to the resin system. After printing, debinding, and sintering, the final zirconia ceramics exhibited a uniform microstructure without delamination or cracks, its bending strength reached 682.4 MPa. This study demonstrates that zirconia ceramics fabricated by photopolymerization with oligomer photosensitive resin exhibit excellent mechanical properties, significantly expanding the potential applications for high-performance zirconia ceramic components with additive manufacturing.

Aluminum nitride (AlN) ceramics exhibit exceptional properties that render them highly valuable for diverse industrial applications. However, conventional manufacturing techniques encounter significant challenges in fabricating complex AlN components with precise geometries. To address these limitations, digital light processing (DLP) has emerged as a promising additive manufacturing approach for AlN ceramics. This study presents a systematic investigation of the monomer composition in the photopolymer resin system through a comprehensive experimental evaluation. The results demonstrate that an optimized mixture of monomers ACMO (56.7 wt%), DEGDA (2.7 wt%), and TMPTA (40.6 wt%) yields photopolymer resin with superior comprehensive performance. Utilizing this optimized formulation, a 50 vol% solid loading AlN ceramic slurry was successfully prepared, and subsequently, dense AlN ceramic components were fabricated through DLP. This provides an important basis for optimizing the slurry preparation of AlN ceramic fabrication based on DLP 3D printing.

To break away from the reliance on equipment and time in traditional detection methods, a 3D printed chip with a combined three-dimensional complex cross-section was designed based on microfluidic technology. To verify the theoretical mixing effect, the mixing effect of the microfluidic chip was simulated and analyzed using Ansys Fluent software. Through the analysis of the visualized mixing cloud map and the data-based mixing index, it was found that the fluid achieved initial mixing in the offset mixing zone and supplementary mixing in the deflection mixing zone. The six groups of simulation results showed a stepwise increase, indicating that the microfluidic chip has a good and stable mixing effect. To verify the actual mixing performance, colorimetric mixing experiments and Gas Chromatography-Mass Spectrometry (GC–MS) detection experiments were conducted on the microfluidic chip, with a control experiment set up for the latter. The results showed that the mixing effect of the microfluidic chip at the same Reynolds number (Re) was in good agreement with the simulated cloud map. In the GC–MS detection, the detection value of the pesticide solution (DDV, Dichlorvos) mixed by the microfluidic chip was highly consistent with that of the well-mixed control group, verifying the scientific rationality of the microfluidic chip structure. This microfluidic chip has excellent and stable mixing performance, providing a certain theoretical and practical basis for promoting the integration and interaction of microfluidic technology and GC–MS detection technology, and is expected to be widely applied in the field of pesticide residue detection.

Aluminum nitride (AlN) ceramics exhibit exceptional properties, making them attractive for a wide range of applications. To address the growing need for customized and geometrically intricate AlN components, digital light processing (DLP) has garnered significant interest as a highly promising additive manufacturing technology. In this study, the effects of the sintering process on DLP 3D printing of AlN ceramics were investigated. An optimized slurry formulation with a solid loading of 52 vol% was developed, exhibiting excellent rheological properties. By applying a controlled sintering heating rate of 0.5 °C/min, dense AlN ceramic components were successfully fabricated, achieving a bending strength of 212.6 MPa. This provides a novel approach for optimizing the DLP additive manufacturing process of AlN ceramics.

The separation and recovery of lignin in black liquor is a hot topic in current research. Ceramic membrane technology has become the main method of lignin separation in black liquor due to its advantages of green environmental protection, high efficiency and high recovery rate. However, in the separation process, the problem of ceramic membrane fouling has always existed and has become the key to hinder its continuous separation. Aiming at the problem that the existing filtration methods can not meet the continuous separation of lignin in black liquor, this paper proposes to apply the blade dynamic cross-flow filtration device to the separation process of lignin in black liquor, and the influence of blade rotation speed on the separation performance is studied experimentally. The results showed that increasing the rotating speed of the blade could effectively reduce the accumulation of filter cake on the membrane surface and achieve the purpose of improving the filtration flux.

The discrete element method coupled with the computational fluid dynamic (CFD-DEM) method is effective for studying the micro-flow process of lignin particles in ceramic membranes. Lignin particles may exhibit various shapes in industry, so it is difficult to model their real shapes in CFD-DEM coupled solutions. Meanwhile, the solution of non-spherical particles requires a very small time-step, which significantly lowers the computational efficiency. Based on this, we proposed a method to simplify the shape of lignin particles into spheres. However, the rolling friction coefficient during the replacement was hard to be obtained. Therefore, the CFD-DEM method was employed to simulate the deposition of lignin particles on a ceramic membrane. Impacts of the rolling friction coefficient on the deposition morphology of the lignin particles were analyzed. The coordination number and porosity of the lignin particles after deposition were calculated, based on which the rolling friction coefficient was calibrated. The results indicated that the deposition morphology, coordination number, and porosity of the lignin particles can be significantly affected by the rolling friction coefficient and slightly influenced by that between the lignin particles and membranes. When the rolling friction coefficient among different particles increased from 0.1 to 3.0, the average coordination number decreased from 3.96 to 2.73, and the porosity increased from 0.65 to 0.73. Besides, when the rolling friction coefficient among the lignin particles was set to 0.6–2.4, the spherical lignin particles could replace the non-spherical particles.

In the surface filtration process with pores larger than the particle size, the formation of particle bridges plays a crucial role in the filter cake structure and the filtration efficiency throughout the filtration process. First, to understand the microscopic information required for the bridging mechanism, we use the two-way coupling of computational fluid dynamics (CFD)–discrete element method (DEM) to simulate the deposition characteristics of particles in the pores of ceramic membranes. Next, by dynamically observing the deposition morphology and bridging process of particles, the bridging mechanism was revealed at the level of a single hole. Then, we studied the influence of particle concentration and inlet velocity on the bridge erection process. The results show that the bridging function of particles runs through the clean filtration stage and the transition stage. Particle concentration and inlet flow rate have a crucial influence on the formation of particle bridges and filtration efficiency.

The study about the low-temperature performance of lithium-ion batteries (LIB) is of great significance at extreme temperatures, such as polar scientific research, space exploration, deep-sea exploration, military fields, and so on. In this study, normal devices and symmetrical devices were fabricated by ternary Li(Ni0.5Mn0.3Co0.2)O2 as cathode and graphite as anode at 25 and −20 °C. The results show that the specific discharge capacity of normal device is up to 120 mAh g−1 at 1 C and 25 °C. The specific capacity and energy density at 0.2 C and −20 °C are 106.05 mAh g−1 and 376.53 mWh g−1, respectively, which can reach 92.82% of that at 1 C and 25 °C. The value of activation energy Ea of the interface reaction of the LIB is calculated to be 63.72 kJ/mol by the Arrhenius equation. When the temperature dropped from 25 to −20 °C, the lattice spacing of Li1−x(Ni0.5Mn0.3Co0.2)O2 hardly changed, while the lattice spacing (002) of graphite reduces 0.00248 Å. In addition, some cracks were observed on the charged cathode at −20 °C. We carried out quasi-in situ electrochemical impedance spectroscopy (EIS) when the voltages of normal device discharged to 3.8, 3.6, 3.4, 3.2, and 3.0 V. Unlike the relationship of voltage–resistance at 25 °C, the values of the series resistance (Rs), charge transfer resistance (Rct), and ion transfer resistance (Rit) gradually decrease as the voltage decreases at −20 °C. Compared with the resistance of the symmetrical device based on the anode at 25 °C, the values of Rs and Rit at −20 °C both obviously increase. The main reason of performance degradation for normal device at −20 °C is large ion transfer resistance and the decrease of lattice spacing of the graphite (002).

The optical window is an essential channel for optical signal transmission and return of a deep-sea hydrothermal velocimetry system. Due to its unique structural design, the stress concentration of the optical window will occur under the action of deep-sea high pressure, resulting in cracks at the corner of the high-pressure surface of the optical window, which leads to the inaccurate convergence of the optical signal. A pressure self-balancing optical window package structure is designed to solve the problem. The stress at the optical window is numerically analyzed, and the forces of self-balancing and nonpressure self-balancing optical windows under the same seawater pressure are compared. The results show that the maximum stress at the stress concentration can be reduced by 53% using the pressure self-balancing method, and the phenomenon of stress concentration can be effectively eliminated. In addition, to verify the feasibility of the design and the accuracy of the numerical calculation results, the optical window and its encapsulation structure were experimentally studied, and the deep-sea performance test experiment was carried out on the “Jiaolong” submersible, which further verified the accuracy of the results.

为探究超临界CO2连续萃取环境下合适的料仓用密封件,利用ANSYS软件建立O形、Y形与U杯形密封圈二维对称模型,分析推入过程中压缩量、摩擦因数影响下密封件的接触应力、等效应力和最佳推入形式,以及承压状态下密封件应力分布与应力的变化规律.结果表明:在推入过程中,O形圈拥有较好的预紧密封性能,U杯形圈的等效应力最小且应力分布均匀;随着压缩量与摩擦因数的增大,O形与Y形圈应力变化会发生波动,而U杯形圈各应力保持线性增长;承压工作状态下,唇形的Y形和U杯形密封件密封性能优于O形圈;Y形圈在高压工况下密封性能最优异,但低唇底部容易发生剪切破坏,影响其使用寿命,而U杯形圈在高压工况下密封性能表现最稳定、可靠.

利用Fluent软件对圆盘错流过滤机的一级滤室进行流场模拟,分别模拟了圆盘转速为300r/min和800r/min时不同跨膜压作用下的流场情况.后处理发现动压力和剪切速度均随着圆盘半径的增大而增大.转速800r/min时的动压力大约是300r/min时的12倍;低转速时,剪切速度的最大值随着进口压力的增大而增大,进口压力的变化对剪切速度的影响相对高转速来说更加明显.

作为深海探测技术的重要组成部分,原位分析仪/传感器可原位实时获取大量数据,实现物质的高密度、长时序、多空间尺度连续观测,是深海运载装备和科学研究所需的测量装置.国家重点研发计划"深海关键技术与装备"专项"基于载人潜水器的深海原位多参数化学传感器研制"(项目编号:2016YFC0302200),针对载人潜水器、遥控无人潜水器(ROV)等深海运载装备对"长时序、多空间尺度"数据的需要,采用连续流动分析-分光光度法研发出一种可同时快速测量溶解态Fe(II)、Fe(III)、Mn(II)、硫化物4种组分的深海原位化学分析仪.该分析仪适合于载人潜水器等运载装备搭载,可提高载人潜水器的水下作业能力和效率,为我国深海科学考察和研究提供技术支撑.

Deep-sea in-situ chemical analyzer can obtain data with high frequency, which is very useful for scientific research and necessary for deep-sea transportation equipment. In this work , an in-situ analyzer was developed for automated determination of dissolved Fe(II), Fe(III), Mn(II) and sulfide simultaneously in deep sea based on continuous flow analysis and spectrophotometric detection. The integrated system consisted of a pressure-resistant housing an oil-filled pressure-compensated vessel, and a self-developed hardware to control two multi-channel peristaltic pumps , four solenoid valves and a photoelectric acquisition module. Experimental conditions related to the analysis , including flow path module , spectrometric regent compositions and pH of buffer solution were evaluated and optimized. This deep-sea in-situ chemical analyzer was designed to work at the depth of 7000 m with a measuring frequency of 1 Hz , and showed a limit of detection as low as 0. 013 , 0. 024, 0. 014 , and 0. 012 mu mol/L for dissolved Fe (II), Fe(III) Mn(II) and sulfide, respectively. The calibration curves prepared in standard solutions were consistent over the linear range of 0. 1-60 , 0. 2-100 , 0. 1-40 and 0. 1 -40 mu mol/L for dissolved Fe(II) Fe(III), Mn(II) and sulfide, respectively. After the test of shallow sea, hydrostatic pressure and tank test, this analyzer was implemented on tool shed of Jiaolong deep manned submersible , and perf'ormed sea trial. Spectra and signal intensity changes of the maximum absorption wavelength were obtained in-situ at the depth of 3196 m. This compact automatic analyzer was suitable 14 deep sea in-situ determination of the chemical environment of hydrothermal vent habitats.

针对深海激光流速仪的工作环境,设计了包含光学窗口封头与筒体的深海激光流速仪封装结构.应用ANSYS Workbench软件分别对光学窗口封头和筒体的受力情况进行数值分析,并利用深海高压环境模拟实验室对封装后的深海激光流速仪进行50 MPa耐压试验.结果表明:在60 MPa计算压力下,所设计的深海激光流速仪封装结构耐压性能满足使用要求;封装后深海激光流速仪在50 MPa试验压力下舱体无变形,蓝宝石窗口完好,设备工作正常.通过理论计算与数值分析相结合的方法对深海激光流速仪封装结构进行设计,可以在保证耐压性能的基础上有效提高设计效率,降低成本,对其它深海仪器封装结构的设计也有借鉴作用.

针对深海低温条件下海洋观测锂电池放电能力弱的情况,设计了一种深海耐压双层保温电池舱.利用ANSYS Workbench软件仿真分析了在不同保温层厚度下电池舱内温度分布情况以及电池舱内温度随时间的变化关系.仿真结果显示,随着保温层厚度的不断增加,电池舱内温度不断升高,温度达到稳定的时间也在不断增加,并且发现选用真空保温层2 mm,聚氨酯保温层5 mm的组合保温方式最有效.