The authors constructed a simplified model of spring wheat (Triticum aestivum L.) carbon assimilation and dry matter accumulation (DMA) process which consisted of two independent variables, day length (L) and total...The authors constructed a simplified model of spring wheat (Triticum aestivum L.) carbon assimilation and dry matter accumulation (DMA) process which consisted of two independent variables, day length (L) and total daily radiation (TDR). Leaf water potential (Ψ) was incorporated into the simplified growth model based on the assumption that both light use efficiency (α) and CO 2 conductance of assimilation (g c) were depressed by water limitation. Finally,Ψ was estimated from a regression equation in which the independent variables were relative soil water content in the upper 80 cm (θ R,80 ), ambient temperature (T a), vapor pressure deficit (VPD), the cumulative leaf water potential below thresholds of -1.5 MPa (Ψ c,1.5 ). Some applications in research program of field experiment of atmosphere_land surface processes in Heihe River region were tested. The simulated data agreed well with the data observed at Linze oasis in 1989 for various levels of water supply and at Zhangye oasis in 1992 in the field. The analysis and simulation using the model demonstrated that the simplified growth model could describe very well the DMA process of spring wheat with and without water limitation in the region of HEIFE (Heihe field experiment).展开更多
Let G be a simple graph with no isolated vertices. A set S of vertices of G is a total dominating set if every vertex of G is adjacent to some vertex in S . The total domination number of G , den...Let G be a simple graph with no isolated vertices. A set S of vertices of G is a total dominating set if every vertex of G is adjacent to some vertex in S . The total domination number of G , denoted by γ t (G) , is the minimum cardinality of a total dominating set of G . It is shown that if G is a graph of order n with minimum degree at least 3, then γ t (G)≤n/2 . Thus a conjecture of Favaron, Henning, Mynhart and Puech is settled in the affirmative.展开更多
Let G=(V,E) be a simple graph. For any real valued function f∶V→R and SV, let f(S)=∑ u∈S?f(u). A majority dominating function is a function f∶V→{-1,1} such that f(N)≥1 for at least half the vertices v∈V. Th...Let G=(V,E) be a simple graph. For any real valued function f∶V→R and SV, let f(S)=∑ u∈S?f(u). A majority dominating function is a function f∶V→{-1,1} such that f(N)≥1 for at least half the vertices v∈V. Then majority domination number of a graph G is γ maj(G)=min{f(V)|f is a majority dominating function on G}. We obtain lower bounds on this parameter and generalize some results of Henning.展开更多
A reduced state Soft Input Soft Output (SISO) a posteriori probability algorithm for Seri-ally Concatenated Continuous Phase Modulation (SCCPM) is proposed in this paper. Based on the Reduced State Sequence Detection ...A reduced state Soft Input Soft Output (SISO) a posteriori probability algorithm for Seri-ally Concatenated Continuous Phase Modulation (SCCPM) is proposed in this paper. Based on the Reduced State Sequence Detection (RSSD),it has more general form compared with other reduced state SISO algorithms. The proposed algorithm can greatly reduce the state number,thus leads to the computation complexity reduction. It also minimizes the degradation in Euclidean distance with decision feedback in the reduced state trellis. Analysis and simulation results show that the perform-ance degradation is little with proper reduction scheme.展开更多
The fresh water polyp Hydra belongs to the phylum Cnidaria, which diverged from the metazoan lineage before the appearance of bilaterians. In order to understand the evolution of apoptosis in metazoans, we have begun ...The fresh water polyp Hydra belongs to the phylum Cnidaria, which diverged from the metazoan lineage before the appearance of bilaterians. In order to understand the evolution of apoptosis in metazoans, we have begun to elucidate the molecular cell death machinery in this model organism. Based on ESTs and the whole Hydra genome assembly, we have identified 15 caspases. We show that one is activated during apoptosis, four have characteristics of initiator caspases with N-terminal DED, CARD or DD domain and two undergo autoprocessing in vitro. In addition, we describe seven Bcl-2-1ike and two Bak-like proteins. For most of the Bcl-2 family proteins, we have observed mitochondrial localization. When expressed in mammalian cells, HyBak-like 1 and 2 strongly induced apoptosis. Six of the Bcl-2 family members inhibited apoptosis induced by camptothecin in mammalian ceils with HyBcl-2-1ike 4 showing an especially strong protective effect. This protein also interacted with HyBak-like 1 in a yeast two-hybrid assay. Mutation of the conserved leucine in its BH3 domain abolished both the interaction with HyBak-like 1 and the anti-apoptotic effect. Moreover, we describe novel Hydra BH-3-only proteins. One of these interacted with Bcl-2-1ike 4 and induced apoptosis in mammalian cells. Our data indicate that the evolution of a complex network for cell death regulation arose at the earliest and simplest level of multicellular organization, where it exhibited a substantially higher level of complexity than in the protostome model organisms Caenorhabditis and Drosophila.展开更多
Adaptive Type-2 fuzzy control possesses control performance better than the traditional adaptive fuzzy control.However,heavy computation burden obviously blocks the utilization of adaptive Type-2 fuzzy control in indu...Adaptive Type-2 fuzzy control possesses control performance better than the traditional adaptive fuzzy control.However,heavy computation burden obviously blocks the utilization of adaptive Type-2 fuzzy control in industrial application.By adopting novel piecewise fuzzy sets and center-average type-reduction,a simplified adaptive interval Type-2 fuzzy controller involving less computation is developed for practical industrial application.In the proposed controller,the inputs are divided into several subintervals and then two piecewise fuzzy sets are used for each subinterval.With the manner of piecewise fuzzy sets and a novel fuzzy rules inference engine,only part of fuzzy rules are simultaneously activated in one control loop,which exponentially decreases the computation and makes the controller appropriate in industrial application.The simulation and experimental study,involving the popular magnetic levitation platform,shows the predicted system with theoretical stability and good tracking performance.The analysis indicates that there is far less computation of the proposed controller than the traditional adaptive interval Type-2 fuzzy controller,especially when the number of fuzzy rules and fuzzy sets is large,and the controller still maintains good control performance as the traditional one.展开更多
As a hyper-redundant robot, a 3D snake-like robot can perform many other configurations and types of locomotion adapted to environment except for mimicking the natural snake locomotion. The natural snake locomotion us...As a hyper-redundant robot, a 3D snake-like robot can perform many other configurations and types of locomotion adapted to environment except for mimicking the natural snake locomotion. The natural snake locomotion usually limits locomotion capability of the robot because of inadequacy in the mechanism and actuation to imitate characters of natural snake such as the too many DOFs and the characteristics of the muscle. In order to apply snake-like robots to the unstructured environment, the researchers have designed many gaits for increasing the adaptability to a variety of surroundings. The twist-related locomotion is an effective gait achieved by jointly driving the pitching-DOF and yawing-DOF, with which the snakelike robot can move on rough ground and even climb up some obstacles. In dfis paper, the twist-related locomotion function is firstly solved, and simplified to be expressible by sine or cosine function. The 2D locomotion such as V-shape and U-shape is achieved. Also by applying it to the serpentine locomotion or other types of locomotion, the snake-like robot can complete composite locomotion that combines the serpentine locomotion or others with twist-related locomotion. Then we extend the twist-related locomotion to 3D space. Finally, the experimental results are presented to validate all above analyses.展开更多
A facile impregnation method under mild condition is designed for synthesis of highly dispersed Pt nanoparticles with a narrow size of 4-7 nm on nitrogen-doped carbon nanotubes (CNx). CNx do not need any pre-surface...A facile impregnation method under mild condition is designed for synthesis of highly dispersed Pt nanoparticles with a narrow size of 4-7 nm on nitrogen-doped carbon nanotubes (CNx). CNx do not need any pre-surface modification due to the inherent chemical activity. The structure and nature of Pt/CNx were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive spectroscopy spectrum. All the experimental results revealed that the large amount of doped nitrogen atoms in CNx was virtually effective for capturing the Pt(IV) ions. The improved surface nitrogen functionalities and hydrophilicity contributed to the good dispersion and immobi- lization of Pt nanoparticles on the CNx surface. The Pt/CNx served as active and reusable catalysts in the hydrogenation of allyl alcohol. This could be attributed to high dispersion of Pt nanoparticles and stronger interaction between Pt and the supports, which prevented the Pt nanoparticles from aggregating into less active Pt black and from leaching as well.展开更多
The objective of this study was to isolate Bacillus subtilis produced Bacteriocin from Khmer traditional fermented soybean to control the growth of pathogenic bacteria from 120 SIENG samples from 9 different loca...The objective of this study was to isolate Bacillus subtilis produced Bacteriocin from Khmer traditional fermented soybean to control the growth of pathogenic bacteria from 120 SIENG samples from 9 different local open markets in Phnom Penh, 1 local open market and 2 local producers in Kandal province in Cambodia. 119 out of 120 samples were positive with Bacillus subtilis strains. Fifteen of these isolated strains exhibited antimicrobial activity to Lactobacillus plantarum by agar well diffusion assay and one of them (CeM6-7 strain) exhibited strongest antimicrobial activity. The filtered supernatant of this strain also suppressed the growth of several Gram-positive pathogens (such as Staphylococcus aureus) or lactic acid bacteria in broth. The filtrate could also suppress the growth of L. plantarum inoculated into soymilk. Antimicrobial B. subtilis strain CeM6-7 is thought to be applicable for making a starter culture to produce much safe fermented soybean foods by suppressing the growth of naturally contaminated B. cereus or S. aureus during production. In addition, the use of this starter culture may contribute to prevent spoilage or quality loss of soybean products caused by the over growth lactic acid bacteria or other Gram-positive bacteria.展开更多
Via a galvanic displacement reaction, well-defined micro/nano binary dendritic gold structures were prepared on silicon wafers in fluoride acid solution containing HAuCI4 at 50 ℃. The gold deposits were characterized...Via a galvanic displacement reaction, well-defined micro/nano binary dendritic gold structures were prepared on silicon wafers in fluoride acid solution containing HAuCI4 at 50 ℃. The gold deposits were characterized with scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectrum and X-ray diffraction (XRD). The investigation of the surface-enhanced Raman scattering (SERS) reveals that the film of gold dendrites was an excellent substrate with significant enhancement effect. Also, the gold dendritic structured surface exhibited a remarkable superhydrophobic property with a contact angle of approximately 165° and low contact angle hysteresis after further simple surface modification with n-dodecanethiol.展开更多
This paper examines the relationship between small- and medium-sized enterprises' (SMEs) entrepreneurs' perceptions towards a proper accounting system with the level of accounting staff recruited, preparation of f...This paper examines the relationship between small- and medium-sized enterprises' (SMEs) entrepreneurs' perceptions towards a proper accounting system with the level of accounting staff recruited, preparation of final accounts, meetings with accounting staff, and entrepreneurs' ranking of accounting according to their priority. The methodology used to gather the data is survey questionnaire. It has been distributed to SMEs based on simple random sampling method. Three hundred businesses were selected from the total of 3,390 businesses listed in Kuala Lumpur, Malaysia area obtained from Small and Medium Industries Development Corporation (SMIDEC) website and a few random selected from Ampang and Cheras areas. Regression analysis has been used to analyze the data. The results of the study reveal that there was a significant relation between SMEs entrepreneurs' perceptions on the importance of a good accounting system and the level of professional accounting staff recruited. Furthermore, findings of this study also found that there was an insignificant relationship between SMEs entrepreneurs' perceptions on the importance of a good accounting system and preparation of final accounts of the company and frequency of meetings with accounting staff.展开更多
Frame skipping in low bit video coding could significantly reduce the visual quality of reconstructed video. At the same time, if the complexity of the video sequence remains high for a long period, then driving up th...Frame skipping in low bit video coding could significantly reduce the visual quality of reconstructed video. At the same time, if the complexity of the video sequence remains high for a long period, then driving up the long term average bit rate, the only resort of MPEG-4 Q2 rate control algorithm results in using a high quantization scale, which shows a poor visual quality of the reconstructed video. This paper analyzes the main causes of frame skipping in current MPEG-4 frame rate control scheme, and presents a new rate control algorithm based on the quadratic R-D model over a CBR channel. Key features of the present work are: 1) the bits allocated to each P-frame or B-frame are in proportion to its distance from the end of this GOP, i.e. more bits are allocated to the frames that are nearer to their reference Ⅰ-frame; 2) the target buffer level is changeable in the GOP, at the end of each GOP(five P-frames or B-frames), the target buffer level is linearly reduced from 1/2 to 1/4 of buffer size, to other frames, the target buffer level is set to 1/2 of buffer size; 3) a selective and judicious use of the reduced resolution mode, in addition to a modulation of the quantization scale parameter, is to control the average long term bit rate. Experimental results with different video sequences of varied complexity, encoded at low bit rates show better efficacy of the proposed algorithm than MPEG-4 Q2 rate control scheme, and the experimental results also show that the improved algorithm has significantly reduced the number of frame skipping, increased the overall PSNR, and improved the perceptual quality.展开更多
Forensic accountants today are required to possess a number of characteristics and skills that are derived from a range of disciplines. They must be inquisitive, able to delve into motivations, operations and justific...Forensic accountants today are required to possess a number of characteristics and skills that are derived from a range of disciplines. They must be inquisitive, able to delve into motivations, operations and justifications underlying the behavior of white collar criminals. They must be able to simplify technical accounting information and convey it effectively orally and in writing to a court or tribunal; be able to trace information via information technology tools; have an understanding of the adversarial legal system and the rules of evidence. Universities offering forensic accounting courses in various formats are on the increase. The aim of this paper is to investigate the subject areas that any course specializing in forensic accounting needs to cover.展开更多
In nature,many living organisms exhibit low-angle-dependent or even angle-independent structural colors for wide viewing angle,such as the blue skin of mandrill,feather of blue bird and shell of longhorn beetle,etc.To...In nature,many living organisms exhibit low-angle-dependent or even angle-independent structural colors for wide viewing angle,such as the blue skin of mandrill,feather of blue bird and shell of longhorn beetle,etc.To mimic these structural colors,based on periodic semicircular micro-grooved(PSMG) substrate,silica colloidal photonic crystals provide anisotropic angle-independent structural colors.The PSMG photonic crystals were fabricated by self-assembling monodispersed silica nanoparticles on a micro-grooved template,which can be easily prepared in large scale by a hot embossing method,and no additional materials are needed in the whole preparation process.The PSMG photonic crystals exhibit identical structural colors around the groove axis,whereas it is angle-dependent along the groove axis.In addition,this PSMG surface of photonic crystal also leads to color separation effect and monocolor polarization conversion.This system provides a facile and scalable means to prepare anisotropically angleindependent colloidal photonic crystal,which is considered important in applications in the field of anti-counterfeiting or the manufacture of monochromatic light reflector with wide viewing angles and other novel optical devices.展开更多
Field-effect transistors (FETs) have been fabricated using as-grown single-walled carbon nanotubes (SWNTs) for the channel as well as both source and drain electrodes. The underlying Si substrate was employed as t...Field-effect transistors (FETs) have been fabricated using as-grown single-walled carbon nanotubes (SWNTs) for the channel as well as both source and drain electrodes. The underlying Si substrate was employed as the back-gate electrode. Fabrication consisted of patterned catalyst deposition by surface modification followed by dip-coating and synthesis of SWNTs by alcohol chemical vapor deposition (CVD). The electrodes and channel were grown simultaneously in one CVD process. The resulting FETs exhibited excellent performance, with an I ON/I OFF ratio of 10^6 and a maximum ON-state current (/ON) exceeding 13 uA. The large I ON is attributed to SWNT bundles connecting the SWNT channel with the SWNT electrodes. Bundling creates a large contact area, which results in a small contact resistance despite the presence of Schottky barriers at metallic-semiconducting interfaces. The approach described here demonstrates a significant step toward the realization of metal-free electronics.展开更多
文摘The authors constructed a simplified model of spring wheat (Triticum aestivum L.) carbon assimilation and dry matter accumulation (DMA) process which consisted of two independent variables, day length (L) and total daily radiation (TDR). Leaf water potential (Ψ) was incorporated into the simplified growth model based on the assumption that both light use efficiency (α) and CO 2 conductance of assimilation (g c) were depressed by water limitation. Finally,Ψ was estimated from a regression equation in which the independent variables were relative soil water content in the upper 80 cm (θ R,80 ), ambient temperature (T a), vapor pressure deficit (VPD), the cumulative leaf water potential below thresholds of -1.5 MPa (Ψ c,1.5 ). Some applications in research program of field experiment of atmosphere_land surface processes in Heihe River region were tested. The simulated data agreed well with the data observed at Linze oasis in 1989 for various levels of water supply and at Zhangye oasis in 1992 in the field. The analysis and simulation using the model demonstrated that the simplified growth model could describe very well the DMA process of spring wheat with and without water limitation in the region of HEIFE (Heihe field experiment).
文摘Let G be a simple graph with no isolated vertices. A set S of vertices of G is a total dominating set if every vertex of G is adjacent to some vertex in S . The total domination number of G , denoted by γ t (G) , is the minimum cardinality of a total dominating set of G . It is shown that if G is a graph of order n with minimum degree at least 3, then γ t (G)≤n/2 . Thus a conjecture of Favaron, Henning, Mynhart and Puech is settled in the affirmative.
文摘Let G=(V,E) be a simple graph. For any real valued function f∶V→R and SV, let f(S)=∑ u∈S?f(u). A majority dominating function is a function f∶V→{-1,1} such that f(N)≥1 for at least half the vertices v∈V. Then majority domination number of a graph G is γ maj(G)=min{f(V)|f is a majority dominating function on G}. We obtain lower bounds on this parameter and generalize some results of Henning.
基金Supported by NSFC & Microsoft Asia (60372048)China TRAPOYT, NSFC key project (60496316)+2 种基金863 Project (2005AA123910)RFDP (20050701007)MOE Key Project (104171).
文摘A reduced state Soft Input Soft Output (SISO) a posteriori probability algorithm for Seri-ally Concatenated Continuous Phase Modulation (SCCPM) is proposed in this paper. Based on the Reduced State Sequence Detection (RSSD),it has more general form compared with other reduced state SISO algorithms. The proposed algorithm can greatly reduce the state number,thus leads to the computation complexity reduction. It also minimizes the degradation in Euclidean distance with decision feedback in the reduced state trellis. Analysis and simulation results show that the perform-ance degradation is little with proper reduction scheme.
文摘The fresh water polyp Hydra belongs to the phylum Cnidaria, which diverged from the metazoan lineage before the appearance of bilaterians. In order to understand the evolution of apoptosis in metazoans, we have begun to elucidate the molecular cell death machinery in this model organism. Based on ESTs and the whole Hydra genome assembly, we have identified 15 caspases. We show that one is activated during apoptosis, four have characteristics of initiator caspases with N-terminal DED, CARD or DD domain and two undergo autoprocessing in vitro. In addition, we describe seven Bcl-2-1ike and two Bak-like proteins. For most of the Bcl-2 family proteins, we have observed mitochondrial localization. When expressed in mammalian cells, HyBak-like 1 and 2 strongly induced apoptosis. Six of the Bcl-2 family members inhibited apoptosis induced by camptothecin in mammalian ceils with HyBcl-2-1ike 4 showing an especially strong protective effect. This protein also interacted with HyBak-like 1 in a yeast two-hybrid assay. Mutation of the conserved leucine in its BH3 domain abolished both the interaction with HyBak-like 1 and the anti-apoptotic effect. Moreover, we describe novel Hydra BH-3-only proteins. One of these interacted with Bcl-2-1ike 4 and induced apoptosis in mammalian cells. Our data indicate that the evolution of a complex network for cell death regulation arose at the earliest and simplest level of multicellular organization, where it exhibited a substantially higher level of complexity than in the protostome model organisms Caenorhabditis and Drosophila.
基金Project(51005253) supported by the National Natural Science Foundation of ChinaProject(2012ZX02702006-003) supported by the National Science and Technology Major Program of ChinaProject(JMTZ201101) supported by the Key Laboratory for Precision & Non-traditional Machining of Ministry of Education,Dalian University of Technology,China
文摘Adaptive Type-2 fuzzy control possesses control performance better than the traditional adaptive fuzzy control.However,heavy computation burden obviously blocks the utilization of adaptive Type-2 fuzzy control in industrial application.By adopting novel piecewise fuzzy sets and center-average type-reduction,a simplified adaptive interval Type-2 fuzzy controller involving less computation is developed for practical industrial application.In the proposed controller,the inputs are divided into several subintervals and then two piecewise fuzzy sets are used for each subinterval.With the manner of piecewise fuzzy sets and a novel fuzzy rules inference engine,only part of fuzzy rules are simultaneously activated in one control loop,which exponentially decreases the computation and makes the controller appropriate in industrial application.The simulation and experimental study,involving the popular magnetic levitation platform,shows the predicted system with theoretical stability and good tracking performance.The analysis indicates that there is far less computation of the proposed controller than the traditional adaptive interval Type-2 fuzzy controller,especially when the number of fuzzy rules and fuzzy sets is large,and the controller still maintains good control performance as the traditional one.
文摘As a hyper-redundant robot, a 3D snake-like robot can perform many other configurations and types of locomotion adapted to environment except for mimicking the natural snake locomotion. The natural snake locomotion usually limits locomotion capability of the robot because of inadequacy in the mechanism and actuation to imitate characters of natural snake such as the too many DOFs and the characteristics of the muscle. In order to apply snake-like robots to the unstructured environment, the researchers have designed many gaits for increasing the adaptability to a variety of surroundings. The twist-related locomotion is an effective gait achieved by jointly driving the pitching-DOF and yawing-DOF, with which the snakelike robot can move on rough ground and even climb up some obstacles. In dfis paper, the twist-related locomotion function is firstly solved, and simplified to be expressible by sine or cosine function. The 2D locomotion such as V-shape and U-shape is achieved. Also by applying it to the serpentine locomotion or other types of locomotion, the snake-like robot can complete composite locomotion that combines the serpentine locomotion or others with twist-related locomotion. Then we extend the twist-related locomotion to 3D space. Finally, the experimental results are presented to validate all above analyses.
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (No.21101105 and No.51174274), Innovation Program supported by Shanghai Municipal Education Commission (No.12ZZ195 and No.13YZ134), Shanghai Educational Development Foundation and the Shanghai Municipal Education Commission (No.12CG66), "Shu Guang" Project supported by Shanghai Municipal Education Commission (No.09SG54), and Shanghai Municipal Natural Science Foundation (No.13ZR1454800).
文摘A facile impregnation method under mild condition is designed for synthesis of highly dispersed Pt nanoparticles with a narrow size of 4-7 nm on nitrogen-doped carbon nanotubes (CNx). CNx do not need any pre-surface modification due to the inherent chemical activity. The structure and nature of Pt/CNx were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive spectroscopy spectrum. All the experimental results revealed that the large amount of doped nitrogen atoms in CNx was virtually effective for capturing the Pt(IV) ions. The improved surface nitrogen functionalities and hydrophilicity contributed to the good dispersion and immobi- lization of Pt nanoparticles on the CNx surface. The Pt/CNx served as active and reusable catalysts in the hydrogenation of allyl alcohol. This could be attributed to high dispersion of Pt nanoparticles and stronger interaction between Pt and the supports, which prevented the Pt nanoparticles from aggregating into less active Pt black and from leaching as well.
文摘The objective of this study was to isolate Bacillus subtilis produced Bacteriocin from Khmer traditional fermented soybean to control the growth of pathogenic bacteria from 120 SIENG samples from 9 different local open markets in Phnom Penh, 1 local open market and 2 local producers in Kandal province in Cambodia. 119 out of 120 samples were positive with Bacillus subtilis strains. Fifteen of these isolated strains exhibited antimicrobial activity to Lactobacillus plantarum by agar well diffusion assay and one of them (CeM6-7 strain) exhibited strongest antimicrobial activity. The filtered supernatant of this strain also suppressed the growth of several Gram-positive pathogens (such as Staphylococcus aureus) or lactic acid bacteria in broth. The filtrate could also suppress the growth of L. plantarum inoculated into soymilk. Antimicrobial B. subtilis strain CeM6-7 is thought to be applicable for making a starter culture to produce much safe fermented soybean foods by suppressing the growth of naturally contaminated B. cereus or S. aureus during production. In addition, the use of this starter culture may contribute to prevent spoilage or quality loss of soybean products caused by the over growth lactic acid bacteria or other Gram-positive bacteria.
文摘Via a galvanic displacement reaction, well-defined micro/nano binary dendritic gold structures were prepared on silicon wafers in fluoride acid solution containing HAuCI4 at 50 ℃. The gold deposits were characterized with scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectrum and X-ray diffraction (XRD). The investigation of the surface-enhanced Raman scattering (SERS) reveals that the film of gold dendrites was an excellent substrate with significant enhancement effect. Also, the gold dendritic structured surface exhibited a remarkable superhydrophobic property with a contact angle of approximately 165° and low contact angle hysteresis after further simple surface modification with n-dodecanethiol.
文摘This paper examines the relationship between small- and medium-sized enterprises' (SMEs) entrepreneurs' perceptions towards a proper accounting system with the level of accounting staff recruited, preparation of final accounts, meetings with accounting staff, and entrepreneurs' ranking of accounting according to their priority. The methodology used to gather the data is survey questionnaire. It has been distributed to SMEs based on simple random sampling method. Three hundred businesses were selected from the total of 3,390 businesses listed in Kuala Lumpur, Malaysia area obtained from Small and Medium Industries Development Corporation (SMIDEC) website and a few random selected from Ampang and Cheras areas. Regression analysis has been used to analyze the data. The results of the study reveal that there was a significant relation between SMEs entrepreneurs' perceptions on the importance of a good accounting system and the level of professional accounting staff recruited. Furthermore, findings of this study also found that there was an insignificant relationship between SMEs entrepreneurs' perceptions on the importance of a good accounting system and preparation of final accounts of the company and frequency of meetings with accounting staff.
文摘Frame skipping in low bit video coding could significantly reduce the visual quality of reconstructed video. At the same time, if the complexity of the video sequence remains high for a long period, then driving up the long term average bit rate, the only resort of MPEG-4 Q2 rate control algorithm results in using a high quantization scale, which shows a poor visual quality of the reconstructed video. This paper analyzes the main causes of frame skipping in current MPEG-4 frame rate control scheme, and presents a new rate control algorithm based on the quadratic R-D model over a CBR channel. Key features of the present work are: 1) the bits allocated to each P-frame or B-frame are in proportion to its distance from the end of this GOP, i.e. more bits are allocated to the frames that are nearer to their reference Ⅰ-frame; 2) the target buffer level is changeable in the GOP, at the end of each GOP(five P-frames or B-frames), the target buffer level is linearly reduced from 1/2 to 1/4 of buffer size, to other frames, the target buffer level is set to 1/2 of buffer size; 3) a selective and judicious use of the reduced resolution mode, in addition to a modulation of the quantization scale parameter, is to control the average long term bit rate. Experimental results with different video sequences of varied complexity, encoded at low bit rates show better efficacy of the proposed algorithm than MPEG-4 Q2 rate control scheme, and the experimental results also show that the improved algorithm has significantly reduced the number of frame skipping, increased the overall PSNR, and improved the perceptual quality.
文摘Forensic accountants today are required to possess a number of characteristics and skills that are derived from a range of disciplines. They must be inquisitive, able to delve into motivations, operations and justifications underlying the behavior of white collar criminals. They must be able to simplify technical accounting information and convey it effectively orally and in writing to a court or tribunal; be able to trace information via information technology tools; have an understanding of the adversarial legal system and the rules of evidence. Universities offering forensic accounting courses in various formats are on the increase. The aim of this paper is to investigate the subject areas that any course specializing in forensic accounting needs to cover.
基金supported by the National Key Research and Development Program of China(2016YFA0200800, 2013CB834505)he National Natural Science Foundation of China(U1430128,21503244)
文摘In nature,many living organisms exhibit low-angle-dependent or even angle-independent structural colors for wide viewing angle,such as the blue skin of mandrill,feather of blue bird and shell of longhorn beetle,etc.To mimic these structural colors,based on periodic semicircular micro-grooved(PSMG) substrate,silica colloidal photonic crystals provide anisotropic angle-independent structural colors.The PSMG photonic crystals were fabricated by self-assembling monodispersed silica nanoparticles on a micro-grooved template,which can be easily prepared in large scale by a hot embossing method,and no additional materials are needed in the whole preparation process.The PSMG photonic crystals exhibit identical structural colors around the groove axis,whereas it is angle-dependent along the groove axis.In addition,this PSMG surface of photonic crystal also leads to color separation effect and monocolor polarization conversion.This system provides a facile and scalable means to prepare anisotropically angleindependent colloidal photonic crystal,which is considered important in applications in the field of anti-counterfeiting or the manufacture of monochromatic light reflector with wide viewing angles and other novel optical devices.
文摘Field-effect transistors (FETs) have been fabricated using as-grown single-walled carbon nanotubes (SWNTs) for the channel as well as both source and drain electrodes. The underlying Si substrate was employed as the back-gate electrode. Fabrication consisted of patterned catalyst deposition by surface modification followed by dip-coating and synthesis of SWNTs by alcohol chemical vapor deposition (CVD). The electrodes and channel were grown simultaneously in one CVD process. The resulting FETs exhibited excellent performance, with an I ON/I OFF ratio of 10^6 and a maximum ON-state current (/ON) exceeding 13 uA. The large I ON is attributed to SWNT bundles connecting the SWNT channel with the SWNT electrodes. Bundling creates a large contact area, which results in a small contact resistance despite the presence of Schottky barriers at metallic-semiconducting interfaces. The approach described here demonstrates a significant step toward the realization of metal-free electronics.