Flakes of natural carbyne in a diamond mine

Flakes of natural carbyne were found in Liao-Ning diamond mine, China, and examined by HRTEM, XRD and EDX. Lattice fringes and clear SAD patterns were obtained. The interlayer spacings obtained with SAD were in good agreement with those determined on the powders found in Ries crater meteorite by X-ray diffraction. However, they are different in color and shape, the one found in China being black and flaky, but the one in Ries crater meteorite being silver-white and particulate. It was assumed that carbyne might be stabilized by the intercalation of either Si or Fe in nature.     

多声路超声波流量计在引水明渠中的流量测量分析

介绍了多声路超声波流量计在明渠中的流量测量原理,并通过多声路时差式超声波流量计在引水明渠上的实例应用对影响流量测量的误差源进行了具体的分析。     

煤化工专用黑水阀阀座流通性能研究

介绍了一种煤化工专用黑水阀的结构构成,并提出进行该型号阀门流通性能研究的重要性。建立流道三维模型,应用CFD有限元分析软件,模拟黑水阀内部流场分布情况,分析可视化结果,确定阀座/阀芯易损位置。分别对不同阀座渐扩角时模型进行仿真模拟,得到阀门进、出口压力值,并依此计算Cv值大小,拟合流量系数曲线,提出阀门在实现最大介质流通时阀座渐扩角范围,为阀门设计提供重要的理论参考。     

Gel-size dependence of temperature-induced microphase separation in weakly-charged polymer gels

The gel-size dependence of microphase separation in weakly-charged gels of N-isopropylacrylamide (NIPA) and 1-vinylimidazole (VI) copolymers has been investigated using swelling measurement, small-angle neutron scattering (SANS), and dynamic and static light scattering (DLS/SLS). It is known that weakly-charged polymer gels undergo microphase separation in a poor solvent as a result of competing interactions involving hydrophobic attraction versus electrostatic repulsion. The microphase separation is characterized by a scattering maximum in SANS intensity functions of which Bragg spacing, Λ, is around 20-30 nm. However, when gel size was reduced to the order of Λ, no microphase separation was observed. Instead, a typical scattering of isolated spherical particles was clearly observed. On the basis of the experimental evidence, we conclude that microphase separation has its own wavelength independent of gel size, and nanometer-order gels, i.e., nanogels, do not undergo microphase separation.     

毛细管SDS无胶筛分电泳测定小分子多肽相对分子质量

目的建立快速毛细管SDS无胶筛分电泳法(SDS-NGS),测定小分子多肽相对分子质量。方法涂层毛细管(管长30cm,内径100μm);分离电压为9kV(300V/cm),分离温度为20℃;检测波长为214nm,检测时间为18min;所用SDS-多肽相对分子质量标准范围为2 512~16 949;以橙G(OG)为内标参照物。结果在相对分子质量2512~16949范围内,多肽相对分子质量的对数与其相对迁移率具有良好的线性关系(r=0.996);应用该方法测定了重组人奈西立肽、重组人表皮生长因子、虎纹镇痛肽、重组人心钠肽4种重组小分子多肽的相对分子质量,所测结果变异系数CV均小于3%。结论毛细管SDS无胶筛分电泳方便快速,灵敏度高,重现性好,结果准确,可作为小分子多肽相对分子质量的检测方法。     

Comparison of different flowability tests for powders for inhalation

A series of placebo powders for inhalation was characterized regarding bulk density and powder flowability using different techniques. The powders were of the ordered mixture type and were prepared by mixing a pharmaceutical carrier grade of lactose with different fractions of intermediate sized and fine (i.e., micronized) lactose. A modified Hausner Ratio was obtained by measurement of the poured and the compressed bulk densities. Other tests investigated were the angle of repose, the avalanching behaviour using the AeroFlow, and the yield strength using the Uniaxial tester. Furthermore, the relation between ordered mixture composition and flowability was examined.Of the methods investigated, the modified Hausner Ratio discriminates well between the investigated powders and seems to have the widest measuring range. It was also found that the poured and compressed bulk densities provide information about the packing of the particles in the powders. A good correlation was obtained between the modified Hausner Ratio and the angle of repose. The AeroFlow was suitable for powders with a low percentage of fine particles, but could not discriminate between the more cohesive powders. The Uniaxial tester, on the other hand, seems to be better suited for more cohesive powders.Regarding the powder composition, addition of micronized particles has a strong influence on the flowability of ordered mixtures, while intermediate sized particles have little impact on the powder flow.     

微波着陆引导系统多径效应的数字仿真

为分析和评估多路径效应对MLS测角误差影响,提出了一种基于几何光学和射线寻迹理论的MLS多路径角度误差数字仿真新方法. 该方法依据几何光学和几何绕射理论在获得多径信号与直达信号电压比的基础上,通过射线寻迹计算多径直达信号相位差,而后对叠加包络的角度误差方向图分解为波束内和波束外多路径误差进行研究,实现角度误差数字仿真. 利用该方法对某机场典型环境的多路径问题进行了数字仿真,并将仿真结果与经典模型进行了对比,验证了其可行性.     

A small samples training framework for deep Learning-based automatic information extraction: Case study of construction accident news reports analysis

Knowledge management is crucial for construction safety management. Widely collected and well-organized safety-related documents are recognized to be significant in raising the workers' security awareness and then to prevent hazards and accidents. To improve document processing efficiency, automatic information extraction plays an important role. However, currently, automatic information extraction modeling requires large scale training datasets. It is a big challenge for the engineering industry, especially for the fields which heavily rely on the experts’ knowledge. Limited data sources, and high time and labor costs make it not practical to establish a large-scale dataset. This work proposed a natural language data augmentation-based small samples training framework for automatic information extraction modeling. With the designed cross combination-based text data augmentation algorithm, the deep neural network can be employed to build up automatic information extraction models without large-scale raw data and manual annotations. Characters semantic coding is employed to avoid word segmentation and make sure that the framework can be utilized in different writing language systems. The BiLSTM-CRF model is adopted as the detection core to conduct character classification. Through a case study of two independent accident news report datasets analysis, the proposed framework has been validated. A reliable and robust automatic information extraction model can be established, even though with small samples training.     

隧道钢架开孔施工超前小导管的研究与设计

超前小导管是隧道工程施工的一种工艺方法,主要用于不良地质地段的预支护。设计有超前小导管支护的地段,初期支护常以工字钢钢架为主,施工单位常在工字钢腹板中部开小孔来定位超前小导管,以满足间距和角度的要求,特别是当钢架间距较小、作业空间狭小时,都会采取开孔措施方便施工节约时间。开孔后工字钢的支护性能必然下降,监理单位往往不会要求施工单位对开孔后的工字钢架采取补强措施。本文就开孔后工字钢架与未开孔工字钢架做比较,采用力学理论和试验相结合的方法,研究开孔后对工字钢的影响,并探讨其补强措施。     

依据角度位置变速的铺匀器控制系统

用角度测量传感器，检测铺匀器的角度变化，并用新型的电、液控制技术，实施了对铺匀器的变速控制。此设计经实际使用，效果良好。