黄河口海域春季和夏季须子网渔获物组成分析

须子网是黄河口海区应用较广的陷阱类网具之一。为养护和管理黄河口海区渔业资源,对该海域春季和夏季须子网渔获物组成进行分析。2013年5月和2014年8月对东营黄河口海区进行了3次导陷插网网具须子网的渔获物调查,采用相对重要性指数(IRI)、种类丰富度指数和Sorensen相似性系数Ss对调查数据进行了分析。结果显示,春季和夏季须子网捕获渔获物共计45种;春季和夏季渔获物优势种(IRI>1 000)分别为7种和9种,共同优势种为2种;春季和夏季渔获种类的Sorensen相似性系数Ss为0.39,该海域春季和夏季的渔获物丰富度指数(R)、Shannon-Wiener多样性指数(H)、均匀度指数(J)分别为15.81和2.91、0.51和11.26、2.17和0.43;春季和夏季平均每网渔获量和尾数分别为55.04 kg和8 766尾、50.56 kg和3 390尾。调查结果表明,春季生物群落优势度较夏季优势高,使用须子网,其渔获物组成混杂、渔获幼体组成比例较高,长此以往不利于资源的繁殖保护,对黄河口渔业资源破坏较为严重。调研结果可为我国黄河口海区渔具管理以及渔业资源的可持续发展与管理提供科学参考。

基于生计渔业调查的黄河口西南侧潮间带渔业生物多样性及其季节变化

基于2020年黄河口须子网生计渔业和生物组成周年监测数据,开展黄河口潮间带渔业生物多样性及其季节变化研究,评价须子网生产对黄河口渔业资源补充的影响。结果显示,黄河口潮间带的渔业生物种类丰富,共鉴定记录61种生物,以鱼类和甲壳类居多。生物多样性和优势种组成均具有明显的月变化。多样性水平以夏季7―8月较高,秋季10―11月较低;5―9月、10―11月组群分别具有较高的种类组成相似度。各类群的数量组成中,4―7月螺类数量居多,8月螺类和鱼类数量居多,9月鱼类数量居多,10―11月蟹类数量居多。鱼类是各调查月渔获的优势类群,其中,花鲈(Lateolabrax maculatus)和[鱼夋](Liza haematocheila)为各调查月都出现的优势种。个体大小–频数百分比分布显示,黄河口潮间带是小型渔业生物以及多种幼鱼分布的重要区域。4―9月,渔获物的主体均由个体重量<2 g的生物组成(44%~82%),鱼类以个体质量<20 g为主,优势种类组成月更替明显。研究表明,开展须子网生计渔业调查和监测是采集黄河口沿岸咸、淡水交汇区潮间带包括鱼类补充群体在内的诸多渔业生物分布资料的有效途径。研究还表明,须子网渔业生产虽为黄河口沿岸当地传统的生计渔业,但其低选择性及在迁移通道的布设方式等易对渔业资源自然补充和增殖养护群体造成破坏,建议主管部门根据幼鱼种类组成和出现季节特征,重点在夏季和初秋季对该渔业的网目和布设区域进行相应管控。

Residual elastic stress strain field and geometrically necessary dislocation density distribution around nano-indentation in TA15 titanium alloy

Nanoindentation and high resolution electron backscatter diffraction（EBSD） were combined to examine the elastic modulus and hardness of α and β phases,anisotropy in residual elastic stress strain fields and distributions of geometrically necessary dislocation（GND） density around the indentations within TA15 titanium alloy.The nano-indention tests were conducted on α and β phases,respectively.The residual stress strain fields surrounding the indentation were calculated through crosscorrelation method from recorded patterns.The GND density distribution around the indentation was calculated based on the strain gradient theories to reveal the micro-mechanism of plastic deformation.The results indicate that the elastic modulus and hardness for α p hase are 129.05 GPas and 6.44 GPa,while for β phase,their values are 109.80 GPa and 4.29 GPa,respectively.The residual Mises stress distribution around the indentation is relatively heterogeneous and significantly influenced by neighboring soft β phase.The region with low residual stress around the indentation is accompanied with markedly high a type and prismatic-GND density.

The U.S. Men＇s Shaving Cream Market： A Competitive Profile

Porter identifies high market share with cost leadership strategy which is based on the idea of competing on a price lower than that of the competition. However, in most consumer markets a business should serve the middle class by competing in the mid-price segment, offering quality better than that of the competition at a somewhat higher price. It is this path that can lead to market share leadership： a strategy that can be both profitable and sustainable. The U.S. men＇s shaving cream market consists of two major product-market segments： gel and foam. We test the hypothesis that the best-selling brand is very likely to be a member of the mid-price segment with a price tag that is higher than that of the nearest competition. This study is based on annual U.S. sales data for 2008 and 2007 from discount retail stores, food stores, and drug stores. We performed two separate analyses for 2008 and 2007, using cluster analysis as the main analytic tool. The results were remarkably consistent between the two years. In the gel segment--by far the most important--the price-quality segmentation analysis supported our hypothesis. An interesting finding is that, for both the gel and foam segments, we found the rank order correlation of brand unit price between 2007 and 2008 as highly significant. This means that in this market management considers the price of a brand as a strategic rather than a tactical variable. Although, technically the results for the foam segment were negative, this does not necessarily contradict our hypothesis. Finally, we discovered six strategic groups in the industry and have tried to articulate what their competitive strategy is.

Effects of Different Concentrations of Radix pseudostellariae Fibrous Root Extracts on Serum Cytokines in Mice and Their Correlation Analysis

To investigate the effects of Radix pseudostellariae fibrous root extracts(RPFRE) on serum cytokines in normal and immunosuppressed mice and the correlation between indexes, KM male mice were randomly divided into four groups, which were given 0(control), 0.1, 0.2, 0.4 g/kg RPFRE by gavage. The levels of IL-2, IL-4, IL-6, and IFN-γ in the serum of mice were measured 14 d after gavage. On the 15day, the remaining mice in the experimental group were intraperitoneally injected with cyclophosphamide(CY), and samples were collected on the 18day to measure serum cytokines levels. The results showed that RPFRE improved the serum cytokine level in normal mice. 0.1 g/kg RPFRE significantly increased the content of IL-2and IFN-γ(P<0.05), while 0.4 g/kg RPFRE significantly increased the content of IL-4 and IL-6(P<0.05). Correlation analysis showed that serum cytokines IL-4 and IL-6 in normal mice had an extremely significant positive correlation with RPFRE concentration(P<0.01), IL-2 had a significant or extremely significant positive correlation with IL-4, IL-6, and IFN-γ(P<0.01or P<0.05), and IL-4 had an extremely significant positive correlation with IL-6(P<0.01). After CY injection, serum cytokine levels in mice decreased and immune function was inhibited. Compared with the control group, the experimental group recovered the level of cytokines to some extent. 0.1 g/kg RPFRE significantly increased the content of IL-2 in immunosuppressed mice(P<0.05), and 0.4 g/kg RPFRE significantly increased the content of IL-4, IL-6, and IFN-γ in immunosuppressed mice(P<0.05). Correlation analysis showed that the serum cytokines in immunosuppressed mice were significantly positively correlated with RPFRE concentration(P<0.01), and there was a certain dose dependence. Moreover, the correlation coefficient between IL-2 and IL-4, IL-6, and IFN-γ, IL-4 and IL-6, and IL-6 and IFN-γ reached an extremely significant level(P<0.01). To sum up, RPFRE could improve the serum cytokines level of mice, promote the secretion of cytokines, and have a certain immune protective effect. There was a significant positive correlation between the RPFRE concentration and the serum cytokines in mice, which provided basic data support for the further study of RPFRE immune function.

Microstructural aspects of in-situ TiB reinforced Ti-6Al-4V composite processed by spark plasma sintering

Titanium-matrix composites have important and wide applications in the transport and aerospace industries. The current research was focused on powder metallurgy processing of in-situ reinforced titanium-matrix composite with Ti B whiskers. The Ti-6Al-4V alloy and B4 C additive powders were used as raw materials. Two different consolidation techniques, namely press-and-sintering and spark plasma sintering, were selected. It was observed that in-situ Ti B whiskers were formed during sintering in both methods. The changes in size, aspect ratio and distribution of in-situ whiskers in different composite samples were monitored. The effect of spark plasma sintering temperature on the synthesis of in-situ whiskers was also investigated. Based on the microstructural observations（optical microscopy and scanning electron microscopy） and the energy dispersive spectroscopy analysis, it was concluded that increasing the spark plasma sintering temperature from 900 to 1100 °C would lead to the complete formation of in-situ Ti B whiskers and reduced porosity content.

Development of a SCAR marker for male gametophyte of Gracilariopsis lemaneiformis based on AFLP technique

The red alga Gracilariopsis lemaneiformis(Bory) is an economically valuable macroalgae. As a means to identify the sex of immature Gracilariopsis lemaneiformis, the amplifi ed fragment length polymorphism(AFLP) technique was used to search for possible sex- or phase-related markers in male gametophytes, female gametophytes, and tetrasporophytes, respectively. Seven AFLP selective amplifi cation primers were used in this study. The primer combination E-TG/M-CCA detected a specifi c band linked to male gametophytes. The DNA fragment was recovered and a 402-bp fragment was sequenced. However, no DNA sequence match was found in public databases. Sequence characterized amplifi ed region(SCAR) primers were designed from the sequence to test the repeatability of the relationship to the sex, using 69 male gametophytes, 139 female gametophytes, and 47 tetrasporophytes. The test results demonstrate a good linkage and repeatability of the SCAR marker to sex. The SCAR primers developed in this study could reduce the time required for sex identifi cation of Gracilariopsis lemaneiformis by four to six months. This can reduce both the time investment and number of specimens required in breeding experiments.

Preparation of Magnesium Oxide Whisker by MgSO4·5Mg（OH）2·2H2O Whisker ＂Pseudomorph＂ Technique

To promote the scale-up production and industrial application of magnesium oxide （MgO） whiskers, MgO whiskers were prepared by the calcination method of the precursor. The precursor MgSO4·5Mg（OH）2·2H2O （152 MOS） single component was prepared by hydrothermal synthesis reaction in MgSO4 solution and NaOH solution. MgO whisker was prepared by heating treatment of the precursor at low heating speed to keep the structure of the precursor not be destroyed. The composition, the morphology and the structure of these whiskers were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The results indicate that the MgO whisker was about 0.5-1.2 μm in diameter and 20-80 μm in length, with an aspect ratio no less than 100.

童心需要童语

童心需要童语高进德童心如泉，清澈纯净；童言无忌，天真无邪。这是儿童的天性，也是儿童的需要。＿笔者曾听到这样一段父子对白。六岁的孩子问：“爸爸，英雄是什么？”其父稍加思索后十分严肃地说：“英雄是一把钢刀插进肚子里，血哗哗地流出来也不怕的人。”父亲的话还...

TEM observation of tin whisker

The tin whiskers spontaneously grew from the NdSn3 intermetallic compound(IMC) after exposure to ambient conditions.One such fine tin whisker with a diameter of about 600 nm was observed by transmission electron microscope(TEM).The results showed the whisker was a perfect β-Sn single-crystal without dislocations or low angle grain boundaries.The whisker growth axis was calculated as [111].There were interference fringes in the bright-field image of the tin whisker,which reflected the existence of growth stress in the whisker.A 15-18 nm native tin-oxide film on the tin whisker containing many crystal defects was also found.The new results are helpful in understanding the tin whisker growth mechanism.

Molecular geochemical characteristics of gas source rocks from the Upper Triassic Xujiahe Formation indicate transgression events in the Sichuan Basin

The geochemical characteristics of saturated and aromatic hydrocarbons from different formations and lithologies provide ob-vious evidence for transgressions that occurred during Upper Triassic Xujiahe stage in Sichuan Basin with a great impact on the source input and depositional environment.A clear dual peak distribution for normal alkanes and obvious abundant com-pounds sourced from bacteria and algae in whole oil gas chromatogram indicates the abundance of lower organisms input.The ratio of Pr/Ph is low,ranging from 0.33 to 0.86 with an average of 0.60,quite different from Pr/Ph >2.0 for coal measures in swamp environment,representing source rocks from saline lake or marine facies.In the gas source rocks extracts,abundant β-carotane,-carotane,and their degradated series were detected in the whole oil chromatogram,indicating a reducing envi-ronment.The concentrations of methyl steranes and dinosteranes are high.The content of polycyclic aromatic sulfur heterocy-cles(PASH) is relatively higher in aromatic fraction and the assemblage of fluorene,dibenzofuran,and dibenzothiophene is different from the typical saline lake and the regular swamp facies source rocks,manifesting the transgression effects on gas source rocks.

The growth mechanism of the basic magnesium chloride whisker

Based on the theoretical model of anion coordination polyhedron growth units, the growth mechanism of the basic magnesium chloride whisker was discussed in this paper.It was found that the basic magnesium chloride whisker habits were related to the different environments in which anion coordination polyhedra grew. The growth units of basic magnesium chloride whiskers are [Mg - (OH) 4]2 -and [Mg - Cl 4]2 -. The growth process is the incorporation process of growth units. Growth units will have different incorporations and orientations caused by different system characters or heating. Furthermore, the formation mechanism of basic magnesium chloride whiskers was also interpreted using anion coordination polyhedron growth units.