Multimodal background model with noise and shadow suppression for moving object detection

A statistical multimodal background model was described for moving object detection in video surveillance. The solution to some of the problems such as illumination changes, initialization of model with moving objects, and shadows suppression was provided. The background samples were chosen by thresholding inter-frame differences, and the Gaussian kernel density estimation was used to estimate the probability density function of background intensity. Pixel's neighbor information was considered to remove noise due to camera jitter and small motion in the scene. The hue-max-min-diff color information was used to detect and suppress moving cast shadows. The effectiveness of the proposed method in the foreground segmentation was demonstrated in the traffic surveillance application.

Experimental and Theoretical Study of Hydrogen Atom Abstraction from C2H6 and C4H10 by Zirconium Oxide Clusters Anions

The reactions of anionic zirconium oxide clusters ZrxOy- with C2H6 and C4H10 are investi-gated by a time of flight mass spectrometer coupled with a laser vaporization cluster source.Hydrogen containing products Zr2O5H- and Zr3O7H- are observed after the reaction. Den-sity functional theory calculations indicate that the hydrogen abstraction is favorable in the reaction of Zr2O5- with C2H6, which supports that the observed Zr2O5H- and Zr3O7H- are due to hydrogen atom abstraction from the alkane molecules. This work shows a newpossible pathway in the reaction of zirconium oxide cluster anions with alkane molecules.

MULTI-WATERMARKING SCHEME FOR GROUP USERS BASED ON VISUAL CRYPTOGRAPHY

All watermarks are shared into shadow images using VCS(Visual Cryptography Scheme). Only one specific shadow (as a new watermark) is embedded into the host signal and the other ones are distributed to every user in each group as a key. In the watermarking extraction procedure, users in different group can obtain different watermark by combining their shadows with the extracted one from the watermarked signal. Analysis and experimental results show that the new watermarking method is novel, secure and robust.

Interactions of Anionic and Neutral Serine with Pure and Metal-doped Graphene Studied by Density Functional Theory

We present a theoretical study of interactions of anionic and neutral serine （Ser） on pure or metal-doped graphene surfaces using density functional theory calculations. Interactions of both types of Ser with the pure graphene surface show weak non-covalent interactions due to the formation of-COOH…π, -COO^-…π, and -OH…π interactions. On metal- doped graphene, covalent interactions to the surface dominate, due to the formation of strong metal-O and O-metal-O interactions. Furthermore, the doped Fe, Cr, Mn, A1, or Ti enhances the ability of graphene to attract both types of Ser by a combination of the adsorption energy, the density of states, the Mulliken atomic charges, and differences of electron density. At the same time, the interaction strengths of anionic Ser on various graphene surfaces are stronger than those of neutral Ser. These results provide useful insights for the rational design and development of graphene-based sensors for the two forms of Ser by introducing appropriate doped atoms. Ti and Fe are suggested to be the best choices among all doped atoms for the anionic Ser and neutral Ser, respectively.

H2 Dissociation by Au1-Doped Closed-Shell Titanium Oxide Cluster Anions

Dissociation of molecular hydrogen （H2） is extensively studied to understand the mechanism of hydrogenation reactions. In this study, H2 dissociation by Aul-doped closed-shell titanium oxide cluster anions AuTi3O7 and AuTi3O8 has been identified by mass spectrometry and quantum chemistry calculations. The clusters were generated by laser ablation and mass- selected to react with H2 in art ion trap reactor. In the reaction of AuTi3O8 with H2, the ion pair Au＋-O22 rather than Au＋-O2 is the active site to promote H2 dissociation. This finding is in contrast with the previous result that the lattice oxygen is usually the reactive oxygen species in H2 dissociation. The higher reactivity of the peroxide species is further supported by frontier molecular orbital analysis. This study provides new insights into gold catalysis involving H2 activation and dissociation.

Study of the Influence of the Electrolysis Parameters on Mn-Zn, Mn-Cu and Mn-Cu-Zn Alloys Coatings from Electrolytes Containing Complexing Ligands

The process of obtaining of high quality Mn-Zn, Mn-Cu and Mn-Cu-Zn alloy coatings from complexing ligands--citrate, EDTA （ethylene diaminetetra acetic acid） and nitrilotriacetic acid solutions was studied. Factors affecting stability of solutions containing ligand or ligands and influence of electrolysis parameters： electrolyte composition, pH, cathodic current density on chemical composition of the obtained coatings, on their current efficiency, morphology and structure were investigated.

Synthesis of VIB Group Metals Silicides Dispersed Powders by Electrolysis of Halide-Oxide Melts

Study of electrochemical behavior of chromium （molybdenum, tungsten） and silicon containing melts allowed defining conditions for synthesis of silicides of chromium, molybdenum and tungsten in the form of fine powders by electrolysis of halide-oxide melts. Sequence of stages of electrosynthesis of silicides of molybdenum and tungsten was found as follows： deposition of more electroposifve metal （molybdenum or tungsten）, deposition of the second component （silicon） on the surface of metal deposited previously, and reaction diffusion of silicon into the deep of the metal-salt ＂pear＂ with the formation of silicide phases of different compositions up to the higher silicides. In contrast, during the electrodeposition of chromium silicides, one of the components （chromium） is deposited not in elemental form, but in oxide form, and the other （silicon） acts as a reducing agent for this oxide to form binary compounds. Duration of the synthesis first stage （deposition of refractory metal or of its oxide） depends on the refractory metal compound content in the system and on the cathode current density. Synthesis of silicides is possible due to retention of powders of molybdenum （tungsten） or chromium oxide at the cathode without scaling. Optimal values of concentrations ratio, current density, temperature, and duration of electrosynthesis were found. Phase composition of products were obtained, as well as their chemical and thermal stability, were studied.

An efficient approach for shadow detection based on Gaussian mixture model

An efficient approach was proposed for discriminating shadows from moving objects. In the background subtraction stage, moving objects were extracted. Then, the initial classification for moving shadow pixels and foreground object pixels was performed by using color invariant features. In the shadow model learning stage, instead of a single Gaussian distribution, it was assumed that the density function computed on the values of chromaticity difference or bright difference, can be modeled as a mixture of Gaussian consisting of two density functions. Meanwhile, the Gaussian parameter estimation was performed by using EM algorithm. The estimates were used to obtain shadow mask according to two constraints. Finally, experiments were carried out. The visual experiment results confirm the effectiveness of proposed method. Quantitative results in terms of the shadow detection rate and the shadow discrimination rate(the maximum values are 85.79% and 97.56%, respectively) show that the proposed approach achieves a satisfying result with post-processing step.

Influence of Cathode Plasma on Breakdown Formation in Plasma-Anode Explosive-Emission Source

Breakdown formation in an explosive-emission electron source is related to the interelectrode gap filling with plasma propagating from the cathode and formed at the anode and in the interelectrode gap under the electron beam action. Plasma anode is used to increase the beam current density. Preliminary interelectrode gap filling with plasma in the explosive-emission source decreases the influence of uncontrolled plasma arrival from the anode on the diode processes, promotes current density increase and duration of generated electron beams. The paper considers the influence of the cathode geometry on the breakdown formation in the plasma-anode explosive-emission electron source. The data on obtaining of microsecond electron beams with current density of 30 A/cm^2 and 1.5-2 kA/cm^2 are presented.

Comparative Study of Two Carbon Fiber Cathodes and Theoretical Analysis in Microbial Fuel Cells on Ocean Floor

Cathode activity plays an important role in the improvement of the microbial fuel cells on ocean floor （BMFCs）. A comparison study between Rayon-based （CF-R） and PAN-based carbon fiber （CF-P） cathodes is conducted in the paper. The two carbon fibers were heat treated to improve cell performance （CF-R-H ＆ CF-P-H）, and were used to build a new BMFCs structure with a foamy carbon anode. The maximum power density was 112.4mWm-2 for CF-R-H, followed by 66.6mWm-2 for CF-R, 49.7 mWm-2 for CF-P-H and 21.6mWm-2 for CF-P respectively. The higher specific area and deep groove make CF-R have a better power output than with CF-P. Meanwhile, heat treatment of carbon fiber can improve cell power, nearly two-fold higher than heat treatment of plain fiber. This improvement may be due to the quinones group formation to accelerate the reduction of oxygen and electron transfer on the fiber surface in the three phase boundary after heat treatment. Compared to PAN-based carbon fiber, Rayon-based carbon fiber would be preferentially selected as cathode in novel BMFCs design due to its high surface area, low cost and higher power. The comparison research is significant for cathode material selection and cell design.

舉辦安全衛生勞動保護展覽會的经驗

上海市自一九五一年以來曾舉辦了各種類型的安全衛生勞動保護展覽會,對廣大職工羣眾進行了廣泛的安全衛生教育,交流了各種具體的經驗,改進了各廠的安全衛生工作,培養和提高了勞動保護工作幹部,同時,我們也積累一些舉辦展覽會的經驗,現在把它寫出來供大家研究參考: 一、籌備階段:由舉辦單位抽出一部分幹部,組成籌備展覽會的辦公室,擬訂計劃,說明舉辦展覽會的要求、內容,初步估計規模大小,從而計算會場面積、經費數目、籌備時間及所需參加工作的人員數目,並提出舉辦各單位所應負担的人力、物力和財力,分送各舉辦單位,必要時送請上級黨、政機關審核批准。計割批准後,按計劃訂出籌備工作的日程,辦公室成員應適當分工,如祕書、財務、宣教、組織動員、技術設計及會場佈置等,分頭進行具體工作。覓定會場,收集及製造展覽品,購置材料。

息影八首秋日返旧居作

埽叶学书地。穷秋独闭门。小山丛桂发。孤月此心存酱瓿玄经字。盐车老■魂。偶来驯鹤径。息影融听潺湲。文苑诗录二六卷■松阴密。飞帘水石宽。稻凉农事缓。莺老燕泥闲。晓露侵书幌。夕风下井栏。遂初方赋罢。佛意此中看。暸亮吹横笛。风回衣袂长。好怀得句稳。初雁过江凉。沆砀秋生白。崦嵫日已黄。

养阴、温阳密骨片治疗原发性骨质疏松症肾阴、阳虚证型的疗效观察

目的探讨养阴、温阳密骨片分别治疗原发性骨质疏松症肾阴、阳虚证型症状变化。方法按照中医虚证辨证参考标准对患者进行辨证,原发性骨质疏松患者92例,分为肾阴虚组和肾阳虚组。肾阴虚者52例,给服养阴密骨片;肾阳虚者40例,给服温阳密骨片。结果养阴、温阳密骨片分别治疗原发性骨质疏松症肾阴、阳虚证型过程中,各个单项症状积分值逐渐下降。养阴密骨片对目眩症状疗效最佳,温阳密骨片对头晕症状疗效最佳。结论养阴、温阳密骨片均可明显缓解原发性骨质疏松症肾阴、阳虚证型的临床症状。

Large Area Thermionic Cathode and Its Prilimiary Experimental Results

A 2MeV thermionic cathode test stand was established to meet the requirement of the large area thermionic cathode system.A 100ram in diameter type'B'thermionic dispenser cathode was developed.A 1000A emission current was produced at the voltage of the diode about 1.8MV,the pulse width about 90ns(FWHM),and the cathode temperature about 1350℃.The emission current density is 12A/cm^2.The results indicate that a large area thermionic cathode which produces high quality and high current electron beams is visible.The results also indicate that the ability of cathode emission relies on the diode-vacuum and cathode-temperature.

Facile microwave approach towards high performance MoS2/graphene nanocomposite for hydrogen evolution reaction

Low-cost, highly efficient catalysts for hydrogen evolution reaction(HER) are very important to advance energy economy based on clean hydrogen gas. Intensive studies on two-dimensional molybdenum disulfides(2 D Mo S2) have been conducted due to their remarkable catalytic properties.However, most of the reported syntheses are time consuming,complicated and less efficient. The present work demonstrates the production of Mo S2/graphene catalyst via an ultra-fast(60 s) microwave-initiated approach. High specific surface area and conductivity of graphene delivers a favorable conductive network for the growth of Mo S2 nanosheets, along with rapid charge transfer kinetics. As-produced Mo S2/graphene nanocomposites exhibit superior electrocatalytic activity for the HER in acidic medium, with a low onset potential of62 m V, high cathodic currents and a Tafel slope of43.3 m V/decade. Beyond excellent catalytic activity, Mo S2/graphene reveals long cycling stability with a very high cathodic current density of around 1000 m A cm^-2 at an overpotential of 250 m V. Moreover, the Mo S2/graphene-catalyst exhibits outstanding HER activities in a temperature range of 30 to 120°C with low activation energy of36.51 k J mol^-1, providing the opportunity of practical scalable processing.

Mesoporous Fe_(3)O_(4)@C nanoarrays as high-performance anode for rechargeable Ni/Fe battery

Rechargeable aqueous batteries with high power density and energy density are highly desired for electrochemical energy storage.Despite the recent reports of various cathode materials with ultrahigh pseudocapacitance exceeding3000 F g^(-1)(or 800 mA h g^(-1)),the development of anode materials is relatively insufficient,which limits the whole performance of the devices far from practical applications.Herein,we report the preparation of mesoporous Fe_(3)O_(4)@C nanoarrays as high-performance anode for rechargeable Ni/Fe battery by a self-generated sacrificial template method.Zn O/Fe_(3)O_(4)composite was first synthesized by a co-deposition process,and Zn O was subsequently removed by alkali etching to construct the mesoporous structure.A thin carbon film was introduced onto the surface of the electrode by the carbonization of glucose to increase the structural stability of the electrode.The unique mesoporous nanoarray architecture endows the electrode with larger specific surface area,faster charge/mass transport and higher utilization of Fe_(3)O_(4),which shows an ultrahigh specific capacity (292.4 mA h g^(-1)at a current density of 5 mA cm^(-2)) and superior stability in aqueous electrolyte (capacitance retention of 90.8%after 5000cycles).After assembled with hierarchical mesoporous Ni O nanoarray as a cathode,an optimized rechargeable Ni/Fe battery with double mesoporous nanoarray electrodes was fabricated,which provided high energy/power densities(213.3 W h kg^(-1)at 0.658 kW kg^(-1)and 20.7 kW kg^(-1)at113.9 W h kg^(-1),based on the total mass of the active materials)in the potential window of 1.5 V with excellent cyclability(81.7%retention after 5000 charge/discharge cycles).

Large field emission current and density from robust carbon nanotube cathodes for continuous and pulsed electron sources

Highly adhesive cold cathodes with high field emission performance are fabricated by using a screen-print- ing method. The emission density of carbon nanotube （CNT） cold cathode reaches 207.0 mA cm-2 at an electric field of 4.5 Vμm-1 under continuous driving mode, and high peak current emission of 315.8 mA corresponding to 4.5 A cm 2 at the electric field of 10.3 V μm-1 under pulsed driving mode. The emission patterns of the cold cathodes are of excellent uniformity that was revealed by vivid luminescent patterns of phosphor coated transparent indium tin oxide （ITO） an- ode. The cold cathodes also exhibit highly stable emission under continuous and pulsed driving modes. The high adhe- sion of CNTs to molybdenum substrates results in robust cold cathodes and is responsible for the high field emission performance. This robust CNT emitter could meet the operating requirements of continuous and pulsed electron sources, and it provides promising applications in various vacuum- micro/nanoelectronic devices.

Field Emission from Carbon Nanotube/Tin Composite

Powder metallurgy was used to fabricate carbon nanotube(CNT) field emission cathodes.CNTs and tin(Sn) powder were blended,compacted and sintered.After polishing and etching,CNTs were exposed and protruded from the metal surface.CNTs were embedded into the Sn matrix,which acted as stable field emitters. The J-E curves show excellent field emission properties,such as low turn-on field of 2.8 V/μm,high emission current density and good current stability.

Density Functional Study of Cationic and Anionic Ag_mCu_n (m + n ≤ 5) Clusters

Abstract The structural and energetic properties of bimetallic AgmCun （m ＋n ≤ 5） in the cationic and anionic charged states have been investigated by density functional theory with relativistic effective core potentails. The stable cationic pentamers have three-dimensional structures in contrast to anionic clusters assume planar structures. For the given cluster size the electron affinities decrease as the Cu content increases, while no clear trend can be found in adiabatic ionization potentials. The binding energy per atom also increases with the increasing Cu content and follows the order anion 〈 cation. The most probable dissociation channels of the clusters considered are also discussed.