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Both uncontrolled Li dendrite growth and corrosion are major obstacles to the practical application of Li-metal batteries. Despite numerous attempts to address these challenges, effective solutions for dendrite-free reversible Li electrodeposition have remained elusive. Here, we demonstrate the horizontal Li electrodeposition on top of atomically polarized monolayer hexagonal boron nitride (hBN). Theoretical investigations revealed that the hexagonal lattice configuration and polarity of the monolayer hBN, devoid of dangling bonds, reduced the energy barrier for the surface diffusion of Li, thus facilitating reversible in-plane Li growth. Moreover, the single-atom-thick hBN deposited on a Cu current collector (monolayer hBN/Cu) facilitated the formation of an inorganic-rich, homogeneous solid electrolyte interphase layer, which enabled the uniform Li+flux and suppressed Li corrosion. Consequently, Li-metal and anode-free full cells containing the monolayer hBN/Cu exhibited improved rate performance and cycle life. This study suggests that the monolayer hBN is a promising class of underlying seed layers to enable dendrite- and corrosion-free, horizontal Li electrodeposition for sustainable Li-metal anodes in next-generation batteries.

Abstract: We studied homogeneity in the microwave surface resistance of Au-coated YBa2Cu3O7−δ(Au/YBCO) films. The Au/YBCO film with 4-inches in diameter was prepared in-situ with the thicknesses of 68 nm and 365 nm for the Au layer and the YBa2Cu3O7−δ(YBCO) layer, respectively. We measured the effective surface resistance (RS,eff) of the Au/YBCO film at temperatures of 25 K, 60 K, 70 K, and 77 K, respectively, at 29 different positions on the film. The RS,effvalues were analyzed with the finite thicknesses of the Au and the YBCO layers taken into consideration. The local RS,effvalues of the Au/YBCO film appeared to be almost uniform at 25 K. Meanwhile significant positional dependences were observed for the RS,effof the Au/YBCO film at 60 K, 70 K and 77 K, respectively, which seemed to be due to non-uniform local penetration depth (λ) of the YBCO layer rather than due to variations in the local real-part conductivity of the YBCO layer. The observed results could not be attributed to the properties of the Au layer. At temperatures below the critical temperature of YBCO, the observed RS,effvalues of the Au/YBCO film were significantly lower than those estimated using the surface resistance of Au and YBCO, which reflected proximity effects of the normal-metal Au layer in contact with the superconducting YBCO layer. Homogeneity in the RS,effof the Au/YBCO film might be correlated with the distributions in the local λof the YBCO layer, providing valuable information needed for designing microwave filters. Graphic Abstract:

Hydrocarbon (HC)-based block copolymers have been recognized as promising candidates for proton exchange membranes (PEMs) due to their distinct hydrophilic–hydrophobic separation, which results in improved proton transport compared to that of random copolymers. However, most PEMs derived from HC-based ionomers, including block copolymers, encounter challenges related to durability in electrochemical cells due to their low mechanical and chemical properties. One method for reinforcing HC-based ionomers involves incorporating the ionomers into commercially available low surface tension PTFE porous substrates. Nevertheless, the high interfacial energy between the hydrocarbon-based ionomer solution and PTFE remains a challenge in this reinforcement process, which necessitates the application of surface energy treatment to PTFE. Here, multiblock sulfonated poly(arylene ether sulfone) (SPAES) ionomers are being reinforced using untreated PE on the surface, and this is compared to reinforcement using surface-treated porous PTFE. The PE support layer exhibits a lower surface energy barrier compared to the surface-treated PTFE layer for the infiltration of the multiblock SPAES solution. This is characterized by the absence of noticeable voids, high translucency, gas impermeability, and a physical and chemical stability. By utilizing a high surface tension PE support with a comparable value to the multiblock SPAES, effective reinforcement of the multiblock SPAES ionomers is achieved for a PEM, which is potentially applicable to various hydrogen energy-based electrochemical cells.

A class of solvent-free covalent organic framework (COF) single-ion conductors (Li-COF@P) has been designed via ion–dipole interaction as opposed to traditional ion–ion interaction, promoting ion dissociation and Li+migration through directional ionic channels.The Li-COF@P enabled long cycle life (88.3% after 2000 cycles) in all-solid-state Li organic batteries (ASSLOBs) under ambient operating conditions, which outperformed those of previously reported ASSOLBs.This Li-COF@P strategy holds promise as a viable alternative to the currently prevalent inorganic solid electrolytes.

Lithium–sulfur batteries are afflicted with capacity fading on account of polysulfide shuttling. A novel cost-effective electrode that can hinder the polysulfide shuttling and realize high active material utilization is highly required. Here, we demonstrate a flexible, electrically conductive, nanostructured, and asymmetric hybrid cathode by integrating a high-aspect-ratio wood nanocellulose and a low-cost commercial carbon nanotube (∼$ 0.2 g–1) into an entangled aerogel film. The vacuum filtration combined with lyophilization enables the aerogel film with quite different nanofiber/nanotube packing densities and pore structures at its two sides. The cooperative effects of the entangled building blocks and the asymmetric porous structure of the aerogel film stimulate the simultaneous increase of active sulfur loading, enhancing the electrolyte penetration, alleviating dissolution and shuttling of polysulfide ions, and promoting the fast electron transportation. The as-generated cathode exhibited a capacity fading of 0.01% per cycle over 1000 discharge/charge cycles at a 0.5 C rate (1 C = 1675 mA g–1). The average Coulombic efficiency reached ∼99.7%.

Here we demonstrate an unconventional fabrication of highly transparent supercapacitors and electrodes using random networks of nanostructured metallic glass nanotroughs for their integrations as wirelessly rechargeable and invisible, skin heat patches. Transparent supercapacitors with fine conductive patterns were printed using an electrohydrodynamic jet-printing. Also, transparent and stretchable electrodes, for wireless antennas, heaters and interconnects, were formed using random network based on nanostructured CuZr nanotroughs and Ag nanowires with superb optoelectronic properties (sheet resistance of 3.0 Ω/sq at transmittance of 91.1%). Their full integrations, as an invisible heat patch on skin, enabled the wireless recharge of supercapacitors and the functions of heaters for thermal therapy of skin tissue. The demonstration of this transparent thermotherapy patch to control the blood perfusion level and hydration rate of skin suggests a promising strategy toward next-generation wearable electronics.

The forthcoming smart and ubiquitous electronics era presents significant interest in wireless interconnectivity and shape aesthetics. To fulfill this demand, a new class of advanced power sources with various form factors that are different from existing commercial ones is needed. Printed power sources have recently garnered substantial attention because of their design diversity, shape and performance compatibility with electronics, and scalable and low-cost processability. They are fabricated directly on complex-structured objects via application-customized printing techniques, enabling monolithic integration and electrochemical coupling with target devices. In this Perspective, we describe the current status and challenges of printed power sources, focusing on their role as built-in power sources. Various printing techniques and ink materials and chemistry of electrodes and electrolytes are discussed as key enabling factors. Noteworthy progress in printed built-in power sources is reviewed to highlight their design diversity and electrochemical superiority. Finally, development direction and outlook of printed built-in power sources are discussed in conjunction with their application fields.

Lithium (Li) metal has garnered considerable attention in next-generation battery anodes. However, its environmental vulnerability, along with the electrochemical instability and safety failures, poses a formidable challenge to commercial use. Here, we describe a new class of antioxidative Li reservoir based on interstitial channels of single-walled carbon nanotube (SWCNT) bundles. The Li preferentially confined in the interstitial channels exhibits unusual thermodynamic stability and exceptional capacity even after exposure to harsh environmental conditions, thereby enabling us to propose a new lithiation/delithiation mechanism in carbon nanotubes. To explore practical application of this approach, the Li confined in the SWCNT bundles is electrochemically extracted and subsequently plated on a copper foil. The resulting Li-plated copper foil shows reliable charge/discharge behavior comparable to those of pristine Li foils. Benefiting from the confinement effect of the interstitial channels, the SWCNT bundles hold great promise as an environmentally tolerant, high-capacity Li reservoir.

Mechanistic understanding of ion transport phenomena in composite solid-state electrolytes (CSEs) for practical solid-state batteries is conducted.Percolation threshold formation of the inorganic (LPSCl) phase in the CSEs depends on elasticity of the gel polymer electrolyte (GPE) phase.Manipulating the solvation/desolvation behavior of the GPE phase facilitates ion conduction across the LPSCl-GPE interfaces.

Reactive oxygen species or superoxide (O2–), which damages or ages biological cells, is generated during metabolic pathways using oxygen as an electron acceptor in biological systems. Superoxide dismutase (SOD) protects cells from superoxide-triggered apoptosis by converting superoxide to oxygen and peroxide. Lithium–oxygen battery (LOB) cells have the same aging problems caused by superoxide-triggered side reactions. We transplanted the function of SOD of biological systems into LOB cells. Malonic acid-decorated fullerene (MA-C60) was used as a superoxide disproportionation chemocatalyst mimicking the function of SOD. As expected, MA-C60as the superoxide scavenger improved capacity retention along charge/discharge cycles successfully. A LOB cell that failed to provide a meaningful capacity just after several cycles at high current (0.5 mA cm–2) with 0.5 mAh cm–2cutoff survived up to 50 cycles after MA-C60was introduced to the electrolyte. Moreover, the SOD-mimetic catalyst increased capacity, e.g., more than a 6-fold increase at 0.2 mA cm–2. The experimentally observed toroidal morphology of the final discharge product of oxygen reduction (Li2O2) and density functional theory calculation confirmed that the solution mechanism of Li2O2formation, more beneficial than the surface mechanism from the capacity-gain standpoint, was preferred in the presence of MA-C60.

Wireless communication through linkage with a smartphone and other portable devices in the sensor area are essential for increasing the efficiency of utilization by storing sensing-value data. Thus, the demand for wireless technology is increasing due to the advantages it provides for the various applications that use these data. However, there is still considerable ambiguity concerning the low portability of such technology due to the increased volume with component integration, the high consumption of power, and the necessity of having a separate battery. Herein, we present solutions for these problems with demonstrations that involve 1) the miniaturization of the device by altering the structure of the built-in battery, 2) the use of a pressure-activated switch for the low-power driving technology, and 3) the implementation of a wireless communication platform by integrating a Bluetooth module with the devices. In addition, we demonstrate a human-interactive display that enables users to instantly observe the changes in the brightness of the organic light-emitting diodes (OLED) as the pressure changes. We show that the system can display the measured, real-time pressure values on the screens of mobile devices, which represents a significant advancement in the fields of energy science and biomedical science.

Porous crystalline materials such as covalent organic frameworks and metal–organic frameworks have garnered considerable attention as promising ion conducting media. However, most of them additionally incorporate lithium salts and/or solvents inside the pores of frameworks, thus failing to realize solid-state single lithium-ion conduction behavior. Herein, we demonstrate a lithium sulfonated covalent organic framework (denoted as TpPa-SO3Li) as a new class of solvent-free, single lithium-ion conductors. Benefiting from well-designed directional ion channels, a high number density of lithium-ions, and covalently tethered anion groups, TpPa-SO3Liexhibits an ionic conductivity of 2.7 × 10–5S cm–1with a lithium-ion transference number of 0.9 at room temperature and an activation energy of 0.18 eV without additionally incorporating lithium salts and organic solvents. Such unusual ion transport phenomena of TpPa-SO3Liallow reversible and stable lithium plating/stripping on lithium metal electrodes, demonstrating its potential use for lithium metal electrodes.

The increasing demand for advanced rechargeable batteries spurs development of new power sources beyond currently most widespread lithium-ion batteries. Here, we demonstrate a new class of flexible/rechargeable zinc (Zn)–air batteries based on multifunctional heteronanomat architecture as a scalable/versatile strategy to address this issue. In contrast to conventional electrodes that are mostly prepared by slurry-casting techniques, heteronanomat (denoted as “HM”) framework-supported electrodes are fabricated through one-pot concurrent electrospraying (for electrode powders/single-walled carbon nanotubes (SWCNTs)) and electrospinning (for polyetherimide (PEI) nanofibers) process. Zn powders (in anodes) and rambutan-shaped cobalt oxide (Co3O4)/multiwalled carbon nanotube (MWCNT) composite powders (in cathodes) are used as electrode active materials for proof of concept. The Zn (or Co3O4/MWCNT) powders are densely packed and spatially bound by the all-fibrous HM frameworks that consist of PEI nanofibers (for structural stability)/SWCNTs (for electrical conduction) networks, leading to the formation of three-dimensional bicontinuous ion/electron transport channels in the electrodes. The HM electrodes are assembled with cross-linked polyvinyl alcohol/polyvinyl acrylic acid gel polymer electrolytes (acting as zincate ion crossover-suppressing, permselective separator membranes). Benefiting from its unique structure and chemical functionalities, the HM-structured Zn–air cell significantly improves mechanical flexibility and electrochemical rechargeability, which are difficult to achieve with conventional Zn–air battery technologies.

Modern identification technologies such as radio-frequency identification, or RFID, have become increasingly important for streamlining production and logistics operations in almost every industry. In steel industrial enterprise, there is many logistic information which is still collected manually. It brings out many disadvantages such as inaccurate logistics information, irregular logistics, be lasted feedback and so on. In this paper, presents the feasibility of deploying RFID for the steel industry as a tool to reduce the production costs. Steel industry that is applicable to RFID-based tracking management system is proposed. And basically small and medium-sized steel industries, reflecting the characteristics of the building systems and by allowing for faster application time, while minimizing the capital investment.

This paper reviews zero energy building programs and regulations in the USA, Europe, Australia and South Korea, and suggest the implication of zero energy housing (ZEH) policy for low-income households to allow for better access, management and modification of homes. Low-income households in Australia are most vulnerable to 'energy poverty' due to ever increasing energy costs such as electricity and gas services. This study identifies three barriers in promoting zero energy housing for low-income households, its affordability, accessibility and occupants' behaviours. It suggests that both provision of financial incentives and assistance for zero energy housing retrofit is required as a regulatory practice in Australia.

Cellulose, which is one of the most-abundant and -renewable natural resources, has been extensively explored as an alternative substance for electrode materials such as activated carbons. Here, we demonstrate a new class of coffee-mediated green activation of cellulose as a new environmentally benign chemical-activation strategy and its potential use for all-paper flexible supercapacitors. A piece of paper towel is soaked in espresso coffee (acting as a natural activating agent) and then pyrolyzed to yield paper-derived activated carbons (denoted as “EK-ACs”). Potassium ions (K+), a core ingredient of espresso, play a viable role in facilitating pyrolysis kinetics and also in achieving a well-developed microporous structure in the EK-ACs. As a result, the EK-ACs show significant improvement in specific capacitance (131 F g–1at a scan rate of 1.0 mV s–1) over control ACs (64 F g–1) obtained from the carbonization of a pristine paper towel. All-paper flexible supercapacitors are fabricated by assembling EK-ACs/carbon nanotube mixture-embedded paper towels (as electrodes), poly(vinyl alcohol)/KOH mixture-impregnated paper towels (as electrolytes), and polydimethylsiloxane-infiltrated paper towels (as packaging substances). The introduction of the EK-ACs (as an electrode material) and the paper towel (as a deformable and compliant substrate) enables the resulting all-paper supercapacitor to provide reliable and sustainable cell performance as well as exceptional mechanical flexibility. Notably, no appreciable loss in the cell capacitance is observed after repeated bending (over 5000 cycles) or multiple folding. The coffee-mediated green activation of cellulose and the resultant all-paper flexible supercapacitors open new material and system opportunities for eco-friendly high-performance flexible power sources.

Background: Scarf osteotomy has been used in hallux valgus surgery due to its large fixation surface for screws and low postoperative complications. However, screws may cause skin irritation from their head, which may require an additional surgical procedure to remove.Methods: This study included 115 patients (106 females and 9 males, 115 feet) who underwent hallux valgus correction with a scarf osteotomy using bioabsorbable screws between September 2010 and September 2012. Preoperative and postoperative 1-month and 1-year radiographic measurements, including intermetatarsal angle (IMA), hallux valgus angle (HVA), distal metatarsal articular angle (DMAA), proximal phalangeal articular angle (PPAA), and lateral translational distance (LTD), were obtained. American Orthopaedic Foot & Ankle Society (AOFAS) hallux/forefoot scores were used for patient satisfaction.Results: Preoperative mean values of HVA, IMA, and PPA of 32.8 degrees, 14.6 degrees, and 7.52 degrees, respectively, improved to 10.7 degrees, 6.0 degrees, and 4.6 degrees, respectively at 1-year follow up (P< .05). The difference in LTD between the 1-month and 1-year follow-up was not statistically significant. AOFAS hallux/forefoot score improved from 69.1 to 96.1 at the 1-year follow up (P< .001). Complete screw absorption was not seen radiographically. Sixteen feet had complications reported. One patient complained of skin irritation over a small protrusion of the screw, and another patient had a foreign body reaction. There were 3 patients with neurologic injury from a popliteal block and 3 patients with dorsal cutaneous nerve symptoms. Four feet had metatarsal fracture during surgery.Conclusion: We found the scarf osteotomy using bioabsorbable screws to have satisfactory clinical and radiographic results with a low complication rate.Level of Evidence: Level IV, case series.

Subpleural micronodules and interlobular septal thickening are common computed tomography (CT) findings in tuberculous (TB) pleural effusion. These CT features could help us differentiate between TB pleural effusion and non-tuberculous empyema.

Background: We aimed to find a new radiographic measurement for evaluating first metatarsal pronation and sesamoid position in hallux valgus (HV) deformity.Methods: Data from a clinical study of 19 control patients (19 feet) with no HV deformity were compared with preoperative data of 138 patients (166 feet) with HV deformities. Using a weightbearing plain radiograph in anteroposterior (AP) view, the intermetatarsal angles (IMAs) and the hallux valgus angles (HVAs) of the control and study groups were measured. Using a semi-weightbearing coronal computed tomography (CT) axial view, the α angle was measured in the control and study groups. In addition, the tibial sesamoid grades in plain radiograph tangential view and the CT axial view were measured. The tibial sesamoid position in an AP view was checked preoperatively. Based on these measurements, 4 types of HV deformities were defined.Results: The mean values of the α angle in the control and HV deformity groups (control group µ = 13.8 degrees, study group µ = 21.9 degrees) was significantly different. Among 166 HV feet, 145 feet (87.3%) had an α angle of more than 15.8 degrees, which is the upper value of the 95% confidence interval of the control group, indicating the existence of abnormal first metatarsal pronation in HV deformity. Four types of HV deformities were defined based on their α angles and tibial sesamoid grades in CT axial view (CT 4 position). Among 25.9% (43/166) of the study group, abnormal first metatarsal pronation with an absence of sesamoid deviation from its articular facet was observed. The prominent characteristic of this group was that they had high grades in the AP 7 position (≥5); however, in the CT 4 position, their grade was 0. This group was defined as the “pseudo-sesamoid subluxation” group.Conclusions: Patients with HV deformities had a more pronated first metatarsal than the control group, with a greater α angle. Pseudo-subluxation of the sesamoids existed in 25.9% of our study group. From our results, we suggest that the use of the CT axial view in assessments of HV deformity may benefit surgeons when they make operative choices to correct these deformities. With regard to the pseudo-sesamoid subluxation group, the use of the distal soft tissue procedure is not surgically recommended.Level of Evidence: Level III, retrospective comparative study.

Rapid growth of mobile and even wearable electronics is in pursuit of high-energy-density lithium-ion batteries. One simple and facile way to achieve this goal is the elimination of nonelectroactive components of electrodes such as binders and conductive agents. Here, we present a new concept of monocomponent electrodes comprising solely electroactive materials that are wrapped with an insignificant amount (less than 0.4 wt %) of conducting polymer (PEDOT:PSS or poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate)). The PEDOT:PSS as an ultraskinny surface layer on electroactive materials (LiCoO2(LCO) powders are chosen as a model system to explore feasibility of this new concept) successfully acts as a kind of binder as well as mixed (both electrically and ionically) conductive film, playing a key role in enabling the monocomponent electrode. The electric conductivity of the monocomponent LCO cathode is controlled by simply varying the PSS content and also the structural conformation (benzoid-favoring coil structure and quinoid-favoring linear or extended coil structure) of PEDOT in the PEDOT:PSS skin. Notably, a substantial increase in the mass-loading density of the LCO cathode is realized with the PEDOT:PSS skin without sacrificing electronic/ionic transport pathways. We envisage that the PEDOT:PSS-skinned electrode strategy opens a scalable and versatile route for making practically meaningful binder-/conductive agent-free (monocomponent) electrodes.

Poly (ether sulfone) membranes (PHP) were prepared with 25 mol% of 1,2-bis (4-hydroxybenzene)-3,4,5,6-tetraphenylbenzene (BHPTPB). BHPTPB has a conjugated propeller-like nonplanar conformation structure containing the peripheral seven aromatic rings which facilitate the formation of π-π interactions. A series of sulfonated poly (ethersulfone) s (SHP 25) was synthesized with concentrated sulfuric acid. The sulfonation took place selectively on the multiphenyl unit, and simultaneously on the side-chain phenyl groups. Composite membranes were prepared with copolymers and SiO2 nanoparticles (20 nm, 4~10%wt). The composite membranes were cast from DMSO. A series of composite membranes structures and characteristic were evaluated by the 1H-NMR spectroscopy, and thermal stabilities. The membranes were performed by ion exchange capacity (IEC), water uptake and proton conductivity.

We demonstrate highly flexible, proton-conductive silicate glass electrolytes integrated with polyimide (PI) nonwoven fabrics (referred to as “b-SS glass electrolytes”) for potential use in medium-temperature/low-humidity proton exchange membrane fuel cells (PEMFCs). The b-SS glass electrolytes are fabricated via in situ sol–gel synthesis of 3-trihydroxysilyl-1-propanesulfonic acid (THPSA)/3-glycidyloxypropyl trimethoxysilane (GPTMS) mixtures inside PI nonwoven substrates that serve as a porous reinforcing framework. Owing to this structural uniqueness, the b-SS glass electrolytes provide noticeable improvements in mechanical bendability and membrane thickness, in comparison to typical bulk silicate glass electrolytes that are thick and easily fragile. Another salient feature of the b-SS glass electrolytes is the excellent proton conductivity at harsh measurement conditions of medium temperature/low humidity, which is highly important for PEMFC-powered electric vehicle applications. This beneficial performance is attributed to the presence of a highly interconnected, proton-conductive (THPSA/GPTMS-based) silicate glass matrix in the PI reinforcing framework. Notably, the b-SS glass electrolyte synthesized from THPSA/GPTMS = 9/1 (mol/mol) exhibits a higher proton conductivity than water-swollen sulfonated polymer electrolyte membranes (here, sulfonated poly(arylene ether sulfone) and Nafion are chosen as control samples). This intriguing behavior in the proton conductivity of the b-SS glass electrolytes is discussed in great detail by considering its structural novelty and Grotthuss mechanism-driven proton migration that is strongly affected by ion exchange capacity (IEC) values and also state of water.

We developed a novel injectable type I collagen/hyaluronic acid/fibrinogen (COL/HA/FG) composite gel that encapsulated synovium-derived mesenchymal stem cells (SDSCs) for the repair of damaged articular cartilage. We first analyzed the suitability of the composite gel as a three-dimensional injectable cell carrier in vitro. In an in vivorabbit model, the COL/HA/FG composite gel displayed the potential to regenerate and repair osteochondral defects in the knee. Culture of the SDSCs encapsulated COL/HA/FG composite gel in a chondrogenic medium resulted in high viability of the SDSCs and high expressions of type II collagen, aggrecan, and sox 9 mRNA. Moreover, glycosaminoglycans and type II collagen were accumulated within the extracellular matrix. In the animal model, the SDSCs encapsulated COL/HA/FG composite gel produced a hyaline-like cartilage construct. Twenty-four weeks after transplantation, the defects had been repaired with hyaline cartilage-like tissue that was densely stained by safranin-O and immunostained by a type II collagen antibody. This data suggest that the SDSC-encapsulated COL/HA/FG composite gel can be a good therapeutic candidate/strategy for repairing of damaged articular cartilage.

A facile approach to fabricate a self‐standing GPE for flexible lithium‐ion batteries is demonstrated using a UV‐cured trivalent/monovalent acrylate polymer matrix and a liquid electrolyte. The polymer matrix is successfully synthesized with the co‐presence of the liquid electrolyte by UV polymerization of ETPTA, which has trivalent vinyl groups, and EGMEA, which contains monovalent vinyl groups, with the ETPTA/EGMEA ratio fixed at 90/10 (wt%/wt%). The ETPTA/EGMEA matrix shows a lower Tgthan the ETPTA matrix alone, which helps improve the mechanical flexibility and ionic transport of the resulting GPE. These features of the ETPTA/EGMEA‐based GPE, together with its superior interfacial compatibility towards electrodes, play crucial roles in obtaining a better cell performance compared to the ETPTA‐based GPE.

A thermoplastic material lamination process has various problems of layer deformation, misalignment, and delamination. In particular, Liquid Crystal Polymer (LCP) causes more severe interlayer distortion because it needs a higher lamination temperature than other thermoplastic materials. To solve this, three different types of compression methods were proposed to build an LCP-based 5G patch: Batch (BC), Partial (PC), and Thermal-Partial compression (TPC). The antenna was successfully fabricated using the TPC process showing antenna performance at 28 GHz (low band) and 39 GHz (high band). Furthermore, results proved that circuit alignment of the antenna was influenced by lamination temperature and compression order.

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AIM: To evaluate the feasibility and safety of fluoroscopic-guided covered metallic stent placements in providing palliative care for patients with inoperable malignant gastric outlet obstruction. MATERIALS AND METHODS: Under fluoroscopic guidance, placement of self-expandable, covered stents was attempted in 20 patients with inoperable or recurrent gastric cancer (age range 36–79 years). All patients had inoperable gastric outlet obstruction, 13 with native anatomy and seven with post-operative anatomy (gastrointestinal anastomotic sites). All patients had intolerance to oral alimentation and/or vomiting after ingestion. Success was defined both technically and clinically. RESULTS: The placement of the stent was technically successful in 18 patients and failed in two patients (technical success: 90%). The cause of the technical failures was an inability to negotiate the guide wire through the obstruction sites in spite of the use of both fluoroscopic and endoscopic guidance. After stent placement, 15 patients were able to ingest at least liquids and had a markedly decreased incidence of vomiting (clinical success: 75%). During the mean follow-up of 6 weeks, there have been no stent reocclusion and no life-threatening complications except migration of two stents in one patient. CONCLUSION: Fluoroscopically guided covered metallic stent placement appears to be valuable for the palliative treatment of malignant obstruction of gastric outlet and post-operative gastrointestinal anastomoses. Lee, J. M. et al. (2001). Clinical Radiology56, 560–567.

This paper attempts to figure out the rent determinants of the office market in the Seoul Area, experiencing radical changes after the IMFbailout program. Employing the hedonic price model with the empirical data, this paper compares two different dependent variables: the potential gross income, and net operation income reflecting the present value. This paper also attempts to analyze the impacts of Chonsei system on rent determination, and reviewes how the segmentation of sub markets in the Seoul area influences rents. The results of office rent determination model estimation can be summarized as follows: First, among the physical characteristics of buildings, the size of the building is the important determinant of the office rent level. Second, the rents are mostly influenced by the type of contract. Third, there exist the distinct differences in sub markets of the Seoul Area. Such results can be attributed to the history and pattern of the office market growth and the type of the building owners. Fourth, it is difficult and sometimes debatable to define “rent” mostly due to the “Chonsei” system in Korea.

Properties of blends having two types of hybrid dispersed phases as laminar morphology were investigated. The hybrid dispersed phases were prepared by preblending nylon and ethylene–vinyl alcohol (EVOH) in solid state (E + N) and in melt state (E/N). Oxygen and toluene barrier properties through the hybrid-dispersed phases in low-density polyethylene (LDPE) matrix were analyzed considering the morphological changes (number and size of layers). Oxygen barrier properties of the blends of LDPE–E + N hybrid dispersed phase having separate domains of nylon and EVOH were found to be linearly dependent on EVOH composition in the blend, but toluene barrier properties of the blends exhibited negative deviation. The other hybrid dispersed phase (E/N) in LDPE matrix, having comingled dispersed phase of nylon and EVOH, exhibited positive deviations in both oxygen and toluene barrier properties. Tensile properties also showed positive deviation. Basic studies on the melt blend (E/N) of EVOH and nylon 6 showed some miscibility, which was revealed from melting point depression, and positive deviation in complex viscosity and tensile properties of the blend. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:2001–2014, 1998

The effect of various modifiers on the performance of a commercial Cu/ZnO/Al2O3 catalyst in methanol synthesis from CO2/H2 and CO/H2 at 523 K and 30 bar has been studied. Several modifiers improved significantly the rate of methanol formation from CO2/H2, while all modified catalysts showed decreased rates for the synthesis from CO/H2 in comparison with the unmodified Cu/ZnO/Al2O3 catalyst. The synthesis rates from both CO2/H2 and CO/H2 correlated with the oxygen coverage of copper surface measured after the reaction by N2O titration.

The effect of the compatibilizer on the crystallization, rheological, and tensile properties of low-density polyethylene (LDPE)/ethylene vinyl alcohol (EVOH) (70/30) blends was investigated. Maleic anhydride-grafted linear low-density polyethylene (LLD-g-MAH) was used as the compatibilizer in various concentrations (from 1 to 12 phr). The interesting effect of compatibilization on the crystallization kinetics of the blends was noted, and the correlation between the morphology and the rheological and tensile properties was also discussed. Morphological analysis showed that the blends exhibited a regular and finer dispersion of the EVOH phase when LLD-g-MAH was added. Nonisothermal crystallization exotherms of the compatibilized LDPE/EVOH blends showed the retarded crystallization of the dispersed EVOH phase, which probably resulted from the constraint effect of the grafted EVOH (EVOH-g-LLD) as well as the size reduction of the EVOH domains. The blends exhibited increased melt viscosity and storage modulus and also enhanced tensile properties with the addition of LLD-g-MAH, which seemed to be attributable to both dispersed particle-size reduction and improved interfacial adhesion. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1245–1256, 1998

A cholesterol-oxidase-producing microorganism, strain COX629, isolated from soil was identified as Pseudomonas sp. The cholesterol oxidase produced by Pseudomonas sp. strain COX629 was purified 2400-fold to homogeneity in an overall yield of 60% from culture broth. The enzyme was a monomer with a molecular weight of 56 000, as estimated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Sephadex G-150 gel column chromatography. The enzyme showed optimum activity at pH 7.0 and was stable over a rather wide pH range of 4.0 to 11.0. The enzyme showed a high substrate specificity for 3ß-hydroxysteroids and the Km value for the oxidation of cholesterol by this enzyme was about 0.2 mM. A characteristic of the enzyme is marked stability at high temperature.

Novel sulfonated poly(ether sulfone ketone)s containing mesonaphthobifluorene (MNF) moiety were synthesized and their properties characterized. The prepared polymers had a partial graphene structure due to the MNF group. Poly(ether sulfone ketone)s bearing tetraphenylethylene (TPE) on the polymer backbone were synthesized by polycondensation, after which MNF was formed by the intra-cyclization of TPE by Friedel-Crafts reaction with Lewis acid (FeCl3). The sulfonation was performed selectively on MNF units with concentrated sulfuric acid. The synthesized polymer electrolyte membranes showed better thermal and dimensional stabilities owing to the MNF-induced graphene structure in the polymer backbone. The water uptake of the synthesized membranes ranged from 30%–55%, compared with 32.13% for Nafion 211® at 80°C. The proton conductivity (80°C, RH 90%) ranged from 74.6–101.2 mS/cm, compared with 102.7 mS/cm for Nafion 211®.

The effect of deposition temperature and post deposition annealing (PDA) on the electrical properties of HfO2films grown on a Ge substrate by atomic layer deposition (ALD) was investigated. The HfO2films deposited at 280°C (280°C-HfO2) showed a large capacitance-voltage (C-V) hysteresis, but it was significantly reduced at 200°C (200°C-HfO2). Further reduction of deposition temperature to 160°C resulted in the abrupt increase of C-V hysteresis. The reduction of C-V hysteresis was originated from the smaller degree of intermixing between the HfO2and Ge substrate with decreasing temperature, while the increase of C-V hysteresis comes from the low density of films grown at low temperatures. The C-V hysteresis characteristics were also strongly influenced by PDA temperatures. PDA temperatures higher than 550°C induced a large C-V hysteresis regardless of deposition temperature. Interestingly, after the PDA process, the HfO2grown at 200°C is crystallized to the tetragonal phase, while the HfO2grown at 280°C is crystallized to the monoclinic phase. These different crystalline phases result in a lower equivalent oxide thickness in the 200°C-HfO2compared to the 280°C-HfO2

The effect of the carbon concentration on the crystalline phase and dielectric constant (k) of atomic layer deposited HfO2films on Ge substrate was investigated. After annealing, the HfO2films grown at 200°C and 280°C were crystallized to the tetragonal (t) and monoclinic (m) phases, respectively, which was related to the carbon contents within the films and grain boundary energy. To clarify this, the energy difference between a t- and a m- phases (ΔEtetra) was calculated by first principles calculations. The higher k value of t-HfO2compared to amorphous and monoclinic HfO2was experimentally confirmed.

This study examined the effects of postdeposition annealing (PDA) on the electrical characteristics of atomic layer deposited ZrO2and HfO2films using similar precursors and process conditions. After PDA at 600ºC, the insulating properties of ZrO2improved but those of HfO2deteriorated. The improved insulating properties of ZrO2were attributed to the negligible increase in the interfacial layer thickness and an amorphous to tetragonal phase transformation. In addition, the degraded insulating properties of HfO2after PDA at high temperatures were attributed to an abrupt increase in the interfacial layer thickness and the generation of conducting paths through the grain boundaries.

Ru top electrode etching techniques for Ru∕TiO2∕Ru(RTR) thin film capacitor fabrication were examined. A dry etching process using a plasma mixture of O2, Cl2, and Ar gases deteriorated the leakage current properties significantly, which were not recovered by postannealing processes. The surface roughness was not a critical factor in determining the leakage characteristics. The etching damage along the etched edges was not the main cause of the leakage degradation but it was observed over the entire area, which was confirmed according to a comparison of capacitors with different perimeter/area ratios. For the wet etching of Ru films, the etch rates were evaluated using a periodic acid solution at various concentrations at 60°C. The Ru films etched using a 14wt%periodic acid solution showed a moderate etch rate and a reasonable etching selectivity on the TiO2and Al2O3films. The as-wet-etched RTR capacitors showed a lower leakage current level than the dry-etched capacitors. Furthermore, the electrical properties of the wet-etched capacitor were improved significantly by a postannealing process.

Interfacial barrier layers (IBLs), such as a thermally grown SiO2using O3, thermally nitrided SiOxNyusing NH3, and an atomic layer deposited (ALD) HfO2layer, were used as an interface layer between a sputtered SrTiO3film and a Si substrate. Sr-silicate phase formation at the interface between the SrTiO3film and Si substrate was suppressed by these IBLs. The ALD HfO2layer was the most effective diffusion/reaction barrier against Si diffusion and the interfacial reactions among the IBLs examined. However, the crystallinity of the SrTiO3layer deteriorated as a result of a chemical reaction with the underlying ALD HfO2layer, which decreased the permittivity of the SrTiO3layer. The SrTiO3film with a SiOxNyIBL showed lower Si diffusion and better crystallinity, which provided the optimum dielectric properties of the film.

Amorphous HfInZnO (HIZO) - thin film transistor (TFT) with the bottom gate structure were fabricated to investigate the effect of light illumination on the transfer curves and stability characteristics under negative bias stress. The TFTs with passivation layers showed promising characteristics when measured in the dark, with a saturation mobility (µsat) of 9.0 cm2/Vs, a sub-threshold swing (SS) of 0.34 V/dec and an on/off ratio of ~108. However, when exposed to light of wavelengths below 500nm, the transfer curve changes remarkably, with an increase of SS and off-current (Ioff). The change in the transfer curves were also studied by examining them before and after negative bias-temperature-illumination stress. The increase of SS under light illumination can be due to the increase in the number of activated interfacial traps by photon energy.

The effect of atomic layer deposited Al2O3, SrO, and La2O3 capping layers with HfO2 gate dielectrics were examined ffor flat band voltage (VFB) modulation. Al2O3 capping layers cause a VFB shift into the positive voltage direction, while SrO and La2O3 capping layers cause a shift into the negative voltage direction. The bottom capping layer, which positions between the Si substrate and the HfO2 dielectric was more effective in modulating the VFB compared to the top capping layer. The insulating properties of the gate dielectric stacks with different capping layers were also examined. X-ray photoelectron spectroscopy analysis verified that top capping layers did not generally diffuse to the interface between the Si substrate and the HfO2 dielectrics, which supports the result that bottom capping layers are more effective in modulating the VFB.

The effect of nitrogen incorporation on the dielectric properties and bias temperature instability characteristics of HfOxNy and ZrOxNy were investigated. The incorporated nitrogen induces a reduction in the capacitance equivalent oxide thickness value, increases the leakage current, and causes the turn around of Vth shift under the positive bias stress in nMOSFET. In addition, compared to HfOxNy, ZrOxNy shows a significantly lower initial Vth shift under positive gate stress due to the lower number of shallow bulk traps related to oxygen vacancies.

Hf1-xSixOy (HfSiO) gate dielectrics with a wide range of Si composition are grown by an atomic layer deposition (ALD). The Si composition in HfSiO films can be tailored with precision by manipulating the ALD sub-cycle sequence of Hf and Si precursors. Through this method, the effects of Si composition of HfSiO films on the physical and electrical properties are investigated with different thermal budget. Si incorporation into HfO2 delays the crystallization of the films, which improved the leakage current characteristics. However, it also increases capacitance equivalent oxide thickness values due to the increased SiO2 content which has a relatively lower dielectric constant. By optimizing the Si composition, high quality HfSiO gate dielectrics having comparable insulator properties to HfO2 but improved thermal stability were achieved

The dielectric properties and bias temperature instability characteristics of in situ nitrogen incorporated ZrOxNygate dielectrics were compared with those of ZrO2, HfO2, and HfOxNy. ZrOxNyshowed a much smaller capacitance equivalent oxide thickness (1.43 nm) than ZrO2(2.13 nm) and exhibited a turn-around effect under a positive gate stress bias in n-type metal oxide semiconductor field-effect transistor, which is consistent with HfOxNy. However, compared to HfOxNy, ZrOxNyshowed a significantly lower initial Vthshift under a positive gate stress bias due to the lower number of shallow bulk traps related to oxygen vacancies.

The dielectric properties and n-type metal oxide semiconductor field-effect transistor (nMOSFET) positive bias temperature instability (PBTI) characteristics of in situ nitrogen-incorporated plasma-enhanced atomic layer deposited HfOxNygate dielectrics were compared with those of the HfO2films. Although the physical thickness of the HfOxNyand HfO2films were almost identical (∼4.1nm), the capacitance equivalent oxide thickness of HfOxNy(1.43 nm) was much lower than that of HfO2(2.28 nm), suggesting that HfOxNyhas a larger dielectric constant. However, HfOxNyshowed a higher leakage current than HfO2due to a decrease in bandgap. HfOxNyshowed a turnaround effect under a positive gate stress bias in nMOSFET. The threshold voltage (Vth)shifted to the positive direction during the first second due to the trapping of electrons at pre-existing trap sites in Hf-based gate dielectrics. Subsequently, the Vthshifted in the negative direction due to hole trapping, which originated from the generation of electron–hole pairs related to the surface plasmon. HfOxNyshowed a higher initial interface trap density but a lower interface trap generation rate during n-type MOS PBTI stress than HfO2.

This study examined the positive bias temperature instability (PBTI) of n-type metal-oxide-semiconductor field effect transistor (nMOSFET) characteristics and the negative bias temperature instability (NBTI) of p-type metal-oxide-semiconductor field effect transistor (pMOSFET) characteristics of HfO2gate dielectrics with a metal gate. The interface trap charge (ΔNit)and bulk oxide trap charge (ΔNot)densities were separately estimated to determine the defects responsible for the threshold voltage (Vth)shift during the BTI stress. The contribution of ΔNitto the Vthshift for nMOSFET PBTI and pMOSFET NBTI was ∼5and ∼30%, respectively. In addition, the estimated activation energy (Ea)of ΔNitand ΔNotwas 0.10 and 0.03 eV, respectively, for nMOSFET PBTI, and 0.11 and 0.17 eV, respectively, for pMOSFET NBTI. It was confirmed that the main degradation mechanism of nMOSFET PBTI is related to the generation of oxide trap charges. However, the degradation under pMOSFET NBTI stress is due to the generation of both interface states and oxide trap charges. By measuring the stress and recovery characteristics under various bias conditions, it was also found that the electron trapping/detrapping characteristics are dominant in the nMOSFET, whereas the generation of both hole trapping/detrapping and interface states competitively occurs in the pMOSFET.