Effects of Free-air CO2 Enrichment on Root Characteristics and C:N Ratio of Rice at the Heading Stage

A hydroponics experiment was conducted to investigate the rice root growth in FACE （free-air carbon dioxide enrichment）. The root biomass, root volume, ratio of root/shoot, number of adventitious roots and root diameter significantly increased under FACE conditions, while the CO2 enrichment decreased the N concentration in rice roots without any change in the C content, leading to an increase in root C：N ratio. Moreover, the elevated CO2 resulted in a remarkable decrease of root activity, expressed as per unit root dry weight, which might be responsible for decreased N concentration in roots.

Organic matter transformation ratio, hydrocarbon expulsion efficiency and shale oil enrichment type in Chang 7_(3) shale of Upper Triassic Yanchang Formation in Ordos Basin, NW China

The major enrichment type of shale oil in the Chang 7_(3) shale of Upper Triassic Yanchang Formation in the Ordos Basin is unknown.This paper analyzes the organic matter transformation ratio,hydrocarbon expulsion efficiency and roof/floor sealing conditions of the Chang 7_(3) shale,and evaluates the major enrichment type of shale oil in this interval.The average organic matter transformation ratio of the Chang 7_(3) shale is about 45%;in other words,more than 50%of the organic matters have not transformed to hydrocarbons,and the lower the maturity,the greater the proportion of untransformed organic matters.The cumulative hydrocarbon expulsion efficiency of the transformed hydrocarbon is 27.5% on average,and the total proportion of untransformed organic matters plus retained hydrocarbons is greater than 70%.The relative hydrocarbon expulsion efficiency of the Chang 7_(3) shale is 60%on average,that is,about 40% of hydrocarbons retain in the shale.The Chang 7_(3) shale corresponds to Chang 7_(1+2) and Chang 8 sandstones as the roof and floor,respectively,and is further overlaid by Chang 6 shale,where extensive low porosity and low permeability–tight oil reservoirs have formed in the parts with relatively good porosity and permeability.Moreover,the Chang 7_(3) shale is tested to be in a negative pressure system(the pressure coefficient of 0.80–0.85).Therefore,the roof/floor sealing conditions of the Chang 7_(3) shale are poor.The retained hydrocarbons appear mostly in absorbed status,with low mobility.It is concluded that the medium–high mature shale oil is not the major enrichment type of shale oil in the Chang 7_(3) shale,but there may be enrichment opportunity for shale oil with good mobility in the areas where the sealing conditions are good without faults and fractures and oil reservoirs are formed off Chang 7_(1+2),Chang 6 and Chang 8.Furthermore,low–medium mature shale oil is believed to have great potential and is the major enrichment type of shale oil in the Chang 7_(3) shale.It is recommended to prepare relevant in-situ conversion technologies by pilot test and figure out the resource availability and distribution.

Evaporative enrichment of stable isotopes(δ^(18)O and δD) in lake water and the relation to lake-level change of Lake Qinghai, Northeast Tibetan Plateau of China

Stable isotopic compositions （δ18O and 6D） have been utilized as a useful indicator for evaluating the current and historical climatic and environmental changes. Therefore, it is vital to understand the relationship be- tween the stable isotopic contents in lake water and the variations of lake level, particularly in Lake Qinghai, China. In this study, we analyzed the variations of isotope compositions （δ18O, 6D and d-excess） in lake water and pre- cipitation by using the samples that were collected from Lake Qinghai region during the period from 2009 to 2012. The results showed that the average isotopic contents of δ18O and 6D in lake water were higher than those in pre- cipitation, which were contrary to the variations of d-excess. The linear regression correlations between δ18O and 6D in lake water and precipitation showed that the local evaporative line （LEL） in lake water （δD=5.88δ18O-2.41） deviated significantly from the local meteoric water line （LMWL）in precipitation （δD=8.26δ18O＋16.91）, indicating that evaporative enrichment had a significant impact on isotopic contents in lake water. Moreover, we also quanti- fied the Eli ratio （evaporation-to-input ratio） in Lake Qinghai based on the lake water isotopic enrichment model derived from the Rayleigh equation. The changes of E/I ratios （ranging from 0.29 to 0.36 between 2009 and 2012） clearly revealed the shifts of lake levels in Lake Qinghai in recent years. The average E/I ratio of 0.40 reflected that water budget in Lake Qinghai was positive, and consistent with the rising lake levels and the increasing lake areas in many lakes of the Tibetan Plateau. These findings provide some evidences for studying the hydrological balance or water budget by using δ18O values of lake sedimentary materials and contribute to the reconstruction of paleo- lake water level and paleoclimate from an isotopic enrichment model in Lake Qinghai.

Grade-Tonnage, Ore Value-Tonnage, andEnrichment Ratio-Tonnage Models forResource Assessment

According to grade-tonnage diagrams of nickel and zinc deposits, their critical grades are 0.4 % and 3. 4 %, respectively, and hence the former resources can be considered optimistic and the latter pessimistic. The grade-tonnage diagram of gold deposits is convex downwards suggesting that the critical grade is 1 X 10-6 in the low-grade part. The ore value (OV)-tonnage diagram of all deposits In the world consists of three parts: high, middle and low vain f classes. The enrichment ratio (ER)-tonnage diagram of all deposits in the world ho consists of three parts: high, middle and low ratio classes.Nine quality categories defined by ER and OV are characterized by some keywords indicating deposit types as follows: category RH (high ER-high OV: 0. 7 %) by 'unconformity' and 'Mississippi Val-ley', category HM (high ER-middle: OV: 0.7 %) by 'vein', category ML (middle ER-low OV: 0 %) by 'sandstone', 'stockwork' and' dissemination', category LM by 'orthomagmatic',' laterite',komatiite and ' chemical', and category LL by 'porphyry', 'dissemination' and 'placer'. Category MM is not characterized by any keyword. If the commodities of a deposit are defined by both the enrichment ratio and the ore value, the defined commodities are relatively coincident for gold and nickel,but different for copper, silver and zinc, and greatly different for molybdenum and lead. Deposits containing lead and/or zinc are complimentary. If the commodity Ph+Zn is applied, most lead or zinc deposits are classified as Ph+Zu by both definitions. Accessory metals are commonly expected for deposits of kuroko-type zinc, epithermal silver, massive sulfide-type zinc and volcanogenic zinc, but uncommon for deposits of orthomagmatic chromium, chemically precipitated copper and sandstone-type uranium.

The enrichments of organic matter and total nitrogen in sediment as affected by relavant factors

Serious soil erosion has already resulted in degradation of the Loess Plateau of China. Soil erosion is commonly accompanied by extensive soil nutrient loss. Because of enrichment processes,sediment nutrient content is often higher than that of natural soil. The objective of this study is to determine the enrichments of organic matter and total nitrogen in sediment in hilly and gully loess areas on the Loess Plateau of China. Measurements of enrichment ratios (ER) of organic matter (EROM) and total nitrogen (ERTN) in sediment as affected by rainfall, slope gradient, tillage, and fertilization were made in the field under natural rainfall conditions. The results showed that the enrichment of clay in sediment resulted in the enrichment of organic matter (OM) and total nitrogen (TN) in sediment. The averages of sediment clay ER, EROM and ERTN for the various slope gradients were 1.77, 2.09 and 1.61, respectively. The soil erosive module was negatively correlated with EROM and ERTN. Our results indicate that measures to reduce soil erosion, i.e. reducing rainfall erosivity, decreasing soil slope gradient, decreasing fertilizer use, and using level trenches, may increase EROM and ERTN. Both quantity and quality of sediment yield should be considered when implementing erosion control measures.

Effects of elevated CO_2 concentration on growth and water usage of tomato seedlings under different ammonium/nitrate ratios

Increasing atmospheric CO2 concentration is generally expected to enhance photosynthesis and growth of agricultural C3 vegetable crops, and therefore results in an increase in crop yield. However, little is known about the combined effect of elevated CO2 and N species on plant growth and development. Two growth-chamber experiments were conducted to determine the effects of NH4^＋/NO3^- ratio and elevated CO2 concentration on the physiological development and water use of tomato seedlings. Tomato was grown for 45 d in containers with nutrient solutions varying in NH4^＋/NO3^- ratios and CO2 concentrations in growth chambers. Results showed that plant height, stem thickness, total dry weight, dry weight of the leaves, stems and roots, G value （total plant dry weight/seedling days）, chlorophyll content, photosynthetic rate, leaf-level and whole plant-level water use efficiency and cumulative water consumption of tomato seedlings were increased with increasing proportion of NO3- in nutrient solutions in the elevated CO2 treatment. Plant biomass, plant height, stem thickness and photosynthetic rate were 67%, 22%, 24% and 55% higher at elevated CO2 concentration than at ambient CO2 concentration, depending on the values of NH4^＋/NO3^- ratio. These results indicated that elevating CO2 concentration did not mitigate the adverse effects of 100% NH4^＋-N （in nutrient solution） on the tomato seedlings. At both CO2 levels, NH4^＋/NO3^- ratios of nutrient solutions strongly influenced almost every measure of plant performance, and nitrate-fed plants attained a greater biomass production, as compared to ammonium-fed plants. These phenomena seem to be related to the coordinated regulation of photosynthetic rate and cumulative water consumption of tomato seedlings.

Enrichment of Semi-Volatile Organic Acids from Aqueous Solutions by Multiple-Effect Membrane Distillation

Multiple-effect membrane distillation （MEMD） process for enriching semi-volatile organic acids from their individual aqueous solutions was performed by using a hollow fiber-based air gap membrane distillation （AGMD） module with the function of internal heat recovery. Aqueous solutions of glyoxylic acid, glycolic acid, lactic acid, pyrnvic acid, malonic acid and glutaric acid were used as model feed. For a feed of 1% （mass fraction）, each acid could be enriched for 8--20 times, which depended on the surface tension of the concentrate. The operation performance of MEMD process was characterized by permeation flux J, performance ratio PR and acid rejection rate R. The effects of cold feed-in temperature, heated feed-in temperature, feed-in volumetric flow rate and feed-in concen- tration on MEMD performance were experimentally evaluated. Maximum values of J, PR and R were 4.8 L/（h-m2）, 9.84 and 99.93%, respectively. Moreover, MEMD process demonstrated a fairly good stability in a long-term experiment lasting for 30 d when aqueous solution of 4% （mass fraction） lactic acid was used as a feed.

Seasonal Variability of Phytoplankton Community Structure in Relation to Different Nitrogen-Phosphorus Ratios in the Southern Coastal Waters of Zhejiang, China

With the rapid development of economy and increase of population in the drainage areas, the nutrient loading has increased dramatically in the Changjiang estuary and adjacent coastal waters. To properly assess the impact of nutrient enrichment on phytoplankton community, seasonal microcosm experiments were conducted during August 2010-July 2011 in the coastal waters of Zhejiang Province. The results of the present study indicated that the chl a concentration, cell abundance, diversity indices, species composition and community succession of the phytoplankton varied significantly with different N/P ratios and seasons. Higher growth was observed in the 64：1 （spring）, 32：1 （summer）, 16：1 （autumn） and 128：1,256：1 （winter） treatments, respectively. The values of Shannon-Wiener index （H） and Pielou evenness index （J） were lower in the 8：1 and 16：1 treatments in autumn test, while H value was higher in the 128：1 and 8：1 treatments in winter test. A definite community succession order from diatoms to dinoflagel lares was observed in the autumn and winter tests, while the diatoms dominated the community throughout the culture in the spring and summer tests.

Fundamental Study on Coke Degradation in BF with Oxygen Enriched Blast and High Hydrogen Atmosphere

The effects of gas composition, temperature, ore to coke ratio and prereduction rate of ore on coke degradation were studied. The results showed that 1% increment in solution loss of coke reduces coke strength by 0.6%, and the coke degradation is accelerated with the temperature. The higher the temperature, the more coke surface is involved in reactions, and the less negative effect on coke strength is. Hydrogen exerts stronger effect on coke degradation than CO at high temperature. The coke degradation is decreased with the reduction of ore to coke ratio and increase of ore prereduction rate.

锌镁比对Al-Zn-Mg-Cu-Er-Sc-Zr合金显微组织与耐腐蚀性能影响的研究

通过调整Al-Zn-Mg-Cu-Er-Sc-Zr合金中的Mg元素含量,研究了Zn/Mg比的变化对合金相演变以及腐蚀性能的影响规律。结果表明:Al_(8)Cu_(4)Er相、Al_(3)(Er,Sc)相与含Fe相存在明显的伴生关系,二者依附于含Fe相生长。Zn/Mg比的变化可显著改变三者间的交互形式,高的Zn/Mg比例有利于稀土相独立生长,且在比值为4.18的条件下,Al_(8)Cu_(4)Er相与含Fe相均得到了显著细化。细化的晶界第二相使腐蚀坑深度仅为82μm,而连续的伴生混合相、粗大稀土相等均会不同程度降低合金的耐蚀性能。

Origin of enriched uranium contained in Japanese atmospheric deposits

The chemical compositions of atmospheric deposits collected in Fukuoka, Japan, in 1964 and 2000, which are known to have high 235U/238U uranium isotope ratio were determined. High uranium contents relative to that of continental crust were observed for the deposition samples in 1964 together with the high 235U/238U ratios, which indicated that the origin of uranium is fallout materials due to the large-scale 1961- 1962 nuclear explosions conducted by US and former USSR. The deposits in 2000 were mainly composed of dusts from the East Asia. This suggested that uranium with a high 235U/238U ratio in the deposits in 2000 has been transported as a component of mineral dust particles contaminated with nuclear debris from nuclear test sites from the East Asian deserts and arid regions by the prevailing wind.

高热稳定CaGdAlO_(4)∶Er^(3+)/Yb^(3+)荧光粉的上转换发光及其温度传感性能

获得具有良好热稳定性和发光性能的非接触式光学温度传感材料是目前的研究热点之一,本工作通过高温固相法制备了Er^(3+)/Yb^(3+)共掺CaGdAlO_(4)∶Er_(x),Yb_(0.10)(x=0.006、0.008、0.010、0.012、0.014)荧光粉,尺寸大小分布在0.6~4.2μm。在980 nm激光激发下,该荧光粉在500~700 nm发射谱由两个发射带组成,528和550 nm处两个较强的绿光发射带,归属于Er^(3+)的^(2)H_(11/2)→^(4)I_(15/2)、^(4)S_(3/2)→^(4)I_(15/2)能级跃迁,663 nm处较弱的红光发射带,归属于Er^(3+)的^(4)F_(9/2)→^(4)I_(15/2)能级跃迁。上转换发光强度最大组分为CaGdAlO_(4)∶Er_(0.010),Yb_(0.10)。300~573 K变温发射谱表明,基于荧光强度比FIR_(528/550)参数,温度传感绝对灵敏度S_(A)从44.4×10^(-4) K^(-1)(@300 K)先增大到52.0×10^(-4) K^(-1)(@445 K)随后减小到49.0×10^(-4) K^(-1)(@573 K)。相对灵敏度S_(R)则从0.95×10^(-2) K^(-1)(@300 K)单调减小到0.27×10^(-2) K^(-1)(@573 K)。冷热循环实验表明该材料的热重复性优于98%。结果表明,CaGdAlO_(4)∶Er_(0.010),Yb_(0.10)荧光粉在光学温度传感领域具有潜在的应用前景。

Er_(2)SiO_(5)纳米粉体的并流共沉淀法合成

以Er_(2)O_(3)和正硅酸乙酯(TEOS)为原料,采用并流共沉淀法合成了纳米Er_(2)SiO_(5)粉体。研究了前驱体Si/Er摩尔比、煅烧温度以及反应体系pH值对Er_(2)SiO_(5)物相组成和显微结构的影响,并探讨了Er_(2)SiO_(5)粉体的合成机理。结果表明:前驱体Er/Si摩尔比为20∶12,煅烧温度为1300℃时,Er_(2)SiO_(5)粉体由X2-Er_(2)SiO_(5)纯相组成,具有近球形形貌特征。低Er/Si摩尔比可降低Er_(2)SiO_(5)的结晶温度并促进X2-Er_(2)SiO_(5)的生成,反应体系pH值的升高则对[Si—O—Er]结构的生成具有一定的促进作用。Er_(2)SiO_(5)前驱体是以[Si—O—Er]网络结构形式存在的,煅烧过程中通过分解和结构重组逐步生成Er_(2)SiO_(5),Er_(2)O_(3)杂质相的生成是高Er/Si摩尔比前驱体[Si—O—Er]网络结构中的Er^(3+)在Er_(2)SiO_(5)结晶过程中的析出造成的。

La_(6)W_(2)O_(15):Er^(3+)的发光特性与温敏特性研究

采用高温固相法制备了La_(6)W_(2)O_(15):Er^(3+)荧光粉样品,并对其热耦合能级和非热耦合能级的温度传感特性进行分析.研究发现:La_(6)W_(2)O_(15):Er^(3+)荧光粉样品的最佳掺杂浓度为1.5%,最佳激发位置为380 nm,以549、524、660 nm为中心,有3处发射峰,强度依次减弱.利用变温光谱和能级跃迁关系,计算得到2组荧光强度比,即热耦合能级I524 nm/I549 nm和非热耦合能级I660 nm/I549 nm,其中最大绝对灵敏度分别为0.0074 K^(-1)和0.0004 K^(-1),最大相对灵敏度分别为4.553 K^(-1)和0.321 K^(-1).在室温300 K附近,热耦合能级的相对灵敏度为1.245%K^(-1),数值在几种已报道的同类文献里处于中档.该研究结果表明,La_(6)W_(2)O_(15):Er^(3+)荧光粉样品在温度传感方面具备良好的应用潜力.

Er,Cr:YSGG激光照射后牙周病牙根面的形态学研究和钙磷比率分析

目的观察Er,Cr:YSGG激光照射后牙周病牙根面的形态学变化及主要元素钙、磷的改变。方法收集中、老年人离体牙周病牙18颗、健康阻生第三磨牙6颗。对18颗牙周病患牙根面进行平整后,随机选取12颗作激光照射研究;其余6颗作酸处理研究;6颗第三磨牙作健康对照。扫描电镜下观察不同根面处理方式导致的根面形态变化,用色谱分析仪分析各组根面钙磷比率(Ca/P),并进行统计学比较。结果激光照射组可有效去除玷污层,得到粗糙度较均匀、洁净的根面。酸处理组去除根面玷污层能力较强,但电镜观察两组根面形态有差异。两组均未发现熔融、炭化、裂纹及牙本质暴露。色谱分析仪分析结果显示激光照射组与酸处理组根面钙磷比率无明显差异(P>0.05)。结论Er,Cr:YSGG激光照射根面平整后的牙周病牙根面可有效去除玷污层及表层病变牙骨质,具有潜在的应用价值。

挤压比对Al-Cu-Mg-Ag-Er合金线材组织及性能影响

通过热挤压工艺制备了不同挤压比的Al-Cu-Mg-Ag-Er线材,采用光学显微镜(OM)、扫描电镜(SEM)、差示扫描量热分析(DSC)和拉伸性能以及电阻率测试等方法研究了不同挤压比对合金线材显微组织、力学性能和导电性能的影响。结果表明,随挤压比增大,晶粒尺寸减小;同时,合金挤压过程中,合金中原骨骼状的Al2Cu相和Al8Cu4Er相破碎,分别呈块状和颗粒状。在较高的挤压比(λ=50~100)下,块状的Al2Cu相部分溶解,Al8Cu4Er相仍稳定存在。随挤压比增大,合金的抗拉强度和伸长率提高,电阻率增大;挤压合金的力学性能和电阻率受到晶粒细化,析出相粒子熔化和材料加工硬化的综合影响。

Er^(3+)／Yb^(3+)共掺LiNbO_(3+)晶体中Er^(3+)的光谱特性分析

在室温下,测量了采用Czochralski方法生长的as-grown和经退火处理的Z切Er3+／Yb3+共掺同成 分LiNbO3晶体的a偏振吸收光谱(300-1 650 nm)。运用Judd-Ofelt理论对该晶体中Er3+的光谱特性进行 了分析。由所测得的吸收系数的积分计算得到了从基态到激发态的若干个主要的电子跃迁强度实验值。利 用最小二乘法确定出Er3+／Yb3+共掺LiNbO3晶体中Er3+的Judd-Ofelt参数。进而确定了自发辐射概率,从 激发态能级到其各个下能级的荧光分支比以及能级辐射寿命。此外,还讨论了Yb3+的共掺和退火处理对 LiNbO3晶体中Er3+光谱特性的影响。

纳米NaYb_(1-x)F_(4)∶Er^(3+)_(x)中Er^(3+)/Yb^(3+)掺杂浓度变化引起的相变和发光增强

在Yb^(3+)和Er^(3+)共掺杂氟化物纳米体系中,2%Er^(3+)掺杂浓度为上转换发光的最佳浓度,高于这个浓度,随着Er^(3+)掺杂浓度的增加,将发生严重上转换发光浓度猝灭,已为人们广泛认知和接受。本文合成了不同Er^(3+)/Yb^(3+)掺杂浓度比的NaYb_(1-x)F_(4)∶Er^(3+)_(x)系列上转换发光纳米粒子。通过扫描电镜、XRD和荧光光谱等分析方法对这些合成的样品进行了表征。研究结果表明,当Er^(3+)/Yb^(3+)掺杂浓度比在0.02/0.98~0.2/0.8和0.6/0.4~0.8/0.2范围时,合成的NaYb_(1-x)F_(4)∶Er^(3+)_(x)纳米粒子分别为α相和β相结构;而特别值得注意的是,当掺杂浓度比在0.3/0.7~0.4/0.6范围时,合成的纳米粒子为从α相向β相过渡的α相和β相共存相结构。Er^(3+)/Yb^(3+)最佳掺杂浓度比分别为0.02/0.98和0.4/0.6的两种α相和β相共存相结构的纳米粒子都展现了非常好的上转换发光增强。这些结果对于理解稀土离子浓度发光猝灭机制,提高上转换发光效率,促进稀土纳米发光材料在新型光源、生物医学和激光等领域的应用都具有重要的科学研究意义和启发作用。

Difference in Organic Carbon Contents and Distributions in Particle-size Fractions between Soil and Sediment on the Southern Loess Plateau, China

The purpose of this study was to assess the effect of long-term cultivation and water erosion on the soil organic carbon （OC） in particle-size fractions. The study site is located at Nihegou Watershed in the Southern Loess Plateau, China. The soil at this site is loess with loose and silty structure, and contains macropores. The results showed that the OC concentrations in sediments and in the particle-size fractions of sediments were higher than those in soils and in the particle-size fractions of soils. The OC concentration was highest in the clay particles and was lowest in the sand particles. Clay particles possessed higher OC enrichment ability than silt and sand particles. The proportions of OC in the silt fractions of soil and sediment were the highest （mean value of 53.87% and 58.48%, respectively）, and the total proportion of OC in the clay and silt fractions accounted for 96% and 98% of the total OC in the soil and sediment, respectively. The loss of OC was highest in silt particles, with an average value of 0.16 Mg ha^-1 y^-1, and was lowest in the sand （0.003 Mg ha^-1 y^-l）. This result suggests that the fine particle-size fraction in the removed sediment may be an important indicator to assess soil OC losses.

Lu_(2)O_(3)∶Er^(3+)/Yb^(3+)荧光材料的上转换发光及其温度传感特性

采用CO_(2)激光区熔法制备了Lu_(2)O_(3)∶0.5%Er^(3+)/x%Yb^(3+)(x=1,3,5)上转换荧光材料。X射线衍射结果表明,所制备的Lu_(2)O_(3)∶Er^(3+)/Yb^(3+)荧光材料具有纯Lu_(2)O_(3)晶相。在980 nm激光激发下,样品发出明亮的上转换荧光。光谱测试结果表明,样品上转换荧光强度和荧光中绿光与红光比例随Yb^(3+)离子浓度改变,当Er^(3+)和Yb^(3+)离子浓度分别为0.5%和3%时,样品上转换荧光强度最强。通过荧光强度比(FIR)技术研究了样品Lu_(2)O_(3)∶0.5%Er^(3+)/3%Yb^(3+)在298~873 K温度范围内上转换荧光温度传感特性,在532.8 K时最大绝对灵敏度为0.0060 K^(-1),在298 K时最大相对灵敏度为0.0090 K^(-1)。结果表明,Lu_(2)O_(3)∶Er^(3+)/Yb^(3+)荧光材料非常适合用于宽温度范围荧光温度传感。