大型地下洞室开挖期全过程智能监测反馈

对大型地下洞室开挖期进行智能化监测的必要性、可行性、难点及对应措施进行了系统介绍,并对所取得的成果进行分析,旨在为其他水电工程开挖的自动化监测提供借鉴。     

令牌损失信息的通用文本攻击检测

目的 文本对抗攻击主要分为实例型攻击和通用非实例型攻击。以通用触发器（universal trigger,UniTrigger）为代表的通用非实例型攻击对文本预测任务造成严重影响,该方法通过生成特定攻击序列使得目标模型预测精度降至接近零。为了抵御通用文本触发器攻击的侵扰,本文从图像对抗性样本检测器中得到启发,提出一种基于令牌损失权重信息的对抗性文本检测方法（loss-based detect universal adversarial attack,LBD-UAA）,针对 UniTrigger攻击进行防御。方法 首先 LBD-UAA 分割目标样本为独立令牌序列,其次计算每个序列的令牌损失权重度量值（token-loss value,TLV）以此建立全样本序列查询表。最后基于 UniTrigger 攻击的扰动序列在查询表中影响值较大,将全序列查询表输入设定的差异性检测器中通过阈值阀门进行对抗性文本检测。结果 通过在 4 个数据集上进行性能检测实验,验证所提出方法的有效性。结果表明,此方法在对抗性样本识别准确率上高达 97. 17%,最高对抗样本召回率达到 100%。与其他 3 种检测方法相比,LBD-UAA 在真阳率和假阳率的最佳性能达到 99. 6% 和 6. 8%,均实现大幅度超越。同时,通过设置先验判断将短样本检测的误判率降低约 50%。结论 针对 UniTrigger 为代表的非实例通用式对抗性攻击提出 LBD-UAA 检测方法,并在多个数据集上取得最优的检测结果,为文本对抗检测提供一种更有效的参考机制。     

Context-conditioned generalization in adaptation to distorted speech.

People were trained to decode noise-vocoded speech by hearing monosyllabic stimuli in distorted and unaltered forms. When later presented with different stimuli, listeners were able to successfully generalize their experience. However, generalization was modulated by the degree to which testing stimuli resembled training stimuli: Testing stimuli's consonants were easier to recognize when they had occurred in the same position at training, or flanked by the same vowel, than when they did not. Furthermore, greater generalization occurred when listeners had been trained on existing words than on nonsense strings. We propose that the process by which adult listeners learn to interpret distorted speech is akin to building phonological categories in one's native language, a process where categories and structure emerge from the words in the ambient language without completely abstracting from them. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simultaneous counter-flow of chlorinated volatile organic compounds across the saturated-unsaturated interface region of an aquifer

Concentrations of chlorinated volatile organic compounds (Cl-VOCs) at the saturated-unsaturated interface region (SUIR; depth of ∼18 m) of a sandy phreatic aquifer were measured in two monitoring wells located 25 m apart. The concentrations of the Cl-VOCs obtained above and below the water table along a 413-day period are interpreted to depict variable, simultaneous and independent movement of trichlorothene, tetrachloroethene, 1,1-dichloroethene, cis-1,2-dichloroethene, 1,1,1-trichloroethane, chloroform and 1,1-dichloroethane vapors in opposite directions across the SUIR.     

Evaluation of the one-step hydrogen–oxygen global reaction rate in a non-premixed mixture to predict auto-ignition limits

Evaluation of the hydrogen–oxygen global reaction rate was conducted to predict auto-ignition onset and delay.     

Efficient V-V energy transfer in a multiphoton excited mixture of SF6and CF4

Spectral and temporal measurements of infrared fluorescence (IRF) in SF6, CF4, and mixtures of SF6and CF4gases excited by a pulsed CO2laser are reported. Using the 944.2 cm^-1[P(20)] laser line for excitation and measuring the IRF spectra between 700 and 1500 cm^-1, a strong red shifted IRF peak of the ν3mode in pure SF6was found. No IRF was observed under these conditions in pure CF4. In a 13:10 mixture of SF6and CF4, two strong IRF peaks of the ν3modes, shifted to the red relative to the room-temperature fundamentals at 948 cm^-1and 1283.2 cm^-1, were observed. The peaks are almost equal in height and since both molecules have almost the same ν3band intensity, the present result suggests that efficient intermolecularV-Venergy transfer occurs from excited SF6to cold CF4molecules. The temporal behavior of the IRF signals under high excitation (langlenrangle approx 6) in pure SF6exhibits two relaxation times, one of bulk cooling withtau_{1} approx 1ms and the other of aV-Tnature withPtau_{2} approx 20 mus . torr. In the mixture, an additional relaxation of the intermolecularV-Venergy transfer process is observed withPtau_{3} approx 10 mus . torr. The red shift dependence of the IRF peaks on the degree of excitation was also measured and used to examine population distributions, specific IRF transitions, and anharmonicity parameters.     

预硫化型CoMo加氢脱硫催化剂性能

采用等体积浸渍方法制备CoMo催化剂,选用不同预硫化方法制备一系列硫化型CoMo催化剂,考察反应温度和空速对加氢脱硫性能的影响,并与对比剂进行比较。结果表明,硫化型CoMo催化剂在不同温度和空速下,具有较好活性,在200 h周期实验中,硫化型CoMo催化剂表现出良好的稳定性,脱硫率98.7%。TEM表征显示,硫化型CoMo催化剂具有更多的MoS_2堆垛层,形成更多高活性Co-Mo-SⅡ型活性相。     

Pitting corrosion inhibition of 316 stainless steel in phosphoric acid-chloride solutions Part I Potentiodynamic and potentiostatic polarization studiess

The electrochemical behaviour of 316 stainless steel in H3PO4-CI– solutions containing nitrate, dichromate, tungstate, and molybdate anions as inhibitors are presented and discussed using potentiodynamic and potentiostatic polarization techniques. The results showed that most additives improve the corrosion resistance of the alloy. The additives retard both active and pitting attack to an extent depending on the type and concentration of the additive. Results were correlated with the beneficial action of the corresponding alloying elements.