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Open access

Huili Yang, Jie Chen, Naomi Porat, Tao Li, Wenqiao Li and Weipeng Xiao

Abstract

Optical dating of earthquake related sediments were investigated including one modern sample and three samples from a trench excavated across the 1985 Ms7.4 Wuqia Earthquake surface rupture. The results indicated that equivalent dose (De) values vary with grain size and the method used for De determination. The residual dose of the modern sample is 0.1 ka ( 0.20.1+0.2 Gy) for the quartz single grain measurements. Only 1.5–3.6% of the grains have a detectable OSL signal. Single grain quartz ages are similar to the expected ages. Fine grain quartz results overestimate the De values and are much older than single grain quartz and coarse grain quartz small aliquot standardized growth curve (SA-SGC) ages. Single grain quartz OSL dating may be optimal for dating earthquake related deposits, but SA-SGC can save measurement time and has potential for dating some poorly bleaching samples.

Open access

Yawen Zeng, Xiaoying Pu, Xiaomeng Yang, Jiazhen Yang, Juan Du, Tao Yang and Xia Li

Open access

Wang Hong, Qi-Sheng Liang, Lan-Ren Cheng, Xiao-Hong Li, Fu Wei, Wen-Tao Dai and Shi-Tong Li

Abstract

Background: Rocuronium is an alternative to succinylcholine for rapid tracheal intubation after major thermal injury and other forms of critical illness that cause denervation changes in skeletal muscle. Rocuronium may decrease the potencies of non-depolarizing muscle relaxants.

Objectives: Examine whether potency of rocuronium changed during the first month after denervation, and investigate the effects of skeletal muscle denervation on potency of rocuronium.

Methods: The denervation mouse model was developed to create denervated individual cells from the flexor digitorum brevis of the hindfoot. The skeletal muscle cells were examined at day 0 in the innervated control and days 1, 4, 7, 14, 21, and 28 in the denervation group. Nicotinic acetylcholine receptors in the cells were activated with 30 M acetylcholine, alone or in combination with various concentrations of rocuronium. Currents were recorded with a whole-cell patch-clamp technique.

Results: Rocuronium reversibly inhibited acetylcholine-activated currents in a dose-dependent fashion at different times after denervation. The inhibition concentration for the half-maximal responses of rocuronium increased 1.2- (p >0.05), 1.8-, 2.8-, 2.3-, 2.1-, and 1.9-fold (p <0.01) at day 1, 4, 7, 14, 21, and 28 after denervation, respectively, compared to that at day 0 after denervation.

Conclusion: Rocuronium dose required to achieve satisfactory clinical effects changed at different durations after skeletal muscle denervation.

Open access

Zaopeng Dong, Lei Wan, Yueming Li, Tao Liu and Guocheng Zhang

Abstract

This paper presents a state feedback based backstepping control algorithm to address the trajectory tracking problem of an underactuated Unmanned Surface Vessel (USV) in the horizontal plane. A nonlinear three Degree of Freedom (DOF) underactuated dynamic model for USV is considered, and trajectory tracking controller that can track both curve trajectory and straight line trajectory with high accuracy is designed as the well known Persistent Exciting (PE) conditions of yaw velocity is completely relaxed in our study. The proposed controller has further been enriched by incorporating an integral action additionally for enhancing the steady state performance and control precision of the USV trajectory tracking control system. Global stability of the overall system is proved by Lyapunov theory and Barbalat’s Lemma, and then simulation experiments are carried out to demonstrate the effectiveness of the controller designed.

Open access

Qiong Liu, Tao Li, Shaowen Zhang, Lingbo Qu and Baozeng Ren

Abstract

A novel effi cient adsorbent, alkali-pretreated Paeonia ostii seed coats (AP-PSC), was investigated for the removal of methylene blue (MB) dye from solution. Orthogonal array design was applied to optimize the process parameters viz. alkali concentration, liquid-solid ratio (LSR) and pretreatment time. The results revealed that the optimal pretreatment conditions were at 0.8% (w/w) NaOH with LSR of 0.35 L g-1 treating for 50 min. Equilibrium and kinetic studies indicated that Langmuir isotherm and Pseudo-second-order models described the experimental data well. The maximum adsorption capability was of 368.2 mg g-1 for MB at 25oC. Thermodynamic parameters suggested that the AP-PSC adsorption process was physical, endothermic and spontaneous. Furthermore, the adsorption process was infl uenced by several interactive mechanisms, including ion-exchange, as well as Van der Waals forces and hydrogen bonds that occur concomitantly. It was concluded that AP-PSC may be potential as an effi cient adsorbent to remove MB from solution.

Open access

Tao Zhang, Ping Li, Ci Fang and Rongfeng Jiang

Abstract

The problem of phosphorus discharge is related to environmental protection and food security. Struvite crystallization is a useful technology for phosphate recovery from wastewater. In the research, struvite crystallization process with CO2 degasification continuous U-shape reactor (CUSR) was application for phosphate recovery from animal manure wastewater. The result indicated PO4 3--P recovery ratio could achieve 47-53% without magnesium addition when CUSR hydraulic retention time controlled at 60 min. With extra magnesium addition, PO4 3--P recovery ratio could significant achieve 80-86% at magnesium addition amount 57.5 mg/dm3. PHREEQC modeling predictions trend of struvite crystallization was close to CUSR experimental results. The modeling calculation can provide a theoretical guide for operational parameters design. For seeding technology, high phosphate recovery efficiency was obtained and preformed struvite was the most effective seeding material. Surface characterization analysis demonstrated the dominant composition of chemical solids was struvite. Water extraction analysis indicated chemical solids recovery from animal manure wastewater could release PO4 3--P slowly and be available as slow-release fertilizer.

Open access

Xiping Liu, Ya Li, Zhangqi Liu, Tao Ling and Zhenhua Luo

Abstract

This paper proposes a permanent magnet (PM)-assisted synchronous reluctance machine (PMASynRM) using ferrite magnets with the same power density as rareearth PM synchronous motors employed in Toyota Prius 2010. A suitable rotor structure for high torque density and high power density is discussed with respect to the demagnetization of ferrite magnets, mechanical strength and torque ripple. Some electromagnetic characteristics including torque, output power, loss and efficiency are calculated by 2-D finite element analysis (FEA). The analysis results show that a high power density and high efficiency of PMASynRM are obtained by using ferrite magnets.

Open access

Zenghui Wang, Junqiang Xia, Shanshan Deng, Junhua Zhang and Tao Li

Abstract

Traditional depth-averaged morphodynamic models for turbidity currents usually focus on the propagation of currents after plunging. However, owing to the unsteady characteristic of the plunge point locations and the tough conditions of field measurement within the plunge zone in a reservoir, it is difficult in practice to directly provide upstream boundary conditions for these models. A one-dimensional (1D) morphodynamic model coupling open-channel flow and turbidity current in a reservoir was proposed to simulate the whole processes of turbidity current evolution, from formation and propagation to recession. The 1D governing equations adopted are applicable to open-channel flows and turbidity currents over a mobile bed with irregular cross-section geometry. The coupled solution is obtained by a two-step calculation mode which alternates the calculations of open-channel flow and turbidity current, and a plunge criterion is used to determine the location of the upstream boundary for the turbidity current, and to specify the corresponding boundary conditions. This calculation mode leads to consecutive predictions of the hydrodynamic and morphological factors, from the open-channel reach to the turbidity current reach. Turbidity current events in two laboratory experiments with different set-ups were used to test the capabilities of the proposed model, with the effect of free-surface gradient also being investigated. A field-scale application of the coupled model was conducted to simulate two turbidity current events occurring in the Sanmenxia Reservoir, and the method for calculating the limiting height of aspiration was adopted to estimate the outflow discharge after the turbidity currents arrived in front of the dam. The predicted plunge locations and arrival times at different cross-sections were in agreement with the measurements. Moreover, the calculated interface evolution processes and the sediment delivery ratios also agreed generally with the observed results. Therefore, the 1D morphodynamic model proposed herein can help to select the design capacity of the outlets, and optimize the procedure for sediment release in reservoirs.

Open access

Feng-feng Kang, Shu-yan Cao, Yan-ming Li, Jiang-tao Li, Qing He, Yi Li and Yun-jian Hu

Abstract

Objective To investigate the clinical application of Real-Time PCR for rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) directly from nasopharyngeal swab specimens.

Methods We collected the nasal and throat swab specimens from patients or medical staffs in 3 intensive care units, blood laminar flow ward and respiratory ward in Beijing Hospital, Ministry of Health from December 2010 to April 2011. Each sample was tested by RT-PCR and conventional culture-based method for the presence of MRSA.

Results The total number of the specimens was 206. Compared with the conventional culture-based method, we demonstrated the diagnostic values for Real-Time PCR were 96.4% sensitivity, 96.6% specificity, 81.8% positive predictive rate, and 99.4% negative predictive rate. And the limit of detection was 102CFU/ml.

Conclusions This Real-Time PCR is a simple, rapid, sensitive and specific method. With the high negative predictive value, it can be used for the exclusion of MRSA colonization or infection. However, the application of its low positive predictive value should be further evaluated.