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Objective The objective of the present study was to evaluate the safety and efficacy of percutaneous transforaminal endoscopic discectomy (PTED) and open fenestration discectomy (OFD) in the treatment of lumbar disc herniation (LDH). Methods Patients in our hospital with LDH who received PTED (n = 71) and OFD (n = 39) from 2013 to 2014 were retrospectively studied. Patient information, including age, gender, visual analogue scale (VAS) score for low back pain and leg pain, body weight, height, Oswestry disability index (ODI), Japanese Orthopedic Association (JOA), and recurrence, was collected. The patients in the two groups were followed up for an average of 63 months after surgery. Results A total of 136 patients completed the operation and 110 patients were followed up completely. There was no significant difference in baseline data between the two groups (P > 0.05). The postoperative low back pain, leg pain, ODI, and JOA of the two groups were better than those preoperatively (P 0.05). At the end of the follow up, 89.7% (35/39) of patients in the OFD group had excellent improvement in the JOA score, and 88.7% (63/71) of patients in the PTED group had an excellent improvement. There was no significant difference between the two (P > 0.05). There was also no significant difference in the recurrence rate between the two groups [(5/71) vs (3/39); P > 0.05]. [Correction added on 05 March 2021, after first online publication: “3/29” was amended to “3/39” in the preceding sentence.] Conclusion Both PTED and OFD can achieve good mid‐term efficacy in the treatment of LDH but PTED has certain advantages, including the small incision, a shorter hospital stay, and quicker, earlier recovery. However, prospective randomized controlled studies with a larger sample size are needed., This retrospective study evaluates the safety and efficacy of PTED and OFD in the treatment of lumbar disc herniation.

To better capture the phase information of single-phase power grids, a novel single-phase phase-locked loop method is proposed in this paper. The method uses a tracking differentiator as an orthogonal signal generator. Because the generator is sensitive to the input signal’s frequency, the amplitudes of the tracking and differential signals may not be equivalent, causing a failed phase tracking. Therefore, the amplitude correction of the differential signal needs to be done. Then, the corrected differential signal and the tracking signal are both input to the phase detector. To further verify the practical feasibility of the method, the voltage sampling and phase tracking experiments were performed on a digital signal processor-based inverter experimental platform, which is aimed to simulate the grid. The experimental results show that the proposed algorithm has strong dynamic performance and steady-state performance under different states of the power grid, and the phase-locked method has a practical feasibility in single-phase grid-connected applications.

A large number of studies have been conducted to examine China’s CO2 emissions problem disaggregated to the city level. However, few studies have delved further into the black box of economic production to examine the characteristics of CO2 emissions at the city supply chain level. In the context of the reality that Beijing takes the lead in achieving CO2 emissions reduction, this study decomposes CO2 emissions change in Beijing at three levels: overall, supply stage, and supply chain, using structural decomposition analysis (SDA) and structural path decomposition (SPD), filling the gap in urban CO2 emissions studies. The results show that: (i) energy consumption intensity is the most significant driver of emissions reduction, while per capita final demand is the largest factor in increasing emissions; (ii) Beijing’s emissions reduction contribution is mainly reflected in the first supply stage (76.50%) and the second supply stage (18.85%); (iii) the expansion of domestic exports and thus greater demand for transportation is significant in emissions increase supply chains; (iv) the improvement of the demand structure for electricity from domestic exports contributes a large part in emissions reduction supply chains; (v) the existence of many offsetting effects, such as the ebb and flow of domestic exports on the demand for different products, has led to the loss of emissions reduction. Finally, corresponding policy recommendations are presented from the energy, industry, and demand perspectives. Our study will provide assistance in developing more microscopic policies to reduce emissions and replicating the Beijing experience.

A contact model that accounts for interfacial cohesion and thermal conduction is developed to investigate the influence of bonding on the final residual stresses build-up in cold spray. The residual stress evolution in the cold-sprayed Al-6061 coating on an Al-6061 substrate is investigated via three-dimensional single-particle and multi-particle impact simulations. It is shown that the interface bonding mainly affects the local residual stress distribution near the interfaces. The residual stresses are largely due to the kinetic peening and bonding effects. The thermal cooling has negligible influence. In general, this work finds that peening introduces compressive stress, while bonding causes relaxation. The balance between the peening and the bonding effects, which depends strongly on the local bonding environment, determines the final residual stress in the system. This work suggests that the interface bonding should be considered as one of the essential factors in numerical modeling of the residual stresses evolution in cold spray.

Recently, the permanent magnet linear synchronous motor (PMLSM) servo control technology has become a research hotspot. However, the control performance under the traditional PID control is not ideal, which usually has the problems of slow response speed, large overshoot and poor anti-interference performance. In addition, adding nonlinear links with certain characteristics purposefully can greatly improve the performance of the system and achieve the expected effect that the traditional linear controllers cannot achieve. Based on this, this paper introduces the nonlinear PID control strategy into the field of servo control, and proposes a nonlinear control strategy of the three-loop of the servo system to improve the above problems. Firstly, the proposed structure is explained and the rule of nonlinear parameters selection is discussed. Secondly, the conditions for the structural stability of the proposed nonlinear control strategy are analyzed. Finally, experiments on the servo system platform are carried out and the results verify the fast dynamic response, precise positioning and good anti-disturbance performance.

Active power filter (APF) has become an effective approach to suppress harmonic and compensating the reactive power of a power grid. In this paper, the topological structure of the single-phase APF is T-type three-level which can suppress harmonic. For the traditional dual-loop PI control of APF, the voltage loop has poor disturbance rejection performance and long response time under nonlinear load and load mutation. To eliminate the impact on the reduction of power quality of the power grid, this paper uses a PI control of the current loop and a linear active disturbance rejection control (LADRC) of voltage loop. The first-order LADRC controller, which uses a linear extended state observer (ESO) and a linear state error feedback (SEF), does not depend on an explicit mathematical model of the controlled object. In this paper, a 2kVA experimental prototype with a processor of TMS320F28335 is designed to testify the performance and effectiveness of the presented method. The results of simulation and experiments show that the LADRC has better disturbance rejection performance and faster dynamic response than PI control under nonlinear load and load mutation.

In this study, the LMDI method is used to decompose the production power consumption changes of the Yangtze River Economic Zone into an advanced technology effect, structural effect, income effect, and population effect. The regional and industry differences in the driving effect of electricity consumption change are also investigated. From the perspective of time differences, the progress of power-saving technology is the main factor restraining the growth of electricity consumption; whereas, economic growth, industry structure adjustment, and population size adjustment promote the growth of electricity consumption; and the other three influencing factors, in turn, decrease. From the perspective of regional differences, regional electricity consumption varies significantly, and various regions have great room for improvement in industry structure. Regional population affects electricity consumption from two aspects: absolute population quantity change and population mobility. From the perspective of industry differences, electricity consumption varies significantly among industries and is mainly reflected in the effect of technological progress and structural effects. As a result, control measures on electricity consumption in the Yangtze River Economic Zone should focus on the promotion of power-saving technology and industry structure adjustment.

In cold spray, 5-150 μm particles (of metal, ceramic, composite, and other materials) are accelerated to supersonic velocities through a deLaval nozzle with an inert gas (generally He or N2) that can reach 1000 °C. In the process, the gas jet impingement on the target and the extreme plastic deformation of impacting particles cause heat generation in the coating layers and the substrate. The heat generation has been argued to cause residual stress, which may cause coating-substrate delamination. In this study, heat generation due to gas impingement and particle plastic deformation has been predicted from CFD and FEA simulations, respectively. Furthermore, a finite volume method has been presented for transiently simulating the coating buildup and bulk heat generation in the coating and the substrate. The model is intended to assist researchers understand thermal affects in the coating process and help design more informed coating patterns to reduce negative thermal effects.

Impact of spherical particles onto a flat sapphire surface was investigated in 50-950 m/s impact speed range experimentally and theoretically. Material parameters of the bilinear Johnson–Cook model were determined based on comparison of deformed particle shapes from experiment and simulation. Effects of high-strain-rate plastic flow, heat generation due to plasticity, material damage, interfacial friction and heat transfer were modeled. Four distinct regions were identified inside the particle by analyzing temporal variation of material flow. A relatively small volume of material near the impact zone becomes unstable due to plasticity-induced heating, accompanied by severe drop in the flow stress for impact velocity that exceeds ~ 500 m/s. Outside of this region, flow stress is reduced due to temperature effects without the instability. Load carrying capacity of the material degrades and the material expands horizontally leading to jetting. The increase in overall plastic and frictional dissipation with impact velocity was found to be inherently lower than the increase in the kinetic energy at high speeds, leading to the instability. This work introduces a novel method to characterize HSR (109 s−1) material properties and also explains coupling between HSR material behavior and mechanics that lead to extreme deformation.

To study the distribution of bone cement in unilateral puncture percutaneous vertebroplasty (PVP). A total of 64 patients with osteoporotic vertebral compression fractures (OVCF) who underwent unilateral PVP were included in this study. The vertebral body was longitudinally divided into four equal parts. The intermediate layer between each part was representative of the part and there were four layers in total. Each layer was divided into 4 regions a, b, c, and d by the crossed lines at the center of the vertebral body. Region c was the first half of the puncture side and region d was the second half of the puncture side. Region a was the first half of the opposite side, and b was the second half of the opposite side. Bone cement filling areas in the four layers and the four regions of each layer were compared. There were significant differences in visual analogue scale (VAS) scores before and after surgery (P

Trade has been substantially influencing regional economic development, environmental sustainability, and human well-being. Enabled by the decomposition analysis, pollution haven hypothesis or “no-trade” scenarios (NTSs), the effects of trade on global/national social-economic-environmental development have been revealed. However, major limitations (e.g., using with-trade economic structures or neglecting price differences) existed in previous studies, and thus made the previous assessments of trade's effects unsatisfactorily. This study develops a novel NTS that addresses the existing limitations, and further applies it to estimate the effect of trade on global economic development and greenhouse gas (GHG) emissions. We show that current international trade benefits the global economic growth but with a consequence of more GHG emissions compared with the NTS. The hypothetical production in small countries (e.g., Luxembourg or Japan) would be more constrained by the production factors (e.g., land) under the NTS, compared with those factor-endowment countries (e.g., the United States or India). For country-specific analysis, we find that today's developed countries would have a substantial increase in their GHG emissions of clothing- and service-related products under the NTS, whereas countries with net-export (e.g., China or Brazil) would have less GHG emissions under the NTS. Enhancing future global collaborations is vital, especially for small or resource-deficient economies, if they are to achieve the Sustainable Development Goals.

Metallic microparticles can acquire remarkable nanoscale morphologies after experiencing high velocity collisions, but materials science regarding the extreme events has been limited due to a lack of controlled experiments. In this work, collision dynamics and nonlinear material characteristics of aluminum microparticles are investigated through precise single particle collisions with two distinctive substrates, sapphire and aluminum, across a broad range of collision velocities, from 50 to 1,100 m/s. An empirical constitutive model is calibrated based on the experimental results, and is used to investigate the mechanics of particle deformation history. Real-time and post-impact characterizations, as well as model based simulations, show that significant material flow occurs during the impact, especially with the sapphire substrate. A material instability stemming from plasticity-induced heating is identified. The presented methodology, based on the use of controlled single particle impact data and constitutive models, provides an innovative approach for the prediction of extreme material behavior.

In order to reduce the position overshoot of the permanent magnet synchronous linear motor (PMSLM) vector control system and improve the system response, on the basis of given mathematical model and mechanical motion equations of PMSLM in the d-q rotating coordinate system, controlled auto regressive integrated moving average (CARIMA) model have been introduced. A new generalized predictive controller of PMSLM system have been designed based on this model and Sun Jun’s proposed generalized predictive control algorithm that takes full advantage of predictive information. Simulation results show that this controller has the advantages of small overshoot and excellent tracking performance.

Permanent magnet synchronous linear motor (PMLSM) has excellent performance and wide application, but its special structure makes it sensitive to external disturbance. This paper aims at the disturbance problem of X-Y motion platform driven by PMLSM under actual operating conditions. In the cross-coupling control strategy, the input command is compensated by the coupling control quantity between axes, and the linear active disturbance rejection controller (LADRC) is applied to the position loop in the three-loop control strategy to suppress the external disturbance and reduce the influences caused when the coupling control quantity is compensated to the uniaxial servo system. Finally, it is verified by Simulink. The simulation results show that the LADRC-based disturbance compensation method has better dynamic performance than the traditional cross-coupling control, and the contour control accuracy is higher.

There are some problems accompanied by detecting rotor parameters of the traditional method on the permanent magnet linear synchronous motor (PMLSM), such as inaccurate detection and poor anti-interference ability. Based on this, this paper proposes a speed closed-loop control strategy based on PID neural network (PIDNN) without speed sensor. The algorithm obtains the error between real current and the given current of the q-axis by calculating the observation angle and the actual angle. The algorithm obtains the error between the given current and the feedback value of the q-axis, and uses the gradient descent algorithm to update the parameters and to obtain the fitted electrical angle. When the current error converges to zero, the output is the velocity of the mover. The simulation and experimental results show that the algorithm can track the speed very well, which reduces the cost and improves the reliability of the system.

In this study, finite element models are used to simulate the impact of porous WC-Co and Al particles cold sprayed onto substrates of the same materials. Effects of high strain rate, heat generation due to plasticity, interfacial friction, heat transfer, and material damage and failure are taken into account as are differences in the initial kinetic energy and strength of the materials. It was found that the influence of porosity increases with impact velocity and that the pores channel stress waves in unique ways not observed for solid particles. The results suggest that using porous particles for solid-state consolidation, as in cold spraying, could have advantages in terms of energy dissipation, although further investigation is required.

A new esterified starch, rosin acid starch (RAS), had been synthesized under mild conditions, using rosin as a starting material directly with Novozym 435 as a catalyst. In order to improve the efficiency of the enzymatic reaction, native cassava starch (NCS) was pretreated by heat-moisture, ultrasonic, gelatinized, microwave and alkali before the enzymatic esterification. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis showed that the morphology and crystallinity of the NCS were changed according to the pretreated methods. Compared with NCS, the surface of ultrasonic and heat-moisture pretreated starch (PS) maintained a smooth and circular morphology structure, and the PS remained highly crystalline. The surface of alkali, microwave and gelatinized PS was changed from smooth to crude, with reducing crystalline, but they maintained some kinds of granule shapes. The activated effect of pretreatment on the degree of substitution (DS) of RAS was as follows: alkali RAS (0.0808) > microwave RAS (0.0174) > gelatinized RAS (0.0153) > ultrasonic RAS (0.0099) > heat-moisture RAS (0.0073) > native RAS (0.0053). The esterified products from PS were confirmed by FT-IR spectroscopy and nuclear magnetic resonance (NMR) analysis.

A contact model that accounts for interfacial cohesion and thermal conduction is developed to investigate the influence of bonding on the final residual stresses build-up in cold spray. The residual stress evolution in the cold sprayed Al-6061 coating on an Al-6061 substrate is investigated via three-dimensional (3D) single-particle and multi-particle impact simulations. It is shown that the interface bonding mainly affects the local residual stress distribution near the interfaces. The residual stresses are largely due to the kinetic peening and bonding effects. The thermal cooling has negligible influence. In general, the peening effect introduces a compressive stress while the bonding effect results in a relaxation to this compressive stress. This work suggests that the interface bonding should be considered as one of the essential factors in numerical modeling of the residual stresses evolution in cold spray.

A 4 × 3 two-factor experiment was designed to study the effects of dietary protein and lipid on growth performances and feed utilization of two species of juvenile catfish, Silurus meridionalis Chen and S. asotus Linnaeus, with the initial weight 9.16 ± 0.01 g and 9.10 ± 0.01 g, respectively. Twelve extruded pellet diets were formulated to contain four levels of protein (46%, 43%, 40% and 37%) and three levels of lipid (13%, 10% and 7%). Each diet was fed to a triplicate group of catfish for 8 weeks in a flow-through water system. The results showed that dietary protein had significant effects on the weight gain rate (WGR) of S. meridionalis Chen, and the feed intake (FI), feed efficiency ratio (FER) and protein efficiency ratio (PER) of both catfish ( P S. meridionalis Chen was found as 1193.10 % in the group with 46% of dietary protein and 7% of dietary lipid. And that for S. asotus Linnaeu was found as 939.98 % with 43% of dietary protein and 7% of dietary lipid. The FI of both catfish decreased with the increasing of dietary protein level. The FER of both catfish were positively related with dietary protein level ( S. meridionalis Chen, r = 0.820, p = 0.000; S. asotus Linnaeus, r = 0.630, p = 0.000), but negatively related with FI ( S. meridionalis Chen, r = − 0.947, p = 0.000; S. asotus Linnaeus, r = − 0.927, p = 0.000). The PER of both catfish were significantly affected by dietary protein ( P S. meridionalis Chen and S. asotus Linnaeu was 43: 10 and 43: 7, respectively. Furthermore, S. meridionalis Chen got relatively higher growth, feed utilization and better body morphological indices than S. asotus Linnaeu under the present experimental conditions.

A feeding experiment was conducted to determine the effects of α-lipoic acid (LA) on the growth and antioxidative responses of juvenile abalone Haliotis discus hannai Ino. Six purified diets supplemented with 0, 200, 400, 800, 1600 and 3200 mg kg−1 of LA, respectively, were fed to abalone for 16 weeks in a flow-through water system. The results showed that the weight gain ratio (WGR) increased with the dietary LA levels, and reached the highest value in the group with 800 mg kg−1 dietary LA supplement. Glutathione peroxidase activity in the 800 mg kg−1 dietary LA group was significantly higher than that in the dietary LA-deficient (0 mg kg−1) group. Superoxide dismutase activities in the 200, 400 and 800 mg kg−1 groups were significantly increased. Supplements of 200, 400 and 800 mg kg−1 dietary LA elevated the total antioxidative capacity significantly. The glutathione level in the hepatopancreas increased significantly with the dietary LA supplements in a dose-dependent manner (except for the 200 mg kg−1 group). Catalase and malondialdehyde in the hepatopancreas were not significantly affected by dietary LA. In conclusion, dietary LA promoted the growth and stimulated the antioxidative defence capacity of abalone. Based on the data of WGR, the optimal dietary LA supplement for juvenile abalone was found to be 709 mg kg−1 using piece-wise linear analysis.

An acknowledgement was omitted by the authors. The following should have been included with the published article.

We develop a pre-treatment planning method for optimum hepatic radiofrequency (RF) ablation. In conventional methods, pre-treatment planning is minimal and for a specific tumor size, it only includes reading pre-specified treatment length and input voltage values from a look-up table that lists experimentally obtained ablation parameters. Such planning, in order to assure certain level of cell death, usually results in more healthy cell damage than desired. Different than the conventional methods, here, we develop a model-based pre-treatment optimal planning framework. As an example, we use 1-D axisymmetric tissue geometry and over this geometry, we solve Pennes' bioheat and Laplace equations to model the RF heating. Using the solutions of these equations, we define constrained nonlinear optimization problems to achieve specific temperature profiles in certain areas of the tissue. Results demonstrate that compared to the conventional methods, our approach significantly improves the healthy tissue preservation.

A novel, simple, and rapid method for the quantification of 27 commonly used pesticides in ginseng incorporating a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) procedure was developed and validated. The pesticides were extracted with 1% acetic acid in acetonitrile and extracts purified by use of the mixed sorbents primary-secondary amine, C18, and graphitized carbon black. Quantitative analysis of all pesticides was performed by ultra-performance LC/MS/MS in the positive ionization mode in a single run due to the fast polarity switching capability of the mass spectrometer. Two precursor-product ion transitions were monitored for each compound in the multiple reaction monitoring mode. Quantification was carried out using matrix-matched standards for calibration. Recoveries of the proposed method from the spiked samples were achieved in the range 62.8–108.5%, and RSD ranged from 1.5 to 11.8%.

This article presents a model-based pre-treatment optimal planning framework for hepatic tumour radiofrequency (RF) ablation. Conventional hepatic radiofrequency (RF) ablation methods rely on pre-specified input voltage and treatment length based on the tumour size. Using these experimentally obtained pre-specified treatment parameters in RF ablation is not optimal to achieve the expected level of cell death and usually results in more healthy tissue damage than desired. In this study we present a pre-treatment planning framework that provides tools to control the levels of both the healthy tissue preservation and tumour cell death. Over the geometry of tumour and surrounding tissue, we formulate the RF ablation planning as a constrained optimization problem. With specific constraints over the temperature profile (TP) in pre-determined areas of the target geometry, we consider two different cost functions based on the history of the TP and Arrhenius index (AI) of the target location, respectively. We optimally compute the input voltage variation to minimize the damage to the healthy tissue while ensuring a complete cell death in the tumour and immediate area covering the tumour. As an example, we use a simulation of a 1D symmetric target geometry mimicking the application of single electrode RF probe. Results demonstrate that compared to the conventional methods both cost functions improve the healthy tissue preservation.

Scholars from home and abroad have done much theoretical and empirical research on competitiveness of high and new technological industry, based on their research, this article establishes the evaluation index system on competitiveness of high and new technological industry, and uses principal component analysis in the way of factor analysis to compare the competitiveness of Changzhou, Suzhou and Wuxi area. At last this article combines the results of assessment and analysis to propose some countermeasures to enhance the competitiveness of Changzhou high and new technological industry.

In the present study, the cDNA of heat shock protein 90 from Pacific abalone Haliotis discus hannai Ino (HdhHSP90) was cloned by the combination of homology cloning and rapid amplification of cDNA ends (RACE) approaches. The full-length cDNA of HdhHSP90 was of 2660 bp, including an open reading frame (ORF) of 2187 bp encoding a polypeptide of 728 amino acids with predicted molecular weight of 84.134 kDa and theoretical isoelectric point of 4.619. BLAST analysis revealed that HdhHSP90 shared high similarity with other known HSP90s, and the five conserved amino acid blocks defined as HSP90 protein family signatures were also identified in HdhHSP90, which indicated that HdhHSP90 should be a cytosolic member of the HSP90 family. The expression levels of HdhHSP90 in haemocytes and hepatopancreas were measured by real-time PCR after Pacific abalone were fed with semi-purified diets containing graded levels of selenium (0.15, 1.32 and 48.70 mg Kg(-1)) for 20 weeks, respectively. The results showed that the expression levels of HdhHSP90 transcript were significantly up-regulated and reached the maximum (0.47-fold) in hepatopancreas of Pacific abalone fed with optimal dietary Se (1.32 mg Kg(-1)) (p < 0.05). However, these levels significantly decreased in hepatopancreas at the excessive dietary Se (48.70 mg Kg(-1)) (p < 0.01). In haemocytes, the expression of HdhHSP90 mRNA increased and reached the maximum (0.96-fold) at the excessive dietary Se (48.70 mg Kg(-1)) (p < 0.01). It is implied that the expression levels of HdhHSP90 could be affected by dietary Se in hepatopancreas and haemocytes, and HdhHSP90 was potentially involved in the anti-oxidation responses in Pacific abalone H. discus hannai.