微纤织物的机械和化学整理

０．引言日本采用较低旦长丝及碱减量工艺生产涤纶织物的方法始于７０年代。在这种加工过程中，先用传统的长丝（即大于１旦的长丝）制成机织物，然后用热碱溶液对织物进行水解处理，使长丝表面的聚合物溶解，从而减少单丝和束丝的纤度。这种碱减量处理工艺提高了织物的回弹性、悬垂性和覆盖性，同时也产生了温暖、干燥和仿真丝手感，并带丝鸣效果。日本厂家采用的碱减量率高达４０～５０％，但在美国典型的碱减量率仅为８～１５％。当日本纤维制造商认识了碱减量处理的优点后，根据杜帮６０年代发表的专利，开发了１旦及小于１旦的长丝。这…     

Methods of reducing loss of efficiency due to discreteness of distributions

All models of this paper involve R x C contingency tables in which the total frequency is fixed (full multinomial model), or in which the row totals are fixed (product multinomial model). For the most part, we assume that the column categories are ordered. For the full multinomial model the null hypothesis of interest is independence, i.e., the (ij)th cell probability is the product of the marginal probabilities of the ith row and jth column. In the product multinomial model the null hypothesis is that the R multinomial distributions have the same vector of cell probabilities. Our review includes (1) a careful listing of two-sided and one-sided alternatives, and (2) methodology to reduce the loss of efficiency of tests because of the discreteness of the model (The methodologies discussed are efficient in several senses. Tests are exact. Tests have very favorable and robust power properties. Tests make use of back-up statistics, thereby providing a finer grid of p-values. In some special cases, e.g., a 2 x C table and a one-sided alternative, conditional p-values are found, within seconds, simply by entering row frequencies into a given website. Thus, computational efficiency is exceptional.), and (3) a critique of some exact linear permutation tests (that are conditional on row and column margins) for both two-sided and some one-sided alternatives. Furthermore, recommendations as to which tests to use for specific alternatives are made.     

用改性褐煤改良盐碱土

用有自动氧化倾向的褐煤为主,在工业条件下制备了土壤改良剂,该改良剂用于提高盐碱土作作的产量。选择能使土壤酸—碱性质及氧化—还原性质正常化的磷酸氢二铵作为褐煤改性的添加剂。     

Comparison of indoor air quality in electrified and un-electrified dwellings in rural South African villages

A feasibility study was undertaken to assess the suitability of South African rural villages due to be electrified, for the purposes of undertaking a large-scale study of the impact of reductions in indoor air pollution on acute lower respiratory infections. As part of the feasibility study, quantitative assessments of indoor air pollution in non-electrified and electrified dwellings were performed. Concurrent measurements were made of levels of respirable particulate matter (RSP-stationary), and carbon monoxide (CO) (personal on children <18 months), as well as a stationary co-located with RSP) over a 24-h period in 52 un-electrified and 53 electrified dwellings. The proportion of dwellings with a detectable 24-h concentration of RSP was significantly higher in un-electrified (48.1%) than electrified dwellings (24.5%) (chi(2) = 6.30 on 1 d.f., P = 0.012). In addition a Kruskal-Wallis test (adjusted for ties) showed that the distribution of RSP differed between un-electrified and electrified areas (Kruskal-Wallis chi(2) = 8.20 on 1 d.f., P = 0.014). In those dwellings where some RSP was detected, the amount was on average higher in the un-electrified areas (mean 162 microg/m(3), median 107 microg/m(3)) than in the electrified areas (mean 77 microg/m(3), median 37.5 microg/m(3)). Stationary (kitchen CO) levels in un-electrified dwellings ranged from 0.36 to 20.95 p.p.m. However, in electrified dwellings, kitchen levels ranged from 0 to 11.8 p.p.m. When mean concentrations of CO were compared between electrified and un-electrified dwellings using a two-sample t-test (on log-transformed data), there was overwhelming evidence (P = 0.0004) that the mean level of log (CO) in the kitchen was higher in the un-electrified areas (1.25 vs. 0.69) and also overwhelming evidence (P < 0.0001) that the mean level of log (CO) on the child was higher in the un-electrified areas (0.83 vs. 0.34). Of importance in terms of both policy and for a potential future large-scale study, is that measurable significant differences in indoor pollutants between electrified and un-electrified dwellings during summer were found in spite of only partial transition to electricity use for cooking in electrified villages. PRACTICAL IMPLICATIONS: It is estimated that at least two-thirds of all households in the developing world are still primary dependent on biomass fuels and coal. This situation applies to 59% of rural households in South Africa. In the last decade a program of providing electricity to three million homes has been underway in South Africa. Among others this intervention aims to reduce exposure to pollutants from burning biomass fuels and reduce detrimental health effects, especially in young children. This study provides scientific evidence that electrified homes in South African villages have lower levels of air pollution (RSP and CO) relative to their non-electrified counterparts.     

Mutasynthesis-derived myxalamids and origin of the isobutyryl-CoA starter unit of myxalamid B

Myxalamids are potent inhibitors of the eukaryotic electron transport chain produced by different myxobacteria. Here, we describe the identification of the myxalamid biosynthesis gene cluster from Myxococcus xanthus. Additionally, new myxalamids (5-13) have been obtained by mutasynthesis from bkd mutants of M. xanthus and Stigmatella aurantiaca. Moreover, as these bkd mutants are still able to produce myxalamid B (2), the origin of the isobutyryl-CoA (IB-CoA) starter unit required for its biosynthesis has been determined. In a M. xanthus bkd mutant, IB-CoA originates from valine, but in S. aurantiaca this starter unit is derived from alpha-oxidation of iso-odd fatty acids, thereby connecting primary and secondary metabolism.     

Exciton diffusion and charge transfer dynamics in nano phase-separated P3HT/PCBM blend films

Exciton quenching dynamics has been systematically studied in pristine P3HT and nano phase separated P3HT/PCBM blend films under various excitation intensities by femtosecond fluorescence up-conversion technique. The behaviors of excitons in the films can be well described by a three-dimensional diffusion model. The small diffusion length and large charge transfer radius indicate that excitons reach the interface most likely by the delocalization of the excitons in P3HT fibrillar at a range of 4.8-9 nm so that the excitons can quickly delocalize in the P3HT domain to reach the interface (instead of by diffusion).     

Asymmetric anatase TiO₂ nanocrystals with exposed high-index facets and their excellent lithium storage properties

In this work, we demonstrate a unique organic solvent system to synthesize asymmetric anatase TiO(2) nanocrystals with a bipyramidal structure, where the upper pyramid is bound by (201) facets, and the lower pyramid is bound by (401) surfaces. Due to the high surface energy of these (401) high-index facets, the nanocrystals tend to assemble on these facets to minimize the free energy, leading to the formation of a dandelion-like hierarchical structure.     

The individual and combined effects of deoxynivalenol and aflatoxin b(1) on primary hepatocytes of cyprinus carpio

Aflatoxin B(1) (AFB(1)) and deoxynivalenol (DON) are important food-borne mycotoxins that have been implicated in animal and human health. In this study, individual and combinative effects of AFB(1) and DON were tested in primary hepatocytes of Cyprinus carpio. The results indicated that the combinative effects of AFB(1) and DON (0.01 μg/mL AFB(1) and 0.25 μg/mL DON; 0.02 μg/mL AFB(1) and 0.25 μg/mL DON; 0.02 μg/mL AFB(1) and 0.5 μg/mL DON) were higher than that of individual mycotoxin (P < 0.05). The activity of AST, ALT and LDH in cell supernatant was higher than that of control group (P < 0.05) when the mycotoxins were exposed to primary hepatocytes for 4 h. The decreased cell number was observed in tested group by inverted light microscopy. The mitochondrial swelling, endoplasmic reticulum dilation and a lot of lipid droplets were observed in primary hepatocytes by transmission electron microscope. Therefore, this combination was classified as an additive response of the two mycotoxins.