Browsing by Issue Date, starting with "2012-12-13"

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HIGH EFFICIENCY BUCK-BOOST POWER CONVERTER
(2012-12-13)
CHEN KE-HORNG
;
WU WEI-QUAN
;
HO HSIN-HSIN
A buck-boost power converter switches the switches thereof with a novel sequence and extends the switching periods of the switches to reduce the switching loss and conduction loss when the input voltage thereof approaches the output voltage thereof. The influence of the load current of the power converter on the duty thereof is taken into account to switch the power converter between modes at correct time points, so as to prevent the output voltage from being affected by the mode switching.
HETEROSTRUCTURE CONTAINING IC AND LED AND METHOD FOR FABRICATING THE SAME
(2012-12-13)
CHEN KUAN-NENG
;
KO CHENG-TA
;
LO WEI-CHUNG
A heterostructure contains an IC and an LED. An IC and an LED are initially provided. The IC has at least one first electric-conduction block and at least one first connection block. The IC electrically connects with the first electric-conduction block. The first face of the LED has at least one second electric-conduction block and at least one second connection block. The LED electrically connects to the second electric-conduction block. Subsequently, the first electric-conduction block and the first connection block are respectively joined to the second electric-conduction block and the second connection block. The first electric-conduction block is electrically connected with the second electric-conduction block and forms a heterostructure. The system simultaneously provides functions of heat radiation and electric communication for the IC and LED resulting in a high-density, multifunctional heterostructure.
Whole-genome sequencing and identification of Morganella morganii KT pathogenicity-related genes
(2012-12-13)
Chen, Yu-Tin
;
Peng, Hwei-Ling
;
Shia, Wei-Chung
;
Hsu, Fang-Rong
;
Ken, Chuian-Fu
Background: The opportunistic enterobacterium, Morganella morganii, which can cause bacteraemia, is the ninth most prevalent cause of clinical infections in patients at Changhua Christian Hospital, Taiwan. The KT strain of M. morganii was isolated during postoperative care of a cancer patient with a gallbladder stone who developed sepsis caused by bacteraemia. M. morganii is sometimes encountered in nosocomial settings and has been causally linked to catheter-associated bacteriuria, complex infections of the urinary and/or hepatobiliary tracts, wound infection, and septicaemia. M. morganii infection is associated with a high mortality rate, although most patients respond well to appropriate antibiotic therapy. To obtain insights into the genome biology of M. morganii and the mechanisms underlying its pathogenicity, we used Illumina technology to sequence the genome of the KT strain and compared its sequence with the genome sequences of related bacteria. Results: The 3,826,919-bp sequence contained in 58 contigs has a GC content of 51.15% and includes 3,565 protein-coding sequences, 72 tRNA genes, and 10 rRNA genes. The pathogenicity-related genes encode determinants of drug resistance, fimbrial adhesins, an IgA protease, haemolysins, ureases, and insecticidal and apoptotic toxins as well as proteins found in flagellae, the iron acquisition system, a type-3 secretion system (T3SS), and several two-component systems. Comparison with 14 genome sequences from other members of Enterobacteriaceae revealed different degrees of similarity to several systems found in M. morganii. The most striking similarities were found in the IS4 family of transposases, insecticidal toxins, T3SS components, and proteins required for ethanolamine use (eut operon) and cobalamin (vitamin B-12) biosynthesis. The eut operon and the gene cluster for cobalamin biosynthesis are not present in the other Proteeae genomes analysed. Moreover, organisation of the 19 genes of the eut operon differs from that found in the other non-Proteeae enterobacterial genomes. Conclusions: This is the first genome sequence of M. morganii, which is a clinically relevant pathogen. Comparative genome analysis revealed several pathogenicity-related genes and novel genes not found in the genomes of other members of Proteeae. Thus, the genome sequence of M. morganii provides important information concerning virulence and determinants of fitness in this pathogen.
Time-dependent universal conductance fluctuations in IrO2 nanowires
(2012-12-13)
Lin, Yong-Han
;
Wang, Lu-Yao
;
Lin, Juhn-Jong
;
電子物理學系
;
物理研究所
Single-crystalline iridium dioxide nanowires show the time-dependent universal conductance fluctuations (TUCFs) at cryogenic temperatures. The conductance fluctuations persist up to temperature T as high as nearly 10 K. The root-mean-square TUCF magnitudes increase with decreasing T, reaching approximately 0.1 e (2) / h at 1.7 K. We ascribe these conductance fluctuations to originating from the conduction electrons scattering upon mobile defects (moving scattering centers). Our measured TUCF characteristics are satisfactorily explained in terms of the existing TUCF theory in its three-dimensional form. The extracted electron dephasing length L (phi) (1.7 K) a parts per thousand integral 90 nm is smaller than the diameter (a parts per thousand 180 nm) of our nanowires.
ANALOG MEMORY CELL CIRCUIT FOR THE LTPS TFT-LCD
(2012-12-13)
LIU Po-Tsun
;
Chu Li-Wei
;
Zheng Guang-Ting
The present invention provides an analog memory cell circuit for the LTPS TFT-LCD. The circuit comprises the first transistor, second transistor, the third transistor, the fourth transistor, the fifth transistor, the sixth transistor, the seventh transistor, and the capacitor. It comprises a plurality of operation period, wherein the transistors are controlled in accordance with the first scan signal, the second scan signal, and the third scan signal, the output signal is output in the opposite to the output jack.
Does Ozone-Water Complex Produce Additional OH Radicals in the Atmosphere?
(2012-12-13)
Jin, Bing
;
Su, Man-Nung
;
Lin, Jim Jr-Min
;
應用化學系
;
Department of Applied Chemistry
Ozone-water complex has been thought to play a role in producing atmospheric OH radicals through its photolysis. Here, we re-examined the absorption cross-section of the ozone-water complex with a new method to tell whether the above speculation is valid. With argon solvation and photoionization by tunable vacuum ultraviolet light, we were able to selectively probe the ozone-water 1:1 complex. The measured cross-section of the complex is only similar to the sum of the cross-sections of ozone and water monomers at 157.6, 248.4, and 308.4 nm. In addition, we did not observe any absorption of the complex at 351.8 nm. The results indicate that the OH production through the photolysis of the ozone-water complex is much slower than previously thought.
Space-related pharma-motifs for fast search of protein binding motifs and polypharmacological targets
(2012-12-13)
Chiu, Yi-Yuan
;
Lin, Chun-Yu
;
Lin, Chih-Ta
;
Hsu, Kai-Cheng
;
Chang, Li-Zen
Background: To discover a compound inhibiting multiple proteins (i.e. polypharmacological targets) is a new paradigm for the complex diseases (e.g. cancers and diabetes). In general, the polypharmacological proteins often share similar local binding environments and motifs. As the exponential growth of the number of protein structures, to find the similar structural binding motifs (pharma-motifs) is an emergency task for drug discovery (e. g. side effects and new uses for old drugs) and protein functions. Results: We have developed a Space-Related Pharmamotifs (called SRPmotif) method to recognize the binding motifs by searching against protein structure database. SRPmotif is able to recognize conserved binding environments containing spatially discontinuous pharma-motifs which are often short conserved peptides with specific physico-chemical properties for protein functions. Among 356 pharma-motifs, 56.5% interacting residues are highly conserved. Experimental results indicate that 81.1% and 92.7% polypharmacological targets of each protein-ligand complex are annotated with same biological process (BP) and molecular function (MF) terms, respectively, based on Gene Ontology (GO). Our experimental results show that the identified pharma-motifs often consist of key residues in functional (active) sites and play the key roles for protein functions. The SRPmotif is available at http://gemdock.life.nctu.edu.tw/SRP/. Conclusions: SRPmotif is able to identify similar pharma-interfaces and pharma-motifs sharing similar binding environments for polypharmacological targets by rapidly searching against the protein structure database. Pharmamotifs describe the conservations of binding environments for drug discovery and protein functions. Additionally, these pharma-motifs provide the clues for discovering new sequence-based motifs to predict protein functions from protein sequence databases. We believe that SRPmotif is useful for elucidating protein functions and drug discovery.
Semiconductor Device
(2012-12-13)
CHANG Yi
;
CHANG Chia-Hua
;
LIN Yueh-Chin
;
CHEN Yu-Kong
;
SHIE Ting-En
A semiconductor device includes a main body made of a GaN-based semiconductor material, and at least one electrode structure. The electrode structure includes an ohmic contact layer that is formed on the main body, a buffer layer that is formed on the ohmic contact layer opposite to the main body, and a circuit layer that is made of a copper-based material and that is formed on the buffer layer opposite to the ohmic contact layer. The ohmic contact layer is made of a material selected from titanium, aluminum, nickel, and alloys thereof. The buffer layer is made of a material different from the material of the ohmic contact layer and selected from titanium, tungsten, titanium nitride, tungsten nitride, and combinations thereof.
Prediction and analysis of protein solubility using a novel scoring card method with dipeptide composition
(2012-12-13)
Huang, Hui-Ling
;
Charoenkwan, Phasit
;
Kao, Te-Fen
;
Lee, Hua-Chin
;
Chang, Fang-Lin
Background: Existing methods for predicting protein solubility on overexpression in Escherichia coli advance performance by using ensemble classifiers such as two-stage support vector machine (SVM) based classifiers and a number of feature types such as physicochemical properties, amino acid and dipeptide composition, accompanied with feature selection. It is desirable to develop a simple and easily interpretable method for predicting protein solubility, compared to existing complex SVM-based methods. Results: This study proposes a novel scoring card method (SCM) by using dipeptide composition only to estimate solubility scores of sequences for predicting protein solubility. SCM calculates the propensities of 400 individual dipeptides to be soluble using statistic discrimination between soluble and insoluble proteins of a training data set. Consequently, the propensity scores of all dipeptides are further optimized using an intelligent genetic algorithm. The solubility score of a sequence is determined by the weighted sum of all propensity scores and dipeptide composition. To evaluate SCM by performance comparisons, four data sets with different sizes and variation degrees of experimental conditions were used. The results show that the simple method SCM with interpretable propensities of dipeptides has promising performance, compared with existing SVM-based ensemble methods with a number of feature types. Furthermore, the propensities of dipeptides and solubility scores of sequences can provide insights to protein solubility. For example, the analysis of dipeptide scores shows high propensity of a-helix structure and thermophilic proteins to be soluble. Conclusions: The propensities of individual dipeptides to be soluble are varied for proteins under altered experimental conditions. For accurately predicting protein solubility using SCM, it is better to customize the score card of dipeptide propensities by using a training data set under the same specified experimental conditions. The proposed method SCM with solubility scores and dipeptide propensities can be easily applied to the protein function prediction problems that dipeptide composition features play an important role. Availability: The used datasets, source codes of SCM, and supplementary files are available at http://iclab.life.nctu.edu.tw/SCM/.
FastAnnotator- an efficient transcript annotation web tool
(2012-12-13)
Chen, Ting-Wen
;
Gan, Ruei-Chi Richie
;
Wu, Timothy H.
;
Huang, Po-Jung
;
Lee, Cheng-Yang
Background: Recent developments in high-throughput sequencing (HTS) technologies have made it feasible to sequence the complete transcriptomes of non-model organisms or metatranscriptomes from environmental samples. The challenge after generating hundreds of millions of sequences is to annotate these transcripts and classify the transcripts based on their putative functions. Because many biological scientists lack the knowledge to install Linux-based software packages or maintain databases used for transcript annotation, we developed an automatic annotation tool with an easy-to-use interface. Methods: To elucidate the potential functions of gene transcripts, we integrated well-established annotation tools: Blast2GO, PRIAM and RPS BLAST in a web-based service, FastAnnotator, which can assign Gene Ontology (GO) terms, Enzyme Commission numbers (EC numbers) and functional domains to query sequences. Results: Using six transcriptome sequence datasets as examples, we demonstrated the ability of FastAnnotator to assign functional annotations. FastAnnotator annotated 88.1% and 81.3% of the transcripts from the well-studied organisms Caenorhabditis elegans and Streptococcus parasanguinis, respectively. Furthermore, FastAnnotator annotated 62.9%, 20.4%, 53.1% and 42.0% of the sequences from the transcriptomes of sweet potato, clam, amoeba, and Trichomonas vaginalis, respectively, which lack reference genomes. We demonstrated that FastAnnotator can complete the annotation process in a reasonable amount of time and is suitable for the annotation of transcriptomes from model organisms or organisms for which annotated reference genomes are not avaiable. Conclusions: The sequencing process no longer represents the bottleneck in the study of genomics, and automatic annotation tools have become invaluable as the annotation procedure has become the limiting step. We present FastAnnotator, which was an automated annotation web tool designed to efficiently annotate sequences with their gene functions, enzyme functions or domains. FastAnnotator is useful in transcriptome studies and especially for those focusing on non-model organisms or metatranscriptomes. FastAnnotator does not require local installation and is freely available at http://fastannotator.cgu.edu.tw.
Prediction and analysis of protein solubility using a novel scoring card method with dipeptide composition
(2012-12-13)
Huang, Hui-Ling
;
Charoenkwan, Phasit
;
Kao, Te-Fen
;
Lee, Hua-Chin
;
Chang, Fang-Lin
Background: Existing methods for predicting protein solubility on overexpression in Escherichia coli advance performance by using ensemble classifiers such as two-stage support vector machine (SVM) based classifiers and a number of feature types such as physicochemical properties, amino acid and dipeptide composition, accompanied with feature selection. It is desirable to develop a simple and easily interpretable method for predicting protein solubility, compared to existing complex SVM-based methods. Results: This study proposes a novel scoring card method (SCM) by using dipeptide composition only to estimate solubility scores of sequences for predicting protein solubility. SCM calculates the propensities of 400 individual dipeptides to be soluble using statistic discrimination between soluble and insoluble proteins of a training data set. Consequently, the propensity scores of all dipeptides are further optimized using an intelligent genetic algorithm. The solubility score of a sequence is determined by the weighted sum of all propensity scores and dipeptide composition. To evaluate SCM by performance comparisons, four data sets with different sizes and variation degrees of experimental conditions were used. The results show that the simple method SCM with interpretable propensities of dipeptides has promising performance, compared with existing SVM-based ensemble methods with a number of feature types. Furthermore, the propensities of dipeptides and solubility scores of sequences can provide insights to protein solubility. For example, the analysis of dipeptide scores shows high propensity of a-helix structure and thermophilic proteins to be soluble. Conclusions: The propensities of individual dipeptides to be soluble are varied for proteins under altered experimental conditions. For accurately predicting protein solubility using SCM, it is better to customize the score card of dipeptide propensities by using a training data set under the same specified experimental conditions. The proposed method SCM with solubility scores and dipeptide propensities can be easily applied to the protein function prediction problems that dipeptide composition features play an important role. Availability: The used datasets, source codes of SCM, and supplementary files are available at http://iclab.life.nctu.edu.tw/SCM/.
Orthorhombic BiFeO3
(2012-12-14)
Yang, J. C.
;
He, Q.
;
Suresha, S. J.
;
Kuo, C. Y.
;
Peng, C. Y.
A new orthorhombic phase of the multiferroic BiFeO3 has been created via strain engineering by growing it on a NdScO3(110)(o) substrate. The tensile-strained orthorhombic BiFeO3 phase is ferroelectric and antiferromagnetic at room temperature. A combination of nonlinear optical second harmonic generation and piezoresponse force microscopy revealed that the ferroelectric polarization in the orthorhombic phase is along the in-plane < 110 >(pc) directions. In addition, the corresponding rotation of the antiferromagnetic axis in this new phase was observed using x-ray linear dichroism. DOI: 10.1103/PhysRevLett.109.247606
Enhanced photocatalytic decomposition of methylene blue by the heterostructure of PdO nanoflakes and TiO2 nanoparticles
(2012-12-15)
Huang, Chien-Jung
;
Pan, Fu-Ming
;
Chang, I-Chun
;
材料科學與工程學系
;
Department of Materials Science and Engineering
We prepared PdO nanoflakes by reactive sputter deposition to form a heterostructure with TiO2 nanoparticles on the SiO2 substrate for the study of photocatalytic decomposition of methylene blue (MB) molecules. Although the PdO nanoflake has little photocatalytic activity toward MB decomposition, the PdO/TiO2 heterostructure has a photocatalytic activity toward MB decomposition under UV light illumination as large as twice that of bare TiO2 nanoparticles. The enhancement in the photocatalytic activity is ascribed to the fast photogenerated carrier separation resulting from the potential barrier formed at the heterojunction between the two oxide semiconductors. Although PdO nanoflakes can be photoexcited under visible light illumination, the PdO/TiO2 heterostructure exhibits little photocatalytic activity toward the MB decomposition. (C) 2012 Elsevier B. V. All rights reserved.
Improvement of Epitaxy GaN Quality Using Liquid-Phase Deposited Nano-Patterned Sapphire Substrates
(2012-12-15)
Hsieh, Cheng-Yu
;
Lin, Bo-Wen
;
Cho, Hsin-Ju
;
Wang, Bau-Ming
;
Chang, Nancy
A relatively simple and easy and inexpensive liquid-phase deposition (LPD) method is employed to introduce nanoscale silica hemispheres on sapphire substrates for fabricating a nano-patterned sapphire substrate (NPSS). Compared with GaN grown on sapphire without any pattern, the NPSS-GaN film is of much better quality as observed by scanning electron microscopy, transmission electron-microscopy, X-ray diffraction, cathodoluminescence, and photoluminescence. This is because GaN is initiated from the c-plane instead of the LPD-silica surface. In addition, many dislocations within the NPSS-GaN bend toward the patterns, or end at the GaN/void interfaces.
Porphyrin-diindenothieno[2,3-b]thiophene alternating copolymerua blue-light harvester in ternary-blend polymer solar cells
(2012-12-15)
Wu, Yu-Chun
;
Chao, Yi-Hsiang
;
Wang, Chien-Lung
;
Wu, Chun-Ta
;
Hsu, Chain-Shu
Porphyrin, despite chosen by Nature as light harvesting units, hasn't revealed its full potentials as a structural unit in porphyrin-incorporated polymers (PPors). A novel PPor was synthesized to investigate the origins of the low performances of PPor-based polymer solar cells (PSCs). The polymer features broad absorption in the blue-light region, because the diindenothieno[2,3-b]thiophene (DITT) unit extended the conjugation in the polymer backbone. PPor-DITT/PC71BM based PSCs have a high Voc (0.79 V). Their low Jsc and fill factor (FF) were attributed to the un-optimized morphology, as indicated by the photoluminescence quenching and atomic force microscopy (AFM) experiments. Using PPor-DITT as a blue-light harvesting dopant in an amorphous host leverage the strong 400550 nm absorption of PPor-DITT and circumvent the difficulties in reaching optimized morphology in the PPor/PCBM thin films. An addition of 2 wt % of PPor-DITT in ternary-blend PSCs resulted in a 10 % increase of external quantum efficiency (EQE) in the blue-light region. However, in a crystalline host, the dopant decreased the crystallinity of the host and led to large drops in FF and power conversion efficiencies (PCEs). The study provides an alternative route and expands the application of PPors in PSCs as a blue-light harvester in ternary-blend PSCs using amorphous polymers as host. (C) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Synthesis of novel dithienothiophene- and 2,7-carbazole-based conjugated polymers and H-bonded effects on electrochromic and photovoltaic properties
(2012-12-15)
Fang, Hsiao-Ping
;
Lin, Jia-Wei
;
Chiang, I-Hung
;
Chu, Chih-Wei
;
Wei, Kung-Hwa
Three kinds of dithienothiophene/carbazole-based conjugated polymers (P1P3), which bear acid-protected and benzoic acid pendants in P2 and P3, respectively, were synthesized via Suzuki coupling reaction. Interestingly, P1P3 exhibited reversible electrochromism during the oxidation processes of cyclic voltammogram studies, and P3 (with H-bonds) revealed the best electrochromic property with the most noticeable color change. According to powder X-ray diffraction (XRD) analysis, these polymers exhibited obvious diffraction features indicating bilayered packings between polymer backbones and p-p stacking between layers in the solid state. Compared with the XRD data of P2 (without H-bands), H-bonds of P3 induced a higher crystallinity in the small-angle region (corresponding to a higher ordered bilayered packings between polymer backbones), but with a similar crystallinity in the wide angle region indicating a comparable p-p stacking distance between layers. Moreover, based on the preliminary photovoltaic properties of PSC devices (P1P3 blended individually with PCBM acceptor in the weight ratio of 1:1), P3 (with H-bonds) possessed the highest power conversion efficiency of 0.61% (with Jsc = 2.26 mA/cm2, FF = 29.8%, and Voc = 0.9 V). In contrast to P2 (without H-bands), the thermal stability, crystallinity, and electrochromic along with photovoltaic properties of P3 were generally enhanced due to its H-bonded effects. (C) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Direct-detection polarization division multiplexed orthogonal frequency-division multiplexing transmission systems without polarization tracking
(2012-12-15)
Wang, Chih-Yun
;
Wei, Chia-Chien
;
Lin, Chun-Ting
;
Chi, Sien
;
光電系統研究所
We experimentally demonstrate a direct-detection polarization division multiplexed (PDM) orthogonal frequency-division multiplexing (OFDM) scheme without dynamic polarization tracking. Simply using a polarization-diverse receiver, the proposed multiple-input multiple-output assisted system can achieve bit-error rate of 10(-3) over all possible received states of polarization. Moreover, 50 Gbps PDM-OFDM transmission over 100 km single-mode fiber is successfully demonstrated without dispersion-induced penalty. (C) 2012 Optical Society of America
A transition of three to two dimensional Si growth on Ge (100) substrate
(2012-12-15)
Tu, W. -H.
;
Lee, C. -H.
;
Chang, H. T.
;
Lin, B. -H.
;
Hsu, C. -H.
For the initial growth of Si on Ge, three-dimensional Si quantum dots grown on the Ge surface were observed. With increasing Si thickness, the Si growth changes from three-dimensional to two-dimensional growth mode and the dots disappear gradually. Finally, the surface is smooth with the roughness of 0.26 nm, similar to the original Ge substrate, when 15 nm Si is deposited. More Ge segregation on the wetting layer leads to more open sites to increase the subsequent Si growth rate on the wetting layer than on the Si dots. The in-plane x-ray diffraction by synchrotron radiation is used to observe the evolution of tensile strain in the Si layer grown on Ge (100) substrate. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4770408]
Concentrating Photovoltaic System Using a Liquid Crystal Lens
(2012-12-15)
Tsou, Yu-Shih
;
Lin, Yi-Hsin
;
Wei, An-Chi
;
光電工程學系
;
Department of Photonics
A concentrating photovoltaic (CPV) system with a steady electric output adopting an electrically tunable concentration ratio of the liquid crystals (LC) lens is demonstrated. The distribution of the LC directors of the LC lens can be controlled by an applied voltage in order to adjust the number of incident photons in an area. As a result, the CPV system adopting an LC lens can be operated with a static and maximum output power density under different ambient illuminations because the LC lens with an electrically tunable concentration ratio helps to increase the photocurrent at a low illumination and prevent the effect of the series resistance at a high illumination. The detailed operating principles are discussed, and the experimental results are performed. We believe this letter can help enhance the output power density of CPV systems by using active optical elements whose concentration ratio is tunable.
張芷瑄　當身體是創作武器
(2012-12-16)
王柔婷
;
Department of Communication and Technology
;
傳播與科技學系
剛畢業於實踐大學服裝設計系的張芷瑄，從外表看來，文靜內向，從她身旁走過，還以為只是個平凡的女學生，很難想像隱藏在文靜表象下的她，會選擇用那麼前衛的方式創作：透過裸體、剃髮為自己的內心發聲。