DSpace community: 理工學院

都市化與環境 : 都市之自然地理

Mon, 11 May 2026 06:09:59 GMT

title: 都市化與環境 : 都市之自然地理

測量及空間資訊硏討會秩序冊及論文摘要集. 第三十一屆

Mon, 11 May 2026 06:01:10 GMT

title: 測量及空間資訊硏討會秩序冊及論文摘要集. 第三十一屆

應用於電子設備之板翅式散熱片設計與冷卻性能分析研究

Fri, 17 Apr 2026 08:00:14 GMT

title: 應用於電子設備之板翅式散熱片設計與冷卻性能分析研究 abstract: 隨著電子設備功率密度的急劇提升，如何在有限空間與被動散熱條件下提升熱管理效率，已成為系統穩定運作之關鍵。本研究旨在探討不同幾何構型對板翅式散熱器在開放式流場下之熱流性能影響。研究整合了數值模擬分析與場域量測實驗，針對七種不同構型（包含平直、波浪、V型及其錯列排列）進行系統性分析，並以實驗數據驗證模擬模型之準確性。研究結果顯示，在缺乏導流罩的開放流場中，流場旁通效應為決定散熱效能之主導因素。雖然波浪與錯列結構能增加散熱表面積並誘導擾流，但其伴隨的高阻力導致翅片本身氣流嚴重流失，使翅片間隙內的有效流速與對流熱傳係數顯著下降。數據證實，結構最簡單的單排平形翅片因具備最低流動阻力，能維持本實驗最高的內部平均流速與最佳的紐塞數表現，其熱阻顯著低於結構複雜的雙排錯列V型翅片。本研究之核心貢獻在於揭示了開放流場中流動阻抗與熱傳增強間的權衡機制，證實了低流阻以維持有效流量之重要性遠大於幾何擾流以增加表面積。此結論推翻了盲目追求複雜幾何的迷思，為伺服器與自然對流散熱模組提供了明確的設計準則。 This study aims to investigate the impact of different geometric configurations on the thermal-hydraulic performance of plate-fin heat sinks in an open flow environment. The research integrates numerical simulations with experimental measurements to systematically analyze seven different configurations, including straight, wavy, V-shaped, and their staggered arrangements. The results indicate that in an open flow environment lacking flow shrouds, the flow bypass effect is the dominant factor determining thermal performance. Although wavy and staggered structures can increase the heat transfer surface area and induce turbulence, the associated high flow resistance leads to severe airflow loss around the fins. This significantly reduces the effective flow velocity and the convective heat transfer coefficient within the fin channels. The data confirms that the simplest single-row straight fin design, due to its lowest flow resistance, maintains the highest internal average velocity and optimal Nusselt number performance, achieving significantly lower thermal resistance than the complex double-row staggered V-shaped fin. The core contribution of this study lies in revealing the trade-off mechanism between flow resistance and heat transfer enhancement, proving that the importance of low flow resistance for maintaining effective flow rate far outweighs that of geometric turbulence for increasing surface area.

由回收細菌纖維素製得纖維素奈米纖維及其應用

Fri, 17 Apr 2026 03:26:30 GMT

title: 由回收細菌纖維素製得纖維素奈米纖維及其應用 abstract: 細菌纖維素（Bacterial Cellulose, BC）具有高純度、高生物相容性、高保水力、高結晶度與高機械強度，因其特性被廣泛應用於高單價的工業、生醫與美容產品，如耐震膜料、敷料與面膜等。然而這類產品通常都為一次性產品，在造成浪費的同時，也限制了BC材料永續與循環再利用的潛力。因此本實驗以「將廢棄BC回收再利用」為核心，透過奈米化處理將回收之BC轉化為BC奈米材料（BCNs），其中包含BC奈米纖維（BCNF）與BC奈米晶體（BCNC），並進一步將其回添至BC培養或成膜過程中，探討不同方法對於BC產量、BC和羽角蛋白材料性質的影響。本研究先以不同製程(超音波均質法、酶水解法)製備BCNF與BCNC，分析其分散情形與粒徑分不差異。接著採用原位修飾法：直接添加於培養基中、培養過程中以噴霧或滴入法添加；異位修飾法：浸泡法、抽氣過濾法等方式，再進行水釋放、保水復水和使用儀器對膜材進行分析，探討不同添加量對BC和羽角蛋白的影響。實驗結果顯示，將BCNs回添至培養BC系統中能夠有效提升BC產量，增幅約18-23%，顯示BCNs可能在培養基中產生成核效應，促進BC的生成。在材料分析中，根據XRD和FTIR的結果顯示，這些添加方式並未破壞BC與羽角蛋白典型結構，在結晶度上與BC膜的複合影響不明顯，但在角蛋白膜上則能從59%提升至最高67%，且在多數情況下BCNC在高濃度條件下對於原材料的改變最明顯。而熱分析結果則顯示出材料在添加BCNs後形成的複合材料於熱裂解與熱穩定性上出現了變化，複合膜相比於純材料其主要裂解溫度最大提升近20℃。在吸水與保水能力上，根據累績釋放率分析顯示，添加了BCNs後都能有效使材料獲得緩慢釋放的效果，其中以BCNC的表現更佳，從復水能力上也能看出BCNC對於原材料的提升；相反的BCNF在保水能力上通常能維持BC原本的高保水力，BCNC則隨著添加濃度的提升產生團聚效應，從而降低BC的保水力。以上結果顯示不同的奈米化處理、濃度與添加方法都會成為影響材料結構與功能上的關鍵因素。綜上所述，本研究成功建立將回收的BC經奈米化處理後，再回添至BC系統與羽角蛋白複合的循環再利用，不僅提升材料的產量和功能性，也為BC由一次性高單價產品邁向高附加價值與永續利用提供可行方案。 Bacterial Cellulose (BC) is characterized by its high purity, biocompatibility, water-holding capacity, crystallinity, and mechanical strength. Due to these exceptional properties, it is widely utilized in high-value industrial, biomedical, and cosmetic products, such as acoustic diaphragms, wound dressings, and facial masks. However, these products are typically single-use, leading to waste and limiting the potential for the sustainability and circular reuse of BC materials. Therefore, this study centers on the "recycling and reuse of waste BC." Through nano structural processing, recovered BC was transformed into Bacterial Cellulose Nanofibers (BCNF) and Bacterial Cellulose Nanocrystals (BCNC). These were subsequently re-incorporated into the BC cultivation or film-forming processes to investigate the effects of different methodologies on BC yield and the material properties of BC-feather keratin composites. This study first prepared BCNF and BCNC using different processes (ultrasonic homogenization and enzymatic hydrolysis) to analyze their dispersion and particle size distribution differences. Subsequently, in-situ modification methods (direct addition to the culture medium, and addition via spraying or dropping during cultivation) and ex-situ modification methods (immersion and vacuum filtration) were employed. The resulting membranes were then subjected to water release, water retention, and rehydration tests, along with instrumental analysis, to investigate the effects of different dosages on Bacterial Cellulose (BC) and feather keratin. Experimental results indicate that reintroducing BCNs into the BC cultivation system effectively increased BC yield by approximately 18–23%, suggesting that BCNs may create a nucleation effect in the medium that promotes BC generation. In material analysis, XRD and FTIR results showed that these addition methods did not disrupt the typical structures of BC and feather keratin. While the impact on the crystallinity of BC membranes was not significant, the crystallinity of keratin membranes increased from 59% to a maximum of 67%. In most cases, BCNC at high concentrations caused the most significant changes to the raw materials. Thermal analysis revealed changes in the thermal degradation and stability of the BCN-added composites, with the composite membranes showing an increase of nearly 20°C in their primary degradation temperature compared to pure materials. In terms of water absorption and retention capacity, cumulative release rate analysis shows that adding BCNs effectively allows the material to achieve a slow-release effect, with BCNC performing the best. Rehydration capacity also demonstrated the improvement BCNC brought to the raw materials. Conversely, BCNF generally maintained the high-water retention capacity inherent to BC, while BCNC tended to undergo agglomeration as concentration increased, thereby reducing the water retention capacity of the BC. These results indicate that different nanofabrication treatments, concentrations, and addition methods are key factors influencing the structural and functional properties of the materials. In conclusion, this research successfully establishes a circular reuse model by converting recycled BC into nanomaterials and re-incorporating them into BC systems and feather keratin composites. This approach not only enhances material yield and functionality but also provides a viable pathway for transitioning BC from a single-use high-cost product toward a high-value, sustainable, and circular resource.