气藏平均地层压力跟踪计算新方法

平均地层压力是产能评价和动态分析的基础，准确、快速获取平均地层压力对高效开发气藏意义重大。基于地层压力随时间变化的规律，分析了平均地层压力的变化规律。研究结果表明：平均地层压力等效点仅随时间发生改变，平均地层压力的下降速率等于或者近似等于井底流压的下降速率。从封闭弹性驱动气藏的物质平衡方程出发，考虑偏差系数和井底流压随平均地层压力的变化，推导建立了平均地层压力跟踪计算新方法，根据生产数据可迭代计算平均地层压力。方法验证结果显示，采气速度和采出程度共同影响模型的计算结果。应用实例表明，跟踪计算法与压力恢复试井和物质平衡法之间的相对误差均较小，满足工程计算精度要求，且跟踪计算法不需依托生产测试数据，节约了测试费用，避免了测试占产。     

Experimental Investigation on Low-Velocity Impact Performance of 3D Woven Textile Composites

Applied Composite Materials - The objectives of this experimental study are to develop impact-resistant three-dimensional (3D) woven textile-reinforced composites as well as to clarify the...     

Fabrication of high-efficiency Yb:Y2O3 laser ceramics without photodarkening

High-efficiency Yb:Y₂O₃ laser ceramics were fabricated using the vacuum-sintering plus hot isostatic pressing (HIP) without sintering additives. High-purity well-dispersed nanocrystalline Yb:Y₂O₃ powder was synthesized using a modified co-precipitation method in-house. The green bodies were first vacuum sintered at a temperature as low as 1430°C and then HIPed at 1450°C. Finally, the samples were air annealed at 800°C for 10 h. Although no sintering aids were used, full density of the samples with excellent optical homogeneity and an inline transmission of 80% at 400 nm could be obtained. Moreover, photodarkening phenomenon was not detected in the ceramics. Preliminary laser experiment with the fabricated ceramics in a two-mirror cavity has demonstrated 32 W continuous-wave (CW) output at ∼1077 nm with an optical-to-optical conversion efficiency of 58.2%. To the best of our knowledge, this is so far the highest CW output power and optical-to-optical conversion efficiency achieved with the Yb³⁺-doped sesquioxide ceramics in a simple two-mirror cavity.     

无黏土相盐水储层钻开液体系构建及其抗污染性能评价

采用NaCl/KCl/HCOONa复配欠饱和盐水作为钻开液的基础液相,自研的聚合物VIS-B作为流型调节剂,可酸溶的改性淀粉STA作为体系的降失水剂,Dua及Jqw作为暂堵材料,构建了一套无黏土相钻开液体系。该体系在密度1.10~1.28 g/cm^3间稳定可调,抗温可达130℃,具有较高的低剪切速率黏度和较好的润滑性能,且能有效抵抗各类储层污染物的污染,满足了Missan油田不同储层段的作业需求。     

Combining molybdenum carbide with ceria overlayers to boost Mo/CeO2 catalyzed ammonia synthesis

The design of an efficient non-noble metal catalyst is of burgeoning interest for ammonia synthesis. Herein, we report a Mo₂C/CeO₂ catalyst that is superior in ammonia synthesis activity. In this catalyst, molybdenum carbide coexisted with the ceria overlayers which is from the ceria support as the strong metal–support interaction. There is a high proportion of low-valent Mo species, as well as high concentration of Ce³⁺ and surface oxygen species. The presence of Mo₂C and CeO₂ overlayers not only leads to enhancement of hydrogen and nitrogen adsorption, but also facilitates the desorption and exchange of adsorbed species with the gaseous reagents. Compared with the Mo/CeO₂ catalyst prepared without carbonization, the Mo₂C/CeO₂ catalyst is more than sevenfold higher in ammonia synthesis rate. This work not only presents an explicit example of designing Mo-based catalyst that is highly efficient for ammonia synthesis by tuning the adsorption and desorption properties of the reactant gases, but opens a perspective for other elements in ammonia synthesis.     

Fabrication strategies and application fields of novel 2D Ti3C2Tx (MXene) composite hydrogels: A mini-review

Ti₃C₂T_x (MXene), a new kind of 2D ceramic nanosheets, is receiving more and more attention in the fields of medicine, biology, energy, electronics, etc. However, the preparation and application of MXene in hydrogel is still in its infancy period. Here, we review the latest progress (after 2018) related to MXene hydrogels in time. Aiming at the key issue of the dispersion stability of MXene in hydrogel systems, the preparation strategy, mechanism, advantages and disadvantages of MXene hydrogels are sorted out in detail, and the potential application prospects of MXene composite hydrogel are introduced. Finally, future viewpoints are put forward for the dispersion stability challenges that need solving in the design of MXene hydrogel.     

β-Cypermethrin Alleviated the Inhibitory Effect of Medium from RAW 264.7 Cells on 3T3-L1 Cell Maturation into Adipocytes

Studies have elucidated that pyrethroids induce adipogenesis. It is also known that macrophages can affect the homeostasis of adipose tissue. However, whether and how the β-cypermethrin (β-CYP)-mediated inhibition of the macrophages affects adipogenesis remain unknown. To explore the effects of β-CYP on adipogenesis through modulating the function of macrophages, 3T3-L1 cells, a preadipocyte cell line, were exposed to culture medium from either RAW 264.7 cells, a macrophage cell line (RM), or β-CYP-treated RAW 264.7 cells (CRM). CRM decreased the inhibitory effects of RM treatment on cell proliferation and adipogenesis, as lipid accumulation, the CEBPA content, and Fasn and Acaca expression in 3T3-L1 cells were higher following CRM treatment than following RM treatment through the higher levels of the demethylated CEBPA promoter in 3T3-L1 cells. However, the medium from β-CYP- and N-acetyl-L-cysteine-cotreated RAW 264.7 cells (CNRM) partially restored the inhibitory effects of RAW 264.7 cells on 3T3-L1 cells that had been reduced by CRM, indicating that β-CYP might reduce the cytotoxicity and inhibitory effects of RAW 264.7 cells on the adipogenesis of 3T3-L1 cells through elevating ROS levels in RAW 264.7 cells. Moreover, exposure to β-CYP downregulated the TNF-α secretion in RAW 264.7 cells. In conclusion, these data demonstrated that β-CYP affected the function of RAW 264.7 cells, alleviating their inhibitory effects on adipogenesis and CEBPA demethylation in 3T3-L1 cells. β-CYP might achieve these effects through downregulating the secretion of TNF-α via elevating ROS levels in RAW 264.7 cells. Our experiments provide a new perspective on the obesogenic effect of pyrethroids.     

Effect of different quenching processes following solid-solution treatment on properties and precipitation behaviors of 7050 alloy

The effects of quenching in different ways following solid-solution treatment on properties and precipitation behaviors of 7050 alloy were investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM), selected area electron diffraction (SAED), hardness and electrical conductivity tests. Results show that after quenching in different ways, electrical conductivity of the alloy decreases rapidly in the first 48 h of natural aging. The electrical conductivity of 7050 alloy in natural aging state is determined by the size and density of GP zones, and the size of GP zones is the main factor. After natural aging for 70 d, the size of GP zones is 1.8–2.6 nm in matrix of the immersion quenched sample and it is 1.4–1.8 nm in matrix of both water mist and forced air quenched samples. After natural and artificial peak aging, the hardness of the water mist quenched sample is HV 193.6 and its electrical conductivity is 30.5% (IACS) which are both higher than those of the immersion quenched sample. Therefore, water mist quenching is an ideal quenching method for 7050 alloy sheets after solid-solution treatment.     

由低浓度钛液制备偏钛酸的水解工艺研究

钛是一种重要的战略资源,在废弃脱硝催化剂中钛含量远远高于我们常用的钛精矿。近年来,各种从废弃催化剂中回收钛新技术的发展,使得人们对钛回收过程水解工艺的研究更加重视。本文以废弃催化剂经过高温钠化焙烧后硫酸酸解得到的低浓度钛液为原料,采用常压自生晶种热水稀释水解工艺制备偏钛酸,通过对自生晶种常压水解工艺中影响钛液水解产品平均粒径的五个关键因素:钛液F值、水解温度、钛液初始浓度、熟化时间、搅拌速度进行正交设计,然后比较各因素的极差,最终得到影响水解产品偏钛酸粒径各因素主次关系如下:水解温度>钛液初始浓度>钛液F值>熟化时间>搅拌速度。然后采用单因素控制变量法,研究了水解温度、钛液初始浓度、钛液F值、熟化时间、搅拌速度对影响钛水解产品偏钛酸粒径的较佳条件。结果表明:在水解温度95℃,钛液初始浓度200 g/L,钛液F值为1.8,熟化时间在50 min,搅拌速度300 r/min时,得到的偏钛酸平均粒径更接近2 μm。