改进的多方向融合图像插值算法

为了解决数字图像插值过程中出现的边缘模糊和锯齿现象,提出一种改进的多方向融合图像插值算法.该算法将图像分为平坦区域和边缘区域,平坦区域采用双线性插值算法进行插值,边缘区域采用多方向融合算法进行插值.实验结果表明,该算法运算复杂度小,其结果在主观视觉效果和客观指标方面都有很大的改善,且适用于任意倍数的插值放大.     

A genetic interaction network of five genes for human polycystic kidney and liver diseases defines polycystin-1 as the central determinant of cyst formation

Autosomal dominant polycystic liver disease results from mutations in PRKCSH or SEC63. The respective gene products, glucosidase IIβ and SEC63p, function in protein translocation and quality control pathways in the endoplasmic reticulum. Here we show that glucosidase IIβ and Sec63p are required in mice for adequate expression of a functional complex of the polycystic kidney disease gene products, polycystin-1 and polycystin-2. We find that polycystin-1 is the rate-limiting component of this complex and that there is a dose-response relationship between cystic dilation and levels of functional polycystin-1 following mutation of Prkcsh or Sec63. Reduced expression of polycystin-1 also serves to sensitize the kidney to cyst formation resulting from mutations in Pkhd1, the recessive polycystic kidney disease gene. Finally, we show that proteasome inhibition increases steady-state levels of polycystin-1 in cells lacking glucosidase IIβ and that treatment with a proteasome inhibitor reduces cystic disease in orthologous gene models of human autosomal dominant polycystic liver disease.     

Control of a key transition from prostrate to erect growth in rice domestication

The transition from the prostrate growth of ancestral wild rice (O. rufipogon Griff.) to the erect growth of Oryza sativa cultivars was one of the most critical events in rice domestication. This evolutionary step importantly improved plant architecture and increased grain yield. Here we find that prostrate growth of wild rice from Yuanjiang County in China is controlled by a semi-dominant gene, PROG1 (PROSTRATE GROWTH 1), on chromosome 7 that encodes a single Cys(2)-His(2) zinc-finger protein. prog1 variants identified in O. sativa disrupt the prog1 function and inactivate prog1 expression, leading to erect growth, greater grain number and higher grain yield in cultivated rice. Sequence comparison shows that 182 varieties of cultivated rice, including 87 indica and 95 japonica cultivars from 17 countries, carry identical mutations in the prog1 coding region that may have become fixed during rice domestication.     

浅析抗震设计中短柱问题及其防治

在历次地震灾害中,根据对灾区大量的房屋建筑的研究调查,房屋中大量出现由于形成短柱而产生的破坏。文章叙述了形成短柱的原因,明确了短柱的判定方法,并提出了一些处理措施。从而提高建筑物的抗震性能,避免发生脆性破坏,达到抗震设计的基本要求。     

2.5 Gbit/s PHEMT前置放大器噪声分析与验证

根据OMMIC公司通过测量得到的0.2μm GaAs PHEMT器件参数模型和噪声模型,设计了2.5 Gbit/s的共源跨阻前置放大器.并根据PHEMT晶体管Y参数下的噪声模型,结合Y参数和ABCD参数下的噪声密度矩阵,分析了电路在带有晶体管噪声源情况下整个电路的噪声电压,得出了共源跨阻前置放大器等效输入噪声电流密度的理论公式.实现了芯片制作,并且对芯片进行了噪声参数的测量,测量结果、仿真结果和理论分析结论在6GHz的频率范围内基本符合.     

煤粉高压密相气力输送特性

在输送压力可达4.0MPa,固体输送流率达840kg/h的仓式泵高压气力输送试验装置上进行粉煤高压浓相气力输送试验研究.考察了流化风量、充压风量、输送总差压对煤粉输送量、固气比的影响.研究表明:随着流化风量的增大,煤粉输送量逐渐增大,固气体积比先增大然后减小;当煤粉在发料罐内被充分流化后,再加大充压风量,固气体积比逐渐减小,而煤粉输送量略有增加;输送总压差对煤粉输送量有显著影响,随着总压差的增加,煤粉输送量呈线性增加.研究结果对高压超浓相气力输送系统的设计、运行和控制具有指导作用.     

Lipids of sulfate-reducing bacteria and sulfur-oxidizing bacteria found in the Dongsheng uranium deposit

U-bearing sandstones from the Dongsheng deposit in Ordos Basin contain abundant C15-C18 fatty acids. The fatty acids may have been derived from modern and ancient organisms including organisms from the intervals of U mineralization. A certain amount of i15:0, a15:0, a17:0 fatty acids coexist with small amounts of i17:1ω7c and 10me16:0, characteristic biomarkers of Desulfovibrio and Desulfobacter sp., respectively. This indicates the existence of sulfate-reducing bacteria (SRB) in the sandstones. The presence of sulfur-oxidizing bacteria (SOB), such as Beggiatoa and Thioploca, is indicated by significant amounts of 16:1ω7c and 18:1ω7c fatty acids. The existence of the SRB in the deposit, as inferred from the fatty acids, is consistent with results from fossilized microorganisms and isotopic compositions of ore-stage pyrite. This suggests that the environment may have been favorable for the SRB to grow since ore formation (9.8-22 Ma). The bacteria may have degraded hydrocarbons directly, or indirectly utilized hydrocarbons degraded by oxic microbes in the deposits. This process may have produced 12C-rich calcite and prominent baseline humps of unresolved complex mixtures (UCM), and 25-demethylated hopanes and tricyclic terpanes. The existence of sulfur-oxidizing bacteria and sulfate-reducing bacteria in the deposit may have resulted in bacterial sulfate reduction to sulfide, re-oxidization of the sulfide to sulfate and subsequent reduction of the sulfate to sulfide. This assertion is supported by ore-stage pyrite with δ34S values as low as-39.2‰, and the lightest sulfate (about 11‰) measured during the Phanerozoic, a difference of more than 46‰.     

宋词创作观念矛盾与词文学美学体征的变化

作为一代文学之胜的宋词发展流变是一个充满矛盾同时也是充满了活力的进程:在审美观念上,虽然雅化潮流成为一种强势往前推进,但是,俗词的创作传播作为一种源于市井民间的活力涵养着词的生命肌体;理性上的拒斥与实践的热衷这一心理矛盾使宋词从政治教化的重负中逃逸出来,保持一种感性鲜活的审美品质;执着悲哀与超越悲哀两极的情感趋向冲撞对流衍化出宋词丰富多采的审美形态;在性别上,一种整合了双性特点的的抒情范式使宋词具有了更为隽永的滋味;文体上虽有尊体与破体之辩,但在创作实践中,词的破体而行却为词带来了多元多姿的审美风貌;风格上婉约与豪放的消长变化这组过去探讨的最多的矛盾则更多的和以上五组矛盾有着密切的关联。     

Guest Editorial： Special Issue on Parameterized Complexity

<正>Dedication.This Special Issue on Parameterized Complexity of Tsinghua Science and Technology is a tribute to the influential contributions of Jianer Chen to parameterized complexity algorithmics.It is an occasion to celebrate the many important contributions to this new and prospering branch of theoretical computer science made by Jianer Chen,as he reaches the ripe young age of 60.Happy birthday,Jianer,from     

利用CFD技术研究叶片斜度对贯流风机性能的影响

为了考察贯流风机多结构参数同时变化对其内部流场的影响,引出与多结构参数联系紧密的叶片斜度,文章利用CFD技术对不同叶片斜度的贯流风机进行非稳态数值模拟,考察流量系数、风机效率及总压系数的变化情况,并用焓差法风量实验验证模拟结果的正确性。结果表明,叶片斜度对风机性能影响显著,通过优化叶片斜度,可以使其流场内偏心涡移向蜗舌,进口段脱落涡减少,出口流速增大,风机性能得到提升。