Composite-based piezoelectric devices are extensively studied to develop sustainable power supply and selfpowered devices owing to their excellent mechanical durability and output performance. In this study, we design a leadfree piezoelectric nanocomposite utilizing (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 (BCTZ) nanomaterials for realizing highly flexible energy harvesters. To improve the output performance of the devices, we incorporate porous BCTZ nanowires (NWs) into the nanoparticle (NP)-based piezoelectric nanocomposite. BCTZ NPs and NWs are synthesized through the solidstate reaction and sol-gel-based electrospinning, respectively; subsequently, they are dispersed inside a polyimide matrix. The output performance of the energy harvesters is measured using an optimized measurement system during repetitive mechanical deformation by varying the composition of the NPs and NWs. A nanocomposite-based energy harvester with 4:1 weight ratio generates the maximum open-circuit voltage and short-circuit current of 0.83 V and 0.28 A, respectively. In this study, self-powered devices are constructed with enhanced output performance by using piezoelectric energy harvesting for application in flexible and wearable devices.

본 연구는 유연근무제 관련 공무원 인식조사를 활용하여 다음 두 가지의 주요 목적 을 위한 통계적 분석을 수행하고자 한다. 첫째, 유연근무제 활용 만족도 수준과 조직 만족도 수준 간의 영향 관계를 정량적으로 검증하는 것이다. 둘째, 유연근무제 활용 만족도와 조직만족도 수준 간의 영향 관계에서 공무원의 성별과 연령이 갖는 조절효 과를 분석하는 것이다. 본 연구의 목적 달성과 가설 검증을 위해 우리나라 D 자치단체 공무원을 대상으로 설문조사를 수행하였다. 응답자 공무원의 소속은 D 자치단체 본 청, 직속기관, 산하기관, 사업소 등이 포함되었으며, 정규직 신분의 지방직 공무원이 다. 기초통계분석, 상관관계분석과 더불어 본 연구의 가설 검증을 위해 회귀분석을 수 행하였다. 분석 결과, 유연근무제 활용 만족도 수준과 조직만족도 수준 간은 통계적 으로 유의미한 양의 관계가 있음이 검증되었다. 또한, 공무원의 성별과 연령대 변수 모두 유연근무제 활용 만족도 수준과 조직만족도 간의 관계를 유의미하게 조절하는 효과가 있음이 검증되었다. 특히, 성별과 유연근무제 활용 만족도의 상호작용항과 연 령대와 유연근무제 활용 만족도의 상호작용항의 회귀계수가 모두 통계적으로 유의 미하게 나타난 점은 정부조직의 유연근무제 활용과 정책 집행에 있어 중요한 시사점 이 있다고 판단된다. 본 연구를 통해서 지금까지 유연근무제 활용 여부 자체에 대한 효 과 검증에 치우쳐 있던 국내 공공기관 대상 유연근무제 연구의 이론적 확장이 이루어 지길 기대한다. 유연근무제 이용 여부 자체에서 벗어나 유연근무제 활용 만족도 수준 이 여러 다양한 조직결과변수들에 미치는 효과를 검증함으로써 국내 공공부문 유연 근무제 연구는 더욱 더 다양하고 심도있게 추진될 수 있을 것으로 기대한다. 아울러, 정부조직에서의 유연근무제의 보다 합리적인 정착과 적극적인 활용이라는 실무적 관점에서 본 연구에서 제시하고 있는 통계분석 결과가 이에 기여할 수 있을 것이다.

Background: The flexible flatfoot is characterized by a flattening of the foot arch due to excessive bodyweight. The use of shoe insoles or taping methods has been identified as effective in realigning the navicular or calcaneus bones and addressing supination in pronated feet. Objects: This study aimed to analyze the difference between the arch taping attachment method, introduced in a previous study, and a novel taping method designed to provide support to the inner aspect of the heel bone in cases of flexible flatfoot. Methods: A navicular drop test was performed to discriminate flexible flatfoot. To analyze the differences in pressure distribution during walking for each taping method, the subjects underwent testing in the barefoot state with no attachments. The procedure included a sequence of arch taping and heel taping. Subsequent analysis of pressure distribution during walking utilized the GaitRite® system (GAITRite Gold, CIR Systems Inc.). Results: Arch taping and calcaneus taping significantly reduced the integrated pressure over time and peak pressure on the medial side of the midfoot for both feet compared to the barefoot state. Conclusion: The findings of this study suggest that supporting the inside of the heel through calcaneus taping, without direct stimulation to the longitudinal arch and navicular bone, is an effective intervention for flexible flatfoot.

Piezoelectric technology, which converts mechanical energy into electrical energy, has recently attracted drawn considerable attention in the industry. Among the many kinds of piezoelectric materials, BaTiO3 nanotube arrays, which have outstanding uniformity and anisotropic orientation compared to nanowire-based arrays, can be fabricated using a simple synthesis process. In this study, we developed a flexible piezoelectric energy harvester (f-PEH) based on a composite film with PVDF-coated BaTiO3 nanotube arrays through sequential anodization and hydrothermal synthesis processes. The f-PEH fabricated using the piezoelectric composite film exhibited excellent piezoelectric performance and high flexibility compared to the previously reported BaTiO3 nanotube array-based energy harvester. These results demonstrate the possibility for widely application with high performance by our advanced f-PEH technique based on BaTiO3 nanotube arrays.

The equivalent static load for non-structural elements has a limitation in that the sloshing effect and the interaction between the fluid and the water tank cannot be considered. In this study, the equations to evaluate the impulse and convective components in the design codes and previous research were compared with the shaking table test results of a rectangular water tank with flexible wall panels. The conclusions of this study can be summarized as follows: (1) It was observed that the natural periods of the impulsive component according to ACI 350.3 were longer than system identification results. Thus, ACI 350.3 may underestimate the earthquake load in the case of water tanks with flexible walls. (2) In the case of water tanks with flexible walls, the side walls deform due to bending of the front and back walls. When such three-dimensional fluid-structure interaction was included, the natural period of the impulsive component became similar to the experimental results. (3) When a detailed finite element (FE) model of the water tank was unavailable, the assumption   could be used, resulting in a reasonably conservative design earthquake load.

Graphene is a suitable transducer for wearable sensors because of its high conductivity, large specific surface area, flexibility, and other unique considerable features. Using a simple, fast galvanic pulse electrodeposition approach, a unique nonenzymatic glucose amperometric electrode was successfully developed based on well-distributed fine Cu nanoparticles anchored on the surface of 3D structure laser-induced graphene. The fabricated electrode allows glucose detection with a sensitivity of 2665 μA/mM/cm2, a response time of less than 5 s, a linear range of 0.03–4.5 mM, and a LOD of 0.023 μM. It also detects glucose selectively in the presence of interfering species such as ascorbic acid and urea. These provide the designed electrode the advantages for glucose sensing in saliva with 97% accuracy and present it among the best saliva-range non-enzymatic glucose sensors reported to date for real-life diagnostic applications.

Flexible supercapacitors (FS) are ideal as power backups for upcoming stretchable electronics due to their high power density and good mechanical compliance. However, lacking technology for FS mass manufacturing is still a significant obstacle. The present study describes a novel method for preparing FS based on reduced graphene oxide (RGO) using the N+ plasma technique, in which N+ reduces graphene oxide on the surface of a cotton/polyester substrate. The effect of aloe vera (AV) as a natural reducing & capping agent and carbon nanotubes (CNT) as nanoconductors on the electrochemical performance of the electrodes is studied. FESEM and XPS were employed to investigate the electrodes' structural and chemical composition of electrodes. The galvanostatic charge–discharge curves of electrodes revealed the enhancement of the electrochemical activity of the as-prepared electrode upon additions of AV and CNT. The areal capacitance of the RGO, RGO/AV, and RGO/ AV/CNT supercapacitors at 5 mV/s was 511, 1244.5, and 1879 mF/cm2, respectively. The RGO electrode showed capacitive retention of 80.9% after 2000 cycles enhanced to 89.7% and 92% for RGO/AV and RGO/AV/CNT electrodes, respectively. The equivalent series resistance of the RGO electrode was 126.28 Ω, decreased to 56.62 and 40.06 Ω for RGO/AV and RGO/ AV/CNT electrodes, respectively.

As the demand for flexible wearable electronic devices increases, the development of light, thin and flexible high-performance energy-storage devices to power them is a research priority. This review highlights the latest research advances in flexible wearable supercapacitors, covering functional classifications such as stretchability, permeability, self-healing and shapememory capabilities, as well as practical studies on energy harvesting capabilities.

일인가구의 증가 SNS와 온라인을 통한 소통의 증대 등 점차 파편화 되는 현대사회에서 개인들이 직접 대면하고 소통할 수 있는 물리적 커뮤니티공간의 필요성은 점차 증가하고 있지만 이의 확충은 경제 및 개발 논리에 밀려 쉽게 이루어지기 어렵다. 본 연구는 커뮤니티공간의 부족함을 완화시키고 공평하게 향유할 수 있는 커뮤니티공간을 제공할 수 있는 대안으로 도시의 가로공간에 집중하고 도로가 가진 높 은 접근성을 활용하여 도로를 커뮤니티 활성화를 위한 커뮤니티공간으로 전환시키는 기법을 고찰하 고 시사점을 제공하고자 한다. 먼저 선행연구와 관련문헌을 통해 커뮤니티 활성화를 위한 주요 요소들 을 도출하여 분석의 틀을 만든다. 다음으로 뉴욕시에서 진행하고 있는 세 가지 프로그램인 뉴욕시 오픈 레스토랑, 뉴욕시 오픈 스트리트, 뉴욕시 플라자 프로그램의 사례연구 및 분석을 진행한다. 그리고 커 뮤니티공간에 커뮤니티를 위한 프로그램을 제공하는 방식도 함께 살펴본다. 분석 결과 세 개 프로그램 을 통해 가로공간을 전용하여 확보한 커뮤니티공간들이 커뮤니티의 활성화를 위한 다음의 요소들 안 전, 참여, 접근성과 보행성, 가로의 활력, 경제적 이득, 유연성과 적응력, 다양성과 포용성을 증진 시킬 수 있음을 확인하였다. 이를 통해 본 연구가 제시하는 시사점은 다음과 같다. 먼저, 지역 커뮤니티가 계 획 단계에서부터 커뮤니티공간의 조성, 운영, 관리의 주체가 되어야 한다. 두 번째, 시정부는 커뮤니티 들이 활용할 수 있는 프로그램을 개발, 운영하고 이를 제공하여야 한다. 세 번째, 커뮤니티와 그 주변 여건의 변화에 쉽게 적응하고 변화할 수 있는 가변적이면서도 능동적인 조성이 필요하다. 마지막으로 는 모든 커뮤니티공간에 적용될 수 있는 동일한 규격, 기준, 가이드라인의 제공이 필요하다.

Thermoelectric (TE) energy harvesting, which converts available thermal resources into electrical energy, is attracting significant attention, as it facilitates wireless and self-powered electronics. Recently, as demand for portable/wearable electronic devices and sensors increases, organic-inorganic TE films with polymeric matrix are being studied to realize flexible thermoelectric energy harvesters (f-TEHs). Here, we developed flexible organic-inorganic TE films with p-type Bi0.5Sb1.5Te3 powder and polymeric matrices such as poly(3,4-eethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and poly (vinylidene fluoride) (PVDF). The fabricated TE films with a PEDOT:PSS matrix and 1 wt% of multi-walled carbon nanotube (MWCNT) exhibited a power factor value of 3.96 μW ‧ m-1 ‧ K-2 which is about 2.8 times higher than that of PVDF-based TE film. We also fabricated f-TEHs using both types of TE films and investigated the TE output performance. The f-TEH made of PEDOT:PSS-based TE films harvested the maximum load voltage of 3.4 mV, with a load current of 17.4 μA, and output power of 15.7 nW at a temperature difference of 25 K, whereas the f-TEH with PVDF-based TE films generated values of 0.6 mV, 3.3 μA, and 0.54 nW. This study will broaden the fields of the research on methods to improve TE efficiency and the development of flexible organic-inorganic TE films and f-TEH.

This work reports the fabrication of a flexible Photodetector (PD) using Carbon Dots (CDs)/Polymer composite for Deep UV (DUV) photodetection. The CDs have been prepared using a simple and inexpensive heating process. The syncretic studies reveal the disordered graphitic core with surface functional groups and the excitation-dependent character of CDs. The synthesized CDs are stabilized via Poly Vinyl Alcohol (PVA) through a synergistic effect and investigated for different compositions (2–10 weight %) of CDs. The CDs/PVA composites shows improved absorbance at 208 and 335 nm compared to pure CDs owing to the bonding between them. This advantageous property of high absorption and photo response in the DUV region is utilized by employing CDs/PVA composite as a photo-sensing layer on the ITO-coated PET substrate in the PD. The performance of the PD was measured under dark, short (254 nm) and long (365 nm) UV region. Among all the compositions, 4% CDs/PVA PD exhibits superior performance in terms of high photo-to-dark current ratio (IPh/Id), responsivity and detectivity. The PD functioning and other parameters are discussed in detail and reported.

The present study examines the impact of COVID-19 anxiety on employees’ psychological resources and behaviors, drawing on the conservation of resources theory. We also investigate whether flexibility in work contexts has a meaningful effect on employees’ responses to the pandemic. A total of 284 working adults participated in an online survey consisting of self-reporting questionnaires that assessed levels of COVID-19 anxiety, vigor, innovative work behavior, and flexible working arrangements. The results showed that the level of vigor mediated the positive relationship between COVID-19 anxiety and innovative work behavior, and the perceived level of flexible working arrangements moderated this mediation effect positively. The findings highlight the importance of considering employees’ psychological resources and work arrangements in managing the negative impact of COVID-19-related anxiety. This study provides theoretical and practical implications for organizations to better understand the psychological processes that employees undergo during a crisis. Further research on diverse work settings and cultural backgrounds is needed to expand on the present findings.

The fast expanding field of wearable technology requires light-weight, low-cost, scalable, flexible and efficient energy harvesters as a source of uninterrupted green power. This work reports fabrication of sub-micron graphite platelet/PVDF composite film-based flexible piezoelectric energy harvester (PGEH) for scavenging the wasted mechanical energy associated with human body motion. The addition of graphite platelet leads to the enhancement of electroactive β phase in PVDF; consequently, the piezoelectric and dielectric properties of the composite are enhanced. 0.5 wt% filler-loaded composite has 96% β phase fraction and dielectric constant 32 at 100 Hz (tanδ = 0.18).The PGEH produces open circuit voltage of 40 V and instantaneous power density of 3.35 mW cm− 3 with energy conversion efficiency of 22.5% under periodic finger tapping. It can generate fair electrical output under gentle heel (0.8 V) and toe movements (1.2 V). A PGEH is directly employed for powering 50 commercial LEDs and quick charging of a 2.2-μF capacitor upto 19.2 V. The device is also employed as self-powered dynamic pressure sensor which shows high sensitivity (0.9 VkPa− 1) with fast response time (1 ms). Therefore, this durable, flexible, efficient PGEH can have promising applications in wearable electronics as a green power source cum self-powered mechanosensor.

A facile and efficient method was developed to prepare highly stretchable and conductive graphene conductors with wrinkled structures by the mechanical stretching and shrinking of elastomeric substrates, in which graphene inks were printed on a prestretched elastomeric substrate. Stretchable and exfoliated graphene inks were prepared by mixing graphite and Ecoflex in a shear-assisted fluid dynamics reactor. The resultant graphene conductor exhibited excellent stretchability at 150% strain and high electrical conductivity of 64 ± 1.2 S m− 1. The resistance of the conductor did not change in bent, twisted, and stretched states. The resistance did not change during 10,000 cycles of stretching/releasing, with a maximum strain of 150%. Based on the graphene conductor, a stretchable conductometric sensor with a two-electrode configuration was fabricated to measure impedance changes at different concentrations of electrolyte ions. This sensor exhibited a good and linear sensitivity curve (298.61 Ω mM− 1, R2 = 0.999) in bent and stretched states.

Flexible zinc-air batteries have many merits, including low cost, high safety, environmentally friendliness applicability, etc. One of the key factors to improve the performance of flexible zinc-air batteries is to use a gel electrolyte. In this study, gel electrolytes were synthesized from potato, sweet potato, and corn starch. In a comparison of each starch, the corn starch-based gel electrolyte showed the highest discharge capacity of 12.41 mAh/cm2 in 20 mA and 6.47 mAh/cm2 in 30 mA. It also delivered a higher specific discharge capacity of 7.06 mAh/cm2 than the other materials after 100° bending. In addition, the electrochemical impedance spectroscopy (EIS) was analyzed to calculate the ionic conductivity. The potato, sweet potato, and corn starch-based gel electrolytes showed electrolyte resistances (Re) of 0.306, 0.298, and 0.207 Ω, respectively. In addition, the corn starch-based gel electrolyte delivered the highest ionic conductivity of 0.121 S cm-1 among the other gel electrolytes. Thus, the corn starch-based gel electrolyte was verified to improve the performance of flexible zinc-air batteries

Piezoelectric composite films which are enabled by inorganic piezoelectric nanomaterials-embedded polymer, have attracted enormous attention as a sustainable power source for low powered electronics, because of their ease of fabrication and flexible nature. However, the absorption of applied stress by the soft polymeric matrices is a major issue that must be solved to expand the fields of piezoelectric composite applications. Herein, a flexible and porous piezoelectric composite (piezoelectric sponge) comprised of BaTiO3 nanoparticles and polydimethylsiloxane was developed using template method to enhance the energy conversion efficiency by minimizing the stress that vanishes into the polymer matrix. In the porous structure, effective stress transfer can occur between the piezoelectric active materials in compression mode due to direct contact between the ceramic particles embedded in the pore-polymer interface. The piezoelectric sponge with 30 wt% of BaTiO3 particles generated an open-circuit voltage of ~12 V and a short-circuit current of ~150 nA. A finite element method-based simulation was conducted to theoretically back up that the piezoelectric output performance was effectively improved by introducing the sponge structure. Furthermore, to demonstrate the feasibility of pressure detecting applications using the BaTiO3 particles-embedded piezoelectric sponge, the composite was arranged in a 3 × 3 array and integrated into a single pressure sensor. The fabricated sensor array successfully detected the shape of the applied pressure. This work can provide a cost-effective, biocompatible, and structural strategy for realizing piezoelectric composite-based energy harvesters and self-powered sensors with improved energy conversion efficiency