Quadratic nonlinear technologies for femtosecond lasers

Quadratic optical nonlinearity chi((2)) can be exploited in femtosecond lasers and regarded as a significant new degree of freedom for the design of short-pulse sources. We will review our recent progress on developing nonlinear quadratic technologies for femtosecond lasers. Our nonlinear laser technology offers new properties for femtosecond lasers, including optical parametric amplifier with novel working regime, efficient second harmonic generation, and time telescope.

“虚工件”法——提高柔性制造设备生产率和柔性的一种新方法

通常,在一台带有托板输送系统的柔性制造设备(如柔性制造单元)上一次在托板上只装夹一个零件进行加工。“虚工件”法是指在一个托板上装多个相同或不同的零件,将它们视为一个零件投入设备中,用对各零件的NC 程序进行相关处理后得到的 NC 新程序进行加工。应用这种方法可以提高生产率,提高柔性并有利于均衡生产。分析了应用“虚工件”法的一些限制条件及其技术实施中的苦干技术关键.

Filamentation control in the temperature gradient argon gas

A novel technique of controlling the evolution of the filamentation was experimentally demonstrated in an argon gas-filled tube. The entrance of the filament was heated by a furnace and the other end was cooled with air, which resulted in the temperature gradient distribution along the tube. The experimental results show that multiple filaments are merged into a single filament and then no filament by only increasing the temperature at the entrance of the filament. Also, the filament can appear and disappear after increasing the local temperature and input pulse energy in turn. This technique offers another degree of freedom to control the filamentation and opens a new way for multi-mJ level monocycle pulse generation through filamentation in the noble gas.

Some new bounds on eigenvalues of the Hadamard product and the Fan product of matrices

Let A and B be nonsingular M-matrices. A lower bound on the minimum eigenvalue q(B circle A(-1)) for the Hadamard product of A(-1) and B, and a lower bound on the minimum eigenvalue q(A star B) for the Fan product of A and B are given. In addition, an upper bound on the spectral radius rho(A circle B) of nonnegative matrices A and B is also obtained. These bounds improve several existing results in some cases and the estimating formulas are easier to calculate for they are only depending on the entries of matrices A and B. (C) 2009 Elsevier Inc. All rights reserved.

Genetic diversity of Chinese native pigs inferred from protein electrophoresis

We examined protein polymorphism of 20 native pig breeds in China and 3 introduced pig breeds. Thirty loci have been investigated, among which six loci were found to be polymorphic. Especially, the polymorphism of malate dehydrogenase (MDH), adenylate kinase (AK), and two new alleles of adenosine deaminase (ADA) had not been reported in domestic pigs and wild pigs. The percentage of polymorphic loci (P), the mean heterozygosity (H), and the mean number of alleles (A) are 0.200, 0.065, and 1.300, respectively. The degree of genetic variability of Chinese pigs as a whole was higher than that of goats, lower than that of cattle and horses, and similar to that of sheep. Using the gene frequencies of the 30 loci, Nei's genetic distance among the 20 native breeds in China and 3 introduced pig breeds was calculated by the formula of Nei. The program NEIGHBOR in PHYLIP 3.5c was chosen to construct an UPGMA tree and a NJ tree. Our results show that, of the total genetic variation found in the native pig breeds in China, 31% (0.31) is ascribable to genetic differences among breeds. About 69% of the total genetic variation is found within breeds. Most breeds are in linkage disequilibrium. The patterns of genetic similarities between the Chinese native pig breeds were not in agreement with the proposed pig type classification.

New Insights into the Evolution of Intronic Sequences of the beta-fibrinogen Gene and Their Application in Reconstructing Mustelid Phylogeny

Mustelidae is the largest and most diverse family in the order Carnivora. The phylogenetic relationships among the subfamilies have especially long been a focus of study. Herein we are among the first to employ two new introns (4 and 7) of the nuclear P-f

On the origin and evolution of new genes-a genomic and experimental perspective

The inherent interest on the origin of genetic novelties can be traced back to Darwin. But it was not until recently that we were allowed to investigate the fundamental process of origin of new genes by the studies on newly evolved Young genes. Two indisp

Symmetrical 1-pyrrolidineacetamide showing anti-HIV activity through a new binding site on HIV-1 integrase

Aim: To characterize the functional and pharmacological features of a symmetrical 1-pyrrolidineacetamide, N,N'-(methylene-di-4,1-phenylene) bis-1-pyrrolidineacetamide, as a new anti-HIV compound which could competitively inhibit HIV-1 integrase (IN) bindi

Anti HIV-1 Agents 2. Discovery of Dibenzofurans as New HIV-1 Inhibitors In Vitro

Ten dibenzofurans were synthesized and evaluated as human immunodeficiency virus (HIV)-1 inhibitors in vitro for the first time. Among these compounds, compounds 1, 6, 7 and 8 demonstrated significant anti-HIV-1 activity. Especially compound 1 showed the

A NEW SPECIES FROM SOUTHWESTERN CHINA IN THE AFRO-PALEARCTIC LINEAGE OF THE HORSESHOE BATS (RHINOLOPHUS)

A new species of horseshoe bat (Chiroptera: Rhinolophidae) is described from southwestern China. The presence of a wedge-shaped sella and pointed connecting process of the nose leaf aligns the new species to the landeri group in the Afro-Palearctic lineag

Amplitude/frequency of spontaneous mEPSC correlates to the degree of long-term depression in the CA1 region of the hippocampal slice

Prior synaptic or cellular activity influences degree or threshold for subsequent induction of synaptic plasticity, a process known as metaplasticity. Thus, the continual synaptic activity, spontaneous miniature excitatory synaptic current (mEPSC) may correlate to the induction of long-teen depression (LTD). Here, we recorded whole-cell EPSC and mEPSC alternately in the Schaffer-CA1 synapses in brain slice of young rats, and found that this recording configuration affected neither EPSC nor mEPSC. Low frequency stimulation (LFS) induced variable magnitudes of LTD. Remarkably, larger magnitudes of LTD were significantly correlated to smaller amplitude/lower frequency of the basal mEPSC. Furthermore, under the conditions reduced amplitude/frequency of the basal mEPSC by exposure to behavioral stress immediately before slice preparation or low concentration of calcium in bath solution, the magnitudes of LTD were still inversely correlated to mEPSC amplitude/frequency. These new findings suggest that spontaneous mEPSC may reflect functional and/or structural aspects of the synapses, the synaptic history ongoing metaplasticity. (C) 2005 Elsevier B.V. All rights reserved.

New insights into the karyotypic relationships of Chinese muntjac (Muntiacus reevesi), forest musk deer (Moschus berezovskii) and gayal (Bos frontalis)

To investigate the karyotypic relationships between Chinese muntjac (Muntiacus reevesi), forest musk deer (Moschus berezovskii) and gayal (Bos frontalis), a complete set of Chinese muntjac chromosome-specific painting probes has been assigned to G-banded chromosomes of these three species. Sixteen autosomal probes (i.e. 6-10, 12-22) of the Chinese muntjac each delineated one pair of conserved segments in the forest musk deer and gayal, respectively. The remaining six autosomal probes (1-5, and 11) each delineated two to five pairs of conserved segments. In total, the 22 autosomal painting probes of Chinese muntjac delineated 33 and 34 conserved chromosomal segments in the genomes of forest musk deer and gayal, respectively. The combined analysis of comparative chromosome painting and G-band comparison reveals that most interspecific homologous segments show a high degree of conservation in G-banding patterns. Eleven chromosome fissions and five chromosome fusions differentiate the karyotypes of Chinese muntjac and forest musk deer; twelve chromosome fissions and six fusions are required to convert the Chinese muntjac karyotype to that of gayal; one chromosome fission and one fusion separate the forest musk deer and gayal. The musk deer has retained a highly conserved karyotype that closely resembles the proposed ancestral pecoran karyotype but shares none of the rearrangements characteristic for the Cervidae and Bovidae. Our results substantiate that chromosomes 1-5 and 11 of Chinese muntjac originated through exclusive centromere-to-telomere fusions of ancestral acrocentric chromosomes. Copyright (C) 2005 S. Karger AG, Basel.

Geographic variation of the Anderson's Niviventer (Niviventer andersoni) (Thomas, 1911) (Rodentia: Muridae) of two new subspecies in China verified with cranial morphometric variables and pelage characteristics

A total of 66 specimens of Niviventer andersoni with intact skulls was investigated on pelage characteristics and cranial morphometric variables. The data were subjected to principal component analyses as well as to discriminant analyses, and measurement

A new species of Genus Triplophysa (Nemacheilinae: Balitoridae), Triplophysa longipectoralis sp nov, from Guangxi, China

A new species, Triplophysa longipectoralis, is described from Liujiang River, Guangxi, China. The new species is distinguished from other species of Triplophysa by the following combination of characters: pectoral fin highly developed, reaching beyond pel