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High molecular polymers have been widely studied and applied in the field of enhanced oil recovery (EOR). At present, the focus of research has been changed to the design of polymer networks with unique properties such as anti-temperature and anti-salinity, good injection and so on. Supramolecular polymers have high viscoelasticity as well as excellent temperature, salt resistance and injection properties. Can supramolecular polymers become another material choice for polymer flooding to enhance oil recovery? The present review aims to systematically introduce supramolecular polymers, including its design strategy, interactions and rheological properties, and address three main concerns: (1) Why choose supramolecular polymers? (2) How do we synthesize and characterize supramolecular polymers in the field of oilfield chemistry? (3) What has been the application progress of supramolecular polymers in improving oil recovery? The introduction of a supramolecular interaction system provides a new idea for polymer flooding and opens up a new research direction to improve oil recovery. Aiming at the “reversible dynamic” supramolecular polymers, the supramolecular polymers are compared with the conventional covalent macromolecular polymer networks, and the challenges and future research directions of supramolecular polymers in EOR are discussed. Finally, the author’s viewpoints and perspectives in this emerging field are discussed.

As group contribution method is easy to apply and has a wide application range, current study has developed this model to predict flammability limit of hydrocarbons mixed with inert gas using the Marrero/Gani group contribution method, which is significative to the safe application of hydrocarbons in the ORC system. The whole modeling process is divided into two parts: pure compound prediction and mixture prediction. The contribution factors of inert gases and dilute concentration were first introduced in the group contribution method. Moreover, the respective 95%-confidence interval of the mixture based on linear superposition method has been proposed in the developed group contribution model to improve the safety coefficient. For CO2 as inert gas, the average relative error and correlation coefficient are 5.34% and 0.88 for lower flammability limit while 6.99% and 0.95 for upper flammability limit. For N2 as inert gas, the average relative error and correlation coefficient are 7.47% and 0.84 for lower flammability limit while 6.68% and 0.97 for upper flammability limit. Most importantly, this group contribution method has extended the application range to make up the shortcomings of other flammability limit prediction methods aiming at hydrocarbon and inert gas mixtures and proposed the uncertainty analysis to provide reliable prediction range.

In the present study, a novel model is proposed to evaluate the lower flammability limit (LFL) of alkane diluted with CO2. The LFL model is based on flame phenomenon simulation (FS-LFL). The model consists of combustion, turbulence, and igniter models, which are used to characterise the combustion based on the chemical kinetics and CFD, which is not feasible with traditional methods. The flame simulation phenomenon was validated by contrast with experiment and same criterion of flammability limit in the experiment was adopted. The FS-LFL model was used to predict the LFLs of a propane-CO2 mixture and propane at various temperatures. The model performance was analysed by comparing the results with experimental data and predictions obtained from existing methods. The AARDs between the predicted and experimentally determined LFLs of the propane-CO2 mixture are 0.34%, 1.19%, and 1.35% at 30°C, 50°C, and 70°C, respectively. The model also has a good predictive power with respect to the LFLs of propane at initial temperatures ranging from 30°C-300°C, with an AARD of 2.10%. When the dilution of CO2 is 90%, the model yields a better result due to the utilisation of the chemical kinetics mechanism. This result is instructive for the use of this method in the prediction of upper flammability limits.

Many factors need to be considered in the evaluation of tight conglomerate reservoirs, including the microscopic pore-throat structure, pore connectivity, lithology, porosity, permeability, and clay mineral content. The contents and types of clay minerals reflect the mineral evolution process during the deposition of the reservoir and can reflect the reservoir’s physical properties to a certain extent. In this study, cores from the Baikouquan Formation in Mahu were used to comprehensively analyze the effects of the clay mineral content on the physical properties of a tight conglomerate reservoir, including field emission scanning electron microscopy (FE-SEM), casting thin section observations, X-ray diffraction (XRD), interface property testing, high-pressure mercury injection, low temperature N2 adsorption, and nuclear magnetic resonance (NMR)-movable fluid saturation testing. The results revealed that differences in different lithologies lead to differences in clay mineral content and pore structure, which in turn lead to differences in porosity and permeability. The interface electrification, adsorption, and specific surface area of the reservoir are positively correlated with the clay mineral content, which is mainly affected by the smectite content. As the clay mineral content increases, the proportion of nanoscale pore throats increases, and the core becomes denser. The saturation of the movable fluid controlled by the >50 nm pore throats in the tight conglomerate ranges from 8.7% to 33.72%, with an average of 20.24%. The clay mineral content, especially the I/S (mixed layer of Illite and montmorillonite) content, is negatively correlated with the movable fluid. In general, the research results clarified the relationship between the lithology and physical properties of clay minerals and the microscopic pore structure of the tight conglomerate reservoirs in the Baikouquan Formation in the Mahu area.

As an effective waste heat recovery technique, the hydrocarbon-CO2 mixture based Rankine cycle is always operating on a specific temperature, which has a noticeable influence on flammability limits. Thus it is critical to research flammability limit of hydrocarbon-CO2 at various initial temperatures. Focusing on the hydrocarbon-CO2 mixture, this paper first measured its flammability limits at different initial temperatures using an experimental setup based on the ASTM E681-09. Results have shown that lower flammability limit decreases with the elevating initial temperatures while upper flammability limit increases, therefore the flammable zone expands leading to higher potential dangers. Moreover the expansion values of flammable zone from 30 °C to 70 °C have decreased by nearly 0.3 vol% with the dilute concentration changing from 0 to 0.9. A linear relationship between temperature and flammability limits of hydrocarbon-CO2 mixture has been proposed based on thermal theory and verified with experimental values. At the same time, a comprehensive method based on calculated adiabatic flame temperature theory was presented to predict the flammability limit at different temperatures with higher accuracy. The mean relative deviation between the predicted results and observed ones is 2.76% at upper flammability limit and 1.71% at lower flammability limit in the temperature range examined.

Aiming at the problem of energy efficiency of smart grid to be promoted, this paper propose a method of analysis of smart grid energy use based on the multi-level energy transfer model. Firstly, analyze the energy use characteristics of public institution, so as to preliminary ascertain the energy consumption systems of public institution. Then, construct public institution multi-level energy transfer model including energy input and energy use, and propose the procedure of analysis of energy efficiency diagnosis based on the model. Finally, carry out instance analysis, so as to verify the effectiveness of research result.

Energy storage system is an important component in micro-grid. This paper introduces the status of energy storage application, the key technologies of energy storage in micro-grid and the problems and prospects of energy storage.

This paper reported a newly designed retrievable urethral stent used in treatment of urethral strictures. The spiral urethral stent is made of Poly (l-lactide) (PLLA), adding barium sulphate (BaSO4) to certain content, which can be displayed precisely under X-ray after implanted in body. The stent was clinically tested in 32 patients with recurrent urethral strictures and was left in the urethra for 5 to 12 months. The response to the effect of the stent was assessed using symptom scores, peak flow rate (Qmax), residual urine volume (RUV), stent degradation, infection and outcome. During the treatment, there were not any inflammations found. The mechanical properties of the stent are almost the same as those of the PLLA stent without BaSO4. Improvements in patient symptom score, mean Qmax and RUV were significant at the 18 month follow-up. The infection was not observed. The stent was taken out easily through urethral forceps. In no patient was the stent obstructed by incrustation for up to 1.5 years.

Voltage Source Inverters (VSIs) generally use the multi-loop control strategy, while single-loop control strategy has been proposed. In order to maintain low total harmonic distortion content in the output voltage, resonant controllers with parallel structure have also been commonly adopted. Firstly, the parameter design problems for the parallel resonant controllers are discussed. On this basis, a novel single-loop control strategy based on phase-lead correction is proposed. It can simplify the control parameters design process, and improve the performance of VSIs. The experimental results prove the validity of proposed control strategy.

Harmonic currents elimination are significant for improving efficiency and reliability for wind power system with PMSG. Several factors can induce harmonic current, in which the most significant is back EMF distortion. In order to compensate the voltage distortion, we propose a harmonic elimination method in multiple synchronous rotating reference frames in this paper. Different orders of current harmonics are transformed into their corresponding synchronous rotating frames respectively and PI regulators are used to compensate the voltage distortion, which are implemented in parallel with the fundamental regulator. Experiments are carried out to verify the effective of the proposed method, providing good voltage compensation results.

To explore the effect of folic acid and DNA methyltransferase 1 (DNMT1) on cervical cancer and cervix precancerous lesion.100 patients with cervix squamous cell carcinoma (SCC), 101 patients with cervical intraepithelial neoplasm (CIN) and 109 patients with cervix inflammation (CI) diagnosed by histology were included in this study. Radioimmunoassay (RIA), polymerase chain reaction (PCR) and Western blot were used to detect the levels of serum folate, HPV16 infection and the expression of DNMT1 protein, respectively.The average levels of serum folate were (2.60 ± 1.61) ng/ml, (3.14 ± 2.08) ng/ml and (3.32 ± 1.74) ng/ml, and the expression of DNMT1 protein were 2.40 ± 0.99, 1.88 ± 0.33 and 0.89 ± 0.29 in the group of SCC, CIN and CI, respectively. The relationship of folate levels and DNMT1 protein expression showed inverse correlation (r = -0.186, P = 0.001). The results in our study indicated that there was an additive interaction between low-level of serum folate and high-expression of DNMT1 protein related to the risk of CIN and SCC, with OR value as 2.50 (95%CI: 1.21 - 9.22) and 6.03 (95%CI: 2.79 - 21.72) respectively. The relative excess risk of interaction (RERI), attributable proportion of interaction (API) and synergy index (S) were 0.92, 0.36 and 2.59 in the CIN group while 2.47, 0.41 and 1.96 in the SCC group.The low level of serum folate and high expression of DNMT1 protein seemed to be associated with high risk of cervical cancer and its precancerous lesion. It suggested that there might be a synergistic action between serum folate and DNMT1 in the progression of cervix carcinogenesis.

One of the important reasons for male infertility is asthenozoospermia, for which there is no specific cure for the time being. The authors explored the clinical effect of L-carnitine for infertile males with asthenozoospermia.A total of 135 patients with asthenozoospermia were randomly divided into Groups A (n = 68) and B (n = 67), the former treated with L-carnitine (2 g/d) and vitamin E, while the latter with vitamin E only, both for 3 months. All the patients received semen analyses before and after the treatment, and were observed for adverse effects. The pregnancy rates of their wives were recorded.Group A showed a significantly increased percentage of forward motile sperm after the treatment (45.4% +/- 11.1%) as compared with pretreatment (28.6% +/- 9.2%) (P0.01), but no statistically significant differences were found in sperm density and the percentage of the sperm of normal morphology (P0.05). The rate of pregnancy was significantly higher in Group A (31.1%) than in B (3.8%) after the treatment (P0.01). No adverse events were found during the treatment.L-carnitine, capable of significantly improving sperm motility and raising the rate of pregnancy, is a safe and effective therapeutic option for asthenozoospermia.

To study the efficacy and safety of alpha1 adrenoceptor antagonist Naftopidil in the treatment of chronic non-bacterial prostatitis.An opened, self-controlled, multicentral clinical trial was conducted. One hundred and six cases of patients who had been diagnosed as chronic non-bacterial prostatitis (NBP) were treated with Naftopidil (25 mg once a day) for 4 weeks. The efficacy was evaluated by the NIH Chronic Prostatitis Symptom Index (NIH-CPSI) and the WBC in the examination of prostatic secretion (EPS) after the treatment.After 4 weeks therapy, 105 cases were evaluable. After treatment, NIH-CPSI total score were averagely decreased 12.0 points (P0.001), symptom score 7.9 points (P0.001) and QOL score 4.1 points (P0.001). There was a statistically significant difference in WBC count ([(15.2 +/- 15.1)/HP vs (9.5 +/- 12.0)/HP, P0.01] and max flow rate(MFR) [(19.2 +/- 4.8) ml/s vs (22.7 +/- 4.9) ml/s, P0.01]. The total effective rate were 84.8% in the whole group. The clinical adverse rate was 3.81%, including 3 cases of mild dizziness and 1 case of mild inappetence.alpha1 adrenoceptor antagonist Naftopidil is effective and safe for the treatment of chronic non-bacterial prostatitis.