Damped nonlinear Schr\"odinger equation with Stark effect

We study the $L^2$-critical damped NLS with a Stark potential. We prove that the threshold for global existence and finite time blowup of this equation is given by $\|Q\|_2$, where $Q$ is the unique positive radial solution of $\Delta Q + |Q|^{4/d} Q = Q$ in $H^1(\mathbb{R}^d)$. Moreover, in any small neighborhood of $Q$, there exists an initial data $u_0$ above the ground state such that the solution flow admits the log-log blowup speed. This verifies the structural stability for the ``$\log$-$\log$ law'' associated to the NLS mechanism under the perturbation by a damping term and a Stark potential. The proof of our main theorem is based on the Avron-Herbst formula and the analogous result for the unperturbed damped NLS.Comment: 13 page

Investigation on the Rock-Fragmentation Process of Conical-Shaped TBM Cutterhead in Extremely Hard Rock Ground

Conical-shaped cutterhead is one type of tunnel boring machine (TBM) cutterhead which may have advantage of high rock-breaking efficiency in extremely hard rock ground. This study investigated the rock-fragmentation process of disc cutters on the conical-shaped cutterhead via a series of numerical simulations that had been verified by laboratory rock-fragmentation tests. Firstly, the rock-fragmentation numerical model of the six cutters in the 'flat-cone' contiguous part was built based on cutting mode analysis of the conical-shape cutterhead. The rock sample in the numerical model was synthesized using a grain-based discrete element method (GB-DEM) and the reliability of this approach was verified via scaled rock-fragmentation tests conducted on a self-developed linear cutting machine (LCM). Then, a series of numerical simulations were conducted to study the influence of cutterhead cone angle, cutter spacing, and cutter installation angle on the rock-fragmentation performance. The results were as follows: 1) the nature of rock fragmentation in the cone area is the rock fragmentation under side free-face condition; 2) the penetration specific energy can be reduced and thus the rock-fragmentation efficiency can be improved by appropriately increasing the conical angle, reducing the cutter spacing, and increasing the cutter installation angle; 3) for the studied granite, the optimal conical angle is 25°, the cutter spacing is suggested to be no more than 70 mm, and the cutter tilt angle is suggested to be no more than 3°. The results obtained in this paper can be used as guidance for the design of the conical-shaped cutterhead

Provenance of late Paleozoic strata in the Yili Basin : implications for tectonic evolution of the South Tianshan orogenic belt

This research was supported by the 973 Program under grant no. 2015CB453000, the National Natural Science Foundation of China (41502109), the Cultivating Program of Middle-Aged Key Teachers of Chengdu University of Technology (KYGG201718), Innovation Team of Sedimentary Geology of Chengdu University of Technology (KYTD201703), and by the China Postdoctoral Science Foundation (2015M582528). Cawood acknowledges support from the Australian Research Council grant FL160100168.The Yili Basin in NW China preserves a late Paleozoic volcano-sedimentary succession, the provenance of which helps to constrain the tectonic evolution of the South Tianshan orogenic belt. U-Pb ages and trace-element and Hf isotopic compositions of detrital zircons from the Late Devonian to earliest early Carboniferous strata in the Yili Basin suggest that the unit contains detritus mainly derived from basement rocks and contemporaneous arc-related volcanic rocks. The age of the unconformable contact between the Dongtujinhe Formation and underlying arc-related volcanic rocks is constrained to ca. 310 Ma. This age is consistent with published data for tectonic exhumation of high- to ultrahigh-pressure ([U]HP) metamorphic rocks from the northern margin of the South Tianshan orogenic belt. Zircon U-Pb ages from the sedimentary rocks, including clasts in conglomerate, indicate that detritus of the Dongtujinhe Formation was derived from multiple sources related to uplift and erosion of the southern Yili-Central Tianshan block. The presence of abundant eclogite clasts in the conglomerate of the Keguqinshan Formation indicates that (U)HP metamorphic rocks in the South Tianshan orogenic belt were exposed and supplied detritus to the southern Yili Basin at ca. 300 Ma. The early Middle Permian clastic rocks are characterized by Early Permian detrital zircons with a single peak at 278 Ma, derived from the postcollision magmatic rocks. During the Late Permian, input of detritus from old volcanic-sedimentary rocks and basement progressively increased. Integration of the provenance data from late Paleozoic strata in the Yili Basin with the time-equivalent northern Tarim and South Tianshan regions provides a record of the northward subduction of the South Tianshan oceanic crust beneath the Yili-Central Tianshan block in the Late Devonian to late Carboniferous (380-310 Ma), followed by continent-continent collision and final amalgamation at ca. 310-300 Ma, with postcollisional extension in the Permian.Publisher PDFPeer reviewe

MiR-155 protects against sepsis-induced cardiomyocyte apoptosis via activation of NO/cGMP signaling pathway by eNOS

Purpose: To examine the impact of miR-155 on sepsis-induced myocardial apoptosis and heart failure, and to explore its molecular mechanism. Methods: Mice were divided into four groups and septic myocardial dysfunction was induced by intraperitoneal injection of lipopolysaccharide (LPS, 5 mg/kg). The LPS stimulation expression of miR-155 levels was determined by real time-polymerase chain reaction (RT-PCR). In vivo, echocardiography and TUNEL staining were used to investigate the effects of miR-155 in inhibiting cardiac function and myocardial apoptosis. Changes in the expression of eNOS when miR-155 was overexpressed or inhibited were determined by RT-PCR, while double luciferase gene assay assessed the relationship between eNOS and miR-155, eNOS, expression of iNOS, SGC alpha 1, and PKG protein. Results: MiR-155 was significantly increased after LPS stimulation (p < 0.01). In vitro, the inhibition of miR-155 by antagomiR significantly down-regulated the apoptosis of cardiomyocytes (p < 0.05), while overexpression of miR-155 by agomiR significantly up-regulated the apoptosis of cardiomyocytes (p < 0.05). In vivo, ejection fraction, fractional shortening and heart weight were significantly increased (p < 0.05), while apoptosis was significantly decreased (p < 0.05). MiR-155 negatively regulated the expression of eNOS (p < 0.01), and targeted the expression of eNOS mRNA (p < 0.001). In addition, the expression of eNOS, sGCα1 and PKA were significantly up-regulated (p < 0.05), while the expression of iNOS was significantly down-regulated (p < 0.05) after the inhibition of miR-155 in LPS mouse model. Conclusion: MiR-155 regulates sepsis-induced cardiomyocyte apoptosis and heart failure through eNOS /NO/cGMP signaling pathway. Thus, these findings can potentially facilitate the development of an effective strategy for management of heart failure

Bioassessment of a Drinking Water Reservoir Using Plankton: High Throughput Sequencing vs. Traditional Morphological Method

Drinking water safety is increasingly perceived as one of the top global environmental issues. Plankton has been commonly used as a bioindicator for water quality in lakes and reservoirs. Recently, DNA sequencing technology has been applied to bioassessment. In this study, we compared the effectiveness of the 16S and 18S rRNA high throughput sequencing method (HTS) and the traditional optical microscopy method (TOM) in the bioassessment of drinking water quality. Five stations reflecting different habitats and hydrological conditions in Danjiangkou Reservoir, one of the largest drinking water reservoirs in Asia, were sampled May 2016. Non-metric multi-dimensional scaling (NMDS) analysis showed that plankton assemblages varied among the stations and the spatial patterns revealed by the two methods were consistent. The correlation between TOM and HTS in a symmetric Procrustes analysis was 0.61, revealing overall good concordance between the two methods. Procrustes analysis also showed that site-specific differences between the two methods varied among the stations. Station Heijizui (H), a site heavily influenced by two tributaries, had the largest difference while station Qushou (Q), a confluence site close to the outlet dam, had the smallest difference between the two methods. Our results show that DNA sequencing has the potential to provide consistent identification of taxa, and reliable bioassessment in a long-term biomonitoring and assessment program for drinking water reservoirs

Productivity Evaluation Method of Horizontal Well Volume Fracturing in Tight Oil Reservoir

Tight oil resources in north Songliao basin is rich and abundant, which is the most important energy sources foundation of stable and raising oil production in Daqing oil field. However, it is difficult to develop such oil resources by the regular ways for the poor reservoir property and thin reservoir thickness. Using the way of horizontal well by volume fracturing can increase contract area of well and the reservoir, improve reservoir flow performance and reach the high oil production, which has showed good results up till now. The accurate productivity evaluation of volume fracturing horizontal well is an important content of reservoir and production engineering field, which is also to develop solutions and decision-making basis. The current formula of horizontal well in low permeability reservoirs production did not consider the effect of seepage volume form fracturing, so it is poorly adapt to calculate the productivity of volume fracturing horizontal well. Based on the tight oil reservoir geological characteristics and seepage characteristics, equation are solved coupling with flow through fractures in the substrate, productivity prediction model is established and the innovation is based on considering horizontal well reservoir heterogeneity, fracturing scale and any artificial fracture distribution form, the results of which can provides a reliable theoretical basis for tight oil reservoir developed effectively