PREPARATION AND CHARACTERIZATION OF WATER-SOLUBLE NEAR-INFRARED EMITTING PbS QUANTUM DOTS

A new facile method for preparing water-soluble near-infrared （NIR）-emitting PbS quantum dots （QDs） is proposed by using N-acetyl-L-cysteine （NAC, a derivate of L-cysteine） as its stabilizer. The influence of the precursor Pb/S molar ratio, the Pb/NAC molar ratio, and the pH of original solution on optical properties is explored. Results show that aqueous PbS QDs with strong NIR fluorescence can be prepared and their photoluminescence emission peaks can be tuned from 895 nm to 970 nm. Studies indicate that such aqueous QDs have a potential application in biomedical imaging, especially in noninvasive in vivo fluorescence imaging. In addition, the resulting PbS QDs are further characterized by a transmission electron microscopy and X-ray diffraction analysis.

Body composition and compensatory growth in Nile tilapia Oreochromis niloticus under different feeding intervals

We investigated the growth and body composition of Nile tilapia under five different feeding regimes. A control group was fed to satiation twice daily for 185 days; four treatment groups were fed at intervals of 2, 3, 4 or 7 days(dietary ‘restricted' period, days 0–80) and then fed to satiation(‘refeeding' period, days 80–185). Compensatory growth in weight and length of the feed-restricted groups was observed during the refeeding period. However, the growth of none of the restricted groups caught up with that of the control group over the experimental period. Feed intake upon refeeding increased with the duration of deprivation. There were no significant differences in feed efficiency between the restricted and control groups during the refeeding stage, suggesting that hyperphagia was the mechanism responsible for the increased growth rates during this period. Tilapia preferentially used n-3 polyunsaturated fatty acids and nonessential amino acids during the restricted-feeding period. Higher production was achieved by higher feed consumption. We suggest that if attainment of market size in minimum time is required, fish should be consistently fed to satiation, while taking care to avoid the possible negative consequences of overfeeding.

Synthesis and Biological Evaluation of Novel N-Benzoxazolonyluracils as Protox-Inhibitor

Protoporphyrinogen oxidase inhibitor has become the focus research field as herbicides.Seven novel N-benzoxazolonyluracils were obtained by cyclization of 6-aminobenzoxazolone derivatives with ethyl 3-dimethylcarbamoylamido-4,4,4-trifluorocrotonate and then methylation or amination, and the reaction yields were between 5900—8600. The chemical structures of the compounds were identified by Elemental Analysis, MS and 1H NMR. Biological results indicate that some compounds exhibit excellent control of broadleaf weeds at post-emergence by low dosage 18.75 ga.i/ha, but are not effective for grass weeds below dosage 37.5 ga.i/ha. In addition, these compounds show no damage at high-dosage 150 ga.i/ha to wheat and corn, but are unsafe to dicotyledonous plants such as cole, soybean and sorghum even at lower dosage 18.75 ga.i/ha.

Fabrication of cost effective iron ore slime ceramic membrane for the recovery of organic solvent used in coke production

Improvement of coking properties of sub-bituminous coal （A） and bituminous coal （B） was done using blended organic solvents, namely, n-methyl-2-pyrrolidinone （NMP） and ethylenediamine （EDA）. Various solvent blends were employed for the coal extraction under the total reflux condition. A low-cost ceramic membrane was fabricated using industrial waste iron ore slime of M/s TATA steel R＆D, Jamshedpur （India） to separate out the dissolved coking fraction from the solvent-coal mixture. Membrane separations were carried out in a batch cell, and around 75 % recovered NMP was reused. The fractionated coal properties were determined using proximate and ultimate analyses. In the case of bituminous coal, the ash and sulfur contents were decreased by 99.3 % and 79.2 %, respectively, whereas, the carbon content was increased by 23.9 % in the separated coal fraction. Three different cleaning agents, namely deionized water, sodium dodecyl sulphate and NMP were used to regain the original membrane permeability for the reusing.

高炉内Ti(C,N)生成的热力学分析

通过热力学计算，研究了高炉中钛氧化物的还原过程，分析了TiC、TiN在高炉风口回旋区、渣铁层及铁水中的生成和转移，并得到了Ti（C,N）在渣铁界面析出时的炉渣中TiO2临界质量分数。利用Factsage软件计算分析了渣铁平衡时铁水中w（Ti）与w（Si）之间的相互关系, 发现w（Si） 、w（Ti） 和w（Si）/ w（Ti）的值在炉渣成分不改变的情况下随温度升高而增大；炉渣碱度0.9～1.2，炉渣w（TiO2）在5.5%以下时，铁水中的w（Ti）随碱度升高而增加；在炉缸温度一定时，炉缸中Ti（C,N）的生成依赖于渣中w（TiO2）。

On Left (N, U)-Coherent Dimensions of Rings

Let R, S be rings, U a flat right .R-rnodule and V a flat right S-module. We show in this paper that (N, (U, V))-lc.dim(R(?) S) = sup((N, U)-lc.dimR, (N, V)-lc.dimS).

Decay parameter and related properties of n-type branching processes

We consider decay properties including the decay parameter, invariant measures, invariant vectors, and quasistationary distributions for n-type Markov branching processes on the basis of the 1-type Markov branching processes and 2-type Markov branching processes. Investigating such behavior is crucial in realizing life period of branching models. In this paper, some important properties of the generating functions for n-type Markov branching q-matrix are firstly investigated in detail. The exact value of the decay parameter λC of such model is given for the communicating class C = Zn+ \ 0. It is shown that this λC can be directly obtained from the generating functions of the corresponding q-matrix. Moreover, the λC -invariant measures/vectors and quasi-distributions of such processes are deeply considered. λC -invariant measures and quasi-stationary distributions for the process on C are presented.