海洋污损生物藤壶生长过程及附着强度研究

研究海洋污损生物藤壶(Barnacle)不同生长阶段附着强度,可为科学制定藤壶清除规范及设计相关机械设备提供依据。本文采用浸泡法在湛江调顺岛(21°31′N,110°41′E)实海中挂板,结合形貌观察藤壶生长过程,利用自行设计的剪切强度测试装置,选取网纹藤壶测试不同生长阶段剪切强度。结果表明:试板浸泡10 d,幼体藤壶开始附着;30 d试板表面藤壶覆盖面积约占30%,基底直径1~6 mm,部分藤壶死亡形成空壳;60 d试板约50%面积被藤壶覆盖,试板表面有覆膜,空壳现象加剧,藤壶基底直径最大达10 mm;90 d试板约95%面积被藤壶覆盖,出现藤壶相叠现象,基底直径1~13 mm。藤壶附着生长过程中,剪切强度变化符合“快-慢”的特点,以藤壶基底直径为变量,构建藤壶剪切强度Logistic增长模型,决定系数R2=0.99,说明模型拟合良好。利用构建的Logistic增长模型将藤壶剪切强度划分为速增期(基底直径4.0~6.4 mm),缓增期(基底直径6.4~8.7 mm)及渐停期(基底直径>8.7 mm)3个阶段。结合藤壶附着生长过程,藤壶在附着后采用机械方式清除的最佳清除时期在速增期。

External blast flow field evolution and response mechanism of single-layer reticulated dome structure

Single-layer reticulated dome structure are commonly high-profile building in the public and can be attractive targets for terrorist bombings,so the public can benefit from enhanced safety with a stronger understanding of the behavior of single-layer reticulated dome structure under explosion.This paper investigates the fluid-structure interaction process and the dynamic response performance of the singlelayer reticulated dome under external blast load.Both experimental and numerical results shown that structural deformation is remarkably delayed compared with the velocity of blast wave,which advises the dynamic response of large-span reticulated dome structure has a negligible effect on the blast wave propagation under explosion.Four failure modes are identified by comparing the plastic development of each ring and the residual spatial geometric of the structure,i.e.,minor vibration,local depression,severe damage,and overall collapse.The plastic deformation energy and the displacement potential energy of the structure are the main consumers of the blast energy.In addition,the stress performance of the vertex member and the deep plastic ratio of the whole structure can serve as qualitative indicators to distinguish different failure modes.

Broiler Feet Gelatine

The two waves period of the COVID-19 pandemic saw the use of hydro- alcoholic gel and the consumption of capsules containing improved traditional remedies. At one point, there was a stock-out and a price increase forthese products. Furthermore, in the food industry, the catering industry adopts gelatin in its current practice. Pig gelatin dominates the international market. And for some religious practices, pork is forbidden and yet these people consume them without taking notice. The production of gelatin from broiler feet seems economically viable because broiler feet are considered slaughterhouse waste that is sold at very low prices. The poultry industry has seen an increase in broiler farming over the last twenty years. However, the latter has all the characteristics required for the production of gelatin. It will therefore comply with the standards of use described in the international codex oenological for gelatins. Physical and chemical analyses such as, ash content, moisture content, and pH measurements were done for the extracted gelatins. Sensible elements are checked with ED XRF spectroscopy. All the results were good and showed without any doubt that broiler gelatin is edible.

网纹藤壶壳板矿化结构及其碳酸钙含量测定

采用X射线衍射技术,初步研究了网纹藤壶(Balanus reticulates Utinomi)壳板矿化结构特征,并采用钙黄绿素法、钙-羧酸指示剂法和铬黑T指示剂三种方法测量了来自不同海域藤壶壳板的碳酸钙含量。实验发现,网纹藤壶壳板中的矿化组织主要由方解石构成,碳酸钙微晶体排列有一定的取向,较为复杂。海口和陵水两地藤壶壳板中碳酸钙含量没有显著差异(P<0.05),最大值为93.87%,最小值90.77%。尽管三种碳酸钙含量测量法的结果没有显著性差异(P<0.05),但进一步综合分析发现钙黄绿素法测定结果最为稳定,且简单易操作,可作为首选方法。

套袋对‘8306’椪柑果实品质的影响

以‘8306’椪柑(Citrus reticulate Blanco cv.ponkan)为试材,研究套袋后不同拆袋时间对其果实品质的影响。结果表明:套袋后单果重有减少的倾向,果皮厚无变化;果皮类胡萝卜素含量、可滴定酸含量降低,糖酸比和维生素C含量增加;套袋对果实可溶性固形物含量、总糖含量、可食率、出汁率、种子数及囊瓣数均没有影响。综合来看,套袋可提高‘8306'椪柑果实品质,‘8306'椪柑适合套单层纸袋,最佳拆袋时间为采前15d。

砂糖橘精油化学组成及对指状青霉的抑菌活性

采用水蒸气蒸馏法提取砂糖橘(Citrus reticulate Blanco)果皮精油,并用GC-MS对其成分进行分析,共鉴定出17种成分,主要包括柠檬烯(77.99%)、β-月桂烯(3.74%)、β-水芹烯(2.78%)、罗勒烯(2.64%)、β-芳樟醇(2.35%)、α-蒎烯(1.60%)、正辛醇(1.54%)、癸醛(1.24%)、4-松油醇(1.10%)和4-十一烯(1.04%)等。测定不同添加量(0.16、0.31、0.63、1.25、2.50、5.00、10.00μL/mL)砂糖橘精油对指状青霉孢子萌发和菌丝体生长的作用。结果表明:低添加量(<2.5μL/mL)砂糖橘精油对指状青霉孢子萌发无影响甚至有促进作用,对指状青霉菌丝体生长有轻微的抑制;而高添加量(10μL/mL)则显著抑制孢子萌发和菌丝体生长(P<0.05)。本实验表明砂糖橘精油在防治指状青霉具有一定作用。

瓯柑果实的加工性状及综合利用方向

瓯柑（Citrus reticulate Blancocv.Citrus Blancocv.Suavissima）是我国著名的柑橘品种之一,主产于浙江温州与丽水一带。温州民间认为瓯柑有清火疏肝、和胃消食、清凉解毒的作用,素有＂端午瓯柑似羚羊＂之说。《中药大词典》、《本草拾遗》、《随息居饮食谱》等史籍均有关于瓯柑的药效介绍。清《瓯乘补》曾载：＂人之珍瓯柑者,以其能辟煤毒……遇柑稀少,虽颗值二三百钱,必皆求之＂。1962年以来,温州特产部门分别与华中农业大学、上海医工院等单位协作,从瓯柑的药用历史、药用物质成分、药理作用、临床疗效等多方面进行了研究。

孔雀鱼(Poecilia Reticulata)的生态

广泛分布在特立尼达自然水体中的孔雀鱼,因捕食压力形成不同的鱼类群落,这些群落通常离散分布,彼此间被瀑布隔离。一般下游是捕食压力高的群落,上游是捕食压力低的群落。这种分布模式在很多河流中都存在。在每一条河流中,孔雀鱼种群都存在生活史、行为、形态学和生理学的差异。在低捕食压力群落中对生活史、行为、形态学和生理学的选择因素是高种群密度及其相关因素。

氟对孔雀鱼的急性毒性及安全浓度评价

为检测氟对鱼类的生态毒性效应,采用静态生物毒性试验方法研究了氟离子对孔雀鱼(Poecilia reticulate)幼鱼的急性毒性效应,记录其中毒症状及24 h,48 h,72 h和96 h死亡数,并进行统计分析。结果表明:氟暴露条件下孔雀鱼幼鱼出现焦躁不安、失去平衡、呼吸减弱等中毒症状,且随着氟暴露浓度的增加和暴露时间的延长,死亡率逐渐增加,存在明显的剂量效应和时间效应关系;氟对孔雀鱼幼鱼24 h、48 h、72 h、96 h的LC50分别为397.38、231.36、207.73、200.24 mg/L,氟对孔雀鱼幼鱼的安全质量浓度为2.002 4 mg/L,说明氟离子对孔雀鱼幼鱼为低毒性。该值低于我国部分高氟地区地下水、地表水及人为氟污染水体中的氟离子浓度。

Environmental change since mid-Pleistocene recorded in Shangshan achaeological site of Zhejiang

At about 173 ka BP of the late period of mid-Pleistocene, the second terrace of the river had been formed as a result of uplift happening in Shangshan area because of the climate, sea level change and tectonic action. Between 173-75 ka BP, aeolian deposited on the terrace, a layer of reticulate red clayey soil about 80-100 cm thick deposited and developed under the warmer and higher temperature. In the last glacial period, the drop of the temperature and the decrease of the precipitation induced the dust-storms increased, A layer of Xiashu loess about 1.0-1.5 m thick accumulated on Shangshan terrace in the last glacial, which has the reticulate red clayey soil buried. At the beginning of the Holocene （11500 a BP-）, temperature went higher gradually and precipitation got more, the pre-persons moved on the Shangshan terrace （11,400-8600 a BP）, which is one of the most important archaeological sites, and can connect the paleolithic culture with Neolithic culture. It could be assumed from the results that the lower reaches of the Yangtze River are the home of rice cultivation, too. The lower place to the west of the Shangshan site experienced the two cycles process of the fluvial facies and the lacustrine facies, indicating that the water source of the pre-historical Shangshan is the river water or lake water. Two AMS 14C age proved the water source disappeared more than 1000 years ago.

Influential Factors on Electromagnetic Properties of Selected 3D Reticulated Ceramics

3D reticulated ceramics (3DRCs) with the composition containing SrFe12O19-SiC-TiO2 were prepared by a replication process with polyurethane sponges as the template in ceramic slurry. The electrical conductivity, dielectric and magnetic parameters of 3D reticulated ceramics (3DRCs) were measured with changes in cell size of the sponges, contents in the slurry and sintering temperature in this paper. Discussions about the influential factors of those parameters were focused on their electrical conductivity. The experimental results indicated that the electrical conductivity of 3DRCs raised with the increase of cell size, SiC/SrO 6Fe2O3 with weight ratio and sintering temperature. X-ray diffractions and SEM were used to investigate the relationship between electrical conductivity and sintering temperature. Deoxidizing reactions of SrO 6Fe2O3 caused the increasing electrical conductivity. The real part of permittivity (ε') and imaginary part of permeability (μ') raised with the increase of electrical conductivity (σ). The imaginary part of permittivity (ε') has a maximum at 10o S/cm with the increase of a, and the real part of permeability (μ') changes slightly with the increase of a. When a is at the range of 10-4 S/cm to 10o S/cm (a semi conductive state), both the imagine part of permittivity and permeability raises with increasing a, therefore, the 3DRCs present their high electromagnetic loss properties.

Optimal topology design of replaceable bar dampers of a reticulated shell based on sensitivity analysis

In this study,a method for control of reticulated shells is proposed and its practicality is demonstrated.The control is implemented by replacing selected bars of the shell with passive viscoelastic dampers.By applying the eigenvalue perturbation technique and the earthquake spectrum concept,the sensitivities of various topologies of the shell are analyzed,and the optimal topology is determined by taking their symmetries into consideration.The results of this research show that common damper topologies are not effective for all types of responses and recorded earthquakes.The optimal topology identifi ed requires a minimal number of dampers for each type of earthquake record.The displacement control effect of the dynamic responses of the optimal topology is 10% – 20%; the acceleration control effect is also about 10% – 20%; and the axial force control effect is as much as 30% – 45%.Furthermore,the incremental dynamic analysis(IDA) method is used to investigate the stability of the controlled shell.The results show that the dynamic stability of the controlled shell is well preserved when it is vibrated under vibration and is better than the uncontrolled shell.The ultimate load increased by 10% and the elements entered into the plastic stage when the peak acceleration reached 580 Gal,which is 200 Gal larger than the uncontrolled shell.

超高效液相色谱法测定柑橘果肉中四种植物性内源激素的含量

利用超高效液相色谱法同时测定柑橘(Citrus reticulate Bance)果肉中的玉米素、赤霉素、吲哚乙酸和脱落酸的含量。以C8色谱柱,甲醇-0.1%冰乙酸为流动相梯度洗脱,检测波长为262nm,流速0.22mL/min。结果表明,玉米素含量在0.14～0.38μg/mL间线性关系良好,R2为0.999 5,平均回收率为98.7%,RSD为0.99%;赤霉素含量在0.67～1.79μg/mL间线性关系良好,R2为0.999 3,平均回收率为98.6%,RSD为0.70%;吲哚乙酸含量在0.25～0.67μg/mL间线性关系良好,R2为0.999 6,平均回收率为99.0%,RSD为0.68%;脱落酸含量在0.036～0.096μg/mL间线性关系良好,R2为0.999 9,平均回收率为99.1%,RSD为0.61%。该方法简便、快速、精密度高、准确性好,可用于植物样品中激素含量的测定。

Research on mode localization of reticulated shell structures

Reticulated shell structures （RSSs） are characterized as cyclically periodic structures. Mistuning of RSSs will induce structural mode localization. Mode localization has the following two features： some modal vectors of the structure change remarkably when the values of its physical parameters （mass or stiffness） have a slight change; and the vibration of some modes is mainly restricted in some local areas of the structure. In this paper, two quantitative assessment indexes are introduced that correspond to these two features. The first feature is studied through a numerical example of a RSS, and its induced causes are analyzed by using the perturbation theory. The analysis showed that internally, mode localization is closely related to structural frequencies and externally, slight changes of the physical parameters of the structure cause instability to the RSS. A scaled model experiment to examine mode localization was carried out on a Kiewit single-layer spherical RSS, and both features of mode localization are studied. Eight tests that measured the changes of the physical parameters were carried out in the experiment. Since many modes make their contribution in structural dynamic response, six strong vibration modes were tested at random in the experimental analysis. The change and localization of the six modes are analyzed for each test. The results show that slight changes to the physical parameters are likely to induce remarkable changes and localization of some modal vectors in the RSSs.

Experimental study of wind loads on cylindrical reticulated shells

The cylindrical reticulated shell structures without side walls, which are normally arranged in pairs, are usually used as dry-coal sheds in a thermal power plant. The wind loads of these shells do not exist in standards or codes. Therefore, this study investigates the mean and fluctuating wind loads on a cylindrical reticulated shell with a rise-to-span ratio of 0.39 through a series of wind tunnel tests. The characteristics of the wind pressures on the upper and lower surfaces and the net pressures are presented. The results show that the wind direction and another shell structure significantly affect the wind loads on the principal shell. The most unfavorable wind direction is around 30~, whereas the effects of the wind field and the height of the coal stack are small. The surfaces of the shells are divided into nine blocks, and the block mean and fluctuating （rms） pressure coefficients suitable for engineering applications are given as references for wind load codes.

Phylogenetic incongruence in Cymbidium orchids

Cymbidium,which includes approximately 80 species,is one of the most ornamental and cultivated orchid genera.However,a lack of markers and sparse sampling have posed great challenges to resolving the phylogenetic relationships within the genus.In the present study,we reconstructed the phylogenetic relationships by utilizing one nuclear DNA(nrITS)and seven plastid genes(rbcL,trnS,trnG,matK,trnL,psbA,and atpI)from 70 species(varieties)in Cymbidium.We also examined the occurrence of phylogenetic conflict between nuclear(nrITS)and plastid loci and investigated how phylogenetic conflict bears on taxonomic classification within the genus.We found that phylogenetic conflict and low support values may be explained by hybridization and a lack of informative characteristics.Our results do not support previous classification of the subgenera and sections within Cymbidium.Discordance between gene trees and network analysis indicate that reticulate evolution occurred in the genus Cymbidium.Overall,our study indicates that Cymbidium has undergone a complex evolution.

柑橘不同幼果大小与其生长发育动态及品质的相关性

为了探讨影响柑橘（Citrus reticulate Blanco.）果实生长发育动态和果实品质变化的因子及机理,为提高栽培管理水平提供理论依据,试验连续3a（2013~2015年）对柑橘不同幼果大小与其果实生长发育动态及品质变化的相关性进行了调查比较。结果表明,（1）幼果大小与果实纵径、横径年生长量及日生长量的生长高峰期在年生长过程中出现的次数和时间有关;在果实年生长量方面,纵径有8~10次生长高峰期,横径有8~9次生长高峰期。在果实日生长量方面,纵径有5~7次生长高峰期,横径有7~9次生长高峰期。（2）柑橘幼果大小与果实纵径日生长量、横径年生长量和横径日生长量的生长高峰期次数呈正相关,与果实纵径年生长量生长高峰期次数呈负相关。（3）柑橘幼果大小与成熟果实单果重、果实纵径、果实横径和果皮厚度呈极显著相关,与果形指数和果汁含糖量呈显著相关。生产上以选留大的幼果效果最好,其次是选留较大幼果。建议把幼果大小作为柑橘疏花疏果的重要依据之一和影响果实生长发育、果实品质变化的重要因素之一。

Morphological,Molecular and Pathogenicity of Alternaria gaisen Associated with Leaf Brown-Spot on‘Gonggan’Mandarin in China

[Objective]This paper was to identify the pathogen of leaf brown-spot on‘gonggan’mandarin(Citrus reticulate var.gonggan)in Zhaoqing,Guangdong Province.[Method]The pathogen was determined based on sequence analysis of ITS,endoPG,tef1,gapdh,Alt a1,rpb2 and opa10-2 genes;the morphological characteristics were recorded on PDA and PCA;and its pathogenicity on excised and intact host leaves of citrus‘gonggan’was tested.[Result]A detailed description of Alternaria gaisen was obtained based on morphological,molecular and pathogenic characterization,which was the causal agent of brown-spot disease on leaves of‘gonggan’mandarin orchard trees in Zhaoqing,Guangdong,China.[Conclusion]This study provides a scientific basis for the effective control of leaf brown-spot on‘gonggan’mandarin.

NONLINEAR BENDING THEORY OF DIAGONAL SQUARE PYRAMID RETICULATED SHALLOW SHELLS

Double-deck reticulated shells are a main form of large space structures. One of the shells is the diagonal square pyramid reticulated shallow shell, whose its upper and lower faces bear most of the load but its core is comparatively flexible. According to its geometrical and mechanical characteristics, the diagonal square pyramid reticulated shallow shell is treated as a shallow sandwich shell on the basis of three basic assumptions. Its constitutive relations are analyzed from the point of view of energy and internal force equivalence. Basic equations of the geometrically nonlinear bending theory of the diagonal square pyramid reticulated shallow shell are established by means of the virtual work principle.