Investigation of Vaporized Kerosene Injection and Combustion in a Supersonic Model Combustor

Injection and combustion of vaporized kerosene was experimentally investigated in a Mach 2.5 model combustor at various fuel temperatures and injection pressures. A unique kerosene heating and delivery system, which can prepare heated kerosene up to 820 K at a pressure of 5.5 MPa with negligible fuel coking, was developed. A three-species surrogate was employed to simulate the thermophysical properties of kerosene. The calculated thermophysical properties of surrogate provided insight into the fuel flow control in experiments. Kerosene jet structures at various preheat temperatures injecting into both quiescent environment and a Mach 2.5 crossflow were characterized. It was shown that the use ofvaporized kerosene injection holds the potential of enhancing fuel-air mixing and promoting overall burning. Supersonic combustion tests further confirmed the preceding conjecture by comparing the combustor performances of supercritical kerosene with those of liquid kerosene and effervescent atomization with hydrogen barbotage. Under the similar flow conditions and overall kerosene equivalence ratios, experimental results illustrated that the combustion efficiency of supercritical kerosene increased approximately 10-15% over that of liquid kerosene, which was comparable to that of effervescent atomization.

Investigation of Vaporized Kerosene Injection and Combustion in a Supersonic Model Combustor

Injection and combustion of vaporized kerosene was experimentally investigated in a Mach 2.5 model combustor at various fuel temperatures and injection pressures. A unique kerosene heating and delivery system, which can prepare heated kerosene up to 820 K at a pressure of 5.5 MPa with negligible fuel coking, was developed. A three-species surrogate was employed to simulate the thermophysical properties of kerosene. The calculated thermophysical properties of surrogate provided insight into the fuel flow control in experiments. Kerosene jet structures at various preheat temperatures injecting into both quiescent environment and a Mach 2.5 crossflow were characterized. It was shown that the use ofvaporized kerosene injection holds the potential of enhancing fuel-air mixing and promoting overall burning. Supersonic combustion tests further confirmed the preceding conjecture by comparing the combustor performances of supercritical kerosene with those of liquid kerosene and effervescent atomization with hydrogen barbotage. Under the similar flow conditions and overall kerosene equivalence ratios, experimental results illustrated that the combustion efficiency of supercritical kerosene increased approximately 10-15% over that of liquid kerosene, which was comparable to that of effervescent atomization.

蕨属的系统发育及谱系地理学研究

蕨属（Pteridium Gled. ex Scop）分布范围极广，几乎遍布于全世界。关于此属的属下分类一直争论不休，主要是因为此属的分布广，形态变异比较大，变异类型之间形态差异不显著，缺乏明确的鉴别性状，或者变异类型之间存在过渡。 本研究利用叶绿体rps4-trnS DNA序列和trnS-G DNA序列构建了世界不同地区蕨属植物的系统关系及中国区域蕨属植物的系统关系，同时构建了世界不同地区蕨属植物的单倍型关系。我们发现，（1）南美洲和澳洲的蕨属植物分化最早;（2）北美洲的蕨属植物遗传变异最丰富，有多条相互独立的进化线（evolutionary lineages）;（3）欧亚大陆和非洲的蕨属植物都与北美洲具有密切关系;（4）大洋洲的蕨属植物同时受南美洲和亚洲蕨属植物的影响;（5）东亚的蕨属植物直接受北美洲蕨属植物的影响，与欧洲和非洲没有直接的关系;（6）非洲和欧洲的蕨属植物关系密切，有着相同的起源。 根据不同地点的蕨属植物的系统关系和单倍型Network关系，我们认为，蕨属植物起源于南美洲，而后向北美洲和澳洲扩散。在北美洲东部和东南部蕨属植物得到繁荣并分别向三个方向扩散与分化。第一个方向是朝北美西部扩散，第二个方向是两次独立扩散到亚洲，第三个方向是扩散到非洲，进而由非洲向欧洲扩散。 根据叶绿体基因所揭示的世界不同地区蕨属植物的发生和发展规律结合前人的研究，我们认为蕨属包含四个物种。Pteridium aquilinum (L.) Kuhn，分布于北美洲、亚洲、非洲和欧洲。该种分布广泛，存在一定的地理分化，可进一步划分8个亚种。Pteridium esculentum (G. Forst.) Cokayne，分布于南美洲，并扩散到澳大利亚，甚至东南亚国家。Pteridium caudatum (L.) Maxon，分布于中美洲和南美洲，是个异源四倍体。Pteridium semihastatum (Wall. ex Ag.) S.B.Andrews，分布于澳洲和东南亚，是个异源四倍体。 通过分子数据和形态分析相结合，作者认为中国蕨属包括两个亚种，即蕨[Pteridium aquilinum (L.) Kuhn subsp.japonicum (Nakai) Á.Löve & D.Löve]和毛轴蕨[Pteridium aquilinum (L.) Kuhn subsp. revolutum (Bl.) X. Q. Chen, stat. nov.]。作者认为，《中国植物志》中记载的食蕨，特有种云南蕨、糙轴蕨、镰羽蕨和长羽蕨并不存在或只是蕨或毛轴蕨的变形，或者毛轴蕨与蕨的杂交个体。 为了今后更进一步研究蕨属植物的系统与进化关系、居群的遗传结构等问题，作者还分离了8个具有多态性的微卫星位点，探讨了微卫星引物开发设计过程中如何提高效率等问题。

Adaptive diversification of bitter taste receptor genes in mammalian evolution

The diversity and evolution of bitter taste perception in mammals is not well understood. Recent discoveries of bitter taste receptor (T2R) genes provide an opportunity for a genetic approach to this question. We here report the identification of 10 and 30 putative T2R genes from the draft human and mouse genome sequences, respectively, in addition to the 23 and 6 previously known T2R genes from the two species. A phylogenetic analysis of the T2R genes suggests that they can be classified into three main groups, which are designated A, B, and C. Interestingly, while the one-to-one gene orthology between the human and mouse is common to group B and C genes, group A genes show a pattern of species- or lineage-specific duplication. It is possible that group B and C genes are necessary for detecting bitter tastants common to both humans and mice, whereas group A genes are used for species-specific bitter tastants. The analysis also reveals that phylogenetically closely related T2R genes are close in their chromosomal locations, demonstrating tandem gene duplication as the primary source of new T2Rs. For closely related paralogous genes, a rate of nonsynonymous nucleotide substitution significantly higher than the rate of synonymous substitution was observed in the extracellular regions of T2Rs, which are presumably involved in tastant-binding. This suggests the role of positive selection in the diversification of newly duplicated T2R genes. Because many natural poisonous substances are bitter, we conjecture that the mammalian T2R genes are under diversifying selection for the ability to recognize a diverse array of poisons that the organisms may encounter in exploring new habitats and diets.

Culture of the terrestrial cyanobacterium, Nostoc flagelliforme (Cyanophyceae), under aquatic conditions

Both colonies and free-living cells of the terrestrial cyanobacterium, Nostoc flagelliforme (Berk. & Curtis) Bornet & Flahault, were cultured under aquatic conditions to develop the techniques for the cultivation and restoration of this endangered resource. The colonial filaments disintegrated with their sheaths ruptured in about 2 days without any desiccating treatments. Periodic desiccation played an important role in preventing the alga from decomposing, with greater delays to sheath rupture with a higher frequency of exposure to air. The bacterial numbers in the culture treated with seven periods of desiccation per day were about 50% less compared with the cultures without the desiccation treatment. When bacteria in the culture were controlled, the colonial filaments did not disintegrate and maintained the integrity of their sheath for about 20 days even without the desiccation treatments, indicating the importance of desiccation for N. flagelliforme to prevent them from being disintegrated by bacteria. On the other hand, when free-living cells obtained from crushed colonial filaments were cultured in liquid medium, they developed into single filaments with sheaths, within which multiple filaments were formed later on as a colony. Such colonial filaments were developed at 15, 25, and 30degreesC at either 20 or 60 mumol photons.m(-2).s(-1); colonies did not develop at 180 mumol photons.m(-2).s(-1), though this light level resulted in the most rapid growth of the cells. Conditions of 60 mumol photons.m(-2).s(-1) and 25degrees C appeared to result in the best colonial development and faster growth of the sheath-held colonies of N. flagelliforme when cultured indoor under aquatic conditions.

Studies on polysaccharides from three edible species of Nostoc (Cyanobacteria) with different colony morphologies: Comparison of monosaccharide compositions and viscosities of polysaccharides from field colonies and suspension cultures

Hot water-soluble polysaccharides woe extracted from field colonies and suspension cultures of Nostoc commune Vaucher, Nostoc flagelliforme Berkeley et Curtis, and Nostoc sphaeroides Kutzing. Excreted extracellular polymeric substances (EPS) were isolated from the media in which the suspension cultures were grown. The main monosaccharides of the field colony polysaccharides from the three species were glucose, xylose, and galactose, with an approximate ratio of 2:1:1. Mannose was also present, but the levels varied among the species, and arabinose appeared only in N. flagelliforme. The compositions of the cellular polysaccharides and EPS from suspension cultures were more complicated than those of the field samples and varied among the different species. The polysaccharides from the cultures of N. flagelliforme had a relatively simple composition consisting of mannose, galactose, glucose, and glucuronic acid, but no xylose, as was found in the field colony polysaccharides. The polysaccharides from cultures of N. sphaeroides contained glucose (the major component), rhamnose, fucose, xylose, mannose, and galactose. These same sugars were present in the polysaccharides from cultures of N. commune, with xylose as the major component. Combined nitrogen in the media had no qualitative influence on the compositions of the cellular polysaccharides but affected those of the EPS of N. commune and N. flagelliforme. The EPS of N. sphaeroides had a very low fetal carbohydrate content and thus was not considered to be polysaccharide in nature. The field colony polysaccharides could be separated by anion exchange chromatography into neutral and acidic fractions having similar sugar compositions. Preliminary linkage analysis showed that 1) xylose, glucose, and galactose were 1-->4 linked, 2) mannose, galactose, and xylose occurred as terminal residues, and 3) branch points occurred in glucose as 1-->3,4 and 1-->3,6 linkages and in xylose as a 1-->3,4 linkage. The polymer preparations from field colonies had higher kinematic viscosities than those from corresponding suspension cultures. The high viscosities of the polymers suggested that they might DE suitable for industrial uses.

Enhanced near-infrared photoluminescence from isoelectronic luminescent centers in sulfur-implanted silicon with copper or silver coimplantation

Enhanced near-infrared photoluminescence (PL) from sulfur-related isoelectronic luminescent centers in silicon was observed from thermally quenched sulfur-implanted silicon in which additional copper or silver ions had been coimplanted. The PL from the sulfur and copper coimplanted silicon peaked between 70 and 100 K and persisted to 260 K. This result strongly supports the original conjecture from the optical detection of magnetic resonance studies that the strong PL from sulfur-doped silicon comes from S-Cu isoelectronic complexes [Frens , Phys. Rev. B 46, 12316 (1992); Mason , ibid. 58, 7007 (1998).]. (c) 2007 American Institute of Physics.

Light-induced changes in diphasic nanocrystalline silicon films and solar cells

A series of diphasic nanocrystalline silicon films and solar cells was prepared using different hydrogen dilution ratios of silane by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD). It was observed that after light soaking the open circuit voltage (V-oc) of the diphasic solar cells increased, while that of amorphous silicon solar cells decreased. Raman scattering spectroscopy was performed on the series of diphasic silicon films before and after light soaking. It was found that after light soaking the nanostruclures in the diphasic nanocrystalline silicon films were changed. Both the grain sizes and grain volume fraction reduced, while the grain boundary components increased. These results provide experimental evidence for the conjecture that the light-induced increase in V-oc of the diphasic nanocrystalline solar cells might be induced by the changes in the nanostructure of the intrinsic layer. (c) 2006 Elsevier B.V. All rights reserved.

Light-induced changes in diphasic nanocrystalline silicon films and solar cells

A series of diphasic nanocrystalline silicon films and solar cells was prepared using different hydrogen dilution ratios of silane by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD). It was observed that after light soaking the open circuit voltage (V-oc) of the diphasic solar cells increased, while that of amorphous silicon solar cells decreased. Raman scattering spectroscopy was performed on the series of diphasic silicon films before and after light soaking. It was found that after light soaking the nanostruclures in the diphasic nanocrystalline silicon films were changed. Both the grain sizes and grain volume fraction reduced, while the grain boundary components increased. These results provide experimental evidence for the conjecture that the light-induced increase in V-oc of the diphasic nanocrystalline solar cells might be induced by the changes in the nanostructure of the intrinsic layer. (c) 2006 Elsevier B.V. All rights reserved.

华东地区木材腐朽菌多样性与资源研究

木材腐朽菌是生物多样性的重要组成部分，在森林生态系统中起着关键的降解还原作用；同时，木材腐朽菌还是重要的生物资源，与人类的生产与生活密切相关，具有重要的经济价值。因此，木腐菌一直是真菌研究的重点领域之一，然而过去对华东地区木腐菌的研究还非常薄弱，对华东地区木腐菌的种类和资源还缺乏清晰的认识。本文对华东地区不同森林生态类型中的木腐菌进行了广泛的调查采样，通过形态学、分子系统学和单孢融合交配实验，对华东地区的木腐菌多样性与资源进行了系统的研究，同时对具有重要经济意义和潜在应用价值的种类进行了菌种的分离保藏，并初步分析了华东地区木腐菌的区系特点。通过本论文的研究，提高了对华东地区木腐菌资源与多样性的认识，丰富了我国木材腐朽菌的种类，为控制林木病原菌、开发利用有益真菌资源提供了基本信息和科学依据。本论文的主要研究结论如下： 1．华东地区的木腐菌有3目13科92属270种，其中真菌新种6个，分别是：铁杉集毛孔菌Coltricia tsugicola Y.C. Dai & B.K. Cui，香榧嗜蓝孢孔菌Fomitiporia torreyae Y.C. Dai & B.K. Cui，拟囊状体大孔菌Megasporoporia cystidiolophora B.K. Cui & Y.C. Dai，菌索多年卧孔菌Perenniporia rhizomorpha B.K. Cui, Y.C. Dai & Decock，微小硬孔菌Rigidoporus minutus B.K. Cui & Y.C. Dai，浅黄芮氏孔菌Wrightoporia luteola B.K. Cui & Y.C. Dai；中国新记录种9个，分别是：紫多孢孔菌Abundisporus violaceus (Wakef.) Ryvarden，卡玛蜡孔菌Ceriporia camaresiana (Bourdot & Galzin) Bondartsev & Singer，撕裂蜡孔菌Ceriporia lacerata N. Maek., Suhara & R. Kondo，塔斯马尼亚集毛孔菌Coltriciella tasmanica (Cleland & Rodway) D.A. Reid，瑞克纤孔菌Inonotus rickii (Pat.) D.A. Reid，骨质多年卧孔菌Perenniporia minutissima (Yasuda) T. Hatt. & Ryvarden，灰硬孔菌Rigidoporus cinereus Núñez & Ryvarden，凹形栓孔菌Trametes ectypus (Berk. & M.A. Curtis) Gilb. & Ryvarden，变形干酪菌Tyromyces transformatus Núñez & Ryvarden。 2．利用分子系统学方法，确定了一些通过形态学研究难以鉴定或容易混淆的种类的分类地位，并对嗜蓝孢孔菌属、彩孔菌属和多年卧孔菌属进行了系统发育分析，发现木腐菌新种3个：Fomitiporia sp.、Hapalopilus sp. 和Perenniporia sp.。 3．华东地区的异担子菌为岛生异担子菌，并且存在两个生物种：T生物种和Y生物种。T生物种为腐生菌，Y生物种为兼性腐生菌，华东地区不存在多年异担子菌这一严重的森林病原菌。 4．华东地区的木腐菌种类丰富，组成复杂多样。优势科为多孔菌科，其次为锈革孔菌科，这两科的种类构成了华东地区木腐菌类区系的主体；优势属主要有多年卧孔菌属、多孔菌属、针层孔菌属和泊氏孔菌属。 4．华东地区木腐菌科的地理成分分为3类：热带亚热带成分，北温带成分和世界广布成分，以世界广布成分为主。属的地理成分分为5类：世界广布属，北温带分布属，热带–亚热带分布属，东亚–北美分布属，大洋洲–北温带分布属，以世界广布属和北温带分布属为主。种的地理成分分为8类：世界广布种，北温带分布成分，泛热带分布成分，亚–欧共有成分，东亚–北美共有成分，东亚–澳大利亚共有成分，东亚成分，中国特有种，以北温带分布种和世界广布种为主。 5．华东地区木腐菌的各主要区系成分均有分布，以世界广布成分和北温带成分为主，表现出明显的北温带性质，可能起源于北半球，华东地区木腐菌类的区系地理成分与其所处的地理位置、气候特点与植物区系的组成密切相关。此外，华东地区的中国特有种类也较为丰富，说明了华东地区木腐菌类的区系具有一定的独特性，也在一定程度上反映了华东地区生态环境条件的特殊性，而木腐菌的生长与环境条件和寄主树木种类有很大的关系。 6．华东地区的木腐菌资源非常丰富，林木病原菌有36种，其中新发现的病原菌有3种；野生的食用木腐菌有11种，野生的药用木腐菌64种，工业用木腐菌有28种。对其中的一种重要经济真菌——黄白多年卧孔菌进行了分离培养，找出了最佳生长条件：最适生长温度为25℃左右，相对最适pH值为5.5，相对最好的碳源为可溶性淀粉和葡萄糖，相对最好的氮源为酵母汁。

广西主要林区多孔菌生物多样性与资源的初步研究

广西壮族自治区是中国多孔菌资源比较丰富的区域之一，本研究对广西主要林区进行了初步调查，并根据形态学研究方法对广西地区的多孔菌进行了系统分类学研究。 结果显示，广西地区的多孔菌共有15科，60属，140种。研究过程中发现两个新种，分别是菌索容氏孔菌Junghuhnia rhizomorpha H.S. Yuan & Y.C. Dai和小孔大孢卧孔菌Megasporoporia microporela X.S. Zhou &Y.C. Dai；发现7个中国新记录种：萨拉氏灵芝Ganoderma sarasinii Steyaert，唐氏胶囊革菌Gloeocystidiellum donkii S.S. Rattan，线浅孔菌Grammothele lineata Berkeley & M.A. Curtis，粉状捷克革菌Jacksonomyces furfurellus (Bres.) Sheng H. Wu & Z.C. Chen，半伏容氏孔菌Junghuhnia separabilima (Pouzar) Ryvarden，非洲纵隔担孔菌Protomerulius africanus (Ryvarden) Ryvarden和日本芮氏孔菌Wrightoporia japonica Núñez & Ryvarden；78种为广西地区新记录种，占该地区已报道种类的55.7%。 依据分类学的研究结果，对广西地区的多孔菌的种类组成和地理成分进行了初步分析，结果显示，优势科为多孔菌科Polyporaceae（33.3%），其次为皱孔菌科Meripilaceae（10%），优势属为多孔菌属Polyporus（7.9%%）和针层孔菌属Phellinus（5.7%）；属的地理成分以世界广布属（68.3%）和热带–亚热带分布属（23.3%）为主，种的地理成分以泛热带分布成分（35%）和世界广布种（30%）为主。 经研究表明广西地区共有森林干基腐朽病原多孔菌21种，食用多孔菌菌有5种，药用多孔菌32种，工业用多孔菌17种，多孔菌资源较丰富。 对重要种类木蹄层孔菌Fomes fomentarius (L.:Fr.) Fr.进行了固体培养研究，结果显示木蹄层孔菌的营养菌丝生长最适培养温度为28℃，最适培养pH值为7，最适培养碳源为蔗糖，最适培养氮源为蛋白胨。