栉孔扇贝四倍体幼虫的诱导研究

以栉孔扇贝Chlamys farreri为材料，采用浓度为0．5mg／L的细胞松弛素B(CB)处理、抑制受精卵第一极体排放的方法，进行四倍体诱导研究。5次重复实验结果表明，诱导组和对照组的平均受精率分别为45．0％和56．6％，D形幼虫的平均孵化率分别为5．3％和51．1％。经胚胎和幼虫发育观察发现，在诱导组中异常原肠胚的比例高于对照组；受精后48h，诱导组的滞育担轮幼虫的比例显著高于对照组。在受精后48h采用流式细胞术检测孵化的D形幼虫，诱导组中四倍体幼虫的比例为36％-70％，平均为49％，同时发现了平均比例为31％的三倍体幼虫。本研究表明，该项技术能有效地诱发栉孔扇贝四倍体幼虫，但面临四倍体幼虫孵化率低的问题，今后应设法提高四倍体胚胎和幼虫的发育水平。     

单壁碳纳米管对固体培养拟南芥的影响

本试验用含有浓度为6．25μg／mL、12．5μg／mL、25μg／mL、50μg／mL单壁碳纳米管的1/2MS固体培养基培养拟南芥,分别测定固体培养基所培养的拟南芥的叶片在第10天、15天、20天、25天的SOD酶和POD酶活性。结果表明不同浓度的修饰后的单壁碳纳米管能够刺激拟南芥叶片,对拟南芥叶片SOD酶和POD酶活性均产生明显影响。     

混凝-微滤膜工艺处理含铬废水

采用混凝-微滤膜工艺处理含铬废水，流程简单、工作压力低、停留时间短、处理效果好．当进水含六价铬质量浓度为50mg／L时，出水总铬质量浓度低于0．5mg／L，六价铬质量浓度低于0．1mg／L，浊度低于0．5NTU，pH值在6～8，并且装置有良好的抗冲击负荷能力．运行中发现当温度较高时，反应器中有铁氧体形成．     

有益细菌A18在海湾扇贝(Argopecten irradians)育苗中的应用

在海湾扇贝D形幼虫期施用10^3,10^4,10^5CFU／ml三个浓度的有益细菌A18。经该菌处理后，扇贝幼苗的变态率与各个发育期的成活率均比加氯霉素组和未加任何处理的对照组高。其中以10^4CFU/ml处理的扇贝幼苗的变态率和成活率最高。对实验扇贝幼菌水体细菌总数和弧菌数分析发现，经10^5,10^4CFU/ml A18菌处理水体的细菌总数和弧菌数均比相应的对照组低。在扇贝育苗水体加入10^6,10^7,10^8CFU／ml的有益细菌A18，检测高浓度A18对扇贝幼苗的毒害作用，当该菌浓度在10^6CFU/ml时，经48小时扇贝幼苗成活率79％，高于对照组的68.5%；当浓度达10^7,10^8CFU/ml时，处理48小时后的扇贝幼苗死亡率分别为95.6%和100％。     

大花萱草‘奶油卷＇花蕾愈伤组织诱导和植株再生

以大花萱草“奶油卷”花蕾为外植体材料,MS为基本培养基添加不同浓度BA和NAA,诱导其愈伤组织的形成和不定芽的分化,并建立其再生体系。MS＋BA1．5mg／L＋NAA0．2mg／L是大花萱草“奶油卷”愈伤组织较佳的诱导培养基;MS＋BAi．5mg／L＋NAA0．1mg／L是较好不定芽的分化与增殖培养基：而I／2MS＋IBA0．5mg／L则是组培苗较适合的生根培养基。生根小苗移栽至灭菌的基质（泥炭土：蛭石=1：1）经过一定时间的炼苗成活可达到96％,移栽到大田后均可成活。     

紫茎泽兰灭蚜活性物质的分离、纯化及其对棉蚜乙酰胆碱酯酶的影响

紫茎泽兰（Eupatorium adenophorum）氯仿萃取物所含组分Ⅷ对棉蚜（Aphis gossypii）具有较强的毒杀作用且得率较高，从中分离得到的紫茎泽兰素A对棉蚜无翅成蚜的致死中浓度（LC50，浸渍法）为362．8mg/L。紫茎泽兰素A对棉蚜乙酰胆碱酯酶酶活性有一定的抑制作用。棉蚜经2.00mg/ml紫茎泽兰素A溶液处理12h后，其体内的乙酰胆碱酯酶活性仅为对照组棉蚜酶活性的30．3％。     

多壁碳纳米管对鲤鱼各组织SOD酶活性的影响

应用浸浴法研究多壁碳纳米管（MWCNTs）对鲤鱼（cyprinl Jscarpioio）腮、肝、肾和脑中超氧化物歧化酶（SOD）的影响,结果显示：低浓度（0．1,lmg·L^-1）处理组暴露后3d,腮和肝中的SOD活性显著高于对照组（p〈0．01）,肾和脑中SOD活性与对照组无显著差异（p〉0．05）。随着暴露时间延长,各组活性降低,至9d,肝和肾中SOD活性显著低于对照组（p〈0．05）,腮和脑中SOD活性与对照组无显著差异（p〉0．05）。高浓度（10mg·L^-1）处理组,整个暴露期间,肝中SOD的活性显著低于对照组（p〈0．01）,脑中SOD的活性与对照组无显著差异（p〉0．05）,腮和肾中SOD活性在暴露后3d,与对照组无显著差异（p〉0．05）,暴露后6d、9d,活性显著低于对照组（p〈0．05）。提示：MWCNTs对鲤鱼各组织中SOD酶活性的影响有时间和浓度依赖性。     

β-葡聚糖在中国对虾(Penaeus chinensis)育苗中的应用

分别用 5种不同浓度 (0 ,0 .1,0 .3,0 .5 ,1mg/ml)的 β 葡聚糖溶液对中国对虾蚤状、糠虾幼体进行 3h浸浴 ,4 8h后用浓度为 5 .9× 10 6 cfu/ml的副溶血弧菌 (Vibriopara haemolyticus)进行攻毒。攻毒后再养殖 4 8h。结果显示 ,0 .1、0 .3和 0 .5mg/ml处理组均显著提高 (P <0 .0 5 )蚤状和糠虾幼体攻毒后的存活率 ,其中 ,0 .3和 0 .5mg/ml的处理组还显著提高 (P <0 .0 5 )蚤状幼体的变态率和生长 ,但对糠虾幼体生长的影响不显著 (P >0 .0 5 )。本研究结果表明 ,β 葡聚糖可以作为免疫增强剂在中国对虾育苗阶段使用 ,建议浸浴使用的浓度为 0 .3～ 0 .5mg/ml。     

壳聚糖对日光温室黄瓜生长发育状况的影响

研究了不同浓度的壳聚糖对日光温室黄瓜生长发育及产量、品质的影响。结果表明,叶面喷洒壳聚糖溶液,能够极显著日光温室黄瓜的花芽分化,单株雌花数可提高55．3％,第一雌花着生节位降低3．2节,第一雌花开花时间提早6．8d,单株雄花数降低39．6％,雌雄比可提高131．3％,化瓜率降低35．％,这种促雌作用以150mg·L—1处理最显著,其次是200mg·L—1处理;能够改善日光温室黄瓜的营养品质,果实的可溶性糖、可溶性蛋白质、维生素C含量提高值分别可达61．％、44．5％、112．2％,叶面喷洒壳聚糖溶液,能够提高目光温室黄瓜的前期产量和总产量。     

某市内河采用曝气辅助治理方案探讨

东莞运河在莞城段上游采用一级强化处理,处理后尾水排入下游莞城段运河,由于尾水中仍然存在污染物和还原性物质以及河流底泥的好氧作用,需要对该段河流进一步维护复氧。着重探讨了东莞城段运河维护复氧方式、需氧量计算模型、复氧设备的布置形式等,计算得出经曝气的河流末段还原物氧浓度下降了2．492mg／L、BOD5浓度下降了1．217mg／L、NH3＋-H浓度下降了0．322mg／L。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...