Reactive diffusion bonding of SiCp/Al composites by insert layers of mixed Al-Si and Al-Si-SiC powders

Mixed Al-Si and Al-Si-SiC powders were employed as insert layers to reactive diffusion bond SiCp/6063 MMC (metal matrix composites). The results show that SiCp/6063 MMC joints bonded by the insert layer of the mixed Al-Si powder have a dense joining layer with a typical hypoeutectic microstructure. Using the mixed Al-Si-SiC powder as the insert layer, SiCp/6063 MMC can be reactive diffusion bonded by a composite joint. Because of the SiC segregation, however, there are a number of porous zones in the joining layer, which results in the bad shear strength of the joints reactive diffusion bonded by the insert layer of the mixed Al-Si-SiC powder, even lower than that of the joints reactive diffusion bonded by the insert layer of the mixed Al-Si powder. Ti and Mg added in the insert layers obviously improve the strength of the joints reactive diffusion bonded by the insert layer of the mixed Al-Si-SiC powder, especially, Mg has a more obvious effect.     

An Experimental Biotelemetric Study Based on Satellite Tracking During Post—nesting Migrations of Green Turtles

A biotelemetry experiment is conducted to study the migrant behavior of green turtles(Chelonia mydas)in South China Sea and acquire the physical environment data.The method in use is to track the post-nesting migrant routes of green turtles through the satellite linked transmitters attached on the back of turtles and the global satellite signal transmitting system of Argos.We obtained the positions of the post-nesting migrant routes of three green turtles and environment data,which are important in conservation of green turtles and the research of physical oceanography.Based on the test,the concept,principle and method of biotelemetry are also introduced in this paper with a discussion of the further development of this technique and its applying prospection in future.     

成纤维细胞静脉注射途径实施血友病B基因治疗的初步探索

将转有报告基因ｌａｃＺ的成纤维细胞３Ｔ３／ＢＡＧ以５×１０＾５量尾静脉注射到Ｂａｌｂ／ｃ小鼠体内，７ｄ后在主要脏器检测到３ＴＥ／ＢＡＧ的表达且至少可持续３０ｄ。将转有人凝血因子Ⅸ小基因的正向表达载体Ｇ１ＮａＣｉ’Ⅸ和反向表达载体Ｇ１ＮａＣｉ’ⅨＲ的成纤维细胞ＰＡ３１７／Ｇ１ＮａＣｉ’Ⅸ和ＰＡ３１７／Ｇ１ＮａＣｉ’ⅨＲ分别以１×１０＾５量尾静脉注射到Ｂａｌｂ／ｃ小鼠体内，ＥＬＩＳＡ测定小鼠血浆中ｈＦ     

Analysis of intron sequence variability of the conservative HMG-box of Sox9 genes in allotetraploids and their original parents

The Sox genes of allotetraploids and their original maternal red crucian carp （Carassius caassius red var.） and original paternal common carp (Cyprinus carpio L.) were detected by PCR with the designed primers based on the conserved HMG-box sequence in different species. Sequencing of Sox genes indicated that two Sox9 genes (Atsox9a and Atsox9b) existed in allotetraploids, while only one Sox9 gene existed in red crucian carp (Rcsox9a) and common carp (Ccsox9b). All of the four Sox9 genes contained an intron in the HMG-box, with the sizes of 413 bp, 703 bp, 401 bp and 714 bp, respectively. Moreover, the introns obeyed the rule of “GT-AG”. A high similarity was observed between introns of Atsox9a and Rcsox9a (94.4%), Atsox9b and Ccsox9b (97.8%). Interestingly, the deduced amino acid sequences of their corresponding exons all shared 100% identity. Thus, introns of the HMG-domain of Sox9s in allotetraploids and their original parents have not only the length polymorphism but also intron variability. Our results provide significant molecular evidence for the origin and evolution of allotetraploids.     

Present-day crustal movement in China continent and its southeast coast region

Based on the observations of global positioning system (GPS) , a movement model for quantitatively describing the seven continent blocks in China, Tibet, Sichuan-Yunnan, Gansu-Qinghai, Xingjiang, the South China, the North China and Heilongjiang is established, and the derived velocity field (1994—1996) is consistent with the focal mechanism " P" stress axis field and the geological model on the whole. China continent moves toward east (including N\E, NE, E, EES and ES) . Furthermore, the intrablock deformation model for Fujian and its neighboring sea region is also established. The derived velocity field and strain rate field (1995—1997) show that along with the southeast coastal region, the whole China moves toward southeast. There are compression from sea to continent in the northwest direction and extension in the northeast direction. The direction of principal stress axis at present is NW (NWW) SE (SEE) . The collision of India plate with Eurasian plate plays a major role in the crustal movement of China continent, while the collision and pushing of Philippine plate play the direct and important role in the crustal movement and strong earthquake gestation in the southeast eoastal region of China continent.     

Research on the evaluation and mechanism of socio-economic benefit of highway projects

Based on the theory of system dynamics, the paper analyzes the mechanism of socio-economic benefits of highway projects and establishes the system dynamics model of regional economic-highway development. Then taking Jinji（Tianjin--Jixian） Highway of Tianjin as an example, the errors of system simulation are tested, and the system dynamics model built is verified to be quite stable, which has a high performance. Through the comparison of simulation results with and without Jinji Highway, the paper simulates and predicts the socio-economie benefit of each year from 2003 to 2013. Thus the quantification evaluation of socio-economic benefit of highway project is realized and will provide the theory instructions for similar projects in the future.     

Low frequency dispersion law for two-dimensional metallic photonic crystals

Using the rigorous multiple-scattering theory, we study the dispersion relation of electromagnetic （EM） waves in two dimensional dielectric photonic crystals （PCs） and metallic photonic crystals （MPCs） in the low-frequency limit. Analytic formula for the effective velocity of EM waves in PCs and MPCs is obtained. Accuracy of our formula is checked by comparing the results with rigorous calculations. For PCs, our result is exactly the same as the coherent potential approximation （CPA）, which is accurate even when the filling fraction is high. But for MPCs, our approach demonstrates special advantages, while the CPA theory fails, in predicting the effective velocity of EM waves in MPCs at low frequency.     

Pollen-inferred Holocene vegetation and climate histories in Taro Co,southwestern Tibetan Plateau

A 310-cm-long sediment core, covering the last 10,200 years, was collected from Taro Co on the south- western Tibetan Plateau and analyzed for pollen, grain size and total inorganic carbon content. The pollen data showed that vegetation changed from alpine steppe to alpine meadow during 10,200-8,900 cal a BP, to alpine steppe dominated by Artemisia during 8,900-7,400 cal a BP, to alpine meadow during 7,400-3,300 cal a BP and to alpine steppe after 3,300 cal a BP. Correspondingly, the pollen, grain size and total inorganic carbon content results revealed climatic change in this area over four stages. The initial stage was from 10,200 to 8,900 cal a BP, during which the climate changed from cold-dry to warm-humid. The second stage （8,900-7,400 cal a BP） was characterized by a warm and dry climate. However, at approximately 7,400 cal a BP, the climate began to become cold andhumid, which continued until 3,300 cal a BP. The last stage, from 3,300 cal a BP to present, was characterized as cold and increasingly arid. Climatic events of the early and mid-late Holocene showed that the area was significantly affected by the westerlies. However, the mid-Holocene climate in Taro Co was controlled by the Indian monsoon. The mid-late Holocene depositional environment record of Taro Co was very important to further elaborate the degree of influence by the westerlies or Indian monsoon.     

A Way to Find all the Optimal Solutions in Linear Programming

Ingeneral,theoptimalsolutionsformedinactualbusinessmanagementsituationsprovidethebestenforcementplansinthegivenpracticalproblems.Whenthereismorethanoneoptimalsolutioninlinearprogramming,thereexistsunlimitednumberofoptimalsolutions.Tofindthemultipleoptimalsolutionsinlinearprogrammingisaverysignificantwork,becausethedecisionmakercanbegivenmoreoptimalplanstochoosefrom.Sofar,therehavebeenmanypapersdiscussingthesituationofunlimitedoptimalsolutions.However,therearemistakesanddefectsinsomeofthem[1,2]…     

太平洋牡蛎精液的超低温保存

利用解剖法采集太平洋牡蛎精液，用自然海水做基础溶液，配制不同浓度的DMSO（二甲亚砜）作为超低温保护剂，在液氮（LN2）面上不同高度进行预处理,投入LN2内保存，升温解冻后，检测精子成活率。结果表明，DMSO处理浓度、预处理温度及时间和升温方式对超低温保存成活率均具有显著影响。其中，用10％DMSO在LN2面上17cm预处理6min，采用16－17℃流水不完全解冻，效果最好，超低温保存精子成活率可达70％。与新鲜精子相比，在LN2内保存一天的精子，授精能力没有明显变化。