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The bottom hole opening method is generally used to rescue the people trapped inside the capsized vessels. In this paper, a new sealed cabin with flexible cabin shell and rigid pedestal was proposed to rescue people in distress through the inner hole cut on the bottom hull. The parameters of the cabin pedestal and the sealed pedestal are optimized respectively to reduce the weight of the whole cabin. According to response surface methodology to analysis the relationship between the tress and the structural parameters. The maximum equivalent stress and maximum deformation are the constraint conditions and the total mass of the structure is the objective function, and the multi-island genetic algorithm is used to optimize the model, and the approximate optimal solution was finally obtained. The results show that the strength of cabin pedestal and sealing pedestal meet the application requirements.

Phase change buoyancy control systems (PBCS) driven by phase change materials have unique advantages over conventional hydraulically actuated buoyancy control systems, especially in their high adaptability for deep-sea exploration and seamless interaction with humans. Studying the heat transfer process and working mechanism of PBCS is helpful to research the precise control mode of the phase change buoyancy regulation system. In this study, we chose paraffin wax as the phase change material for PBCS. A buoyancy generator for phase change buoyancy regulation is designed and manufactured. By studying the relation between its expansion volume and heating time and heat input, the mathematical model of the volume change of PBCS is established. We obtain the calculation results of the PBCS working process by using the computer-aided software MATLAB. Experimental results show that the theoretical volume expansion velocity and volume expansion rate of paraffin are almost consistent with the experimental results. The mathematical calculation model is available and has a significant reference value for further research on the theoretical basis of the diving depth control of PBCS.

As an important medium of human-computer interaction, flexible tactile sensors have a vital influence on the intelligence and safety of a system by accurately identifying the contact position and force. For now, most of the existing flexible capacitive pressure sensors adopt an array structure, which still cannot meet the requirements including simple manufacturing, simple wiring, and low cost. This paper innovatively proposes a flexible array-less capacitive tactile sensor, a 30 mm × 30 mm sensor prototype, consisting of flexible electrodes and a dielectric layer of a polydimethylsiloxane (PDMS) and multiwalled carbon nanotube (MWCNT) composite. Under the action of a contact force, the contact area is deformed, resulting in a capacitance change in the flexible sensor. First, Poisson’s equation is used to determine the relationship between the electric potential and position. Then, elastic contact mechanics is adopted to describe the relationship between the electric charges and force. Finally, the contact position and force are recognized by measuring the change in capacitance in real time, based on the classical principle of capacitance. Simulation and experimental results verified the effectiveness of the proposed recognition method, showing that the recognition resolution of contact position can reach 500 μm × 100 μm, and the accuracy of contact force is 95.85%. Theoretically, the proposed flexible array-less sensor in this paper has infinite spatial resolution, and most importantly, it does not rely on complex manufacturing, redundant circuits, or sensor cell arrays. Therefore, it has broad application prospects in related fields such as electronic skin and wearable electronic devices.

Oxide thin-film transistors (TFTs) have attracted much attention because they can be applied to flexible and large-scaled switching devices. Especially, oxide semiconductors (OSs) have been developed as active layers of TFTs. Among them, indium-gallium-zinc oxide (IGZO) is actively used in the organic light-emitting diode display field. However, despite their superior off-state properties, IGZO TFTs are limited by low field-effect mobility, which critically affects display resolution and power consumption. Herein, we determine new working mechanisms in dual-stacked OS, and based on this, we develop a dual-stacked OS-based TFT with improved performance: high field-effect mobility (∼80 cm2/V·s), ideal threshold voltage near 0 V, high on-off current ratio (>109), and good stability at bias stress. Induced areas are formed at the interface by the band offset: band offset-induced area (BOIA) and BOIA-induced area (BIA). They connect the gate bias-induced area (GBIA) and electrode bias-induced area (EBIA), resulting in high current flow. Equivalent circuit modeling and the transmission line method are also introduced for more precise verification. By verifying current change with gate voltage in the single OS layer, the current flowing direction in the dual-stacked OS is calculated and estimated. This is powerful evidence to understand the conduction mechanism in a dual-stacked OS-based TFT, and it will provide new design rules for high-performance OS-based TFTs.

Halide perovskites have drawn considerable attention as a remarkable material in advanced optoelectronics. However, toxicity and poor stability of halide perovskites are major challenges hindering ...

The Li metal anode has high theoretical specific capacity and low redox potential, making it suitable as an anode material for next-generation Li ion-based batteries (LIBs); however, challenges remain due to its unstable solid electrolyte interphase (SEI). In this study, we applied graphene-coated aramid attached to an uncoated aramid separator fabricated using a simple painting method to a Li metal anode to address the issues caused by the unstable SEI via fluorinated metathesis on a conjugated carbon network (CCN). The graphene-coated surface was partially fluorinated in a specific solvent environment, and as the Li+ ions were plated, the fluorinated surface induced formation of LiF as a chemically stable SEI component. Additionally, we demonstrated the successful application of fluorinated metathesis using other CCN materials, such as carbon black and activated carbon. The experimental results indicated that the CCN materials induced LiF via fluorination, and that the negative functionalities and lattice structure of the CCN materials affected the fluorination. These results demonstrated the effectiveness of this novel method for stabilizing a Li metal surface using a graphite pencil.

Recently, organic compounds are considered as promising candidates for application in next-generation energy storage systems to overcome the disadvantages of conventional inorganic cathode materials, including their low specific capacity and poor disposal systems. In particular, pillar[5]quinone (P5Q) is very effective as it provides active sites that favor Li uptake and promote a high theoretical capacity. Herein, we propose P5Q-derived cathodes, which are enveloped in multi-walled carbon nanotubes and cellulose nanofibers (CNFs), fabricated by a simple vacuum-filtering method. The designed cathode solves the issues associated with organic materials, including their high solubilities in aprotic electrolytes and low conductivities. Furthermore, CNFs are introduced as alternatives to conventional polyolefin separators. CNF separators can effectively suppress the dissolution of active materials in liquid electrolytes. In addition, CNFs improve ionic conductivity (0.88 mS cm−1), electrolyte wettability (electrolyte uptake: 333.41%, porosity: 70 ± 5%), and thermal shrinkage in contrast to conventional polyolefin separators. The Li-ion battery, assembled with the suggested P5Q cathode and CNF separator, exhibits highly stable capacity retention (76.5% after 50 cycles at a 0.2 C rate) and good rate capability, although an organic electrolyte is used.

Recently, lithium–sulfur batteries (LSBs) have been highlighted as next-generation batteries due to the high theoretical capacity of the sulfur nonmetal and Li metal. However, LSBs are difficult to be commercialized because of the continuous capacity fading phenomenon derived from the shuttle effect of lithium polysulfide. Herein, a novel organic–inorganic composite separator composed of poly(vinylidene fluoride-co-hexafluoropropylene) and anodic aluminum oxide is proposed to overcome these limitations. The proposed separator strongly reduces the dissolution issue of lithium polysulfide and considerably limits the movement of polysulfide. Moreover, it improves the stability of the lithium metal anode by evenly distributing the flux of lithium ions. Also, it shows excellent thermal stability and good electrolyte wettability. Therefore, the ionic conductivity shows a high value of more than 1 mS cm−1, and the coulombic efficiency is over 99%. The LSBs assembled with the composite separator exhibit the maintained specific capacity over of 75% after 100 cycles at 0.5C.

Li metal is an ideal anode material for batteries based on Li ion because of its high theoretical specific capacity and low redox potential. However, the repeated formation and collapse of solid el...

Metal oxide semiconductors doped with additional inorganic cations have insufficient electron mobility for next-generation electronic devices so strategies to realize the semiconductors exhibiting stability and high performance are required. To overcome the limitations of conventional inorganic cation doping to improve the electrical characteristics and stability of metal oxide semiconductors, we propose solution-processed high-performance metal oxide thin-film transistors (TFTs) by incorporating polyaniline (PANI), a conductive polymer, in a metal oxide matrix. The chemical interaction between the metal oxide and PANI demonstrated that the defect sites and crystallinity of the semiconductor layer are controllable. In addition, the change in oxygen-related chemical bonding of PANI-doped indium oxide (InOx) TFTs induces superior electrical characteristics compared to pristine InOx TFTs, even though trace amounts of PANI are doped in the semiconductor. In particular, the average field-effect mobility remarkably enhanced from 15.02 to 26.58 cm2 V-1 s-1, the on/off current ratio improved from 108 to 109, and the threshold voltage became close to 0 V actually from -7.9 to -1.4 V.

Numerous studies have reported the important role of microRNAs (miRNAs) in human cancers. Although abnormal miR-29b expression has been linked to tumorigenesis in several cancers, its role in cholangiocarcinoma remains largely unknown. We found that miR-29b expression is frequently downregulated in human cholangiocarcinoma QBC939 cells and in clinical tumor samples. In cholangiocarcinoma patients, low miR-29b expression predicts poor overall survival. Overexpression of miR-29b in QBC939 cells inhibited proliferation, induced G1 phase cycle arrest, and promoted apoptosis. Methylation-specific PCR (MSP) analysis revealed a decreased methylation imprint at the promoter of the cell cycle inhibitor gene CDKN2B in cells overexpressing miR-29b. After identifying the DNA methyltransferase DNMT3B as a putative miR-29b target, luciferase reporter assays confirmed a suppressive effect of miR-29b on DNMT3B expression. Accordingly, we detected an inverse correlation between miR-29b and DNMT3B expression in clinical cholangiocarcinoma specimens. In QBC939 cells, DNMT3B overexpression promoted proliferation and inhibited apoptosis. DNMT3B silencing, in turn, led to increased CDKN2B expression. We also observed significant growth arrest in subcutaneous tumors formed in nude mice by QBC939 cells overexpressing miR-29b. These findings suggest miR-29b functions as a tumor suppressor in cholangiocarcinoma by relieving DNMT3B-mediated repression of CDKN2B expression.

Lithium metal is one of the most attractive anode materials, due to its high theoretical specific capacity and lowest electrochemical potential. However, low coulombic efficiency and serious safety hazards have still hindered the wide applications of next-generation batteries including Li–S and Li–air. Previous studies have suggested overcoming the problem by applying various structures of current collectors. These structures homogenize the Li ion flux or provide space for volume expansion. However, there are some limitations to solving problems occurring at the Li metal surface, because the current collector is underneath the structures of Li metal. In this work, we propose a facile and cost-effective strategy for stabilizing the lithium metal–electrolyte interface via a three-dimensional stainless steel mesh (SSM) interlayer. Its high specific surface area lowers the local current density and provides an electronic flow path for dead Li. Also, this structure leads to confinement of Li deposits and alleviates volume expansion. As a result, the Li anode with the SSM interlayer operated at current densities of 1 mA cm−2 (1C rate) and 5 mA cm−2, and it exhibited a longer cycle-life than planar structures in a symmetrical cell configuration.

Li metal is one of the best candidate anode materials for next-generation Li ion batteries (LIBs) and the most promising anode material that can replace the carbonaceous anode currently in use because of its high theoretical specific capacity and low redox potential (vs. SHE). Nevertheless, in order to apply Li metal to LIBs as an anode, issues such as those related to the cycle characteristics such as the life span and C-rate capability need to be resolved. These issues arise owing to the solid electrolyte interphase (SEI) formed on the surface of the Li metal anode (LMA). Unlike the conventional graphite anode, which exhibits a stable intercalation/de-intercalation mechanism, the Li metal anode, which utilizes a lithiation-delithiation mechanism known as hostless electrochemical plating/stripping to charge/discharge, undergoes repeated formation/collapse of an unstable SEI layer on its surface. Thus, the LMA is continuously exposed to undesirable interfacial reactions with the liquid electrolyte. The continuous occurrence of these side-reactions deteriorates the cycle characteristics of the LMA. In particular, this phenomenon gradually intensifies as the applied current increases, leaving the LMA operative within limited cycles at a high current density. Thus, the surface of the LMA needs to be subjected to additional treatments, based on studies of interfacial phenomena, for introducing it to LIBs, which many research groups attempted. Of the many approaches, studies that stabilization of the LMA surface by the introduction of a conductive interlayer between the LMA and separator or by applying a functional separator provided excellent results and the advantage using Li metal without structural modification. Similarly, a good interlayer or functional separator should be able to control undesirable interfacial reactions by the formation of the stable SEI layer, which prevents accumulation of an inactive layer and liquid electrolyte depletion, maintaining the cycle characteristics of LMA. In particular, when there is a conductive interlayer above the LMA, the conductive interlayer at the top structurally meets the Li+ ion flux first during the plating step. Therefore, the SEI layer formed is more stable on the conductive interlayer than on the LMA surface and could thus ensure surface stability of the LMA, preventing repeated SEI formation/collapse, dendritic growth, and liquid electrolyte depletion. In consideration of this point, in this work, we proposed non-woven type reduced graphene oxide fibers attached to aramid paper (rGOF-A) as an advanced separator to solve the aforementioned issues presented by an unstable SEI layer. When the rGOF side of rGOF-A contacts the Li metal anode, it functions effectively as a conductive frame, so the electrons can migrate from the underlying the LMA to the rGOF as the current is applied. Thus, the rGOF first meets the Li+ ion flux rather than the LMA, and the SEI layer, which has different chemical characteristics than those of the LMA surface, forms more stably mainly on rGOF in strong reductive conditions. In other words, rGOF can act a conductive layer and induces formation of the SEI layer in rGOF, not the LMA, helping toward stable operation of the LMA. In addition, this formed stable SEI layer can be effectively confined within the rGOF frame to have a high modulus. Moreover, as the electrolyte is consumed to form the SEI layer on the surface of rGOF, chemically reactive C–F bonds are generated at the surface of rGOF and the partially fluorinated rGOF surface induces the formation of LiF known as the component of the stable SEI during the Li+ ion plating process. LiF is a key component in a stable SEI layer on the LMA because it has a wide electrochemical stability window and improves the surface diffusion of ions, which can lead to smooth Li plating. Thus, LiF protects the LMA from further repeated SEI layer formation/collapse processes and helps the LMA to operate reliably. This passivation effect of rGOF on the LMA surface allows the LMA to maintain its cycle characteristics for a rapid charging/discharging condition (20 mA cm-2, 1 mAh cm-2) as well as at a higher areal capacity (20 mA cm-2,20 mAh cm-2) than practical application condition. Thus, the rGOF-A functional separator ensures cycling stability of the LMA without any deteriorating factor, which contributes to large Li source irreversibility, and this does not involve a structural change for the LMA or additional treatments such as those involving additives to maintain to the cycle characteristics or lifespan. Figure 1

Lithium-ion batteries (LIBs) have been widely used in many industries in recent years. In particular, the electrical vehicles (EVs) and energy storage system (ESS) markets are growing rapidly, and the requirements for LIBs are also growing. Under these circumstances, the active materials for LIBs that have been used are insufficient in various aspects. The most important characteristics of newly requested LIBs are economics and capacity. Until now, the industry sector where LIBs were mainly used was mainly devices with relatively small size and output, such as portable electronic devices. Therefore, if a certain level of capacity was secured in LIBs, there was no demand for an extremely large-capacity battery. However, due to changes in the industry, devices that require high power and long-term use, such as EVs and ESS, have emerged as new demands, and the requirements of LIBs have gradually changed to emphasize the capacity side. The cathode active materials used in commercially available LIBs are mostly metal oxides containing rare metals such as nickel and cobalt. These metal oxide-based cathode active materials have a relatively low theoretical capacity, unstable supply, and low production. So the price fluctuation is very high and the price is also very expensive. Anode has also been sideways for decades without significant changes in capacity since LIBs were commercialized, and new attempts at the active material level are needed. Research to introduce a new active material to secure these shortcomings has become more active in recent years. Lithium-sulfur batteries (LSBs), which use sulfur as the cathode material and lithium metal as the anode active material, are receiving great attention as next-generation LIBs in this respect. In the case of sulfur used as a cathode active material, charging and discharging proceeds through a conversion reaction between sulfur and lithium, and thus has a very high theoretical capacity. This shows the potential to be a positive electrode active material with a significantly higher capacity than materials having a layered structure of a metal oxide series used in the conventional LIBs. Also, as a by-product of the petrochemical industry, a very large amount of supply is made, but the demand is not so abundant, so it has a very low price. Lithium metal, which is used as an anode active material, also has a very large capacity, making it one of the most actively studied materials in the LIBs field. Lithium metal has a theoretical capacity of over 3800mAh g-1, so its potential is endless. However, despite these great advantages, LSBs have not been commercialized because there are big disadvantages to be solved. When considering the problems caused by the cathode and those caused by the anode, the problem with cathode active material is the lack of life characteristics. In particular, the biggest problem is that the capacity of the system continuously decreases due to the dissolution of lithium polysulfide. Lithium polysulfide, an intermediate produced during the charging and discharging process, dissolves very well in the organic liquid electrolyte, so it moves freely between the cathode and the anode. At this time, since it is continuously reduced in the anode region to form an inactive layer, as the cycle progresses, the amount of active material decreases, so that life characteristics are not secured. Another major problem is that caused by lithium metal used as an anode. Lithium metal shows low coulombic efficiency by repeatedly generating an SEI layer on the surface as charging and discharging progress. Furthermore, it reacts with the liquid electrolyte and continuously consumes electrolyte and active material, showing very poor life characteristics. In this study, we proposed a new type of organic-inorganic composite separator that can solve the above two problems at once. The proposed separator (PAAO) was fabricated by filling poly (vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) on the surface and inside of anodic aluminum oxide (AAO). Since AAO has vertical pores with regular spacing, it provides stability at the interface of lithium metal to improve the life characteristics of the anode. Also, PVdF-HFP provided a passage for lithium ions inside the pores of AAO and effectively prevented the movement of lithium polysulfide. AAO showed an improved lifespan of over 50% compared to a separator made of a commercially available polyolefin-based polymer. As a result, PAAO showed an improved lifespan of more than 50% and high coulomb efficiency in all cycles compared to the separator made of commercially available polyolefin-based polymers. We believe that PAAO has shown potential as a new separator that can be applied to next-generation LSBs. Figure 1

The exact direction, of the surface energy characterized functional group of self-assembled monolayer (SAM), is proposed for achieving the enhanced electrical stability of indium gallium zinc oxide (IGZO) semiconductor thin film transistor (TFT). The SAM treatment, particularly at the SAM functional group having lower surface energy, makes oxygen molecules difficult to be adsorbed onto IGZO. And such an effect much improves positive bias stability (PBS) and clockwise hysteresis stability to the same tendency. For NH2 and CF3 functional group SAMs with surface energies of 49.4 mJ/m2 and 23.5 mJ/m2, respectively, the IGZO TFT PBS was improved from 2.47 V to 0.32 V after the SAM treatment and the IGZO TFT clockwise hysteresis was also enhanced from 0.23 V to 0.11 V without any deterioration of TFT characteristics. Employing lower surface energy functional group to the SAM, of same head group and body group, does passivate and protect the IGZO backchannel region from oxygen molecules in the atmosphere. Consequently, the enhanced electrical stability of IGZO TFT can be achieved by the simple and economic SAM treatment.

The Neoproterozoic strata of the Sichuan Basin are a key target for oil and gas. To evaluate the hydrocarbon evolution and its relationship with tectonic events in the Micang Shan uplift, northernmost Sichuan Basin, we apply solid bitumen geochemistry (bitumen reflectance and fluorescence) and Re-Os geochronology. The geochemistry of the solid bitumen indicates that it is highly mature pyrobitumen that formed contemporaneously with dry-gas generation during oil thermal cracking. The pyrobitumen is enriched in both Re (∼106–191 ppb) and Os (∼3030–5670 parts per trillion). The Re-Os isotope data imply an Early Jurassic date for pyrobitumen formation, which coincides well with age estimates from fluid-inclusion data and basin modeling. The Re-Os date for pyrobitumen formation coupled with previously presented apatite fission-track (AFT) analysis show that exhumation of the Neoproterozoic strata occurred during the Cretaceous in the Micang Shan uplift. This extensive uplift led to the erosion of any potential gas reservoirs and surface exposure of bitumen-bearing Neoproterozoic strata. In contrast, the more southern and central portions of the Sichuan Basin have experienced less severe exhumation and, as a result, Neoproterozoic-sourced gas systems are present. This study shows that, through the combined application of Re-Os and AFT methodologies, the timing of gas generation and subsequent erosion of any potential gas reservoirs in the Micang Shan uplift, northern Sichuan Basin, can be quantified. Moreover, the Re-Os and AFT data illustrate the potential to constrain the timing of gas generation in petroleum systems worldwide.

Rubber hose is normally adopted in the connection between the lifting cylinders and the control valves. Low bulk modulus of hose reduces the natural frequency of hydraulic system and brings difficulties to the controller design. This paper focuses on the model simplification of hoses in the hydraulic system. First, a hydraulic lifting system is presented in the paper. Then, simulation model of the lifting system is built in AMESim, and the simplified model of hose is conducted using an improved lumped parameter method. Finally, comparative simulations with the proposed model and the original model provided in the software are carried out. Results show that the simplified model can be used to replace the original model in the simulation of hydraulic systems.

Driving processes and characteristics are different between the water hydraulic artificial muscle and pneumatic artificial muscle due to the difference of work media employed in muscles. An appropriative hydraulic circuit was designed to control the pressure of the water hydraulic artificial muscle and the performance of this system was analyzed. An AMESim model of the control system was built and the dynamic characteristics are analyzed with various parameters of the hydraulic circuit and various loads by simulation. The results show that the performance of the water hydraulic control valve should agree with the dimension of the water hydraulic artificial muscle. The rated flow rate of the water hydraulic valves can be selected increasingly while the load mass is low. Meanwhile, the overshoot is generated and enlarged along with the increases of the flow rate and load mass. These contribute to the improvements of designs and researches on control systems of water hydraulic artificial muscles.

A mathematic method of ensuring motor-based photoelectric tracking instrumentation work high accurately was introduced, the SCA100T inclinometer was settled under the base, and examine plane of base real-timely. The inclinometer output analog signals and transmit it to AT89C51 through A/D converters, and AT89C51 output digital signals and transmit it to PC through RS-232. The PC convert signals of inclinometer into angle values of horizontal axis and vertical axis and transmit the values to main controlled system of photoelectric tracking instrumentation, the controlled system change the angles of horizontal axis and vertical axis. The CAD model was built and simulated with virtual prototype technology .Analysis and simulation proved that the mathematic method could keep tracking precision of motor-based photoelectric tracking instrumentation.

Ultra-high pressure water jet ship rust is one development direction of ship rust removal technique. In order to ensure the normal working of the system, how to control each equipment is the key-part of the design. This study presents the analytical research on hardware technology of the control system of ultra-high pressure water jet ship rust system, the analysis of the principle of frequency control system and circuit design and control circuit of PLC, by analysis the structure and principles of ultra-high pressure water jet rust, and then demonstrates through experimental test that the hardware electronic circuit works properly.

Ship rust removal is an import part of ship-repair and shipbuilding process. Using high pressure water jet equipment causes no environmental pollution. The control and detection of high pressure water jet equipment is the key technology to ensure the system works properly. This study, in light of research on software programming of control system of ultra high pressure water jet ship rust removal equipment, establishes a control system based on PLC through the analysis of the structure and principles of the ultra-high pressure water jet equipment. On the basis of designing hardware circuit of PLC control system, this study mostly analyses software program, and experimental test suggests that the software programming can meet the requirements of system security.

Ultra high pressure abrasive water jet cutting is a new technology device in salvage, ocean development, military fields, and it also is one of the hottest and most advanced topics in the field of fluid control. The present study is aiming at designing a deep sea abrasive water jet cutting system and executive instrument for core technology of large-tonnage salvage equipment. The analysis on the kinematics of cutting trail about executive instrument of abrasive water jet, and the control of actuator movement through the reverse kinematics solution are of certain significance on the establishment of a technological base of application on ultra high pressure abrasive jet and the improvement of the ocean high-tech equipment level.

Due to the problems about Lubrication and sealing in water hydraulics, the poor performance, large leakage, extreme requirements of processing, high cost and poor anti-pollution properties exist in water hydraulic servo or proportional valves of spool structure and analogue control. A better seal is provided by the structure of the poppet valve comparing to the spool valve, however, poorer linearity and control accuracy accompanying inevitably. Aiming at improving the control performance of poppet valve, the design of the multi-digit numerical control valve is analyzed in this paper. The novel design using ball seat valves for digital bits is proposed to ensure enough seal ability and lower the cost. The simulation model of the multi-digit numerical control valve is built in AMESim software and the results show high linearity in flow control. However, large overshoot and oscillation encounter during the switching of the digits. Especially the switching process of the high digital bits requires to be regulated to reduce the large overshooting. The adjustment of the spring in the sensitive chamber of the bit valve can decrease the overshoot and improve the stability. These above contribute to the improvement of the control performance of water hydraulic control valves and applications of water hydraulics in the industry.

Lubrication and sealing are the key research points in water hydraulic technology. A better seal is provided by the structure form of the poppet valve comparing to the spool valve, however, poorer linearity and control accuracy accompanies inevitably. Aiming at improving the control performance of poppet valves, the design of the water hydraulic digital valve is analyzed in this paper. A high speed digital valve is designed and controlled by PWM (Pulse-Width Modulation) and actuated by a piezoelectric ceramic stack with high frequency response and control stiffness. Another new design using poppet valves for digital bits is proposed to ensure enough seal ability and lower the cost of the valve, namely the multi-digit on-off valve. The simulation models of these two types of valves are built and the results show the different performances between the valves. The high speed digital valve is provided with high control accuracy and responsiveness. In contrast, large overshoot and oscillation are encountered during switching on the digits of the multi-digit on-off valve. Especially the switching process of the high digital bits requires to be regulated to reduce the large overshoot. The above analysis contributes to the improvement of lubrication and sealing in water hydraulic control valves and applications of water hydraulics in the industry.

Lithium ion batteries (LIBs) have been used in portable electronic devices due to high energy density, rechargeable characteristics, and tiny memory effect. However, advanced portable electronic device, electric vehicles (EVs), and large scale energy storage system (EES) require high specific capacity (energy density), light weight, and low cost LIBs. One of the important factors in determining the specific capacity of LIBs is the cathode active material. During the decades, general cathode active materials (lithium, cobalt, nickel, etc.) have some issue of rapid price rise as the demand increment for cathodic materials of EVs and EES. Especially, cobalt, which is the most essential cathode active material, the Democratic Republic of the Congo (DRC) accounts for more than 50% of the world's production. Cobalt supply is very unstable due to civil war in the DRC and exploitation of labor in the process of cobalt production. Therefore, a new cathode active material is necessary. Lithium sulfur (Li-S) batteries use an elemental sulfur as cathode and lithium metal as anode. The elemental sulfur is one of the most abundant materials on earth and has a high theoretical capacity. The theoretical capacity of 1675 mAh/g is up to seven times higher than that of LIBs. And elemental sulfur also has high theoretical gravimetric energy density of 2500 Wh/kg which is over four times higher than the ideal state of common LIBs. Additionally, sulfur is a stable and cost affordable material. Hence, the Li-S battery has attracted attention as a next-generation battery, and much researches have been reported. However, there are some problems that commercialization. The first problem is the dissolution of the polysulfide. The intermediate lithium polysulfides which was formed during the charge and discharge process are soluble in the typical organic electrolytes for LIBs. This phenomenon is called “polysulfide shuttle effect”. This leads to continuous cathode active material consumption, eventually the capacity is faded during cycle. The second problem is the safety and stability of the lithium metal used as the anode. Lithium metal surface control is a necessary step not only for the stability of Li metal anode, but also for a high capacity with a high coulombic efficiency. In this study, we developed poreless poly (vinylidene fluoride-co-hexafluoropropene) (PVdF-HFP) coated anodic aluminum oxide (PAAO) separator to blocking polysulfide shuttle effect and to control lithium metal interface. PAAO was prepared by coating PVdF-HFP solution on anodic aluminum oxide (AAO). AAO provides a highly ordered vertical pore structure and AAO has less tortuosity than conventional separator. The vertical pore structure of AAO evenly distributes the Li ion flux in battery system, so proposed separator effectively prevents the ununiformed growth of lithium. It is also mechanically, chemically, and thermally stable. The vertical aligned pores of AAO are filled with PVdF-HFP which has been used as gel polymer electrolyte, offer high lithium ion conductivity with conventional electrolyte. PVdF-HFP selectively passes lithium ions and effectively blocks dissolution of the polysulfide into the anode region. Consequently, the proposed system conserved high specific capacity with high coulombic efficiency during the cycle. Prepared PAAO showed high specific capacity (∼850 mAh/g, 0.2C), high coulombic efficiency (>98%), and long cycle life (>100 cycles, 0.5C). Reference polyethylene separator shoed low specific capacity (∼550 mAh/g, 0.2C), low coulombic efficiency (~95%) and fast capacity fade during cycle. Compared with a commercial polyethylene separator and bare AAO separator, PAAO separator showed better initial capacity, coulombic efficiency, and electrochemical stability. The suggested PAAO separator effectively block the polysulfide shuttle effect and improve the poor cyclability of the LI-S system. It suggests that this novel poreless separator can be a possible candidate of the powerful separator for LI-S batteries.

Electronic devices have been advanced rapidly over the last few decades with improved performance through high-level integration. Lithium ion batteries (LIB), which is representative rechargeable energy storage system, is increasingly demanding to high-energy-density storage system for the stable operation of high performance devices like mobile, laptop, etc. In addition, a recent quantum leap in electronic vehicles (EVs) require to energy storage system with long cycling stability incomparable to previous electronic devices. To achieve high performances and long lifetime, the use of lithium metal is one of attractive anode for as LIBs, because Li metal has high theoretical specific capacity of 3860 mAh/g, low redox potential of -3.04V (verse the standard hydrogen electrode) and low gravimetric density of 0.59 g/cm3. Nevertheless, since Li metal anode has the lithiation-delithiation mechanism of the ‘hostless’ electrochemical plating/stripping unlike the conventional graphite anode, it is confronted with serious problems occurred from uncontrollable interfacial reaction between surface of lithium metal anode and electrolyte applying to traditional LIB system; that is (1) the uncontrollable formation of solid electrolyte interphase (SEI) layer limitless volume expansion of Li metal anode (2) the dendritic growth and isolation of Li interface derived from inhomogeneous deposition of Li+ ion flux (3) the Li surface fracture induced by heterogeneously plated Li+ ion. Through these process, repetitive formation of undesirable SEI layer at surface of Li anode make fresh electrolyte dissipation and concurrently the anode surface becomes more distorted. These side-phenomena strongly correlate with low coulombic efficiency and decreasing lifetime of lithium metal battery (LMB) system where lithium metal is used as anode. In this works, in a dimensional aspect, to solve such problem mentioned above through stabilizing of surface of lithium metal anode, we introduce Janus-faced protective layer (JPL) as gel polymer electrolyte. JPL was composed with dual layer of Ni (3~7μm) embedded poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) and bare PVdF-HFP through simple casting method. The process of preparing JPL membrane is so simple to instantly bring in existing roll-to-roll process, and it is also possible to make a low cost process considered relatively low nickel price. In terms of mechanical property, it is based on flexible polymer and shows the merit of being foldable enough to able origami. In addition, JPL play a role of protection of Li metal anode. JPL has two functionalities. The metal part of JPL directly contacted with anode, and this layer was frameworks for preventing irregular SEI layer formation through inward plating of Li ion, the polymer part is stable state enough to be used as a gel polymer electrolyte. When lithium metal anode is subjected to cycle-test while keeping in contact with the nickel side of JPL membrane, Scanning electron microscope (SEM) image showed that the surface of lithium metal anode was very clean without any fluctuation compared to the case where only polypropylene (PP) separator was used. (Figure. 1) Moreover, as shown in Figure 2., the LMB system applied JPL show high stability of tolerable overvoltage within 5mV, 15mV even at high-current of 10mA/cm2, 20mA/cm2, respectively, in Li//JPL/JPL//Li symmetric cell. These results are attributable to effective function of each layer as mentioned earlier. JPL consists of two layer, the tough and adhesive nature of PVdF-HFP prevents the polymer part from being damaged or torn by dendritic growth and simultaneously ensure that metal part functions as robust framework for SEI layer formation without escaped particle from the membrane. This frameworks induce the SEI layer, which can act as a resistive element, to grown in the metal part while surface of Li metal anode become get out of main subject from the SEI layer formation. By virtue of that property, JPL has not allow forming resistive elements on the surface of Li metal anode, preventing the voltage rising up due to the formation of resistive elements at surface, so tolerability of overvoltage with clean surface of anode is maintained. In conclusion, the model study of nickel micro-particle/PVdF-HFP composite suggests the straightforward direction of protective layer to apply lithium metal as anode in LIB system with alleviating the problem caused by the ‘hostless’ property of lithium metal anode. Thus, when JPL is introduced to a LIB system, it shows a fairly positive possibility for high performance Lithium metal battery. Figure 1

Rechargeable lithium based batteries have been widely used for portable devices such as cellular phone and laptop computer. Those electronics are more and more being multi-functionalized, and the energy storage devices for them are required much higher energy density. The energy storage system loading high energy density will also dominate the market of large scale power systems, in the rapid development of electric vehicles. Therefore, lithium ion battery with high specific capacity became an essential factor. Although the battery can offer a high gravimetric capacity of 3862 mAh g-1 by using lithium metal as the anode part, most of cathode materials which are represented as lithium (cobalt, nickel, manganese, aluminum) oxide are mainly restricted in capacity. Thus, the cathode is the most important aspect to offer the high capacity. Commonly used inorganic lithium metal oxide materials as the cathode part have drawbacks such as their low theoretical specific capacities (-1), structure stability and their unstable trend of price. Also, the cathodic active materials have a disadvantage in that a high-temperature required for manufacturing process and the side reaction is not environmentally friendly. To overcome the disadvantages, the organic compounds have recently been considered as promising candidates for the next generation of energy storage systems. They have many obvious merit compared to the inorganic materials in high theoretical capacity (>400 mAh g−1), safety, sustainability, environmental friendliness and low cost. In addition, they are electroactive toward lithium metal as well as practically any metals like magnesium, zinc, aluminum owing to their redox electron reactions. Especially, Pillar[5]quinone (P5Q), containing five quinone units linked by methylene bridges at para positions, can not only implement a high theoretical capacity of 446 mAh g−1 but also realize so effective for the use of the active sites that it is able to favorable to Li ion uptake. However, those kinds of organic materials with small molecular weight have two critical problems. First, they are easy to dissolve in aprotic electrolyte such as carbonate-based solvent, leading to poor cyclability and rapid capacity fading. Second is that the low conductivity of organic molecules limits their rate performance. In the effort of solve the problems, we fabricated the cathode using the P5Q enveloped in carbon (e.g. MWCNTs and CMK-3) and silver nanowires (AgNWs) with simple vacuum filtration method. At first, P5Q was obtained after synthesizing 1,4-dimethoxypillar[5]arene and the products obtained by each step were identified by using 1H, 13C NMR and FT-IR spectra. Carbon and AgNWs act as a framework, allowing to trap the active material. Furthermore, they perform a current collector, providing the conductive pathway of electrons for fast charging/discharging the battery. It doesn’t need binders and aluminum foil which is components of traditional slurry type of cathode. As the result, not only constrains the solubility in organic electrolyte, preparing the electrode synthesized with P5Q/carbon/AgNWs nanocomposite gives the enhanced conductivity. The content of each components was verified by Thermogravimetry Analysis(TGA). Suggested cathode has super-lightweight and an extremely low resistance of 2~3 ohm cm. Also, it demonstrates a specific discharge capacity of about 420 mAh g−1 at 0.1C. and an average operation voltage of 2.8 V when applying Li metal battery. For obtaining a high specific initial capacity, ether-based solvents (1,3-dioxolane/dimethoxyethane=1:1) containing high concentration Li salt (Bis(trifluoromethane)sulfonimide lithium salt) were used instead of carbonate-based electrolytes, achieving the reversible cycles. Moreover, the electrolyte was optimized by adding LiNO3 additive, preventing the formation of a protective layer on the surface of Li anode as well as the dissolution of active material (P5Q) in the electrolyte with high Li salt concentration. Likewise, the proposed battery concept reveals a high possibility of future battery and novelty by optimizing the electrolyte and modifying the cathode. Those methods can be applied at other organic cathode for Li based battery to reach their theoretical capacity and improve the cycle performance.