Knotted wave dislocation with the hopf invariant

We study the wave dislocations with an induced gauge potential. The topological current characterized the wave dislocations is constructed with the dual of Abelian gauge field. And the topological charges and locations of the wave dislocations are determined by the phi-mapping topological current theory. Furthermore, it is shown that the knotted wave dislocations can be described with a Hopf invariant in the wave field. At last we discussed the evolution of the knotted wave dislocations.

A Particle-in-cell scheme of the RFQ in the SSC-Linac

A 52 MHz Radio Frequency Quadrupole (RFQ) linear accelerator (linac) is designed to serve as an initial structure for the SSC-Linac system (injector into Separated Sector Cyclotron). The designed injection and output energy are 3.5 keV/u and 143 keV/u, respectively. The beam dynamics in this RFQ have been studied using a three-dimensional Particle-In-Cell (PIC) code BEAMPATH. Simulation results show that this R,FQ structure is characterized by stable values of beam transmission efficiency (at least 95%) for both zero-current mode and the space charge dominated regime. The beam accelerated in the RFQ has good quality in both transverse and longitudinal directions, and could easily be accepted by Drift Tube Linac (DTL). The effect of the vane error and that of the space charge on the beam parameters have been studied as well to define the engineering tolerance for RFQ vane machining and alignment.

低碳:国家可持续发展实验区建设的重要方向

<正>经过20多年的建设与发展,国家可持续发展实验区依靠科技进步、机制创新,在协调社会经济发展与环境资源关系、促进经济发展、提高居民生活质量、探索新型工业化道路等诸多方面进行了积极的探索和实践,极大地推动了区域经济社会的协调发展,已成为实施国家可持续发展战略的

开发生产长效碳酸氢铵增强小氮肥企业活力

<正>市场经济的发展使碳铵企业陷入了困境首先,从产品本身来讲,碳铵的化学性质不稳定,含氮量只有17%,氮素利用率低(25%左右),肥效期短(35～45天),

鱇白鱼的池塘人工驯养方法

本发明涉及一种鱇白鱼的池塘人工驯养方法，属鱼产品养殖技术领域。鱇白鱼的池塘人工驯养方法为先用消毒剂对池塘进行清塘，随后放入清水，其水深为0.8米，此时将鱼苗放入池中，驯养期间水温在8-25℃，鱼苗投喂时间为每日二次，投喂的饲料分别为：一个月前喂蛋黄或轮虫，随后喂蛋黄、豆浆和混合饲料，5个月后投喂混合饲料，饲料的喂量为蛋黄每次5个，豆浆每天0.5公斤黄豆研磨成浆，混合饲料早期每次1公斤，随着鱼体长大酌情增量。采用本鱇白鱼的池塘人工驯养方法，具有操作简便，成本低廉，鱼苗成活率高，并将在自然状况下，生长到5厘米左右时便进入40-50米的深水区生长发育，直到性成熟后才洄游到浅水区的砾石砂滩和溶洞出水口处产卵的抚仙湖特有鱼类——鱇白鱼驯化成为一种池塘人工养殖品种等优点。

Characterization of the structural and functional changes of hemoglobin in dimethyl sulfoxide by spectroscopic techniques

Circular dichroism (CD), fourier transform infrared (FTIR), and fluorescence spectroscopy were used to explore the effect of dimethyl sulfoxide (DMSO) on the structure and function of hemoglobin (Hb). The native tertiary structure was disrupted completely when the concentration of DMSO reached 50% (v/v), which was determined by loss of the characteristic Soret CD spectrum. Loss of the native tertiary structure could be mainly caused by breaking the hydrogen bonds, between the heme propionate groups and nearby surface amino acid residues, and by disorganizing the hydrophobic interior of this protein. Upon exposure of Hb to 52% DMSO for ca. 12 h in a D2O medium no significant change in 1652 cm(-1) band of the FTIR spectrum was produced, which demonstrated that alpha-helical structure predominated. When the concentration of DMSO increased to 57%: (1) the band at 1652 cm(-1) disappeared with the appearance of two new bands located at 1661 and 1648 cm(-1); (2) another new band at 1623 cm(-1) was attributed to the formation of intermolecular beta-sheet or aggregation, which was the direct consequence of breaking of the polypeptide chain by the competition of S=O groups in DMSO with C=O groups in amide bonds. Further increasing the DMSO concentration to 80%, the intensity at 1623 cm(-1) increased, and the bands at 1684, 1661 and 1648 cm(-1) shifted to 1688, 1664 and 1644 cm(-1), respectively. These changes showed that the native secondary structure of Hb was last and led to further aggregation and increase of the content of 'free' amide C=O groups. In pure DMSO solvent, the major band at 1664 cm(-1) indicated that almost all of both the intermolecular beta-sheet and any residual secondary structure were completely disrupted. The red shift of the fluorescence emission maxima showed that the tryptophan residues were exposed to a greater hydrophilic environment as the DMSO content increased. GO-binding experiment suggested that the biological function of Hb was disrupted seriously even if the content of DMSO was 20%. (C) 1998 Elsevier Science B.V. All rights reserved.

Isolation, spectra, structure, and ring-opening polymerization of strained macrocyclic aryl(ether ketone) dimer

Macrocyclic arylene ether ketone dimer was isolated from a mixture of cyclic oligomers obtained by the nucleophilic substitution reaction of bisphenol A and 4,4'-difluorobenzophenone and easily polymerized to high molecular weight linear poly(ether ketone). The cyclic compound was characterized by FTIR, H-1- and C-13-NMR, and single-crystal x-ray diffraction. Analysis of the spectral and crystal structure reveals extreme distortions of he phenyl rings attached to the isopropylidene center and of the turning points of the molecular polygons. The release of the ring strain on ring-opening combined with entropical difference between the linear polymer chain and the more rigid macrocycle at temperatures of polymerization may be the proposed motivating factors in the polymerization of this precursor to high molecular weight poly(ether ketone). (C) 1997 John Wiley & Sons, Inc.

稀土（Nd，Pr）（Ⅲ）双酞菁衍生物的合成、表征和气敏特性

合成了八－４－（四氢糠氧基）酞菁钕（Ⅲ）（Ａ）、八－４－（β－萘氧基）酞菁钕（Ⅲ）（Ｂ）、八－４－（２，４－二叔戊基苯氧基）酞菁钕（Ⅲ）（Ｃ）和八－４－（２，４－二叔戊基苯氧基）酞菁镨（Ⅲ）（Ｄ）４种新的稀土（Ｎｄ、Ｐｒ）（Ⅲ）双酞菁衍生物，经元素分析、红外光谱、核磁共振谱表征．紫外可见光谱表明，它们在氯仿（１０￣（－６）ｍｏｌ／Ｌ）溶液中以单分子形式存在．热重分析证明配合物的热稳定性：Ｂ＞Ｃ～Ｄ＞Ａ．４种配合物成膜性好，Ｚ型沉积形成的单层ＬＢ膜材料对氨气有响应，特别是八－４－（四氢糠氧基）酞菁钕（Ⅲ）的膜材料对氨气很敏感，可与铜酞菁ＬＢ膜气敏性相比．

Sex-linked microsatellite marker detected in the female gametophytes of Undaria pinnatifida (Phaeophyta)

P>In our microsatellite analysis of three male and three female gametophytes of Undaria pinnatifida (Harv.) Suringar, a microsatellite marker (part of the locus Up-AC-2A8, GenBank accession no. AY738602.1) was only polymerase chain reaction-amplified in three female gametophytes. This putative female-specific marker was further tested by the use of 32 male and 21 female gametophytes maintained in the Marine Biological Culture Collection Centre, China. In addition, three sporophytes were included for confirmation. Results showed that the marker was present in all of the female gametophytes and sporophyte cultures, but absent in all of the male gametophytes. To our knowledge, this is the first sex-related marker ever reported in U. pinnatifida. The discovery of this marker will accelerate gender identification and shed light on our understanding of the mechanisms of sex determination at a molecular level in this commercially important seaweed.

Seeding nets with neutral spores of the red alga Porphyra umbilicalis (L.) Kutzing for use in integrated multi-trophic aquaculture (IMTA)

Nets in traditional Porphyra mariculture are seeded with conchospores derived from the conchocelis phase, and spend a nursery period in culture tanks or calm coastal waters until they reach several centimeters in length. Some species of Porphyra can regenerate the foliose phase directly through asexual reproduction, which suggests that the time, infrastructure, and costs associated with conchocelis culture might be avoided by seeding nets with asexual spores. Here, we present work from a short-term mariculture study using nets seeded with asexual spores (neutral spores) of a native Maine species of Porphyra. Porphyra umbilicalis (L.) Kutzing was selected for this proof of concept research because of its reproductive biology, abundance across seasons in Maine, and evidence of its promise as a mariculture crop. We studied the maturation, release, and germination of the neutral spores to develop an appropriate seeding protocol for nets, followed by development of a nursery raceway to provide an easily manipulated environment for the seeded nets. Neutral spores were produced throughout the year on the central Maine coast,however, there was a temporal variability in the number and survival of released neutral spores, depending upon thallus position in the intertidal zone. Small thalli were strictly vegetative, but most thalli reproduced by neutral spores- sexual reproduction was absent. Neutral spores germinated quickly at 10 and 15 'C, but germination was delayed at 5 degrees C. Unlike some algal zygotes and spores, neutral spores of R umbilicalis required light to germinate; however, irradiances of 25 and 100 mu mol photons M-2 S-1 were equally sufficient for germination. Rafts of seeded nets were deployed in Cobscook Bay, Maine, at two distances from salmon aquaculture pens and at a control site on a nearby, fallow aquaculture site (no salmon). There was no difference in nitrogen content of harvested thalli; however, both the density and the surface area of harvested thalli were different among the sites. The possible causes of these differences are discussed in the context of potential use of P umbilicalis in IMTA. (C) 2007 Elsevier B.V. All rights reserved.