Understanding Performance Degradation in Cation‐Disordered Rock‐Salt Oxide Cathodes

The collective redox activities of transition‐metal (TM) cations and oxygen anions have been shown to increase charge storage capacity in both Li‐rich layered and cation‐disordered rock‐salt cathodes. Repeated cycling involving anionic redox is known to trigger TM migration and phase transformation in layered Li‐ and Mn‐rich (LMR) oxides, however, detailed mechanistic understanding on the recently discovered Li‐rich rock‐salt cathodes is largely missing. The present study systematically investigates the effect of oxygen redox on a Li_1.3Nb_0.3Mn_0.4O₂ cathode and demonstrates that performance deterioration is directly correlated to the extent of oxygen redox. It is shown that voltage fade and hysteresis begin only after initiating anionic redox at high voltages, which grows progressively with either deeper oxidation of oxygen at higher potential or extended cycling. In contrast to what is reported on layered LMR oxides, extensive TM reduction is observed but phase transition is not detected in the cycled oxide. A densification/degradation mechanism is proposed accordingly which elucidates how a unique combination of extensive chemical reduction of TM and reduced quality of the Li percolation network in cation‐disordered rock‐salts can lead to performance degradation in these newer cathodes with 3D Li migration pathways. Design strategies to achieve balanced capacity and stability are also discussed.     

大果木姜子的甘油三酯组成

采用光谱法和胰酯酶分解法对大果木姜子油酯中分得的结晶C—I组成进行了分析,结果表明C—I是由11种甘油三酯组成。其中2-位为月硅酸的甘油三酯占91.80％,1,3-位脂肪酸主要为癸酸和月桂酸,甘油三酯的组成中,CLC占62.24％,LLC占24.50％。     

腺苷酸激酶在我国九个民族中的多态分布

用淀粉胶电泳及特异染色的方法,对我国9个民族的腺苷酸激酶(AK)多态分布进行了测定。9个民族中维吾尔族AK表型分布具有多态性。维吾尔族中AK_1~1基因频率为0.965,AK_1~2基因频率为0.035,而侗、回、白、土家、苗、彝、藏、满等8个民族的AK_1~2均未达到多态水平。在9个民族中AK_1表型分布均符合Hardy-Weinberg平衡,并且未发现其它罕见表型。     

云南10个民族红细胞酸性磷酸酶型分布调查

用淀粉凝胶电泳法对云南省汉族及9个少数民族的红细胞酸性磷酸酶(ACP_1)的表型分布进行了调查,检出A、BA和B3种表型,计算得云南汉、彝、白、傣、瑶、佤、哈尼、布朗、基诺和拉祜族ACP_1~A、ACP_1~B的基因频率依次为0.2067、0.7933;0.2406、0.7594;0.2341、0.7659;0.3750、0.6250;0.2300、0.7700;0.2727、0.7273;0.3594、0.6406;0.3036、0.6964;0.2381、0.76119和0.4474、0.5526。未发现ACP_1~C基因及其它稀有基因。研究表明,ACP_1表型的分布存在着一定的种族与民族差异。     

中国食蚜蝇科—新属新种(英文)

本文记述了中国食蚜蝇科Syrphidae、管蚜蝇亚科Eristalinae、管蚜蝇族Eristalini的一新属:艳管蚜蝇属Pseudomeromacrus gen.nov.和新种 刺茎艳管蚜蝇Pseudomeromacrus setipenitus Li,sp.nov.模式标本保存于华南农业大学植保系昆虫标本室。     

The influence of ethnic differences upon human responses due to thermal environment

1. 1. The influence of ethnic differences is discussed with reference to the following issues.

2. 2. It has been found that total numbers of active sweat glands increase in tropical populations compared with people from northern latitudes.

3. 3. It has also been observed that the active sweat glands of Eskimos are fewer than those of Caucasians.

4. 4. The rate of the evaporated sweat loss was calculated by measuring body weight loss and it was found that the evaporated sweat loss of Caucasians is larger than that of Japanese in the same climate.

5. 5. Meteorological factors might have been responsible for the smaller loss in Japanese compared with that of Japanese-Americans.

6. 6. Under the same experimental conditions, it was observed that there were little or no differences between the Caucasians and Negros.

花生种子活力与贮藏蛋白质降解的关系

花生种子吸胀2d后,子叶中肽链内切酶活性上升,贮藏蛋白质开始降解。高活力种子肽链内切酶活性在吸胀2d后迅速上升,至4d时达到高峰,而中等活力种子的肽链内切酶活性上升速度绶慢。高活力种子萌发时贮藏蛋白质降解速度高于中等活力种子。中等活力种子经PEG和PUT处理可提高种子活力,也促进了种子贮藏蛋白质降解能力的提高。     

基于地表水与地下水分割校正的漓江流域水供给服务时空格局研究

喀斯特区域水循环过程与其他地区存在显著区别,其水供给服务也具有独特的空间分布特征。然而,目前针对喀斯特地区产水量的时空变化研究较少考虑喀斯特生态系统的特殊性,导致产水量的空间模拟结果存在一定偏差。根据喀斯特地貌形态和地下水补径排泄特征提出了一种产水量分割方法,并基于水量平衡原理建立了地表水与地下水分割校正概念模型。选取喀斯特山区典型区域漓江流域为研究区,通过上述方法校正了InVEST模型产水量模拟结果,从栅格、地貌分区和子流域3个尺度分析了漓江流域2000—2020年产水量校正前与校正后时空分布格局。研究结果表明：(1)漓江流域2000—2020年InVEST模型产水量呈现先减后增再减的趋势,水供给服务空间分布格局为北高南低。产水深度在岩溶区和非岩溶区几乎没有差异,但在岩溶区内部差异明显：裸露型岩溶区产水深度高于覆盖型和埋藏型,峰林平原产水深度高于峰丛洼地。子流域分区平均产水深度排序为漓江上游区>漓江中游区>恭城河区>荔浦河区>漓江下游区。(2)利用地表与地下水分割校正后,水供给服务空间分布格局为四周高于中部,西北部高于东南部。非岩溶区产水深度明显高于岩溶区,埋...     

New methods for estimating the numbers of synonymous and nonsynonymous substitutions

New methods for estimating the numbers of synonymous and nonsynonymous substitutions per site were developed. The methods are unweighted pathway methods based on Kimura's two-parameter model. Computer simulations were conducted to evaluate the accuracies of the new methods, Nei and Gojobori's (NG) method, Miyata and Yasunaga's (MY) method, Li, Wu, and Luo's (LWL) method, and Pamilo, Bianchi, and Li's (PBL) method. The following results were obtained: (1) The NG, MY, and LWL methods give overestimates of the number of synonymous substitutions and underestimates of the number of nonsynonymous substitutions. The major cause for the biased estimation is that these three methods underestimate the number of synonymous sites and overestimate the number of nonsynonymous sites. (2) The PBL method gives better estimates of the numbers of synonymous and nonsynonymous substitutions than those obtained by the NG, MY, and LWL methods. (3) The new methods also give better estimates of the numbers of synonymous and nonsynonymous substitutions than those obtained by the NG, MY, and LWL methods. In addition, estimates of the numbers of synonymous and nonsynonymous sites obtained by the new methods are reasonably accurate. (4) In some cases, the new methods and the PBL method give biased estimates of substitution numbers. However, from the number of nucleotide substitutions at the third position of codons, we can examine whether estimates obtained by the new methods are good or not, whereas we cannot make an examination of estimates obtained by the PBL method. (5) When there are strong transition/transversion and nucleotide-frequency biases like mitochondrial genes, all of the above methods give biased estimates of substitution numbers. In such cases, Kondo et al.'s method is recommended to be used for estimating the number of synonymous substitutions, although their method cannot estimate the number of nonsynonymous substitutions and is time-consuming. These results, particularly result (1), call for reexaminations of some genes. This is because evolutionary pictures of genes have often been discussed on the basis of results obtained by the NG, MY, and LWL methods, which are favorable for the neutral theory of molecular evolution.     

贡山竹属——我国云南竹亚科一新属

灌木状竹,有时附生于树干基部。地下茎短颈粗型。秆单丛;节问圆筒形;每节分枝单一,与主秆近等粗。秆释宿存性,革质;滓耳大,镰刀状;滓舌较低;算片外展。叶耳镰刀状;