Background: During daily activities, stability is maintained to enhance the function of muscles surrounding the lumbopelvic and hip structures. The core muscles such as the rectus abdominis (RA), external oblique (EO), and internal oblique (IO) responsible for this stability. One effective static exercise for strengthening these muscles is the plank. Objects: This study aimed to compare abdominal electromyographic activation when an unstable support surface was applied to the upper and lower extremities during a standard and a knee plank. Methods: A total of 30 adults (15 males and 15 females) participated in this study. Surface electromyography electrodes were placed on the RA, EO, and IO muscles. Data were collected under six conditions for males, including two plank postures (standard and knee planks) and three unstable surface conditions (a dynamic balance cushion applied to the upper extremities, lower extremities, or no cushion). Female participants performed only the knee plank. A mixed-effects model with a random intercept was used to analyze muscle activation across plank posture and surface position, with statistical significance set at α = 0.05. Results: In males, the standard plank elicited greater muscle activation than the knee plank across all muscles (p < 0.0001). Additionally, applying an unstable support surface to the upper extremities significantly increased muscle activation in both plank postures in EO and IO (p < 0.001). Other muscle, RA, was only affected by the unstable support surface in the standard plank position only. In females, the knee plank with upper limb instability resulted in the highest muscle activation for all muscles. Conclusion: These findings highlight the importance of surface instability in core muscle engagement. However, future studies should further investigate abdominal muscle activation with a more detailed analysis and the inclusion of a control group to enhance comparative validity.

Background: Stroke often results in impaired postural control and asymmetric weight distribution, which negatively affect balance and functional mobility. Previous research has demonstrated that balance training interventions incorporating proprioceptive stimulation and visual feedback can enhance postural stability in stroke survivors. However, there remains debate regarding the relative effectiveness of these two approaches. While proprioception-based training emphasizes sensory input from mechanoreceptors to improve postural control, visual feedback-based training leverages external cues to facilitate balance adjustments. Objectives: To investigation the effects of proprioception-based trunk exercise and visual-auditory feedback-based trunk exercise on sitting balance in patients with chronic stroke. Design: Randomized controlled trial. Methods: A total of 24 participants diagnosed with chronic stroke were randomly assigned to two groups: the proprioception-based trunk exercise group (PTG, n=10) and the visual-auditory feedback-based trunk exercise group (VTG, n=11). Both groups participated in a 6-week intervention program, five sessions per week, lasting 25 minutes per session. Outcome measures included the Limitation of Stability (LOS), the Korean version of the Trunk Impairment Scale (K-TIS), and the Postural Assessment Scale for Stroke (PASS). Pre- and post-intervention assessments were analyzed using paired t-tests and independent t-tests to evaluate within-group and between-group differences. Results: Both PTG and VTG groups demonstrated significant improvements in LOS, K-TIS, and PASS scores following the intervention (P<.05). However, there were no statistically significant differences between the two groups in the amount of change observed. Conclusion: The findings suggest that both proprioception-based and visualauditory feedback-based trunk exercises are effective in improving sitting balance in chronic stroke patients. The lack of a significant difference between the groups indicates that both approaches provide comparable benefits. Future research should explore long-term effects and investigate potential differences in various functional domains beyond sitting balance.

도로에서 소음저감에 대한 대책으로 방음벽, 포장 개선, 차량 속도 제한 등 여러 가지 대책이 제기되고 있으며 최근에는 차세대 표면처리 공법(Next Generation Concrete Surface, NGCS)이 사용되고 있다. 이러한 NGCS는 표면을 그라인딩 후 그루빙 공정을 진행하게됨에 따라 포장두께 감소 및 ITZ(Interfacial Transition Zone)의 표면 노출에 따른 내구성 감소가 발생할 수 있다. 이러한 내구성 감소는 교면포장에서 발생 시 안정성에 크리티컬한 영향을 미치게 됨에 따라, 본 연구는 교면포장에 주로 사용되는 라텍스 개질 콘크리트 (Latex-Modified Concrete, LMC)에 NGCS 적용 시 발생할 수 있는 내구성 감소 중 염해에 관한 연구를 진행하였다. 실제 공용 중인 LMC 교면포장의 현장 코어와 라텍스 혼입율(10, 15, 20%)에 따른 실내 배합을 진행하였으며 NGCS를 시험편에 적용하기 위하여 도로공사 표면처리공법 시방서를 기준에 따른 NGCS 모사 공법을 적용하여 염해 내구성 평가를 진행하였다. 시험 결과 현장코어의 경우 높은 수밀성과 염해저항성을 가지고 있어 NGCS 처리 시 뚜렷한 염해 내구성 저하가 나타나지 않았지만 상대적으로 낮은 수밀성을 가진 LMC 실내 배합의 경우 NGCS 적용 시 소폭의 염해 내구성이 감소함을 확인하였다.

본 연구에서는 친환경적이고 경제적인 수용액 환경에서 금속-유기 골격체(metal-organic frameworks, MOF)인 UiO-66을 합성하는 방법을 개선하고, 합성 조건이 UiO-66의 표면적 및 결정성에 미치는 영향을 분석하였다. 합성 실험은 금 속 용액과 리간드 용액의 주입 순서 및 계면활성제(Tween 20)의 첨가 유무를 변화시키며 진행하였다. 그 결과, 리간드 용액 을 금속 용액에 주입하고 계면활성제를 사용하지 않은 경우, 표면적과 결정성이 더 높은 UiO-66을 얻을 수 있었다. SEM 및 XRD 분석 결과, 계면활성제의 첨가는 입자 크기와 결정 구조에 큰 변화를 주지 않았으나, BET 분석 결과 표면적 감소가 확 인되었다. 이는 합성 과정에서 계면활성제가 핵 형성과 결정 성장에 영향을 미칠 수 있음을 시사한다. 본 연구 결과는 수용액 기반 UiO-66 합성법의 최적화, 대규모 제조 공정 및 다양한 산업적 응용에 유용한 정보를 제공할 수 있을 것이다.

본 연구는 고객의 무례행동이 서비스지향 OCB에 미치는 부정적인 영 향을 분석하고, 그 과정에서 표면연기와 직무소진이 어떠한 역할을 하는 지 살펴보았다. 첫째, 고객의 무례행동은 서비스지향적 OCB와 부정적 관 계를 가질 것으로 예측하였다. 둘째, 고객의 무례행동이 서비스지향적 OCB 에 부정적인 영향을 미치는 과정에서 직무소진이 주요 매개 변수로 작용 할 가능성이 클 것으로 예측하였다. 셋째, 고객의 무례행동은 서비스지향 OCB에 부정적인 영향을 미치는 관계에서 표면연기가 중요한 매개 역할 을 할 것으로 예측하였다. 이를 검증하기 위하여 2020년 10월 15일부터 11월 4일까지 약 20일간 국내 공기업에서 운영하는 수도권 소재 사업장 을 방문하여 고객접점 종사원을 대상으로 설문조사를 진행하였고, 기존 의 선행연구들을 토대로 가설을 설정하고 검증하였다. 분석 결과 고객의 무례행동은 서비스지향 OCB에 부정적인 영향을 미치고, 표면연기와 직 무소진은 고객의 무례행동이 서비스지향 OCB에 미치는 부정적인 영향을 매개하는 것으로 나타났다. 이와 관련하여 이론적·실무적 시사점을 제시 하고, 본 연구의 한계 및 향후 연구의 방향성을 제시하였다.

완도 지역 전복 양식장 주변 표층퇴적물을 대상으로 퇴적물의 입도, 총유기탄소(TOC), 중금속(Fe, Li, Cu, Zn, Pb, Cd, Cr, As, Ni, Hg) 분포와 조절요인을 분석하고, 생태학적 위험성을 평가하였다. 퇴적물은 주로 실트와 점토로 구성되었으며 일부 지역에서는 모래와 자갈이 혼합된 퇴적물이 확인되었다. TOC 함량은 평균입도와 높은 상관성을 보였으며, 평균값은 0.76%로 나타나 양식 과정에서 발생한 유기물과의 연관성을 제시하였다. 퇴적물 내 Ni, Cd, Zn, Cu는 양식장 활동 및 유기물 축적의 영향을 받으며, Cd는 가장 높은 농축을 보임 으로써 주요 오염원으로 확인되었다. 특히, Cd의 축적은 잔류 해조류 침전과 CaCO3 침전 과정에서 치환작용과 연관이 있는 것으로 해석 되었다. 생태학적 위해도 평가에서는 연구지역 대부분이 중간 위험 수준으로 나타났으며, Cd는 주요 생태학적 위해 요인으로 확인되었다.

We prepared porous poly(ε-caprolactone)/poly(lactic-co-glycolic acid) (PCL/PLGA) 3D scaffolds with surfaces that were modified through the co-precipitation of calcium phosphate (CAP) with binary drug components, including risedronate (RSD) and hyaluronic acid (HyA). The 3D porous biodegradable PCL/PLGA scaffolds were fabricated by sintering microspheres prepared with a 30/70 PCL/PLGA blend. The co-precipitation of the CAP coating with binary drug components significantly enhanced the proliferation and differentiation of rat mesenchymal stem cells (rMSCs) on the scaffolds. Although the presence of both HyA and RSD positively improved proliferation and differentiation, HyA and RSD were more effective on osteoblastic proliferation and differentiation, respectively. These results strongly demonstrate that the drug effects on osteoblastic responses were closely interconnected. The two drugs affect rMSCs behavior in a concentration-dependent manner, requiring a balance between proliferation and differentiation for optimal bone regeneration. We expect this surface modification technique could potentially be utilized for the fabrication of functionalized biodegradable scaffolds and delivery of drug mixtures.

The results of the measurements using an optical surface roughness meter are shown according to the angle changes of 0, 0.5, 1, 1.5, 2, and 3°. Through the experiment, it can be seen that the measurement value is 3.140 at 0°, 3.148 at 0.5°, 3.140 at 1°, 3.151 at 1.5°, 5.078 at 2°, and 4.790 at 3° setting. In addition, the test statistic (P) value is 0.000, which is smaller than the significance level of 0.005, so it was confirmed through the experiment that a measurement error occurs according to the angle change when measuring the surface roughness.

In this work the multiple moving magnetic abrasive machining (MAM) process was used to polish the surface of spherical bar that is the components that widely used in many applications such aerospace, medical implantation, and the mechanical engineering industries. The smooth surface of spherical ball plays an important role for improving the lifespan, durability, and functionality of the components. In. Therefore, the moving MAM process was fabricated to achieve high quality surface of the spherical ball sample. This process used the multiple moving actions of the machining tools for polishing the surface sample. The experiments used in this work was set as the rotational speed of sample (50, 120, and 250 rpm), movement of machining tools (X-axis: 12 mm/sec, Y-axis: 12 mm/sec), and the polishing times (0, 2, 4, 6, 8 min). The results demonstrated that within 6 min of the polishing time the surface roughness of sample was significantly reduced from 0.29 μm to 0.02 μm under the polishing action of machining abrasive tool (size: 1-μm). This can be concluded that the multiple moving MAM process is an effective method to achieve high surface quality of sample with extremely low surface roughness (Ra).

본 연구에서는 열유도상분리법으로 제조한 polyvinylidene fluoride (PVDF) 중공사막의 오염성과 화학적 세척에 대한 실험을 진행하였다. 오염수는 소 혈청 단백질(bovine serum albumin, BSA)과 카올린(kaolin)을 이용해 제조하였으며, 차아 염소산나트륨(NaOCl), 구연산(citric acid), 황산(H2SO4)으로 화학적 세척을 진행한 후 뒤 표면 전하 분석기, 주사전자현미경 (scanning electron microscope, SEM) 그리고 에너지 분산 X선 분광법(energy dispersive X-ray spectroscopy, EDX)을 통해 세 척 효율을 평가하였다. PVDF 분리막은 높은 내화학성과 열적 안정성을 가지는 분리막으로 화학적 세척을 진행한 결과 가장 좋은 효율은 차아염소산나트륨으로 세척한 것으로 그 결과 투과도는 793.2 L/(m2.h.bar)로 초기 투과량인 945.3 L/(m2.h.bar) 값과 비교하였을 때 약 84% 회복률을 보여주었다. 이는 수처리 공정에서의 막 오염 방지 및 세척의 중요성을 제시한다.

이 논문에서는 부유식 구조체의 계류선에 작용하는 장력을 계산함에 있어서 동적 효과를 고려할 수 있는 준동적 계류선 해석 방법 을 제안하였다. 준동적 계류선 해석 방법은 매 시간 단계에서 계류선의 탄성 현수선 해석해에 기반한 정적 장력을 계산한 후, 준동적 장력 계수를 적용해 속도와 가속도에 따른 항력 및 관성력의 영향을 반영하는 방법이다. 제안하는 방법은 정적 탄성 현수선 해석해를 구할 때 계산 효율성을 높이기 위해 응답면 기법을 도입하고, 수평 및 수직 방향의 동적 계수를 결합하여 준동적 장력 계수를 결정하 는 새로운 방법을 제안하였다. 제안된 모델은 계류된 바지선의 운동 해석을 통해 검증하였으며, 다양한 파 조건에서 동적, 준정적, 준 동적 모델을 비교한 결과, 제안된 준동적 모델은 상대적으로 계류선의 동적 효과가 큰 주파수 대역에서 동적 모델과 유사한 장력 응답 을 도출할 수 있음을 확인하였다.

This study aims to prepare bamboo-based activated carbons with surface modifications, focusing on carbon dioxide (CO2) capture in public indoor spaces. The surface of the activated carbon adsorbents was chemically modified through three steps: carbonization, steam activation, and chemical treatment using potassium hydroxide (KOH) and potassium sulfamate (KSO3NH2). The specific surface area and pore volume of the obtained adsorbent (BSAC-KN) were 1,246 m2/g and 0.74 cm3/g, respectively. The surface modification resulted in an adsorption capacity of up to 3.79 mmol-CO2/ g-AC for carbon dioxide. In addition, the expansion of the specific surface area and the enhanced physico-chemical interaction between the weak acidic CO2 molecules and the basic AC surface improved adsorption capacity.

This study optimized the gelling agent and rice protein ratio for developing elderly friendly jelly using a response surface methodology. Response surface analysis was conducted with a gelling agent (0.1, 0.2, and 0.3%) and rice protein (3, 6, and 9%) set as independent variables. Increasing the gelling agent and rice protein ratio raised the pH while lowering the total acidity. The sugar content decreased nonlinearly with a higher gelling agent ratio. The lightness (L) and yellowness (b) differed according to the addition ratios of each ingredient, and the hardness peaked at 0.3% gelling agent and 6% rice protein, but excessive rice protein addition led to a decrease in hardness. Response surface analysis indicated an optimal formulation of 0.16% gelling agent and 6.41% rice protein, with all response variables aligning within the predicted ranges, validating the model.

Biomimetic study is being conducted in various fields and applied to the development of technology for the realization of a sustainable society. In this study, we analyzed the cuticular surface structure and wax layer composition of the leaves of Myriophyllum verticillatum and Azolla imbricata to investigate the antifouling characteristics. Field emission scanning electron microscopy analysis (FE-SEM) and contact angle measurement revealed that the surface of M. verticillatum had an irregular and curved layered structure with non-directional filament structures and showed high hydrophobicity. On the leaves of A. imbricata, amphiphilic structures with nano-sized hydrophobic plate-like filament structures and micro-sized irregular hydrophilic spikes were observed. The dorsal surface of the A. imbricata leaves had a denser distribution of hydrophobic nano-structures compared to the ventral surface. The dorsal surface of the leaf showed high hydrophobicity, while the ventral surface showed wettability. Due to the habitat characteristics of A. imbricata, which is a floating plant, the ventral surface is constantly in contact with water, while the front surface has a hydrophobic surface. Analysis of the wax composition of plants revealed that M. verticillatum and A. imbricata were mainly composed of saturated fatty acids, ketones (2-Nonadecanone and 2-Heptadecanon), and sugar alcohols such as 1,30-Triacontanediol. These substances have high antimicrobial activity, and saturated fatty acids form stable and rough anisotropic crystalline surfaces. The hierarchical amphiphilic structure and the non-toxic stable hydrophobic surface observed in the cuticle of aquatic plants are expected to be utilized as materials for the development of sustainable antifouling technologies.

대기 경계층은 특히 마찰로 인한 난류 운동 에너지 소산이 점성 하위층(VS)을 지배하는 표면 근처에서 대기의 자유 전단과 표면 마찰 사이의 복잡한 상호 작용에 의해 결정된다. 또한 로그 프로파일이 공존하며 마찰에 의해 난류가 재생되기도 한다. 현재 일 반적으로 공학적 목적으로 대기 경계층 내의 평균 풍속 프로파일은 표면 근처의 일정한 풍속을 가정하여 지수 법칙 또는 로그 법칙을 사용하여 모델링되는 경우가 많다. 그러나 증발, 복사 등의 열역학적 과정 외에 지표 부근 대기의 움직임에 의해 크게 영향을 받는 현 상을 분석하기 위해서는 지표 부근 풍속 프로파일에 대한 정의가 요구된다. 이에 본 연구에서는 난류 경계층에 대한 이전 연구의 이론 및 실험 결과를 활용하여 표면 거칠기를 고려한 VS 및 완충층 내의 풍속 프로파일을 제안하였다.

Potholes, one of the main causes of road-surface damage, pose a physical hazard to drivers, cause vehicle damage, and increase road maintenance costs. Hence, a model that enhances the accuracy of pothole detection and improves the real-time detection speed is required. A new model based on dilated convolutional neural networks was developed using a dataset that considers various lighting conditions, road conditions, and pothole sizes and shapes. Although the existing YOLOv5 model demonstrated high speed, it exhibited some false-positive pothole detections. In contrast, the proposed dilated convolutional neural network achieved both high accuracy and an appropriate inference speed, making it suitable for real-time detection. Compared with traditional models, the proposed model demonstrated efficiency in terms of model size and inference speed, indicating its potential suitability for systems performing real-time pothole detection when installed directly in vehicles.

Activated carbon is generally recognized as an applicable material for gas or liquid adsorption and electrochemical devices, such as electric double-layer capacitors (EDLCs). Owing to the continuous increase in its price, research aimed at discovering alternative materials and improving its fabrication yield is important. Herein, organic pigments were ingeniously employed to enhance the fabrication of high-surface-area activated carbon with remarkable efficiency. Moreover, the focus was centered on the assessment of activated carbon derived from 2,9-dimethylquinacridone, also known as CI Pigment Red 122 for its capacity to adsorb tetracycline (TC) and its applicability as an electrode material for EDLCs. Activating these organic pigments with varying potassium hydroxide ratios allowed the fabrication of activated carbon with a higher yield than that for conventional activated carbon. Furthermore, it was confirmed that activated carbon with a very high specific surface area can be efficiently fabricated, demonstrating a remarkable potential in various application fields. Notably, this activated carbon exhibited an impressive maximum specific surface area and a total pore volume of 3,935 m2/ g and 2.324 cm3/ g, respectively, showcasing its substantial surface area and distinctive porous characteristics. Additionally, the Langmuir and Freundlich isotherm models were employed to examine the TC adsorption on the activated carbon, with the Langmuir model demonstrating superior suitability than the Freundlich model. Furthermore, the electrochemical performance of an activated carbon-based electrode for EDLCs was rigorously evaluated through cyclic voltammetry. The specific capacitance exhibited a considerable increase in proportion to the expanding specific surface area of the activated carbon.

In recent years, the search on fabrication of highly efficient, stable, and cost-effective alternative to Pt for the hydrogen evolution reaction (HER) has led to the development of new catalysts. In this study, we investigated the electrocatalytic HER activity of the Toray carbon substrate by creating defect sites in its graphitic layer through ultrasonication and anodization process. A series of Toray carbon substrates with active sites are prepared by modifying its surface through ultrasonication, anodization, and ultrasonication followed by anodization procedures at different time periods. The anodization process significantly enhances the surface wettability, consequently resulting in a substantial increase in proton flux at the reaction sites. As an implication, the overpotential for HER is notably reduced for the Toray carbon (TC-3U-10A), subjected to 3 min of ultrasonification followed by 10 min of anodization, which exhibits a significantly lower Tafel slope value of 60 mV/dec. Furthermore, the reactivity of the anodized surface for HER is significantly elevated, especially at higher concentrations of sulfuric acid, owing to the enhanced wettability of the substrate. The lowest Tafel slope value recorded in this study stands at 60 mV/dec underscoring the substantial improvements achieved in catalytic efficiency of the defect-rich carbon materials. These findings hold promise for the advancement of electrocatalytic applications of carbon materials and may have significant implications for various technological and industrial processes.