1,721,041 research outputs found
Observational Constraints on the f(R) Theory of Modified Gravity
No full text我們利用宇宙學以及局部尺度的實驗去制約f(R) 設計者模型(designer f(R) models)。對於宇宙學尺度的制約，我們發現，儘管可以產生任何期望的宇宙膨脹，然而為了要符合大尺度結構實驗的制約，f(R)設計者遭受到微調問題 (fine-tuning problem)。對於局部重力的制約，目前為止，我們找到了通過局部重力測試的f(R)設計者模型；但是對於這些模型，甚至考慮宇宙學以及局部尺度也無法將它們從宇宙常數模型(ΛCDM model)分辨出來。對於其它在這篇碩士論文所考慮的有效狀態方程，我們未找到可通過局部重力測試的f(R)設計者模型。In this thesis we constrain the designer f(R) models by the observations in both cosmological and local scales. For the cosmological observation constraints, we find that although the designer f(R) can generate any desired cosmic expansion his-tory, it suffers from the fine-tuning problem in order to fit the large scale structure constraints well. For local gravity constraints, so far we do search out the viable designer f(R) models that can satisfy the local gravity constraints but would be indistinguishable from the ΛCDM model even considering the observations in both cosmological and local scales and for other effective equation of states we consider in this thesis, we do not find out any viable designer f(R) model
A study of the cloud condensation nuclei (CCN) activity for urban ambient aerosols
No full text氣膠的物理化學特性在大氣系統中扮演十分重要的角色，其特性會影響雲凝結核的形成，更進一步可改變地球的輻射收支平衡。在本研究中，為了研究都市氣膠活化為雲凝結核之影響，於2010年10月15日至11月01日期間在台北地區進行觀測。觀測期間，雲凝結核數量濃度主要是利用連續氣流式雲凝結核計數器在過飽度0.1至1%之範圍進行監測，凝結核的數量濃度則是以凝結核計數器量測。
由觀測資料顯示，凝結核數量濃度(NCN)與氣態汙染物有很好的相關性，表示台北的氣膠主要是人為來源所貢獻，像是廚房油煙以及機動車等排放。NCN範圍在 2000-50000 個/cm3，且在研究期間NCN有明顯的日夜變化，是因為白天受到本地汙染物的排放導致有較高值的發生。在過飽和度0.1至1%時，雲凝結核數量濃度(NCCN)為 500-7000 個/cm3，且NCCN會受到大氣中NCN變化之影響。
在本研究中，由氣膠粒徑分布以及量測的凝結核(CN)與雲凝結核(CCN)資料可推估氣膠成為雲凝結核之最小粒徑(Dss)，並進一步探討CCN的特性。在風速較大的條件下，平均的Dss及吸濕性參數(κ)分別為60 - 220 nm和0.05 - 0.15；風速較弱時，平均的Dss及κ分別為90 - 250 nm和0.01 - 0.1。結果說明，在風速強的條件下可稀釋本地的汙染物及傳送外來的老化氣膠，使得大氣氣膠具有較多的水溶性物質並較易形成雲凝結核。然而，κ值也顯示在風速較弱的情況時有較明顯的日夜循環，可能是因為人為活動影響晚上的氧化過程。因此，相較於本地所排放的初始氣膠，老化氣膠會傾向有較高的κ值，也就是較易成為雲凝結核。The physical chemical properties of aerosol particles play a significant role in atmospheric system by affecting cloud condensation nuclei (CCN) activity and further changing radiative energy budgets on the Earth. In this study, how the urban ambient aerosols affecting the CCN activity was investigated over the period of 15 October to 01 November in Taipei, Taiwan. The CCN concentration were monitored using a continuous flow cloud condensation nuclei counter (CCNc, DMT) at supersaturation (SS) ranging from 0.1% to 1% and the condensation nuclei (CN) concentration were measured using a condensation particles counter (CPC, TSI).
The in-situ observation shows that the strong correlation between the CN number concentration (NCN) vs. gas pollutants and suggested that the Taipei ambient aerosols are mainly contributed by anthropogenic sources such as cooking and vehicle emission. The NCN is ranged from 2000 to 50000 particles / cm3 and show a significant diurnal variation due to the local emission leads to higher NCN at daytime during this study. The CCN number concentration (NCCN) is ranged from 5000 to 7000 particles / cm3 at 0.1-1.0% supersaturation(SS) and is strongly dependent on NCN.
In this study, with the particle size distribution and measured CN and CCN data, the required minimum particle diameter (Dss) acting as CCN was estimated and further investigated the CCN properties. For the strong wind condition, the average value of Dss is 60 to 220 nm (at 0.1-1.0% SS) and hygroscopicity parameter (κ) ~ 0.05 to 0.15. During the weak wind event, the average value of Dss is 90 to 250 nm (at 0.1-1.0% SS) and κ ~ 0.01 to 0.1, respectively. The results suggest that ambient aerosols have more hygroscopic species fraction and easily form to CCN possibly due to the dilution of freshly local emission by the inflow wind containing long range transported aged aerosols during the strong wind condition. However, the κ values also show a significant diurnal cycle as the wind speed was weak possibly due to the continued night oxidation process with less significantly interference caused by human activities. The aged particles tend to have higher κ values as compared to the freshly emitted local aerosols
The Control of Liumang in Post-war Taiwan (1945-2009): A Sociological Inquiry
No full text本文的研究主題是台灣戰後流氓控制的變遷(1945年至2009年)。本文企圖以較後設的社會學觀點述說這段歷史變遷，以對話既有的歷史敘事，並藉此思考「法律是什麼」這個問題。本文藉由爬梳流氓控制相關的文獻，整理出兩大類歷史敘事：人權落後史和防制策略改進史。這兩類歷史敘事是從各自「現在問題之解決」衍生而出。如果將此兩歷史敘事的觀點更加歷史化，其各自可考察流氓控制相關的人權批判存在模式、流氓問題及控制策略的邏輯。但此兩歷史敘事仍有不足：忽略考察控制和批判共存模式，以及法律在其中扮演的角色。本文借由後Foucault學者對Foucault法律觀之討論，提出國家法多元主義作為框架處理法律在控制和批判間扮演的角色。
在有意識地建構自身的歷史考察觀點後，本文重新建構了台灣戰後流氓控制的歷史變遷。本文將台灣戰後流氓控制分成兩大期，1945-1970年代流氓控制的變遷，涉及戰爭相關的考察，1980年代-2009年則涉及大幅脫戰時之民主化相關的考察。這兩大期又按其變遷各自分成兩小期。1945-1950年台灣在中國戰亂的背景下間歇性進入戰時體制，由此建立了帶有中國戰亂統治色彩的戰時流氓控制運作，此時即已存在以「人民」之名提醒政府取締流氓時不要侵擾良民的聲音。1950-1970年代間，國共隔著台灣海峽持續對峙，台灣內部無戰爭但國民黨政府操作戰爭氛圍，以保留戰時體制和戰時社會控制。此時國民黨政府為延續中華民國法統和塑造台灣為自由民主陣營對抗共產鐵幕的灘頭堡，又於戰時體制中部分行憲。於戰時行憲體制中，政府既企圖保留戰時流氓控制又企圖使之獲得合憲性，由此採取了「法律掩蓋」的法律策略，此即為人熟知的1952年、1955年。由此法律掩蓋-控制-批判的三角關係成形，戰時流氓控制在法律掩蓋的庇護下得出長期存在，僅部分控制策略出現有限的脫戰化。人權論述結合「人民」而形成好人人權的批判，但批判的力量有限且常被法律掩蓋所形成之合法性說詞化消。
1980年代-1990年代，台灣進入大幅脫戰化民主抗爭勃興的時代，此時由於原本的法律掩蓋受到釋字166號的動搖，而轉為「法律空間創造」，此即。新出現的法律空間並不穩定，理由之一是戰時流氓控制策略發生圍繞著「人民」理念的重組，其逐漸往刑事法偏移而難以擺脫刑事法理的適用；理由之二是法律空間出現使其本身成為鬥爭的明確目標。隨著流氓控制爆出諸負面事件，人權批判將定位為惡法。但又由於非典型的好人人權問題，難以喚起共同的受苦經驗和抗爭激情，由此法律空間雖不穩但又不致於立刻消滅。到了1990年代，台灣完全脫離戰時體制進入民主體制。此時法律空間-控制-批判三角關係由於法律空間崩壞而逐漸解組，而其遲至2009年才消失的原因，在於好人人權與普遍人權的矛盾浮現。由於的歷次修正，使流氓控制逐漸符合好人人權的標準，由此顯得不必廢止該條例，但是從普遍人權的觀點來看，該條例仍是嚴重侵害人權。於是1990年代之前推動台灣民主化人權化的改革力量，在1990年代後弔詭地被視為阻礙流氓控制改革的力量。
藉由對比此重建的歷史敘事，與既有的兩種歷史敘事，可見既有兩種歷史敘事之不足。既有歷史敘事由於過快地關注於各自焦慮的現在問題，而以其所焦慮的現在問題重構歷史變遷，並忽略自身觀點的後設考察。人權落後史指出流氓控制持續落後於人權標準，但沒有後設地考察人權批判的存在模式，從而也難以說明為何流氓控制相關的法律遲遲無法廢止。防制策略改進史以當代幫派問題及防制策略重塑流氓控制歷史變遷，而忽略流氓控制與戰爭的關係。防制策略改進史也沒有後設地考察當代幫派問題與防制策略的存在模式，由此其陷於治安與人權的兩難，而未能指出兩難的平衡是當代「人民」之名要求的特色，而且兩難難以兼顧是因為其建立在流氓控制重組的軌跡上。
本研究所建立的法律策略類型，可以反饋後Foucault學者對法律的探討。本研究中提到的法律掩蓋類似法律掩蓋規訓；法律空間創造類似自我抵抗的合法性，其中可見規訓滲透法律，主權、權利、規訓形成複雜的共存關係。不過後Foucault學者由於只處理憲政體制中的法律，難以說明非憲政體制中法律掩蓋的特色。後Foucault學者傾向以權力技術學的變遷來解釋法律的變遷，這並不適合用來解釋本研究中法律策略的變遷。本研究指出後Foucault學者對法律探討的不足，非單純為指出其之限制，而是為指出學者在借用Foucault法律觀探討台灣法律時，應避免將之視為普遍理論，把台灣法律當作例證，因為這樣容易被其所限而不自知
Iterative Channel Decoding Using Spatial and Temporal Intrinsic Information for Video Source
No full text在影像壓縮的技術中常利用禎內預測壓縮的來避免錯誤波及到後續的畫面。
尤其是在分散視訊壓縮系統中，禎內預測的畫面更被使用於預測其他禎的畫面。
因此會有更多的畫面只使用到禎內預測。但是禎內預測的壓縮率遠低於使用禎間
預測的壓縮率，於是很多能量浪費在傳輸可以從另一張畫面預測出的資料上。我
們發現只使用禎內預測壓縮出來的資料有很高的關聯性，而這些關連性可以用來
減少所需的傳輸能量。但是這些關連性在傳統的壓縮技術中會非常的難以利用。
於是我們稍微改變了傳統的禎內壓縮，使得這些關連性變得比較好利用。另外，
由於60GH微波系統的興起，這個觀念更可以延伸到未壓縮的視訊壓縮上。我們利
用了雜訊模型以及馬可赫夫隨機場分別來描述禎與禎之間的關聯性和禎內之間像
素的關係。利用這些關連性可以使得經過通道解碼的資料錯誤率降低。因此我們
所提出的系統可以使得每個禎所需傳輸的能量相似於利用禎內壓縮所的畫面所需
的傳輸能量。這表示這個系統可以操作在非常低的信噪比下。由於60GHz這的頻
段的訊號能量遞減效應會非常大，這個系統非常適合這個頻段的視訊傳輸。此
外，由於我們提出的系統的紀錄器複雜度非常的低，非常適合監視系統以及傳輸
連續拍照這類需要低成本和低能量紀錄器的應用。Intra-coded frames are frequently used to prevent error propagation, and moreover, in
the distributed video coding system, the intra-coded frames is used to predict the adjacent
frames. However, the bit-rate of the intra-coded frames is much more than that of the intercoded
frames, which results in power waste. We find that the high correlation between
the coded bitstreams of intra-coded frames can be used for channel decoding to reduce
the transmission power. However the correlation is difficult to be exploited since the
pixel values are encoded as logical bits. Therefore, the source encoder is modified for
the channel decoder to utilize the identical data between the intra-coded frames. This
concept can be extended to the uncompressed video transmissions, mainly due to the
emergence of the 57-66 GHz mmWave systems. To transmit the uncompressed video
power efficiently, we propose a channel decoder that utilizes both temporal and spatial
redundancy among the video frames. The temporal redundancy between the frames is
exploited via a correlation noise model, and the spatial redundancy inside each frame is
exploited with the aid of Markov random field (MRF) model. By combining the above
models and an error control code, the proposed system is more error robust. The recording
devices of the proposed system is less complex than the system transmitting intra-coded
frames while the PSNR performance is maintained under the same transmission power
per frame comparing to the transmission of intra-coded frames. That is, the system can
operate in an extremely low SNR condition which is common in mmWave frequency
bands due to the signals suffer greater propagation loss. Besides, the low-cost and low
power characteristics make it a perfect match for surveillance systems and the applications
transmitting serially shoot images
Electrospun Nanofibers Containing photosensitive polymer for hyperthermia in Cancer Therapy
No full text溫熱療法，將癌細胞組織加熱到 41~45 oC 可以明顯增加使用放射或是化學
性治療法的效果。本論文目的是為了發展出含有光敏感分子之電紡絲應用於溫熱
至療法來治療表面癌症腫瘤，例如皮膚癌。聚左乳酸與銅葉綠素鈉所噴成的電紡
絲，可以經由照射 532 nm 的綠光雷射來加熱，達到殺死細胞的目的。
在第二部分我們將苯乙烯與銅葉綠素鈉聚合以後，得到接枝有銅葉綠素鈉單
體的聚苯乙烯，並且將此產物噴成電紡絲後來應用，之後經由 MTT assay、染
trypan blue、live/dead 三種實驗來觀察綠光雷射強度與照射時間對細胞的影響，最後達到可以控制照射綠光雷射的強度與照射時間，來達到殺死癌細胞的目的，並且不會對周遭正常細胞造成明顯損害，我們可以將此結果應用於溫熱治療法來治療大範圍表面癌症腫瘤。Hyperthermia, the heating of cancerous tissues to between 41 and 45 oC, has
been shown to improve the efficacy of cancer therapy when used in conjunction with
irradiation and/or chemotherapy. The objective of this study was to develop an
incorporation of electrospun sheet with photosensitizer for photodynamic therapy in
surface cancer tumor, such as skin cancer. The blend of poly-L-lactic acid (PLLA)
and chlorophyllin sodium copper (CSC) was electrospinning a sheet was developed.
The electrospun sheets could be remotely heated upon exposure to an external wave
length 532 nm green laser to kill cells.
In the second part of the study, for the purpose to produce high percentage
chlorophyllin sodium copper contain polystyrene , we used chlorophyllin sodium
copper and styrene with ATRP, and electrospinning to sheet for the hyperthermia
purpose. Then we used MTT assay、trypan blue stain and live/dead stain to observe
the effect of green laser intensity and irradiation time to the cell viability. Finally we
can achieve the purpose of killing cancer cell by control the green laser intensity and
irradiation time without hurting the normal cell around. We can use this result on the
hyperthermia of in surface cancer tumor, such as skin cancer.Content
Content ...................................................................................................................................... iv
List of Tables .......................................................................................................................... viii
List of Figures .......................................................................................................................... ix
Chapter 1 Introduction ............................................................................................................. 1
1.1 Thermal therapy for cancer ........................................................................................... 1
1.1.1 Hyperthermia ........................................................................................................... 2
1.1.2 Photothermal therapy .............................................................................................. 3
1.2 Photosensitizer ................................................................................................................ 4
1.2.1 Overview of photosensitizer ..................................................................................... 4
1.2.2 Porphyrin-based molecules ..................................................................................... 7
1.3 Electrospinning ............................................................................................................. 11
1.3.1 Overview of electrospinning ............................................................................. 11
1.3.2 Electrospinning parameters ............................................................................. 14
1.4 Motive and aim ............................................................................................................. 15
1.5 Research frame work .................................................................................................... 16
Chapter 2 Materials and Methods .......................................................................................... 17v
2.1 Materials ................................................................................................................ 17
2.1.1 Photosensitizer ....................................................................................................... 17
2.1.2 Electrospinning ...................................................................................................... 17
2.1.3 Cytotoxicity assay (3-(4,5-Dimethylthiazol-2-yl)-2,5- diphenyltetrazoliumbromide,
MTT assay) ..................................................................................................................... 17
2.1.4 Mouse fibroblast-like cell line L929 culture ......................................................... 17
2.2 Experimental instrument and materials ...................................................................... 18
2.2.1 Experimental instrument .................................................................................. 18
2.2.2 Experimental consumables............................................................................. 19
2.3 Solution formula........................................................................................................... 20
2.4 Methods ......................................................................................................................... 21
2.4.1 Porphyrin-based molecules heat efficiency comparison ...................................... 21
2.4.2 Evaluation of the cytotoxicity of CSC ................................................................... 21
2.4.3 Thermal properties of CSC .................................................................................... 22
2.4.4 Preparation of photosensitizer contained polymer solution. ................................ 22
2.4.5 Synthesis of styrene and photosensitive copolymer .............................................. 23
2.4.6 Preparation of electrospinning nanofiber sheets ................................................. 23vi
2.4.7 Structure of PLLA and PLLA/CSC fibers ............................................................ 24
2.4.8 Cytotoxic assay of PLLA/CSC electrospinning sheets ......................................... 24
2.4.9 Photothermal Conversion Experiments ................................................................ 25
2.4.10 Photothermal hyperthermia on L929 Cells ........................................................ 25
2.4.11 Photothermal hyperthermia via culturing cells on TCPS cover by PLLA/CSC
sheets ............................................................................................................................... 26
Chapter 3 Characterization and photosensity analysis of PLLA/CSC electrospinning sheets
................................................................................................................................................. 27
3.1 Porphyrin-based molecules heat efficiency comparison ............................................. 27
3.2 Synthesis of PLLA/CSC electrospun ........................................................................... 27
3.3 Structure of PLLA and PLLA/CSC fibers ................................................................... 27
3.4 Cytotoxic assay of CSC ................................................................................................. 28
3.5 Cytotoxic assay of PLLA/CSC electrospinning sheets ................................................ 28
3.6 Thermal properties of CSC ........................................................................................... 29
3.7 Thermal properties of PLLA/CSC eletrospinning nanofiber sheet ............................ 29
3.8 L929 adhesion and proliferation on PLLA/CSC fibers ............................................... 30
3.9 Irradiation effects to L929 cells ................................................................................... 30vii
3.10 Photothermal hyperthermia via culturing cells on PLLA/CSC sheets ..................... 30
3.11 Photothermal hyperthermia via culturing cells on TCPS cover by PLLA/CSC sheets
............................................................................................................................................. 31
3.12 Discussion ................................................................................................................... 32
Chapter4 Characterization and photosensity analysis of PS-CSC electrospinning sheets .. 49
4.1 Synthesis of PS-CSC ..................................................................................................... 49
4.2 Structure of PS and PS-CSC fibers ............................................................................. 49
4.3 Thermal properties of PS-CSC eletrospinning nanofiber sheet ................................. 50
4.4 Photothermal hyperthermia via culturing cells on TCPS cover by PS-CSC sheets ... 50
4.5 Discussion ..................................................................................................................... 51
Chapter 5 Conclusion ............................................................................................................. 57
Reference ................................................................................................................................ 5
Mass production of injectable dermal papilla spheroids of controllable size on poly(vinyl alcohol) surface for hair follicle regeneration
No full text禿髮，一種常見的疾病，其造成的心理創傷遠大於對生理方面的影響，所費不貲的植髮手術僅能重新分佈殘餘毛髮至禿髮部位且無法應用於嚴重落髮患者，因此具有誘導毛囊再生能力的毛囊真皮乳頭細胞成為目前最具潛力的解決方案。
真皮乳頭細胞需在聚集成多細胞球體狀態下，才能表現誘導表皮細胞分化成毛囊結構的能力，已有許多利用組織工程培養立體結構多細胞球的方法，但以特定生醫材料表面使細胞貼附並自我聚集的方法，遭遇如何輕易地收集多細胞球而不造成損壞之困擾。另一方面，懸浮培養方式之球體尺寸往往為一區間分佈而非固定尺寸。
根據細胞於親水性材料表面貼附不佳之特性，我們使用塗佈聚乙烯醇(poly(vinyl alcohol), PVA)的聚合酶鏈鎖反應(polymerase chain reaction, PCR)96孔盤中，由於狹小空間內的高碰撞頻率，我們成功地藉由操縱種植細胞的數量，在一天之內即可迅速獲得尺寸可控制的大鼠與人類真皮乳頭細胞球。
進一步分析顯示，大鼠與人類細胞球內細胞能維持80%以上存活率，均顯著高於懸滴培養方式，組織觀察球體內為緊密的細胞堆疊結構，並能維持真皮乳頭細胞與誘導能力有關的基因表現。我們也驗證真皮乳頭細胞球體再通過注射器之後能維持結構完整與細胞生長能力，於毛囊再生測試中，大鼠與人類真皮乳頭細胞球均能成功誘導毛囊再生，檢驗不同尺寸的真皮乳頭細胞球誘導能力，結果建議細胞球內需要達到一個最少的細胞數量值才能獲得較高的誘導效率。
我們成功地建立一個快速形成尺寸可控制之真皮乳頭細胞球的方法，並具有搭配自動化設備大量生產的潛力，我們的毛源性真皮乳頭細胞球大量生產系統未來也能應用於臨床上毛囊再生之研究。Hair loss is a common disorder that often causes more intense influence in psychological than physiological aspect. Expensive hair transplantation can only redistribute remaining hair to bald area and can no be applied to patients with extensive hair loss. Regarding this, hair follicle (HF) dermal papilla(DP) cells beome a promising solution due to their ability to induce HF regeneration.
DP cells exhibit the potential to guide the transdifferentiation of epidermal cells into follicular structure only when they are kept in multicellular aggregates. A number of tissue engineering approaches have been developed to produce three-dimensional multicellular spheroids. Methods depending on intercellular self-assembly of cells attached to biomaterials encounter difficulty in harmlessly harvesting multicellular spheroids with ease. On the other hand, suspension culture methods can result in variation in spheroid sizes.
According to the poor adhesiveness of cells to hydrophilic surface, we culture DP cells in 96-well PCR plate coated with poly(vinyl alcohol)(PVA). Due to high collision frequency in limited space, we can obtain size-controllable human or rat DP spheres rapidly within 24 hours in culture by varying the numbers of cells seeded.
Further analysis reveals that more than 80% of cells within the spheres are viable and this viability is higher than that in spheres obtained by hanging drop method. DP spheres have a compact structure in histology and preserve DP signature gene expression profile that is related to the HF induction ability. We also demonstrate that the structure and cellular viability of DP spheres remain intact after they are injected through a cell delivery injection apparatus. Functionally, both human and rat DP spheres can successfully induce the HF regeneration in HF regeneration assay. The HF induction ability is varied when DP spheres of various sizes are tested and our results suggest that a minimum cell number is required within each DP sphere to obtain a higher HF induction efficiency.
We successfully set up an easy method for fast generation of size-controllable DP cell spheres and this method is of scalable potential with automatic equipment. Our system of mass preparation of trichogenic DP spheres can also be applied to clinical investigation for HF regeneration in the future
Water-vapor-doped Graphene for Temperature Sensor
No full text本研究用石墨烯作為感測元件以設計溫度感測器。由化學氣相沉積法成長之少層石墨烯，以手機保護貼為轉印基材將其轉印於玻璃上，製成溫度感測器，分別於大氣環境、真空環境、水氣環境三種環境中進行電阻對溫度變化的量測，並且藉由氫原子摻雜的前置步驟使石墨烯對水氣的吸附能力和吸附速率提升。電阻由Agilent 34411A之萬用電表量測，溫度由三段式高溫爐控制，最後經由計算得到溫度感測器於各環境下之溫度電阻係數(TCR)，並藉此分析其溫度感測的性質。 研究結果得到，一般大氣環境中重摻雜石墨烯之TCR值容易受環境的影響，其溫度感測能力不佳。真空環境中純質石墨烯為負溫度電阻係數(NTC)，且TCR值為定值，即感測器之靈敏度穩定。而水氣輕摻雜之石墨烯為NTC性質，其|TCR|隨溫度上升而變大，即溫度越高感測器之靈敏度越佳，至於水氣重摻雜時則為PTC性質。另外，氫原子摻雜後的水氣輕摻雜之石墨烯有最大的溫度感測靈敏度，其|TCR|於65 ℃時約為0.35 %/℃。Graphene was taken as the sensing element to design a new temperature sensor in this study. Temperature sensor was made by the few-layer graphene which was grown by chemical vapor deposition (CVD) and then transferred to glass as the transfer substrate. We measured the relationship between temperature and resistance under normal atmospheric environment, vacuum environment and water vapor environment with hydrogen-doping preprocess respectively. Then we calculated temperature coefficient of resistance (TCR) of these cases and analyzed their temperature sensing behaviors. The experimental result indicates that the graphene has poor temperature sensing property under normal atmospheric environment. Intrinsic graphene under vacuum environment is negative temperature coefficient (NTC) and its sensitivity is stable. Lightly-vapor-doped graphene has NTC as well. However, heavily-vapor-doped graphene is positive temperature coefficient (PTC). And the |TCR| or the sensitivity of lightly-vapor-doped graphene increases as temperature rises. Furthermore, hydrogen doping will increase absorption capacity and absorption rate of graphene, which causes larger |TCR|, about 0.35 %/℃ at 65 ℃
Bookwall: An Online Bookstore Interface Based on User Experience in Physical Bookstore
No full textIn recent years, online bookstore has highly thrived and changed consumption behavior; nevertheless, most users usually browse the online bookstore only when they have a specific target to buy. They still enjoy visiting real bookstores. One of the reasons is that information on web bookstore is too complex for users to freely browse. In this paper, we present Bookwall, an online bookstore interface designed based on user experiences in physical bookstores. We proposed four designs in this work, including ``category map'', ``gathering similar books'', ``visualizing methodology to highlight wanted books'', and ``wall view''. Category map is used to solve the problem of spending time on finding the particular category in classic category list on web bookstore. Similar books, like the same topics, series, same manufacturers, same author, and etc., are arranged together in physical bookstore. Gathering resembling books together enables users have more similar choices to browse or compare with each book. Visualizing technique is to highlight merchandises which meet users'' demands. For instance, books with high score and massive number of reviews will have more area in the wall layout. In this case, if users want to find popular books, they can just focus on the books with large space. Modified from grid view, wall view hides basic information and only show book cover (unless the cursor is pointed to the book) so that it can display more books than traditional list view or grid view. These four designs are based on our observation and field study in physical bookstore, and we finally proposed an online bookstore interface which includes the above four designs to improve user experience in web bookstore and increase their intentions to browse online bookstore
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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