299 resultados para PDA
Resumo:
本文以桃(Prunus persica L. cv. Bayuecui.)栽培种‘八月脆’和芒果(Mangifera indica L.)栽培种‘圣心’为材料,研究外源草酸对采后果实的生理生化效应及其作用机理,为果实贮藏保鲜提供新方法。采后桃果实用1、5 mM的草酸溶液浸果10 min,以浸水10 min为对照,然后在常温下贮藏,测定果实在贮藏期间对草酸处理的一些生理生化反应。芒果经采后杀菌剂(post- P)、采后草酸(post-OA)、采前+采后草酸(pre-OA + post-OA)、采前Ca + 采后草酸处理(pre-Ca + post-OA)处理,以采后浸水为对照,然后分别将果实在常温(25 C)、低温(14 C)和控制性气调(3% CO2 + 2% O2 ,14 ± 1 C)下贮藏,测定草酸处理对芒果的成熟进程、病情发展及其相关生理指标的影响。研究结果表明如下: 1.与对照相比,草酸处理的桃果实在贮藏期间果实的电解质渗漏量和呼吸速率降低、果实硬度高、果实的抗氧化酶(超氧化物岐化酶、SOD;过氧化物酶,POD;过氧化氢酶、CAT;抗坏血酸过氧化物酶、APX)和多酚氧化酶(PPO)活性提高、脂氧合酶(LOX)活性降低。同时,在贮藏后期,果实的活性氧自由基(ROS)产量(超氧阴离子、O2.;过氧化氢、H2O2)和丙二醛(MDA)含量降低。草酸的这些生理效应有利于保持膜的完整性和延缓桃果实的成熟;草酸诱导POD、SOD、PPO活性可能有助于提高采后果实的抗病性。 2.外源5、10 mM浓度的草酸(pH值中和或不中和)对芒果炭疽病原菌(Colletotrichum gloeosporioides)孢子萌发和菌丝生长均表现出显著的抑制作用。这种作用不仅与草酸降低培养基(PDA)的pH值相关,而且与草酸独特的化学特性相关。 3.在常温、低温和控制性气调贮藏下,采后草酸、采前 + 采后草酸、采前Ca + 采后草酸处理均能有效减缓芒果果实的软化速率,延缓芒果的成熟进程,降低芒果的病情指数,同时改善芒果成熟时的表皮着色,对果实完全后熟时的可溶性固形物(SSC)、可滴定酸(TA)含量、果肉口感均没有产生负面的影响。 4.草酸处理增强芒果细胞膜的稳定性,诱导提高芒果抗氧化酶活性,特别是提高果皮SOD、APX活性,降低LOX活性,以及降低果皮O2.、H2O2 和果肉H2O2含量,抑制采后果实的乙烯生物合成。这些生理生化效应与延缓芒果的成熟衰老和提高果实的抗病性相关。 5. 采后草酸、采前 + 采后草酸和采前Ca + 采后草酸处理表现出高效低廉、无毒无副作用、易操作等优点,是芒果采后贮藏保鲜的可供选、具有实际应用前景的新方法。
Resumo:
The potential of palm methyl esters (PME) as an alternative fuel for gas turbines is investigated using a swirl burner. The main air flow is preheated to 623 K, and a swirling spray flame is established at atmospheric pressure. The spray combustion characteristics of PME are compared to diesel and Jet-A1 fuel under the same burner power output of 6 kW. Investigation of the fuel atomizing characteristics using phase Doppler anemometry (PDA) shows that most droplets are distributed within the flame reaction zone region. PME droplets exhibit higher Sautermean diameter (SMD) values than baseline fuels, and thus higher droplet penetration length and longer evaporation timescales. The PME swirl flame presents a different visible flame reaction zone while combusting with low luminosity and produces no soot. NO x emissions per unit mass of fuel and per unit energy are reduced by using PME relative to those of conventional fuels. © 2012 Copyright Taylor and Francis Group, LLC.
Resumo:
An increasin g interest in biofuel applications in modern engines requires a better understanding of biodiesel combustion behaviour. Many numerical studies have been carried out on unsteady combustion of biodiesel in situations similar to diesel engines, but very few studies have been done on the steady combustion of biodiesel in situations similar to a gas turbine combustor environment. The study of biodiesel spray combustion in gas turbine applications is of special interest due to the possible use of biodiesel in the power generation and aviation industries. In modelling spray combustion, an accurate representation of the physical properties of the fuel is a first important step, since spray formation is largely influenced by fuel properties such as viscosity, density, surface tension and vapour pressure. In the present work, a calculated biodiesel properties database based on the measured composition of Fatty Acid Methyl Esters (FAME) has been implemented in a multi-dimensional Computational Fluid Dynamics (CFD) spray simulation code. Simulations of non-reacting and reacting atmospheric-pressure sprays of both diesel and biodiesel have been carried out using a spray burner configuration for which experimental data is available. A pre-defined droplet size probability density function (pdf) has been implemented together with droplet dynamics based on phase Doppler anemometry (PDA) measurements in the near-nozzle region. The gas phase boundary condition for the reacting spray cases is similar to that of the experiment which employs a plain air-blast atomiser and a straight-vane axial swirler for flame stabilisation. A reaction mechanism for heptane has been used to represent the chemistry for both diesel and biodiesel. Simulated flame heights, spray characteristics and gas phase velocities have been found to compare well with the experimental results. In the reacting spray cases, biodiesel shows a smaller mean droplet size compared to that of diesel at a constant fuel mass flow rate. A lack of sensitivity towards different fuel properties has been observed based on the non-reacting spray simulations, which indicates a need for improved models of secondary breakup. By comparing the results of the non-reacting and reacting spray simulations, an improvement in the complexity of the physical modelling is achieved which is necessary in the understanding of the complex physical processes involved in spray combustion simulation. Copyright © 2012 SAE International.
Resumo:
The spray combustion characteristics of rapeseed methyl esters (RME) were compared to Jet-A1 fuel using a gas turbine type combustor. The swirling spray flames for both fuels were established at a constant power output of 6 kW. The main swirling air flow was preheated to 350 C prior to coaxially enveloping the airblast-atomized liquid fuel spray at atmospheric pressure. Investigation of the fundamental spray combustion was performed via measurements of the fuel droplet sizes and velocities, gas phase flow fields and flame reaction zones. The spray flame droplets and flow fields in the combustors were characterised using phase Doppler anemometry (PDA) and particle imaging velocimetry (PIV) respectively. Flame chemiluminescence imaging was employed to identify the flame reaction zones. The highest droplet concentration zone extends along a 30 angle from the symmetry axis, inside the flame zone. Only small droplets(<17 μ) (<17 μm)are found around the centreline region, while larger droplets are found at the edge of the spray outside the flame reaction zone. RME exhibits spray characteristics similar to Jet-A1 but with droplet concentration and volume fluxes four times higher, consistent with the expected longer droplet evaporation timescale. The flow field characteristics for both RME and Jet-A1 spray flames are very similar despite the significantly different visible characteristics of the flame reaction zones. © 2013 Elsevier Ltd. All rights reserved.
Resumo:
随着实时系统越来越多地应用于各种快速更新系统,尤其是各种片上系统,如PDA(personal digital assistant),PSP(play station portable)等,性价比已成为系统设计者的主要关注点.实际应用中,实时系统通常仅支持较少的优先级,常出现系统优先级数小于任务数的情况(称为有限优先级),此时,需将多个任务分配到同一系统优先级,RM(rate monotonic),DM(deadline monotonic)等静态优先级分配算法不再适用.为此,静态有限优先级分配是研究在任务集合静态优先级可调度的情况下,可否以及如何用较少或最少的系统优先级保持任务集合可调度.已有静态有限优先级分配可分为两类:固定数目优先级分配和最少优先级分配.给出了任意截止期模型下任务静态有限优先级可调度的充要条件以及不同静态有限优先级分配间转换时的几个重要性质,指出了系统优先级从低到高分配策略的优越性,定义了饱和任务组与饱和分配的概念,证明了在任务集合静态优先级可调度的情况下,最少优先级分配比固定数目优先级分配更具一般性.最后提出一种最少优先级分配算法LNPA(least-number priority assignment).与现有算法相比,LNPA适用范围更广,且复杂度较低.
Resumo:
高分子发光材料除应具有优良发光性能外,还需具有优良电子传输性能和空穴传输性能。本论文以此为出发点,将具有优良空穴传输性能的芳胺类化合物和具有优良电子传输性能的噁二唑类化合物,通过无规共聚合调控发光基元和两类传输基元的含量,合成了系列的传输与发光一体化的即V类高分子发光材料,并探讨了聚合物本身的基本特性。同时,设计和制备了相应的单层结构器件和掺杂器件,考察了器件的器件性能。本论文主要工作内容及结果如下:1、成功的利用三类王芳胺类双醛:4,4'-二醛基-(4-辛氧基-苯基)-二苯胺(TPA双醛)、N,N'-二(4-辛氧基一苯基)-N,N'-二(4-甲醛基-苯基)-1,4-苯二胺(PDA双醛)和N,N,-二(4-辛氧基-苯基)-N,N,-二(4-甲醛基-苯基)-4,4' 联苯二胺(TPD双醛)和wittig麟盐无规共聚,得到三个系列双极传输高分子发光材料。2、聚合物主链中同时引入三芳胺类空穴传输基团和噁二唑电子传输基团,提高了器件性能。在TPA系列中,同时含有三芳胺和噁二唑全基团的聚合物比仅含有三芳胺基团聚合物的单层器件亮度及效率分别提高29和22倍,同时使器件的启动电压从9.3V下降到2.7V。在同样比较的情况下,在PDA系列中,聚合物的器件亮度及效率要提高近8倍,同时使器件的启动电压从5.3V下降到4.5V。在TPD系列中,聚合物的器件亮度及效率要提高44和38倍,同时使器件的启动电压从7.5V下降到5.7V。3、含有噁二唑基团聚合物分子的这种D-A体系所具有的分子内电荷转移性质,导致其荧光光谱和电致发光光谱红移。其中,TPA系列和TPD系列的电致发光光谱从绿光红移到了黄绿光,而PDA系列聚合物的电致发光光谱从黄绿光红移到了橙光。4、刚性的噁二唑基团的引入提高了聚合物的热稳定性,T以系列聚合物、PDA系列聚合物和TPD系列聚合物中含有噁二唑基团的聚合物的玻璃化转变温度在112-229℃之间,其热分解温度超过420℃。5、此三个系列聚合物中同时含有空穴和电子传输基元的双极分子溶液的紫外一可见吸收光谱和荧光光谱都有明显的溶剂化效应,表现出较强的分子内电荷转移特性。6、利用TPA系列聚合物中性能最好的聚合物TPA-OXD-PV1的良好电子和空穴传输性质,构造的单层掺杂器件,实现了橙色和红色发光。
Resumo:
本论文由四章组成,第一、二、三章为实验论文,分别报道了中药羌活、菊花、全缘叶绿绒蒿的化学成分的高效液相色谱(HPLC)和液相色谱-质谱(LC-MS)联用分析以及挥发油的气相色谱-质谱(GC-MS)联用分析。第四章概述了重要藏药材化学成分的研究进展。 第一章首先对28批不同产地的羌活药材进行了HPLC分析,建立了羌活的指纹图谱。结果表明,不同产地羌活的化学成分基本相似,但是各组分在含量上存在较大差异。其次,对羌活的主要化学组分包括紫花前胡苷、紫花前胡素、6'-O-反式阿魏酸紫花前胡苷、茴香酸对羟基苯乙酯、羌活醇和异欧前胡素进行了定量分析。此外,针对同一产地不同采集时间的羌活挥发油进行系统分析,结果表明它们的化学成分基本相似,主要含有a-蒎烯、b-蒎烯、柠檬烯和龙脑乙酸酯等,只是各组分含量有所变化,这说明采集药材时要注意采集时间。 第二章分别报道了不同产地不同品种菊花非挥发性成分的液相色谱-二极管阵列检测-串联质谱(LC-PDA-MSn)分析和挥发性成分的气相色谱-质谱(GC-MS)联用分析比较。首先通过液相色谱-质谱-串联质谱对各色谱峰进行定性分析,通过与标准品对照,以及UV和MSn提供的结构信息,结合文献报道共鉴定了11个化学成分,包括绿原酸和10个黄酮化合物,并比较了不同品种菊花的化学成分相同之处和不同之处。另外,对七种不同品种不同产地的菊花挥发性成分通过GC-MS分析表明其主要挥发性成分为单萜类、倍半萜类化合物,共有成分樟脑、龙脑和龙脑乙酸酯等,各成分在不同挥发油中的含量变化明显。 第三章为藏药全缘叶绿绒蒿不同部位挥发油成分的气相色谱-质谱(GC-MS)联用分析,比较其挥发油化学成分及其含量变化的异同点。研究结果表明,全缘叶绿绒蒿花精油的化学成分明显多于全草部位,且两者主要成分有较大的差别。 第四章综述了青藏高原重要藏药材化学成分的研究进展。分别对藏药的资源特色和110多种常用重要藏药材的化学成分的研究情况以及藏药未来发展思路进行了阐述,以期对相关的研究提供一些信息。 This dissertation consists of four parts. The first part reports studies on the fingerprint of Notopterygium incisum and N. forbesii by HPLC-PDA-MSn, and on the constitutents of essential oil by GC-MS. The second part elaborates the chemical constitutents of Chrysanthemum L. by LC-MS and GC-MS analysis. The third part reports the chemical compositions of the essential oil from the different parts of Meconopsis integrifolia. The fourth part reviews on the progress of the studies on the chemical constitutents in Tibetan medicines. The first chapter is about HPLC analysis of a traditional Chinese herbal medicine Qiang-huo (Notopterygium incisum and N. forbesii ). Firstly, based on analyzing and contrasting the relative retention time and relative paek area in chromatographic fingerprint, the HPLC chromatographic fingerprint of Notopterygium incisum was established, which can used as a scientific basement for the quality evalution of this herb. Secondly, quantitative analysis were performed on the main chemical constitutents of Notopterygium incisum and N. forbesii including nodakenin, nodakenetin, 6’-O-trans-feruloylnodakenin, p-hydroxypenethylanisate, notopterol and isoimperatorin. The results indicated that the contents were variable related to different growth regions. Lastly, the essential oil of Notopterygium incisum collected in different harvest times is analyzed by GC-MS. The second chapter is about HPLC-MS and GC-MS analysis of several species of Chrysanthemum L. Firstly, eleven compounds including chlorogenic acid and ten flavone compounds were identified in the methanol extract of Chrysanthemum morifolium Ramat. from different regions by HPLC-MS analysis. Secondly, the essential oil of seven different species of Chrysanthemum L.were extracted by steam distillation, and its compositions were isolated and identified by GC-MS. The main active constitutents such as camphor, borneol and bornyl acetate were detected, but the relative content varied notably. The third chapter is about GC-MS analysis of the essential oil from different parts of Meconopsis integrifolia. It indicated great difference of the chemical compositions of their oil in the flowers and residual overground part. The last chapter is a review of the research progress of the Tibetan medicines, which includes their features and their main chemical constitutents.
Resumo:
毛壳菌属很多种类具有重要生防价值,其生防机理包括对植物病原真菌的重寄生作用、诱导植物产生抗病性、产生抗真菌活性的次生代谢产物等。迄今,学界对毛壳菌的研究主要集中在毛壳菌的生防机理,毛壳菌活性次生代谢产物的分离等方面。本研究致力于产抗生素的毛壳菌的种间原生质体融合,从产抗生素毛壳菌菌株的筛选开始,进而对产抗生素的角毛壳菌进行诱变选育,最终用产不同抗生素的角毛壳菌与球毛壳菌进行种间原生质体融合。主要有以下五方面研究结果。 1、毛壳菌抗真菌活性物质产生菌株的筛选:不同毛壳菌菌株发酵液采用琼脂扩散法对植物病原真菌进行抑菌活性试验,结果显示,菌株CH08和CH23的发酵液对芒果炭疽、苹果炭疽和马铃薯晚疫菌具有抑制作用。菌株CH16和CH17的发酵液对芒果炭疽菌、苹果炭疽菌有抑制作用。菌株CH21发酵液对辣椒炭疽菌和西瓜枯萎菌有抑制作用。经形态学研究,菌株CH08、CH16、CH17和CH23鉴定为球毛壳菌,菌株CH21鉴定为角毛壳菌。对角毛壳菌与球毛壳菌菌株发酵液抑菌谱比较,发现角毛壳菌与球毛壳菌发酵液具有明显不同的抑菌谱,表明角毛壳菌与球毛壳菌产生不同的抗真菌活性物质。 2、角毛壳菌(CH21)和球毛壳菌(CH08)原生质体制备和再生条件研究:考察了菌龄、酶浓度、稳渗剂及其浓度、酶解温度、酶解时间及再生培养基对原生质体制备和再生的影响。用菌龄为生长54 h的角毛壳菌菌丝,以0.06 M磷酸缓冲液(pH6.0)配制成含蜗牛酶15 mg/ml、溶壁酶10 mg/ml、蔗糖0.6 mol/L的酶解液,30℃酶解1.5 h,原生质体释放量2.02×107个/g;以PDA为再生培养基,0.7 mol/L的蔗糖再生稳渗剂,再生率可达51.45%。用菌龄为生长48 h的球毛壳菌菌丝,以0.06 M磷酸缓冲液(pH6.0)配制成含蜗牛酶15 mg/ml、溶壁酶10 mg/ml、蔗糖0.6 mol/L的酶解液,30℃酶解1 h,原生质体释放量达1.57×108个/g;以PDA为再生培养基,0.7 mol/L的蔗糖为再生稳渗剂,再生率可达41.48%。 3、角毛壳菌(CH21)原生质体紫外诱变选育:以CH21为出发菌株,制备原生质体进行紫外诱变,诱变条件为:15 w紫外灯,距离30 cm,照射90 s,致死率80%~85%。建立了诱变菌株初筛的双层平板筛选模型。经平板初筛和摇瓶复筛,获得一株突变菌株CH21-I-402,其发酵液抑菌活性较出发菌株提高18.3%。 4、抗性标记菌株的获得:菌株CH21-I-402和CH08抗生素药敏试验表明, CH21-I-402菌株对潮霉素有抗性、对G418(Geneticin)敏感,菌株CH08对潮霉素和G418都敏感。根癌农杆菌EHA105介导的新霉素磷酸转移酶基因转化球毛壳菌,经PCR检测,新霉素磷酸转移酶基因成功转化进菌株CH08-GR70,CH08-GR120。转化子对G418抗性提高3~4倍,对潮霉素仍然比较敏感。 5、以G418和潮霉素抗性为筛选标记的原生质体融合与融合菌株AFLP分析:制备角毛壳菌CH21-I-402和球毛壳菌CH08-GR70原生质体,以35%的PEG6000为助融剂进行原生质体融合,以65 μg/ml的潮霉素和60 μg/ml G418为抗性筛选标记,获得46个再生菌株。再生菌株连续传代5代后,再生菌株表现出多种形态类型。利用AFLP技术对再生菌株及亲本菌株基因组DNA分析表明,再生菌株PF1、PF26为融合菌株。抑菌活性测试表明,融合菌株PF26发酵液对芒果炭疽菌和苹果轮纹菌有强的抑制作用,且抑菌活性比亲本球毛壳菌明显提高。 Chaetomium spp. have great potentials as biocontrol agents against a range of plant pathogens on the basis of its mycoparasitism, induced plant disease resistance, production of antifungal metabolites, and so on. Previous researches on C. spp. mostly focused on the mechanisms of its biocontrol and the isolation of secondary metabolites. In this study, screening antifungal C. spp., mutation breeding of C. cupreum and interspecies protoplast fusion between C. cupreum and C. globosum were carried out, respectively. The corresponding results are as follows: Firstly, among more than 40 C. spp., the strains produced anti-fungal antibiotics were screened by agar diffusion experiments. Results showed that both CH08 and CH23 had inhibition against Colletotrichum gloeosporioides, Cladosporium fulvum, and Phytophthora infestans. Both CH16 and CH17 had inhibition against Colletotrichum gloeosporioides and Cladosporium fulvum. In addition, CH21 exhibited anti-fungal activity against Fusarium oxysporum f. sp niveum and Colletotrichum capsici. Furthermore, CH08, CH16, CH17 and CH23 were identified as C. globosum, CH21 was proved to be C. cupreum based on morphology. The comparison of the anti-fungal spectrum between C. cupreum and C. globosum, showed they could produce different antibiotics. Secondly, specified protocols for preparing and regenerating protoplasts from mycelia of C. cupreum CH21 and C. globosum CH08 were studied. The effects of the age mycelia, the concentration of enzyme, digestion temperature and time, kinds of osmotic stabilizer and regeneration medium on protoplasts preparation and regeneration were all optimized, respectively. In one protocol, with 15 mg/mL snailase, 10 mg/mL lywallzyme, 0.6 M sucrose, in 0.06 M phosphate buffer (pH6.0), and digested for 1.5 h at 30 ºC, 2.02×107 protoplasts from each gram mycelia were obtained from cultures of C. cupreum CH21 grown in potato dextrose broth (PDB) medium for 54 h. And when 0.7 M sucrose was used as osmotic stabilizer in the regeneration medium OPDA (potato dextrose agar with osmotic stabilize), the regeneration efficiency of protoplasts was 51.45%. In another protocol, with 15 mg/mL snailase, 10 mg/mL lywallzyme, 0.6 M sucrose, in 0.06 M phosphate buffer (pH6.0), and digested for 1 h at 30 ºC, 1.57×108 protoplasts from each gram mycelia were obtained from cultures of C. globosum CH08 grown in PDB for 48 h. And when 0.7 M sucrose was used as osmotic stabilizer in the regeneration medium OPDA, the regeneration efficiency of protoplasts was 41.48%. Thirdly, the mutagenesis conditions and secondary screening model of C. cupreum CH21 were explored. An 80% to 85% death rate could be achieved when the protoplasts of C. cupreum CH21 were irradiated by 15 w UV lamp from 30 cm distance for 90 s. In addition, the doublelayer plate’s method for the primary screening of high-producing antibiotics strains was established. A high yielding antibiotic mutant CH21-I-402 was obtained through the primary screening on plate and the secondary selection in Erlenmeyer flask, compared to the original CH21 strain, the antifungal activity of the mutant CH21-I-402 was increased by 18.3%. Fourth, the sensitivity to antibiotics of both C. cupreum CH21-I-402 and C. globusm CH08 was detected. Results showed C. cupreum CH21-I-402 was sensitive to G418 (Geneticin) (Gs) and resistant to Hygromycin B(Hr), and C. globusm CH08 was sensitive to both G418 (Geneticin) (Gs) and Hygromycin B(Hs). At the same time, neomycin phosphotransferase II (npt II) gene was transformed into C. globusm CH08(Gs, Hs) mediated by Agrobacterium tumefaciens EHA105, and the npt II gene was verified by polymerase chain reaction in resistance to G418 strains CH08-GR70 and CH08-GR120. The transformants still showed sensitive to Hygromycin B(Hs). Finally, a selection system for hybrids was set up by interspecies protoplast fusion between C. cupreum and C. globusm using dominant selective drug resistance markers. At first, protoplasts of C. cupreum CH21-I-402 (Hr, Gs) and C. globusm CH08-GR70 (Hs, Gr) were prepared, then the protoplasts were fused in the presence of 35% polyethylene glycol 6000 and regenerated on OPDA medium with 65 μg/ml Hygromycin B and 60μg/ml G418, at last 46 colonies with Hr and Gr were obtained. Even after 5 generations’ subculture, most of the colonies displayed significant difference in taxonomic characteristics with their parental strains. Regenerated strains PF1 and PF26 were confirmed as fusants by amplified fragment length polymorphisms analysis with the genomic DNA as the model. PF26 showed higher inhibitory activity against Colletotrichum gloeosporioides and Macrophoma kuwatsukai than that of the parental strain C. globusm.
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在PDA平板培养条件下,研究Cd、Pb及其复合污染对平菇菌丝体生长的影响以及平菇菌丝体对生长基质中Cd、Pb的生物富集作用.结果表明,在实验浓度范围内,菌丝生长势、菌落直径和菌丝体干重等均随着重金属浓度的增大而减弱(小)或降低.平菇菌丝体对Cd、Pb均具有生物富集作用,并且随着重金属浓度的增大菌丝体中重金属含量逐渐增大.Cd、Pb复合污染能促进平菇菌丝体对Pb的吸收,而抑制对Cd的吸收.
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手绘草图是一种自然而直接的思路外化和交流方式。用户传统使用草图的方式为先用草图记录早期想法,想法成熟时转化为正规电子文档,这样存在着冗余性和低效性的问题。随着笔计算设备的普及,数码笔、手写板、手写屏、电子白板、PDA、UMPC等设备不断融入人们的生活,在线手绘草图将成为笔计算设备的主要应用之一。近年来,手绘草图也开始在互联网上出现,成为用户体现个性的方式。理解在线手绘草图将为手绘草图的高效利用和高效编辑提供了保障。 草图理解包括在线草图理解和离线草图理解。在线草图理解的对象为用户用数字笔绘制的在线草图,而离线草图理解的对象为图像。目前,在线草图理解技术是当前的研究热点,但它仍然面临很多挑战,例如草图的自适应识别、新领域草图的理解、草图的高效交互等。本文的研究对象为在线草图理解技术以及面向在线草图理解的交互技术。具体地,从多个层次和角度展开研究,依次为:草图符号识别、手写公式理解、草图结构理解、面向在线草图理解的交互技术、原型系统。 本文首先概述了草图理解技术的发展历史,介绍了在线草图理解技术的需求、输入设备和关键技术,并分析了在线草图理解技术的研究进展。之后,本文对自适应的草图符号识别、手写无机化学公式理解、手绘概念图的结构理解这三个问题进行了讨论,并对面向在线草图理解的交互技术进行了分析,最后研发了一个原型系统IdeaNote。本文研究内容和创新点如下: 1. 自适应的草图符号识别 在草图符号的自适应学习中,不同用户的训练样本数量可能不同,保持在不同样本数量下良好的学习效果成为需要解决的一个重要问题。本文提出一种自适应的草图符号识别方法,该方法采用与训练样本个数相关的分类器组合策略将模板匹配方法和SVM统计分类方法进行了高效组合。它通过利用支持小样本学习的模板匹配方法和支持更多样本学习的SVM方法,并同时利用草图符号中的在线信息和离线信息,实现了不同样本个数下自适应的符号学习和识别。评估表明,该方法可以在24类草图符号分别使用1到20个训练样本时具有较高的识别正确率和较好的时间性能。 2. 手写无机化学公式理解 手写公式是人们学习和生活中的重要部分,本文提出手写无机化学公式的同步识别和异步识别方法。同步识别方法在用户书写无机化学公式的同时进行识别,异步识别方法在用户完成一个或几个化学公式的时候进行识别。两类方法均充分利用了无机化学领域的知识,具有较高的识别正确率。其中,异步识别方法的正确率为93.08%。基于手写无机化学公式的理解结果,可以支持无机化学公式的手写输入、多通道输入、自动错误检测和自动配平等。 3. 手绘概念图的结构理解 草图结构理解是草图编辑和草图应用的基础。手绘概念图是思维产生和交流的重要工具,与正规形式的概念图相比更加自然且符合用户的纸笔习惯。本文提出一种手绘概念图的结构理解方法。它采用动态规划方法提取概念图中的节点和连线笔划块,通过图划分的方法降低图的动态规划的时间复杂度,在此基础上提取由节点、连线和节点连线关系组成的概念图结构。评估表明,该方法可以取得95.18%的节点和连线提取正确率,且概念图结构理解的时间满足实时性要求。 4. 面向在线草图理解的交互技术 草图的交互技术对草图系统至关重要。本文提出手绘概念图的结构化编辑技术和基于语音和笔的多通道输入和纠错技术。其中,手绘概念图的结构化编辑技术,支持结构化的选择、移动、缩放和节点互换等编辑操作。评估表明,该结构化编辑方法比基于笔划的编辑方法更加高效。多通道交互技术包括基于语音和笔的多通道化学公式输入方法和基于语音和笔的多通道数学公式纠错方法。评估表明,基于语音和笔的手写数学公式识别纠错方法比基于笔的纠错方法取得更好的效果。 5. 原型系统IdeaNote 笔记系统是笔计算设备上的重要应用。IdeaNote是一个基于数字笔的笔记系统。它支持数字笔迹的自由输入,并支持笔迹的高效编辑。IdeaNote的基础为在线草图理解技术和面向在线草图理解的交互技术。在线草图理解技术包含笔手势识别方法、支持小样本学习的草图符号识别方法、列表结构理解方法、手绘概念图的结构理解方法和手写公式理解方法。面向在线草图理解的交互技术包括结构化编辑技术和多通道交互技术。另外,系统包含一个用于操纵笔迹的笔手势集合。
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移动计算是当今主流的计算模式之一,以MID、UMPC、Tablet PC、PDA为代表的移动设备为移动计算的实现提供了可行性。在办公软件领域,随着用户需求的多样化发展,办公软件的非结构化、自由化输入是未来发展的趋势,以鼠标、键盘为主的传统办公软件已不能适应移动设备的需求。 思维是人接受信息、存贮信息、加工信息以及输出信息的活动过程。知识工作者是思维最为活跃的人群,是开发和使用知识的人。笔记是思维重要的呈现方式,笔记采集是知识工作者主要的活动之一。笔记采集正朝着个性化、智能化的方向发展,传统的办公软件已不能适应笔记采集的需求,以笔记采集为主要内容的移动办公软件将是办公软件发展的方向之一。 为适应笔记采集的移动性、自由性特点,本文设计和开发了面向知识工作者的笔记采集工具。本文的主要工作如下: 1. 笔记采集工具的需求分析 通过分析知识工作者的代表人群(老师和学生)在特定场景下的手写材料,总结得到笔记采集工具的功能需求。笔记采集工具需要支持笔迹的输入、笔迹结构的高级理解(如概念图理解等)以及一些特定领域下的功能(如动态几何作图等)。 2. 笔记采集工具的系统设计 依据PIBG界面范式,设计了笔记采集工具。具体地,通过剖析笔迹信息处理的层次关系,设计出笔迹处理解析机制;按照功能将系统划分为四个模块:笔迹采集、笔迹编辑、笔迹理解和笔迹管理;设计出包含交互层、任务层、算法层和数据层的软件体系结构。 3. 笔记采集工具的主要算法和特色功能 笔记采集工具的个性化和自由化需要各种高级功能(如概念图理解、动态几何)的支持。工具中采用的算法包括$1模板匹配算法、数学公式理解、概念图结构理解、笔迹搜索以及几何约束求解相关的算法。工具设计了一套笔手势,并为手势交互提供了有效的可视化反馈。 4. 笔记采集工具的实现与应用实例 实现了笔记采集原型工具,并给出一个学生使用该工具进行学习的实例。该工具的主要功能包括笔手势交互、动态几何、手写数学公式输入、概念图结构化编辑、笔迹搜索等。
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在PDA平板培养条件下,研究了镉、铅及其复合污染对田头菇菌丝体生长的影响以及田头菇菌丝体对生长基质中镉、铅的生物富集作用。结果表明,在试验设置质量浓度范围内,菌丝生长势、菌落直径和菌丝体干质量等均随着重金属质量浓度的增大而减弱(小)或降低。田头菇菌丝体对Cd、Pb均具有生物富集作用,并且随着重金属质量浓度的增大菌丝体中重金属质量分数逐渐增大,初步认为Cd、Pb复合污染促进了菌丝体对Pb的吸收而抑制了对Cd的吸收。
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Methacrylic acid based inverse opal hydrogels (MIOHs) have been prepared by controlling the synthesis conditions, including cross-linker content, solvent content, and water content in solvent mixtures to explore the effect of the synthesis conditions (especially solvent content and mixture) on the response performance. Various response events (pH, solvent, ionic strength, 1,4-phenylenediamine dihydrochloride (PDA) response) have been investigated. For pH, solvent response, the same response behaviors have been observed: both the increased solvent (only ethanol) content and the enhanced water content in solvent will lead to the reduced response level of MIOHs compared to that of the increased cross-linker content. However, two different kinds of response behaviors for ionic strength response have been found by adjusting the synthesis conditions. The kinetics of pH response shows characteristics of a diffusion-limited process, and the equilibrium response time is about 20 min, which cannot be reduced by changing the synthesis conditions.
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By incorporating bio-specific receptors, such as p-10,12-pentacosadiyne-1-N-(3,6,9-trioxaundecylamide)-alpha-D-mannopyranoside (MPDA), into 10,12-pentacosadiyonic acid (PDA) monolayer, the MPDA/PDA monolayer underwent affinochromatic transition in response to the bacteria binding to the receptor. Here, we described a new method to study the membrane/macromolececular interaction between Escherichia coli (E coli) and mannose and its relative affinochromism by modifying MPDA/PDA with CdS nano-crystallites (MPDA/PDA-CdS). CdS not only triggered the strong tropism of the bacteria but also reduced the rigidity of the MPDA/PDA backbone, resulting in the enhanced affinochromism. This discovery might be of significance in basic biophysical studies of membrane/macromolececular and designing novel biosensor.
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2-(4-Aminophenyl)-5-aminopyrimidine (4) is synthesized via a condensation reaction of vinamidium salts and amidine chloride salts, followed by hydrazine palladium catalyzed reduction. A series of novel homo- and copolyimides containing pyrimidine unit are prepared from the diamine and 1,4-phenylenediamine (PDA) with pyromellitic dianhydride (PMDA) or 3,3',4,4'-biphenyl tertracarboxylic dianhydride (BPDA) via a conventional two-step thermal imidization method. The poly(amic acid) precursors had inherent viscosities of 0.97-4.38 dL/g (c = 0.5 g/dL, in DMAc, 30 degrees C) and all of them could be cast and thermally converted into flexible and tough polyimide films. All of the polyimides showed excellent thermal stability and mechanical properties. The glass transition temperatures of the resulting polyimides are in the range of 307-434 degrees C and the 10% weight loss temperature is in the range of 556-609 degrees C under air. The polyimide films possess strength at break in the range of 185-271 MPa, elongations at break in the range of 6.8-51%, and tensile modulus in the range of 3.5-6.46 GPa. The polymer films are insoluble in common organic solvents, exhibiting high chemical resistance.