66 research outputs found

    Diaqua­bis[5-(5-carboxy-2-pyridyl)tetra­zolato-κ2 N 1,N 5]cadmium(II) dihydrate

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    In the title complex, [Cd(C7H4N5O2)2(H2O)2]·2H2O, the water-coordinated CdII atom ( symmetry) is coordinated by four N atoms from two symmetry-related 3-carboxy­pyidyl-6-tetra­zolato ligands, forming a distorted octa­hedral complex. The uncoordinated water mol­ecules connect the mononuclear units into a layer structure through O—H⋯N and O—H⋯O hydrogen bonds; similar hydrogen bonds between coordinated water mol­ecules and anionic groups result in a three-dimensional structure

    Bis[μ-5-(5-carboxyl­ato-3-pyrid­yl)tetra­zolato-κ3 N 1,N 5:N 2]bis­[triaqua­zinc(II)]

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    In the title complex, [Zn2(C7H3N5O2)2(H2O)6], the 5-(5-carboxyl­ato-3-pyrid­yl)tetra­zolate ligand chelates the ZnII center through one pyridyl N and one tetra­zolate N atom, and uses another N atom to bridge to the second Zn atom, forming a centrosymmetric dinuclear unit. Three coordinated water mol­ecules complete the distorted octa­hedral geometry of the ZnII atom. O—H⋯O and O—H⋯N hydrogen bonds involving the coordinated water mol­ecules, tetra­zolate N atoms and the carboxyl­ate group result in a three-dimensional structure

    Calcium chloride improve ethanol production in recombinant Zymomonas mobilis

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    The T7-expression system has been very useful for protein expression in Escherichia coli. Here, a T7- expression transposon was constructed, which allowed simple construction of T7-expression Zymomonas mobilis. This transposon contained the T7 RNA polymerase being driven by the gap promoter from Z. mobilis. The T7-expression fadK genomes were introduced into Z. mobilis ATCC 31821 in order to increase ethanol production. The recombinant bacteria were named as Z.M.F-1, Z.M.F-2, Z.M.F-3, and Z.M.F-4. However, Z.M.F-4 had the highest ability of producing ethanol by selection. Compared with Z. mobilis ATCC 3182, there was 7% increase in ethanol production for Z.M.F-4 with corn hydrolyaztes as fermentation medium. The 16 mmolL-1 supplement of calcium chloride could significantly improve the ethanol production. This was also clearly demonstrated by a variety of kinetic parameter values over time in Z.M.F-4 under high sugar osmotic stress. Calcium chloride not only increased the fermentation ability but also improved the stability of cell membrane.Key words: Calcium chloride, fadK, fermentation, Zymomonas mobilis

    Timing of Maximal Weight Reduction Following Bariatric Surgery: A Study in Chinese Patients

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    Introduction: Bariatric surgery is a well-received treatment for obesity with maximal weight loss at 12–36 months postoperatively. We investigated the effect of early bariatric surgery on weight reduction of Chinese patients in accordance with their preoperation characteristics. Materials and Methods: Altogether, 409 patients with obesity from a prospective cohort in a single bariatric center were enrolled retrospectively and evaluated for up to 4 years. Measurements obtained included surgery type, duration of diabetic condition, besides the usual body mass index data tuple. Weight reduction was expressed as percent total weight loss (%TWL) and percent excess weight loss (%EWL). Results: RYGB or SG were performed laparoscopically without mortality or complications. BMI generally plateaued at 12 months, having decreased at a mean of 8.78 kg/m2. Successful weight loss of \u3e 25% TWL was achieved by 35.16, 49.03, 39.22, 27.74, 20.83% of patients at 6, 12, 24, 36, and 48 months after surgery. Overall, 52.91% of our patients had lost 100% of their excess weight at 12 months, although there was a rather wide range among individuals. Similar variability was revealed in women of child-bearing age. Conclusion: Chinese patients undergoing bariatric surgery tend to achieve maximal weight loss and stabilization between 12 and 24 months postoperatively, instead of at \u3e 2 years. The finding of the shorter stabilization interval has importance to earlier intervention of weight loss related conditions and women\u27s conception planning

    A sliding mode controller design for the robust position control problem of series elastic actuators

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    In this paper, a new robust position controller is proposed for Series Elastic Actuators (SEAs) by using Sliding Mode Control (SMC) and a second order Disturbance Observer (DOb). The latter estimates not only disturbances but also their first and second order successive derivatives. A simple yet efficient dynamic model of the position control system is derived by using the analogy of a two-mass-spring-damper system. It is of fourth order and suffers from collocated and non-collocated disturbances. The former is directly cancelled by feeding-back its estimation through control input. The latter is suppressed by treating the estimations of disturbances and their first and second order time derivatives in the design of the SMC-based robust position controller. By cancelling disturbances via their estimations, not only the robustness of the position control system is improved but also the control signal chattering is lowered. The proposed robust controller significantly improves the position control performance of SEAs by suppressing plant uncertainties and external disturbances, such as friction, backlash, inertia variation and load. The validity of the proposed robust position controller is verified by giving experimental results of an SEA

    An Improved Deep Learning Network Structure for Multitask Text Implication Translation Character Recognition

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    With the rapid development of artificial intelligence technology, multitasking textual translation has attracted more and more attention. Especially after the application of deep learning technology, the performance of multitask translation text detection and recognition has been greatly improved. However, because multitasking contains the interference problem faced by the translated text, there is a big gap between recognition performance and actual application requirements. Aiming at multitasking and translation text detection, this paper proposes a text localization method based on multichannel multiscale detection of the largest stable extreme value region and cascade filtering. This paper selects the appropriate color channel and scale to extract the maximum stable extreme value area as the character candidate area and designs a cascaded filter from coarse to fine to remove false detections. The coarse filter is based on some simple morphological features and stroke width features, and the fine filter is trained by a two-recognition convolutional neural network. The remaining character candidate regions are merged into horizontal or multidirectional character strings through the graph model. The experimental results on the text data set prove the effectiveness of the improved deep learning network character model and the feasibility of the textual implication translation analysis method based on this model. Among them, the text contains translation character recognition results prove that the model has good description ability. The characteristics of the model determine that this method is not sensitive to the scale of the sliding window, so it performs better than the existing typical methods in retrieval tasks

    Robust Sliding Mode Control for Robots Driven by Compliant Actuators

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    Numerical Investigation on Propagation Behaviors of a Three-Dimensional Fracture Network Coupled with Microseismicity in Fractured Shale Reservoirs

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    The formation mechanism and propagation behaviors of a three-dimensional hydraulic fracture network in fractured shale reservoirs remain unclear, especially when the scale of hydraulic fractures is much larger than that of natural fractures. In this study, taking the well XH in the Longmaxi shale reservoir in the Sichuan Basin, China as an example, we develop a fully three-dimensional numerical model for hydraulic fracturing coupled with microseismicity based on the discrete lattice method. We introduce a randomly generated discrete fracture network into the proposed model and explore the formation mechanism of the hydraulic fracture network under the condition that the hydraulic fractures are much larger than natural fractures in scale. Moreover, microseismic events are inversely synthesized in the numerical model, which allows the evolution of the fracture network to be monitored and evaluated quantitatively. In addition, we analyze the effects of injection rate, horizontal stress difference, and fluid viscosity on fracture propagation. Our results show that when the scale of hydraulic fractures is much larger than that of natural fractures, the fracture morphology of “main hydraulic fractures + complex secondary fractures” is mainly formed. We find that a high injection rate can not only create a complex fracture network, but also improve the uniform propagation of multi-cluster fractures and enhance far-field stimulation efficiency. Optimizing the horizontal wellbore intervals with low horizontal stress differences as the sweet spots of hydraulic fracturing is also beneficial to improve the stimulation efficiency. For zones with a large number of natural fractures, it is recommended to use an injection schedule with high viscosity fluid early and low viscosity fluid late to allow the hydraulic fractures to propagate to the far-field to maximize the stimulation effect
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