水电水利工程压力钢管灌浆孔应力集中敏感性因素研究

水电水利工程压力钢管开孔灌浆后,需对灌浆孔严密封堵,处理不好会对工程安全运行留下隐患。在总结国内外灌浆孔常用封堵方案基础上,以某水电站地下埋管为例,建立平面有限元模型,分析其灌浆开孔后管壁应力集中现象,研究了补强板厚度及堵头坡口深度对压力钢管灌浆孔应力集中的敏感性。结果表明,应力集中程度随补强板厚度及堵头坡口深度增加递减,堵头坡口深度对其影响更加敏感。对于地下埋管管壁上开灌浆孔的非高强钢,建议灌浆后孔口进行封堵,补强板厚度宜与钢管壁厚相同,并适当增加坡口深度。当钢管壁厚较大时,堵头坡口深度宜不小于钢管壁厚的1/4~1/3。     

MICP技术改性膨胀土试验研究

为了探究膨胀土新型改良技术,引进微生物诱导碳酸钙沉淀(MICP)新型环保的土体加固技术,利用巴氏芽孢八叠球菌开展MICP压力灌浆改性膨胀土室内试验,研究了胶结液浓度对膨胀土力学性能、微观结构及水理特性的影响,揭示了MICP技术改性膨胀土的作用机理,评价了MICP压力灌浆改性膨胀土试验的效果。试验结果表明:灌浆处理后试样的无侧限抗压强度最大增加了379.4%,土体刚度也有所提高;试样的膨胀性、渗透性均有明显改善,膨胀力最高可减少25.3 kPa,渗透系数最大减少3个数量级;试验改性效果随着胶结液浓度的增大而提高,但当胶结液浓度增大到一定程度后,改性效果不再显著。研究成果验证了MICP技术用于改性膨胀土的有效性和可行性。     

有机磷灭蚊剂投放浓度和时间对水体总磷的影响

为分析新型低毒有机磷杀虫剂“1%双硫磷颗粒”投放对河道水质的影响,设置不同药剂投放浓度和不同反应时间的室内试验,以TP、NH₃-N及S^2-为目标因子,分析该药剂投放后水体污染物浓度。结果表明:不同试验组水样中S^2-质量浓度均小于0.02 mg/L,NH₃-N质量浓度处于0.029~0.036 mg/L之间,均达到地表水Ⅰ类标准;不同浓度药剂投放1 h后,水体TP质量浓度已达到稳定状态,且在60 h内均保持稳定,药剂投加量与水体TP质量浓度呈显著正相关(R²=0.85);不同处理组的药剂在水体中的TP释放量无明显差异,均在1.06~1.30 mg/g之间。“1%双硫磷颗粒”推荐适宜投放量不会使河道水质恶化到劣Ⅴ类,但增加药剂投放量会增加水体TP污染及富营养化风险。     

基于CMIP5的中国西北地区暖湿化演变研究

为了解中国西北地区历史与未来时期的气候演变趋势,以CMFD再分析数据集及CMIP5全球气候模式输出数据为基础,从时空维度详细分析了西北地区历史气候的演变特征并对区域未来气候发展进行了预估。结果表明：1979-2018年西北地区的气温、降水量以及近地面空气比湿均呈现出明显的增加趋势,且未来极有可能继续增加;此外,降水量在年内的分配过程越趋均匀化,且降水结构在2001年左右发生了较大突变。整体来看,西北地区的历史气候演变显示出高度的暖湿化倾向。未来情景下,西北地区的气候将继续朝暖湿化方向发展,同时降水量的年内分配不均匀性也将进一步减小,且在RCP8.5排放情景下表现的更为突出。本研究可为西北地区气候变化的影响评估提供参考,同时也为水利、农业、气象和生态等部门的决策提供科学依据。     

Photovoltaic effect and carrier transport mechanisms in Hg1-Mnxtdiodes

Hg_1-xMn_xTe semiconducting semimagnetic alloy has been examined in the context of its possible applications in infrared detectors. For analysis of detector properties the intrinsic carrier concentration has been calculated as a function of temperature and crystal composition. The starting material was In-doped Hg_1-xMn_xTe grown by the modified Bridgman method. The as-grown crystals with manganese content of 12-19% were p-type with carrier concentration and mobility of 100 cm²/ Vs at 77 K. An-type layer was formed on the surface by the annealing process in saturated Hg-vapour at 270-320° for 2 hrs. Capacitance-voltage curves have C^-3 dependence on applied voltage indicating that the junction is linearly graded. From standard electrical measurements and spectral characteristics the main detector parameters were determined and compared to those of Hg_1-xCd_xTe devices. The influence of material properties on detector parameters was analyzed. In order to estimate the carrier transport mechanisms, differential resistivities and current-voltage curves were measured over a wide range of temperaturesi.e. 25 to 300 K. From the temperature dependence of the R₀A product, it was established that at high temperatures (150-300 K) the carrier transport is dominated by a recombination-generation mechanism. In low temperature region the excess current at forward bias is probably attributed to carrier tunneling via energy states distributed randomly within the forbidden gap. At reverse bias the leakage surface or volume currents dominate in the carrier transport.     

二元稀土系AB5型贮氢电极合金的放电容量与晶胞体积和4f电子浓度的关系

制备了6个系列通式为AαA‘1-αB5的RE(NiCoMnTi)5贮氢电极合金(其中，AαA‘1-α为La，Ce，Pr，Nd4个元素中任意2个的组合)，测定了它们在100次循环中的最大放电容量Cmax及部分合金的晶胞体积Vcell．结果表明：Cmax主要由Vcell决定，Cmax先随Vcell的增大而增加，在Vcell≈85．66x10^-^3。nm^3时达到一极大值，然后又随Vcell的增大而减小；同时，Cmax还与4f电子浓度ne4f／naRE有关，A侧具有相同4f电子浓度的合金其Cmax随4f电子浓度的变化趋势相似．     

Continuous electromagnetic separation of inclusion from aluminum melt using alternating current

A novel scheme about the continuous electromagnetic purification of aluminum melt was put forward based on the utilization of a square separation pipe and a 50 Hz alternating current to produce electromagnetic force. It is experimentally found that with electrical current of 400 A/cm^2, it takes only 10 s to remove 95% inclusion from aluminum melt. Comprehensive numerical simulations were carried out to investigate the dynamics mechanisms behind the process. The results show that the removal of inclusion is attributed to the cooperative effects of electromagnetic buoyancy and the secondary flow induced by the rotational electromagnetic force, and the removal efficient increases with the size of inclusion and the electrical current imposed. Theoretical predictions on the distribution and removal efficiency of inclusion were supported by the experiments.     

从热滤渣中富集提取贵金属

介绍了减压蒸馏脱硫，熔炼富集，高温悬浮氯气浸出处理热滤渣的工艺。其综合利用好，元素硫脱除率〉９２％，贱金属浸出率〉９５％，贵金属回收率〉９９％。贵金属富集物可并入贵金属精炼分离工段处理。     

Cation Effect on the Binary and Ternary Phase Behaviors of Double-Tailed Methanesulfonate Amphiphiles

A series of symmetrical dialkyl methanesulfonate amphiphiles [DiC _n CHSO ₃ ] _m M (n = 6, 7, 8) with different counter cations (M^m+ = H⁺, Li⁺, Na⁺, K⁺, Cu²⁺, Zn²⁺, Mg²⁺, Ca²⁺, Sc³⁺) were synthesized in five steps. Their solubility and critical micelle concentration (CMC) in water were determined highlighting a huge effect of the chain length and the nature of the cation. The hydrophilic–lipophilic balance of the surfactants were assessed with the phase inversion temperature (PIT)-slope method based on the deviation from the PIT of the reference C₁₀E₄/n-octane/0.01 M NaCl_(aq) emulsion through addition of increasing amounts of the dialkyl methanesulfonates. The hydrophilicity of the surfactants was thus ranked in terms of dPIT/dx_sulfonate. A “cation” scan with the [DiC ₆ CHSO ₃ ] _m M /benzene/water systems at f_w = 0.5 was finally performed confirming the hydrophilicity ranking obtained with the PIT-slope method. It revealed that the [DiC ₆ CHSO ₃ ] ₂ Mg behaves as a “Balanced Surfactant” able to form spontaneously a three-phase microemulsion system (Winsor III) just in the presence of water and oil, in the same way as the catalytic surfactant dimethyldioctylammonium molybdate, which has the same PIT-slope.     

Integration of Data from Liquid–Liquid Phase Separation Databases Highlights Concentration and Dosage Sensitivity of LLPS Drivers

Liquid–liquid phase separation (LLPS) is a molecular process that leads to the formation of membraneless organelles, representing functionally specialized liquid-like cellular condensates formed by proteins and nucleic acids. Integrating the data on LLPS-associated proteins from dedicated databases revealed only modest agreement between them and yielded a high-confidence dataset of 89 human LLPS drivers. Analysis of the supporting evidence for our dataset uncovered a systematic and potentially concerning difference between protein concentrations used in a good fraction of the in vitro LLPS experiments, a key parameter that governs the phase behavior, and the proteomics-derived cellular abundance levels of the corresponding proteins. Closer scrutiny of the underlying experimental data enabled us to offer a sound rationale for this systematic difference, which draws on our current understanding of the cellular organization of the proteome and the LLPS process. In support of this rationale, we find that genes coding for our human LLPS drivers tend to be dosage-sensitive, suggesting that their cellular availability is tightly regulated to preserve their functional role in direct or indirect relation to condensate formation. Our analysis offers guideposts for increasing agreement between in vitro and in vivo studies, probing the roles of proteins in LLPS.