苝四甲酸标记PVA荧光浆料的制备及其性能

为解决目前纺织业中浆液浸透性与被覆性测定方法精准度低、品种适应性差等问题,以聚乙烯醇(PVA)为常用浆料代表,采用不同质量浓度的荧光分子3,4,9,10-苝四甲酸(PTCA)对PVA进行标记,制备出具有不同标记率的PVA荧光浆料并将其对纯棉经纱进行上浆。在制作成浆纱切片后,以荧光显微镜及Photoshop软件为工具,测定出切片横截面各组成部分面积,推算获取PVA浆液对纱线的浸透率和被覆率,同时对比测试了PTCA-PVA与未标记PVA浆纱的强伸、耐磨及毛羽贴服等主要使用性能。结果表明:当PTCA-PVA的标记率摩尔分数为0.0127%时,此改性PVA显示出良好的荧光性能。经PTCA-PVA上浆后,纱线的主要使用性能与未标记PVA所浆纱线的性能较为相近,选取PTCA对机织生产中的主要浆料进行荧光标记可为浆液对纱线浸透性与被覆性的评估提供一种准确度、普适度更高的研究方法。

荧光标记田菁胶在上浆检测中的应用

探讨用于检测田菁胶浆液浸透率、被覆率的荧光标记物质的制备与应用效果。针对现有测定方法存在精准度低、品种适应性差等问题,制备出具有不同荧光分子异硫氰酸荧光素标记率的田菁胶荧光浆料,测定了田菁胶浆纱切片横截面和被浆液浸透部分的面积,计算田菁胶浆液对棉纱的浸透率和被覆率。结果表明:当异硫氰酸荧光素⁃田菁胶的标记率为0.509%时,其荧光性能较为优异,且其浆纱使用性能与未标记田菁胶浆纱十分接近。认为:采用异硫氰酸荧光素对纺织浆料进行荧光标记可为浆液浸透率和被覆率的准确测定提供一条新路径。

IMPACT OF APPLYING BCTMP TO WOOD-FREE LWC ON ITS PERFORMANCE

Substituting bleached CTMP (BCTMP) for chemical pulps, such as bleached hardwood kraft pulp in many paper grades is in rising demand for reducing cost and improving product performance. In this paper we investigated the effect of substituting aspen BCTMP for hardwood kraft pulp (varying from 10% to 30%) on product performance of light weight coated paper. The results show that the tensile index increases and other strength properties are essentially unchanged as the substitution level increases. With the increased BCTMP substitution level, the surface roughness of base sheets increases slightly, while coating coverage of base sheets is not affected significantly. The increased BCTMP substitution results in an increase in porosity of the base sheets, but does not change the average pore diameter. Increasing BCTMP substitution level leads to a slight decrease in gloss and an increase in surface roughness of the coated paper, however the latter can be compensated by a higher nip load calendering.

Scaling of Soil Carbon,Nitrogen,Phosphorus and C:N:P Ratio Patterns in Peatlands of China

Inspired by the importance of Redfield-type C:N:P ratios in global soils,we looked for analogous patterns in peatlands and aimed at deciphering the potential affecting factors.By analyzing a suite of peatlands soil data(n = 1031),mean soil organic carbon(SOC),total nitrogen(TN) and total phosphorous(TP) contents were 50.51%,1.45% and 0.13%,respectively,while average C:N,C:P and N:P ratios were 26.72,1186.00 and 46.58,respectively.C:N ratios showed smaller variations across different vegetation coverage and had less spatial heterogeneity than C:P and N:P ratios.No consistent C:N:P ratio,though with a general value of 1245:47:1,was found for entire peatland soils in China.The Northeast China,Tibet,Zoigê Plateau and parts of Xinjiang had high soil SOC,TN,TP,and C:P ratio.Qinghai,parts of the lower reaches of the Yangtze River,and the coast zones have low TP and N:P ratio.Significant differences for SOC,TN,TP,C:N,C:P and N:P ratios were observed across groups categorized by predominant vegetation.Moisture,temperature and precipitation all closely related to SOC,TN,TP and their pairwise ratios.The hydrothermal coefficient(RH),defined as annual average precipitation divided by temperature,positively and significantly related to C:N,C:P and N:P ratios,implying that ongoing climate change may prejudice peatlands as carbon sinks during the past 50 years in China.

Degradation of Wetlands on the Qinghai-Tibet Plateau:A Comparison of the Effectiveness of Three Indicators

The Qinghai-Tibet Plateau encompasses a large quantity of wetlands, some of which have been degraded to varying severity levels. In the literature, a number of degradation indicators have been proposed to evaluate ecological health of wetlands, but their effectiveness in the plateau environment remains unknown. In this study, we assessed the effectiveness of three degradation indicators, soil moisture content at lo em deep, vegetative cover, and density of pika burrows. The degradation severity of wetlands in Maduo County on the Qinghai-Tibet Plateau is enumerated at four levels, intact, slight, moderate and severe. Analysis of xo6 samples collected in the field demonstrates that the density of pika burrows is the least reliable indicator. By comparison, vegetative cover and underlying soil moisture content are more reliable, even though neither is a perfect indicator as the difference among adjacent levels of severity as revealed by t-test is not always statistically significant. The imperfection of vegetative cover as an indicator is due to its variation among different types of wetlands. The limitation of moisture content is attributed to its non-linear relationship with wetland degradation. Above the threshold of about 50% in moisture content wetlands are unlikely to be degraded. It is recommended that moisture be measured at the point near the surface and vegetative cover be further differentiated by species in order to improve their effectiveness.

Ranking Agricultural Sub-basins for Environmental Protection

Reconstructing long-term vegetation buffers along streams in agricultural landscapes has become a common environmental restoration strategy for improving water quality and wildlife habitat connectivity.This article developed a linear weighted model to rank the priority of agricultural sub-basins for the establishment of vegetative buffers.The method was applied to an agricultural watershed of 146 km2 in Ontario,Canada.The watershed was divided into 11 sub-basins as basic decision units.In each subbasin,four stream buffer schemes with widths of 5,10,15 and 20m were generated.For each buffer,three benefit-cost attributes of reconstructing vegetation cover were estimated,which include acreage per dollar,sediment abatement per dollar and habitat benefit per dollar.These attributes were first normalized using a linear normalization approach to eliminate the effects across different units.The normalized attributes were then integrated using a simple additive weighting method to rank the 11 sub-basins for prioritizing spatial restoration action.A sensitivity analysis was also conducted to observe the impact of a change in attribute weights on the management decisions.The results suggest that vegetation buffers reconstructed for achieving the water quality goal are not effective in improving habitat connectivity and vice versa.

Economic Value Evaluation of Wetland Service in Yeyahu Wetland Nature Reserve,Beijing

Based on multi-source data,this paper evaluated the economic value of ecological services in the Yeyahu Wetland Nature Reserve,Beijing,China.The ecological services of wetland included gas regulation,water quality im-provement,biodiversity maintenance,erosion control,water supply,recreational opportunity,raw material supply and existence value.Multiple conventional evaluation methods were used to calculate the value of eight wetland services.The results showed that significant values came from biodiversity maintenance and recreational opportunity.The main reasons were as follows.Firstly,Yeyahu Wetland Nature Reserve was the habitat for migrant birds,and government had payed more efforts to protect precious birds.Secondly,the population is large in Beijing.People enjoyed going outside and enjoyed the natural and artificial wetland scenes.At the same time,most people were prepared to pay for wetland conservation.The decline of vegetation cover made the economic value of erosion control the lowest.While the shrink of water resource and the deteriorative water quality caused the economic value of water supply lower.The evaluation results could help decision-makers understand the present status of the Yeyahu Wetland Nature Reserve and provide a scientific basis for strategic decision.

Comparison Between Reconstructions of Global Anthropogenic Land Cover Change over Past Two Millennia

Three global datasets, the History Database of the Global Environment （HYDE）, Kaplan and Krurnhardt （KK） and Pongratz of reconstructed anthropogenic land cover change （ALCC） were introduced and compared in this paper. The HYDE dataset was recon- structed by Goldewijk and his colleagues at the National institute of Public ttealth and the Environment in Netherland, covering the past 12 000 years. The KK dataset was reconstructed by Kaplan and his colleagues, the Soil-Vegetation-Atmosphere Research Group at the Institute of Environmental Engineering in Switzerland, covering the past 8000 years. The Pongratz dataset was reconstructed by Pon- gratz and her colleagues at the Max Planck Institute for Meteorology in Germany, coveting AD 800-1992. The results show that the reconstructed datasets are quite different from each other due to the different methods used. The three datasets all allocated the historical ALCC according to human population density. The main reason causing the differences among the three datasets lies on the different relationships between population density and land use used in each reconstructed dataset. The KK dataset is better than the other two datasets for two important reasons. First, it used the nonlinear relationship between population density and land use, while the other two used the linear relationship. Second, Kaplan and his colleagues adopted the technological development and intensification parameters and considered the wood harvesting and the long-term fallow area resulted from shifting cultivation, which were neglected in the recon- structions of the other two datasets. Therefore, the KK dataset is more suitable as one of the anthropogenic forcing fields for climate simulation over the past two millennia that is recently concerned by two projects, the National Basic Research Program and the Strategic and Special Frontier Project of Science and Technology of the Chinese Academy of Sciences.

Spatiotemporal Dynamics of Forest and Mountain Formations in Auras Area, Algeria

Contrary to the countries of northern coast, the forest formations on Southern and East coast of the Mediterranean are in regression. With the combined action of the ax, fire and pasture, these ecosystems are subjected to a pressure of permanent degradation. Indeed, the degradation of the forest ecosystems represents one of the most important causes of reduction and erosion of the biodiversity in the world. The massif of Aur6s is located in the North-East of Algeria. The analysis of the spatiotemporal dynamics of this vulnerable vegetation is not approached yet. This study proposes a focus on the analysis of the dynamics of this vegetation and to study the factors of its degradation. For that, a methodological approach of diachronic follow-up between two dates was adopted by using any kind of old information sources （archives, aerial photographs, topographic maps） and recent （Images satellite of American Landsat and data of land）. The results reveal a degradation of vegetable cover thus expressing a very thorough reduction of the formations forest replaced by herbaceous formations very sensitive and threatened by the overgrazing.

Grass Cover Influences Hydrophysical Parameters and Heterogeneity of Water Flow in a Sandy Soil

Vegetation cover has a major effect on water flow in soils. Two sites, separated by distance of about 50 m, were selected to quantify the influence of grass cover on hydrophysical parameters and heterogeneity of water flow in a sandy soil emerging during a heavy rain following a long hot, dry period. A control soil （pure sand） with limited impact of vegetation or organic matter was obtained by sampling at 50 cm depth beneath a glade area, and a grassland soil was covered in a 10 cm thick humic layer and colonised by grasses. The persistence of water repellency was measured using the water drop penetration time test, sorptivity and unsaturated hydraulic conductivity using a mini disk infiltrometer, and saturated hydraulic conductivity using a double-ring infiltrometer. Dye tracer experiments were used to assess the heterogeneity of water flow, and both the modified method for estimating effective cross section and an original method for assessing the degree of preferential flow were used to quantify this heterogeneity from the images of dyed soil profiles. Most hydrophysical parameters were substantially different between the two surfaces. The grassland soil had an index of water repellency about 10 times that of pure sand and the persistence of water repellency almost 350 times that of pure sand. Water and ethanol sorptivities in the grassland soil were 7% and 43%, respectively, of those of the pure sand. Hydraulic conductivity and saturated hydraulic conductivities in the grassland soil were 5% and 16% of those of the pure sand, respectively. Dye tracer experiments revealed a stable flow with ＂air-draining＂ condition in pure sand and well-developed preferential flow in grassland soil, corresponding to individual grass tussocks and sinai! micro-depressions. The grassland soil was substantially more water repellent and had 3 times the degree of preferential flow compared to pure sand. The results of this study reinforce our view that the consequences of any change in climate, which will ultimately influence hydrology, will be markedly different between grasslands and bare soils.