摘要：Objective] This study was conducted to optimize cameI ia seed sheI fer-mentation conditions for ceI uIase production by Trichoderma koningi using response surface methodoIogy. [Method] Fermentation conditions for ceI uIase production from Trichoderma koningi were optimized with response surface method （rSM） by taking carboxymethyI ceI uIase （CMCase） activity as a response indicator. Three factors that affecting CMCase activity were screened out using singIe factor test among pretreatment methods of raw material, nitrogen sources, initial pH values, inocuIum voIume, fermentation time and voIume of Iiquid medium, they were fermentation time, initial pH value, and voIume of Iiquid medium. The optimum conditions of fer-mentation and interaction of the three factors were determined through Box-Behnken design and regression analysis using design-Expert software. [result] Pretreatment of cameI ia seed sheI with alkaline was most conducive to CMCase production. The use of 0.2% （NH4）2SO4 as nitrogen source, inocuIum size of 5%, initial pH value of 5.8 and voIume of Iiquid medium at 22 mI were the best fermentation conditions for maximizing CMCase production by T. koningi from cameI ia seed sheI . Under these conditions, 179.15 U/mI of CMCase was obtalned after 5 d of fermentation, which was improved by 24.52% compared with the maximum CMCase activity of singIe factor test. [Conclusion] The resuIts wiI provide some references for use of cameI ia seed sheI and ceI uIase production.

摘要：rendering of large-scale forest scenes is a challenging task, whose highly geometric complexity will put heavy burden on current graphics hardware. When navigating the scene, the overall visual result is generally considered as the core concern. A new method is proposed in this paper for large-scale forest rendering using clustering and merging strategies. Our method improves the rendering effect by clustering polygons according to the point information with relation to neighbours. A fast forest rendering system is developed accordingly. The relative techniques in the system can improve the visual quality on demand of different applications.

摘要：The definition of generalized product of fractal is first put forward for the research on the relations between original fractal and its product of fractal when the transformations of iteration function system （IFS） are incomplete. Then the representations of generalized product of IFS are discussed based on the theory of the product of fractal. Furthermore, the dimensional relations between the product of fractal and its semi-product are obtained. The dimensional relations of self-similar set are discussed. Finally, the examples for rendering fractal graphs are given. These results posses potentials in image compression and pattern recognition.

摘要：In order to compare the sensitivity of short-range ensemble forecasts to different land-surface parameters in the South china region,three perturbation experiments related to the land surface model(LSM),initial soil moisture(ISM),and land–atmosphere coupling coefficient(LCC)were designed,and another control experiment driven by the Global Ensemble Forecast System(GEFS)was also *** ensemble members were initiated at 0000 UTC each day,and integrated for 24 h for a total of 40 days from the period 1 April to 10 May 2019 based on the Weather research and Forecasting *** results showed that the perturbation experiment of the LSM(LSMPE)had the largest ensemble spread,as well as the lowest ensemble-mean root-mean-square error among the three sets of land-surface perturbed experiments,which indicated that it could represent more uncertainty and less *** ensemble spread of the perturbation experiment of the ISM(ISMPE)was generally less than that of LSMPE but greater than that of LCCPE(the perturbation experiment of the LCC).In particular,although the perturbation of the LCC could not produce greater spread,it had an effective influence on the intensity of ***,the ensemble spread of all the land-surface perturbed experiments was smaller than that of GEFSPE(the control experiment).Therefore,in future,land-surface perturbations and atmospheric perturbations should be combined in the design of ensemble forecasting systems to make the model represent more uncertainties.

摘要：A mid-infrared carbon dioxide(CO_2) sensor is presented for the application in greenhouse environment. An integrated multi-pass gas chamber and a dual-channel differential detection method are adopted to decrease response time and suppress environmental influence, respectively. An optical module is developed using a cost-effective wideband mid-infrared light source, a dual-channel pyre electrical detector and a spherical mirror, and the moisture-proof function is specially designed for enabling the application of this sensor in greenhouse with high humidity. Experiments are carried out to evaluate the sensing performance on CO_2 concentration. According to the experimental results, the limit of detection(Lo d) is about 3×10^(-5) with an absorption length of 30 cm. The relative detection error is less than 5% within the measurement range of 3×10^(-5)—5×10^(-3). Based on 10 h long-term stability measurement on 5×10^(-4) and 2×10^(-3) standard CO_2 samples, the maximum fluctuations are 1.08% and 3.6%, respectively. By using a 2.4 GHz wireless network communication system for remote monitoring and data recording, a field measurement of this sensor in a greenhouse is conducted, and good performance is proven in such circumstance.

摘要：利用石墨烯作为新型的阻挡层,设计并制备出具有核壳结构的石墨烯包覆多孔炭/硫复合材料,抑制锂硫电池中的"穿梭效应",以提高正极材料的循环性能。该结构利用多孔炭材料作为储存硫的载体,而石墨烯作为阻挡层可以限制充放电过程中形成的多硫化物向体相电解液中的扩散,从而实现对正极材料的容量和循环性能的提高。此外,提出一种简便的组装方法来实现石墨烯在多孔炭/硫复合材料表面的包覆。利用氧化石墨烯在液相还原过程中官能团的去除来降低亲水性,从而使其自发地包覆在不亲水的多孔炭/硫复合材料表面,形成石墨烯包覆的核壳结构。

摘要：Height extraction for buildings is a fundamental step of 3d scene reconstruction in many virtual reality applications. In this paper, we propose an automatic method to extract the height of buildings in high resolution satellite imagery based on the length of shadow. Taking into account the limitation of traditional algorithms, we make use of the boundary information of a building to facilitate detecting and matching the shadow regions with higher accuracy. Then, we introduce a shadow-cast model to correct the shadow location in our system. The experimental result shows that when extracting the height of buildings from complex urban regions, our method has better accuracy.

摘要：介绍利用计算机软件进行适宜银川气候的建筑设计方法,以图表的形式分析当地的气候数据并明确得到适应银川气候特点的建筑设计策略.气候分析图和被动设计策略对建筑师在草图设计阶段具有指导意义.

摘要：针对油水分离轴向柱塞水液压泵,建立其润滑油腔内各主要运动部件的热力学方程。根据热力学分析的基本理论,创建润滑油腔系统的热平衡方程,并用Matlab软件对其进行数值仿真。根据仿真结果得到润滑油腔内油液的平衡温度,从而分析润滑油腔内的油液粘度变化情况以及润滑油腔内摩擦副的工作状况。研究结果对油水分离水液压泵的设计以及润滑油腔内润滑油的选择具有一定的指导意义和参考价值。

摘要：展示广告是网络广告的重要组成部分。在展示广告投放前对其点击情况进行预测不仅能够减少广告投放的成本也能够提高互联网公司的资源利用效率从而增加收入。随着大数据以及机器学习技术不断成熟,越来越多的公司采用相关技术预测广告点击率。本文从特征重要性以及模型适合性两个方面研究展示广告点击率预测问题。首先,文章通过对比广告特征、用户及上下文特征、媒体特征三大类特征发现广告特征对于广告点击率预测问题最为重要,同时加入媒体特征以及用户上下文特征也能够提升模型效果。其次,本文对比研究了常用于广告点击率预估的机器模型优劣,主要从模型性能以及模型耗时两个维度进行比较。本文发现逻辑回归模型、随机森林模型、梯度提升决策树模型是最适合解决广告点击率预测问题的机器学习模型。