一株海洋红法夫酵母Phaffia rhodozyma RP-306产虾青素的发酵条件优化

为提高海洋红法夫酵母Phaffia rhodozyma RP-306的虾青素产量,本研究利用单因素和响应面实验对其发酵条件进行了优化。首先用单因素实验确定了蔗糖、酵母粉、硫酸铵、pH、温度和装液量6个因素的初始值,再利用Plackett-Burman实验筛选出了影响较大的3个因素:蔗糖、pH、温度,并采用最陡爬坡实验确定了因素的合理范围,最后采用响应面法中的中心组合设计进行优化,其优化发酵条件为:蔗糖29.93 g/L,酵母粉2.0 g/L,硫酸铵5.0 g/L,pH 5.27,温度19.9℃。在此条件下虾青素产量从13.46 mg/L提高到17.04 mg/L,比优化前提高了26.61%。以优化后发酵条件进行分批发酵,虾青素产量达到28.86 mg/L,为进一步发酵放大研究奠定了良好基础。     

Improving the Analyses and Forecasts of a Tropical Squall Line Using Upper Tropospheric Infrared Satellite Observations

The advent of modern geostationary satellite infrared radiance observations has noticeably improved numerical weather forecasts and analyses.However,compared to midlatitude weather systems and tropical cyclones,research into using infrared radiance observations for numerically predicting and analyzing tropical mesoscale convective systems remain mostly fallow.Since tropical mesoscale convective systems play a crucial role in regional and global weather,this deficit should be addressed.This study is the first of its kind to examine the potential impacts of assimilating all-sky upper tropospheric infrared radiance observations on the prediction of a tropical squall line.Even though these all-sky infrared radiance observations are not directly affected by lower-tropospheric winds,the high-frequency assimilation of these all-sky infrared radiance observations improved the analyses of the tropical squall line’s outflow position.Aside from that,the assimilation of all-sky infrared radiance observations improved the analyses and prediction of the squall line’s cloud field.Finally,reducing the frequency of assimilating these all-sky infrared radiance observations weakened these improvements to the analyzed outflow position,as well as the analyses and predictions of cloud fields.     

香港九龙大坑东地下蓄水方案数值研究

香港九龙大坑东地下蓄水方案(Tai Hang Tung Storage Scheme-THTSS)是香港西九龙渠道改善二期计划的一个重要组成部分,其目标是解决香港九龙繁华拥挤、人口稠密的商业中心旺角一带的洪水淹没问题。THTSS即是在经常洪水淹没区域(大坑东和界限街水渠交接处)上游足球场下面建立一个100 000 m3的地下蓄水池。本文建立了一个能处理明渠缓流和急流、封闭管道有压流、侧流堰和渠道汇合处过渡流于一体的一维水力数学模型,用1:22正态物理模型恒定流下的结果进行验证。数值模型计算了在50年一遇暴雨下,非恒定洪水在不同的侧流堰方案下的流动过程。结合物理模型试验结果,选择最佳的地下蓄水方案。计算结果表明,大坑东地下蓄水方案确实能加强旺角地区地洪水控制能力,并能通过50年一遇暴雨的洪水。     

在EBEX-2000实验资料中的湍流宏观量特征

采用2000年8月在美国加州棉花地两个高度上应用超声三分量仪、快速响应温度和湿度仪进行的EBEX-2000 (International Energy Balance Experiment, 2000) 风速三分量、温度和湿度湍流实验观测数据, 计算分析了湍流宏观量(即 u*, T*, σu/u*, σv/u*, σw/u*和σT/T*等), 湍流动能和感热通量等的特征, 并与其他湍流实验得到的结果进行了比较.     

水下运载器系统快速开盖运动学研究

水下运载器根据其使命,通常内部装载不同战斗载荷,其中上浮开盖过程是其作战流程中非常关键的一个动作过程,水下运载器在其工作过程中受到波浪力、火箭推力、重力、流体阻力等外界因素的影响,而开盖动作又使得水下运载器系统构件之间产生相对运动,其运动特性较为复杂。针对水下运载器系统,利用多刚体Kane方法建立了系统的动力学方程,利用混合坐标系法描述刚体之间的位置关系,计算了不同工况下水下运载器系统开盖过程的运动响应,分析了影响开盖动作的因素。研究表明：增大推冲力或者增加推冲器作用行程都能明显缩短开盖时间,开盖动作对运载器壳体的运动影响较小,可以忽略;头盖重心位置越高,头盖翻转过程达到角速度拐点的时间会越短,对开盖越有利;运载器初始倾斜角与头盖转动方向一致时,能较为明显缩短开盖时间;运载器初始倾斜角对推冲器作用效果的影响较小。     

两种微藻凝集素对几种不同类型细胞的凝集作用

经离子交换和分子筛层析从紫球藻（Porphyridium cruentum）和海水小球藻（Chlorella sp．）中分离纯化得到2种凝集素,研究它们对几种不同类型细胞即动物和人血红细胞、海洋和淡水微藻、细菌和真菌的凝集活性。研究结果表明,2种微藻凝集素对它们当中一些类型的细胞或种类具有不同程度的凝集活性,其中对水生聚胞藻（Synechocystis aquetilis）的凝集活性最强,最低质量浓度只需0．0313g／L。     

Impacts of Urbanization on the Precipitation Characteristics in Guangdong Province,China

With the development of urbanization, whether precipitation characteristics in Guangdong Province, China, from 1981 to 2015 have changed are investigated using rain gauge data from 76 stations. These characteristics include annual precipitation, rainfall frequency, intense rainfall(defined as hourly precipitation ≥ 20 mm), light precipitation(defined as hourly precipitation ≤ 2.5 mm), and extreme rainfall(defined as hourly rainfall exceeding the 99.9 th percentile of the hourly rainfall distribu...     

辽河口沉积物反硝化细菌数量及多样性的研究

对辽河口沉积物中反硝化细菌的数量、多样性以及群落结构进行了研究.采用MPN-Griess分析了春夏秋三季的反硝化细菌数量,结果表明其数量春季最多,秋季次之,夏季最低,且从辽河下游及河口向远海区域逐渐降低.采用PCR-RFLP对反硝化细菌的亚硝酸盐还原酶基因(nirS)进行分析,发现沉积物中的反硝化细菌类型较新,大多数细...     

Metallogenic series and regularity of skarn-type deposits in Huaibei area of Anhui Province

Huaibei area is an important iron-copper metallogenic area in northern Anhui Province. In order to summarize the metallogenic series and regularity of skarn-type deposits systematically in this area, based on recent prospecting results and the diagenesis and metallogenic chronology, the authors systematically investigated the geological characteristics and metallogenic conditions of the known deposits and divided thern into three metallogenic series. They are skarn-type iron-copper-gold metallogenic series related to high-K calc-alkali intrusive rocks, skarn-type iron-gypsum metallogenic series related to high-K calc-alkaline intrusive rocks and skarn-type iron-light rare earth metallogenic series related to monzogranite. Then the geological characteristics and metallogenic regularity of four typical deposits were discussed respectively. The results show that the deposit formation can be divided into two stages in this area, and the metallogenic space is controlled by deep faults, arc structures and magmatic belts. Finally, the regional metallogenic models of Qianchang type, Yangqiaozi type and Wangchang type iron polymetallic deposits in the early stage of Early Cretaceous and Qiganlou type iron-light rare earth deposits in the late stage of Early Cretaceous were established.