羊草根茎顶芽分生组织分化的动态研究

羊草以无性繁殖为主,抽穗率低,而抽穗率的多少实质上是花芽分化的数量和质量问题。本研究对羊草根茎顶芽采用石蜡切片法的研究结果表明,在整个生长季的根茎顶芽中,营养芽和花芽均存在,但春秋2季是花芽分化和发育的高峰;而秋季分化和发育花芽的早晚和多少,是限制羊草种群抽穗整齐度和抽穗率的重要因素。本研究首次报道了羊草根茎分生组织分化的动态以及花芽分化的时间和所占比例。

引入动态分化和邻域诱导机制的双蚁群优化算法

为提高传统蚁群算法在解决旅行商问题时的优化效果,提出了一种引入动态分化和邻域诱导机制的双蚁群优化算法。该算法首先引入混沌随机策略,在算法初始化阶段改变原始的贪心策略,使初始信息素混沌分布,以保持种群的多样性,从而提高解的精度;其次,将蚁群分为孤立蚁群与正常蚁群,两组蚂蚁分别在当前最优路径与离群路径附近搜索;在种群间采取诱导机制,正常蚁负责搜索最优路径,孤立蚁混沌随机释放信息素,将正常蚁群诱导至新的路径邻域,从而有效地平衡收敛速度与解的多样性之间的矛盾。通过对不同规模的旅行商问题仿真结果的比较,验证了所提算法的有效性。

家畜分化生长模型的研究

系统探讨了家畜分化生长模型的理论、参数生物学意义及参数估计问题。

单细胞转录组学细胞动态分化数据模拟算法的比较与评估

对9种单细胞转录组学(single cell RNA sequencing,scRNA-seq)细胞动态分化数据模拟算法进行系统性地比较和评估,为算法的开发者和用户提供可靠的参考和帮助。利用多种评价指标对上述算法在准确性、可拓展性、适用性等3个方面进行全面评估,并对运行时间和内存消耗情况进行建模预测。结果显示:9种被评估的算法均不能在数据特征与拓扑结构这2个方面同时有完美的表现;算法Dyngen虽然能模拟与参考数据拓扑结构和细胞分化轨迹相似度较高的数据,但是它的运行时间较长且内存消耗过大;将近一半的算法还需要及时更新版本信息并维护相关功能。用户在使用scRNA-seq细胞动态分化数据模拟算法时应综合考虑不同的使用场景和特点来选择最适合的模拟算法。

Customized Optimization for Vehicle Acoustic Statistical Energy Analysis

Statistical Energy Analysis(SEA) is one of the conventional tools for predicting vehicle high-frequency acoustic responses.This study proposes a new method that can provide customized optimization solutions to meet NVH targets based on the specific needs of different project teams during the initial project stages.This approach innovatively integrates dynamic optimization,Radial Basis Function(RBF),and Fuzzy Design Variables Genetic Algorithm(FDVGA) into the optimization process of Statistical Energy Analysis(SEA),and also takes vehicle sheet metal into account in the optimization of sound packages.In the implementation process,a correlation model is established through Python scripts to link material density with acoustic parameters,weight,and cost.By combining Optimus and VaOne software,an optimization design workflow is constructed and the optimization design process is successfully executed.Under various constraints related to acoustic performance,weight and cost,a globally optimal design is achieved.This technology has been effectively applied in the field of Battery Electric Vehicle(BEV).

统筹城乡发展策略下基于生计风险诊断的农户后顾生计来源识别——以重庆市沙坪坝区中梁镇龙泉村为例

农户后顾生计是改善民生的重要保障,研究其来源不仅可以厘清不同类型农户未来生计发展方向,且能为制定相应的支农惠农政策提供理论参考.研究运用主成分法与改进BP神经网络相结合,通过参与式农户调查建立农户属性数据库作为本研究的数据源,基于农户生计资产量动态划分农户,诊断其生计风险,从而识别不同类型农户的后顾生计来源.结果显示:(1)不同类型农户由于生计状况的差异导致其面临的风险各异,农业多样化发展型农户以自然风险和家庭风险为主,农业专业化发展型农户主要为市场风险,非农多样化和非农专业化发展型农户主要为市场风险及体制风险,兼业化发展型农户兼具各种风险;(2)不同类型农户生计风险程度差异明显,其大小顺序为:农业专业化发展型(0.92),农业多样化发展型(0.71),兼业化发展型(0.65),非农专业化发展型(0.55)和非农多样化发展型(0.46);(3)出于最大限度规避风险的心理思考及适应政策的需要,不同类型的农户后顾生计来源组合差异明显.

Rocky Desertification Dynamic Analysis and the Development of Management Information System

With the background of severe rocky desertification in the west of China and the ohjective of ecological environment construction and poverty elimination, the management information system of rocky desertification was designed according to the natural and humane characteristics in Nanchuan of Sichuan Province. The system was composed of data management module, information query module for rocky desertification, spatial analysis module and dynamic monitoring module.

Simulation Study on the Alkalized-salinized Grassland Ecosystem in the Songnen Plain

Using Object-oriented design and a new programming language JAVA, a physically-based model was built to simulate the hydrological, alkalization/de-alkalization and salinization/desalinization processes in soil. Furthermore, a process-based model was built to evaluate the dynamics of four herbaceous ecosystems (including dynamics of above-ground biomass, below-ground biomass, and litter biomass), each dominated by Aneurolepidium chinense (Trin.) Kitag., Chloris virgata Sw., Puccinellia tenuiflora (Turcz.) Scribn. et Merr. and Suaeda glauca Bunge. This model is a daily-time step model, suitable for simulating hydrological, alkalization/de-alkalization and salinization/desalinization processes of heterogeneous soil, and growth dynamics of different grassland communities. With climatic data and experimental data of Changling Experimental Site in Jilin Province, the soil moisture content (in 1991, 1996, 1997 and 1998), soil salt concentration, exchangeable cation percentage and pH in soil and growth dynamics of these four sorts of grassland communities (in 1991) were simulated and the results were verified to be in accord with observed data.

Comprehensive Pattern of Primordium Initiation in Shoot Apex of Wheat

The time course of the initiation of different types of apical primordia on the stem of wheat (Triticum aestivum L.) was investigated to establish a comprehensive pattern of apical primordium development and quantitative dynamic relationships among different primordium initiation. The results showed that the initiation of leaf and bracteal primordia took the S shape, and that of spikelet and floret took the rise stage of parabolic shape in relation to GDD (growing degree days after sowing) in wheat. The bracteal was much like vegetative rather than reproductive organ in terms of the dynamic pattern of primordium initiation. The progress of spikelet and floret primordium initiation could well reflect the characteristics of different genotypes and the impact of different ecological environments on wheat apical development. The integrated model of different primordium initiation in shoot of wheat was an S_shaped curvilinear, and could be divided into three sub_models. The number of leaf primordia was affected by both genotype and environment, while the numbers of bracteal, spikelet and floret primordia were affected mainly by environmental factors. Measured with mean thermochron, the rates of initiation of leaf, bracteal and spikelet primordia in normal planting were the highest among all the sowing date treatments. In contrast to the relationships among leaf, bracteal, spikelet and their initiation duration, the correlation between the number of floret and its initiation duration was highly significant.

Static and dynamic collaborative optimization of ship hull structure

The goal of this effort was to provide a static and dynamic collaborative optimization （CO） model for the design of ship hull structure. The CO model integrated with static, mode and dynamic analyses. In the system-level optimization model, a new objective function was advised, integrating all the subsystem-levels＇ objective functions, so as to eliminate the effects of dimensions and magnitude order. The proposed CO architecture enabled multi-objectives of the system and subsystem-level to be considered at both levels during optimization. A bi-level optimization strategy was advised, using the multi-island genetic algorithm. The proposed model was demonstrated with a deck optimization problem of container ship stern. The analysis progress and results of example show that the CO strategy is not only feasible and reliable, but also well suited for use in actual optimization problems of ship design.

A Novel CMOSDual-Modulus Prescaler Based on New Optimized Structure and Dynamic Circuit Technique

s:A divide- by- 12 8/ 12 9or6 4/ 6 5 dual- modulus prescaler based on new optimized structure and dynam ic circuit technique im plem ented in 0 .2 5 μm CMOS digital technology is described.New optimized structure reduces the propagation delay and has higher operating speed.Based on this structure,an im proved D- flip- flop(DFF) using dynam ic circuit technique is proposed.A prototype is fabricated and the measured results show that this prescaler works well in gigahertz frequency range and consumes only35 m W(including three power- hungry output buffers) when the input frequency is2 .5 GHz and the power supply voltage is2 .5 V.Due to its excellent perform ance,the prescaler could be applied to many RF system s.

Dynamic Analysis on Organic Matter and Nitrogen Pollution of Dongchang Lake

The aim was to explore dynamic changes of organic matter and nitrogen pol ution in Dongchang Lake. [Method] Monitoring data, including BOD5, CODCr, NH3-N and TN, of Dongchang Lake were chosen for analysis during 2002-2011. [Result] Water quality of the six lake districts showed deteriorating in monitor-ing period, and TN was the dominant pol ution factor; BOD5/CODCr ratio was low, suggesting biodegradability of organic pol utant in the lake was lower. NH3/TN ratio was higher, indicating NH3-N was a major factor causing nitrogen exceeding in 2010. In addition, correlations between BOD5 and CODCr and between NH3-N and TN in the lake districts maintained at a significant level. [Conclusion] The research provides references for improving water in Dongchang Lake.

Effect of Combined Application of Manure and Chemical Fertilizer on the Dynamic Changes of Purple Soil Nutrient and Soil Enzyme Activities

[Objective] The aim was to study the effects of combined of manure and fertilizer on the content of nutrients in purplish soil as well as release dynamics of enzyme activities.[Method] The effects of manure and fertilizer application on the content of AOM,NH＋4-N and NO-3-N in soil as well as release dynamics of enzyme activities were studied by means of simulation culturing.[Result] In the treatments of combined application of simulation culture experiment,the content of active organic matters,NH＋4-N,NO-3-N and soil enzyme activities changed dynamically,which showed a shape of inverted ＂S＂ with two or more peaks.Compared with the treatment of fertilization,their peaks were relatively flat and occurred relatively late,while the treatment of fertilization had only one but the highest peak.The content of active organic matter came to top around 10 d in the order of cow5fertilizer5pig5fertilizer5cow manurepig manurefertilizer Ⅰfertilizer Ⅱ;the activity of urease came to top around 10 d in all treatments and in the order of pig manurecow5fertilizer5cow manurefertilizer Ⅰfertilizer Ⅱpig5fertilizer5.The activity of saccharase was in the order of pig5fertilizer5pig manurecow5fertilizer5cow manureCKfertilizer Ⅱfertilizer Ⅰ.[Conclusion] The study could provide the theoretical basis for reasonable application of manure and fertilizer.

Efficient Coherent Population Transfer of D2 Molecules by Stark-induced Adiabatic Raman Passage

Preparation of a high flux of hydrogen molecules in a specific vibrationally excited state is the major prerequisite and challenge in scattering experiments that use vibrationally excited hydrogen molecules as the target. The widely used scheme of stimulated Raman pumping suffers from coherent population return which severely limits the excitation efficiency. Re- cently we successfully transferred D2 molecules in the molecular beam from （v=0, J=0） to （v=1, J=0） level, with the scheme of Stark-induced adiabatic Raman passage. As high as 75% of the excitation efficiency was achieved. This excitation technique promise to be a unique tool for crossed beam and beam-surface scattering experiments which aim to reveal the role of vibrational excitation of hydrogen molecules in the chemical reaction.

Damping of Magnetorheological Elastomers

The damping property of magnetorheological （MR） elastomers is characterized by a modified dynamic mechanical-magnetic coupled analyzer. The influences of the external magnetic flux density, damping of the matrix, content of iron particles, dynamic strain, and driving frequency on the damping properties of MR elastomers were investigated experimentally. The experimental results indicate that the damping properties of MR elastomers greatly depend on the interfacial slipping between the inner particles and the matrix. Different from general composite materials, the interracial slipping in MR elastomers is affected by the external applied magnetic field.

The Influence of Seasonal Snow on Soil Thermal and Water Dynamics under Different Vegetation Covers in a Permafrost Region

Seasonal snow is one of the most important influences on the development and distribution of permafrost and the hydrothermal regime in surface soil. Alpine meadow, which constitutes the main land type in permafrost regions of the Qinghai-Tibet Plateau, was selected to study the influence of seasonal snow on the temperature and moisture in active soil layers under different vegetation coverage. Monitoring sites for soil moisture and temperature were constructed to observe the hydrothermal processes in active soil layers under different vegetation cover with seasonal snow cover variation for three years from 2010 to 2012. Differences in soil temperature and moisture in areas of diverse vegetation coverage with varying levels of snow cover were analyzed using active soil layer water and temperature indices. The results indicated that snow cover greatly influenced the hydrothermal dynamics of the active soil layer in alpine meadows. In the snow manipulation experiment with a snow depth greater than 15 cm, the snow cover postponed both the freeze-fall and thawrise onset times of soil temperature and moisture in alpine LC(lower vegetation coverage) meadows and of soil moisture in alpine HC(higher vegetation coverage) meadows; however, the opposite response occurred for soil temperatures of alpine HC meadows,where the entire melting period was extended by advancing the thaw-rise and delaying the freeze-fall onset time of the soil temperature. Snow cover resulted in a decreased amplitude and rate of variation in soil temperature, for both alpine HC meadows and alpine LC meadows, whereas the distinct influence of snow cover on the amplitude and rate of soil moisture variation occurred at different soil layers with different vegetation coverages. Snow cover increased the soil moisture of alpine grasslands during thawing periods. The results confirmed that the annual hydrothermal dynamics of active layers in permafrost were subject to the synergistic actions of both snow cover and vegetation coverage.

Molecular Dynamics Simulations for Melting Temperatures of SrF2 and BaF2

The shell-model molecular dynamics method was applied to simulate the melting temper- atures of SrF2 and BaF2 at elevated temperatures and high pressures. The same method was used to calculate the equations of state for SrF2 and BaF2 over the pressure range of 0.1 MPa-3 GPa and 0.1 MPa-7 GPa. Compared with previous results for equations of state, the maximum errors are 0.3% and 2.2%, respectively. Considering the pre-melting in the fluorite-type crystals, we made the necessary corrections for the simulated melting temper- atures of SrF2 and BaF2. Consequently, the melting temperatures of SrF2 and BaF2 were obtained for high pressures. The melting temperatures of SrF2 and BaF2 that were obtained by the simulation are in good agreement with available experimental data.

Harmony search algorithm with differential evolution based control parameter co-evolution and its application in chemical process dynamic optimization

A modified harmony search algorithm with co-evolutional control parameters(DEHS), applied through differential evolution optimization, is proposed. In DEHS, two control parameters, i.e., harmony memory considering rate and pitch adjusting rate, are encoded as a symbiotic individual of an original individual(i.e., harmony vector). Harmony search operators are applied to evolving the original population. DE is applied to co-evolving the symbiotic population based on feedback information from the original population. Thus, with the evolution of the original population in DEHS, the symbiotic population is dynamically and self-adaptively adjusted, and real-time optimum control parameters are obtained. The proposed DEHS algorithm has been applied to various benchmark functions and two typical dynamic optimization problems. The experimental results show that the performance of the proposed algorithm is better than that of other HS variants. Satisfactory results are obtained in the application.

Vibrational Spectra and Potential Energy Surface for Electronic Ground State of Jet-Cooled Molecule S2O

The vibration states of transition molecule S2O, including both bending and stretching vibrations, are studied in the framework of dynamical symmetry groups . We get all the vibration spectra of S2O by fitting 22 spectra data with 10 parameters. The fitting rms of the Hamiltonian is 2.12 cm-1. With the parameters and Lie algebraic theory, we give the analytical expression of the potential energy surface, which helps us to calculate the dissociation energy and force constants of S2O in the electronic ground state.

Enrichment of carbon recovery of high ash coal fines using air fluidized vibratory deck separator

Coal is primarily beneficiated by wet gravity methods. The wet processing of coal is an efficient practice. However, it introduces the moisture in the range of 6%-15%, depending upon the size of coal which is as detrimental as ash content to the heating value of coal. Dry beneficiation of coal fines was carried out using an air fluidized vibrating table in which the coal particles get separated from the heavier mineral particles as a result of horizontal and vertical stratification. Two level factorial design matrix was used to optimize and assess the interactive effects of the operational parameters of a pneumatic table viz. deck eccentric, side tilt and air flow rate on the clean coal yield and its ash content. Double stage processing was found to be more effective for reducing the ash content of the clean coal. Initial stage of processing at a higher ash level generates a reject of high ash with low combustibles. Cleaning of the rougher concentrate at 34%-35% ash level shows significant improvement in the organic efficiency （88.6%） and useful heat value of clean coal （15690 kJ/kg）. The performance of air fluidized vibrating deck was measured by Ep value which is 0.18.