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As the self-weight of superstructures becomes increasingly large, higher requirements are set for the foundation. Therefore, foundation pits become increasingly deep and foundation trenches are narrower, which puts forward stricter requirements for the backfill quality of foundation trenches. Based on a transportation hub project in the south square of a railway station, this study analyzed difficulties in backfilling deep foundation pits and ultra-deep and ultra-narrow foundation trenches and proposed to use high-early-strength soil cement as backfill materials of the above foundation trenches. Moreover, the preparation process of high-early-strength soil cement and supporting equipment were studied and key technologies for backfill construction were elaborated in detail. This can provide engineering practices and technical reference for similar projects.

Background Scientific, accurate, and rapid detection of the composition and content of tea polyphenols is an important basis for their rational use and giving full play to their physiological effect. The spectrophotometric assays for total polyphenols have poor selectivity. Therefore, there is a need to develop a simple and reliable method for the determination of the total polyphenolic level in tea products. Objective The aim of this research was to develop a flow injection chemiluminescence (FI-CL) method based on the Ag(III)-luminol system for the total polyphenol content analysis of tea and substitute tea. Method Through Box–Behnken experimental design, we selected the optimum determination condition. The Ag(III) concentration was 5 × 10–5 mol/L, and the luminol concentration was 3 × 10–7 mol/L (including 0.15 mol/L NaOH). The peristaltic pump is 25 r/min, and the photomultiplier voltage is 600 v. Sample extracts were diluted 100 000 times for the FI-CL assay. Results Under optimal conditions, CL intensities were proportional to total polyphenol content (in terms of gallic acid concentrations) in the range of 0.1∼100 μg/L. The LOD and LOQ were 0.03 μg/L and 0.1 μg/L. The recovery values were in the range of 86.3–111.0% with a RSD of 1.04∼2.62%. The polyphenolic content of 12 teas and 6 substitute teas was determined, and the results of the developed method and Folin–Ciocalteu method were highly correlated (r = 0.9493 for tea and r = 0.8533 for substitute tea). Conclusions The proposed method is better than the Folin–Ciocalteu method in terms of selectivity, sensitivity, and accuracy. It is suitable for the determination of polyphenol content not only in tea, but also in substitute tea. Highlights We developed a new flow-injection analysis method for polyphenolic content determination based on the Ag(III)-luminol chemiluminescence system. It is simple, rapid, sensitive, and accurate. It is suitable for the determination of polyphenols content not only in tea, but also in substitute tea.

Since small objects occupy less pixels in the image and are difficult to recognize. Small object detection has always been a research difficulty in the field of computer vision. Aiming at the problems of low sensitivity and poor detection performance of YOLOv3 for small objects. AFYOLO, which is more sensitive to small objects detection was proposed in this paper. Firstly, the DenseNet module is introduced into the low-level layers of backbone to enhance the transmission ability of objects information. At the same time, a new mechanism combining channel attention and spatial attention is introduced to improve the feature extraction ability of the backbone. Secondly, a new feature pyramid network (FPN) is proposed to better obtain the features of small objects. Finally, ablation studies on ImageNet classification task and MS-COCO object detection task verify the effectiveness of the proposed attention module and FPN. The results on Wider Face datasets show that the AP of the proposed method is 11.89%higher than that of YOLOv3 and 8.59%higher than that of YOLOv4. All of results show that AFYOLO has better ability for small object detection.

A NiVCo-LDHs electrocatalyst with active oxygen vacancies was constructed for the efficient conversion of HMF to FDCA.

A high-zeta-potential h-BN-doped LiZn alloy promotes strong electrokinetic effects to significantly improve Li-ion transport kinetics, which can effectively suppress Li dendrite growth and enable stable Li metal anodes under harsh conditions.

At present, most of the methods used in the research of image semantic segmentation ignore the low-level feature information of image, such as space, edge, etc., which leads to the problems that the segmentation of edge and small part is not precise enough and the accuracy of segmentation result is not high. To solve this problem, this paper proposes a multi-source fusion image semantic segmentation model of generative adversarial networks based on FCN: SCAGAN. In VGG19 network, add super-pixel and edge detection algorithm, and introduce the efficient spatial pyramid module to reduce the number of parameters while adding the spatial and edge information of image; Adjust the skipping structure to better integrate the low-level features and high-level features; build a generation model DeepLab-SCFCN combining with the atrous spatial pyramid pooling to better capture the feature information of different scales of the target for segmentation; The FCN with five modules is designed as the discrimination model for GAN. It is verified on the data set PASCAL VOC 2012 that the model achieves IoU of 70.1% with a small number of network layers, and the segmentation effect of edge and small part is better at the same time. This technology can be used in image semantic segmentation.

Two 2D COFs containing both naphthalene diimides (NDIs) as an electron acceptor (A) and triphenylamine (PT-N-COF) or triphenylbenzene (PT-B-COF) as electron donors (D) were prepared successfully. The in-plane donor and acceptor units were connected through imine bonds with precise spatial distribution. The charge-transfer (CT) process induced from the D–A interactions in the 2D plane results in distinct near-infrared absorption properties. The unique structure modification in the skeleton of the COFs led to a great difference in photophysical properties and photothermal conversion properties. Compared to PT-B-COF, PT-N-COF containing triphenylamine as a donor displayed much stronger D–A interactions and CT effects, and thus exhibited obvious red-shift absorption in the NIR region. The photothermal conversion efficiency reached 66.4% in sharp contrast to 31.2% for PT-B-COF. EPR spectra verified the presence of unpaired electrons, which is consistent with the CT interaction in the ground state. The DFT molecular orbital simulation further revealed the mechanism of the photophysical properties and the CT process.

Emerging evidence demonstrated that traffic-related air pollution induced adverse effects on cardiovascular system. We designed a population-based cross-sectional study to explore the association between residential proximity to major roadways, traffic density and the prevalence of valvular heart disease (VHD). A total of 34040 subjects from a Rural Health Project between 2013 and 2018 were collected. According to the inclusion and exclusion criteria, 4158 participants were enrolled in the final analysis. And we calculated the subjects’ proximity to major roadways and collected the traffic density on the major roadways. Transthoracic echocardiography (TTE) was performed to diagnose the VHD, according to the current AHA/ACC (the American Heart Association and the American College of Cardiology) guidelines. Differences between groups were examined by the one-way ANOVAs for continuous variables and the chi-square tests for categorical variables. A logistic regression models were used to assess the associations. The stratified analysis by age and sex were conducted to further analyze the association. The restricted cubic spline analysis was performed to further evaluate the association between road way distance and VHD. Bonferroni test was used to adjust the significance level. The subjects closer to the major roads had the higher risk of tricuspid regurgitation (TR) (odds risk, OR = 1.519, 95% confidence intervals, 95%CI: 1.058-2.181), especially in female. The risk of VHD was positive (high traffic density VS low traffic density, OR = 1.799, 95%CI: 1.221-2.651), especially in female. In addition, the high traffic density was associated with the risk of mitral regurgitation (MR) (OR = 1.758, 95%CI: 1.085-2.848). The restricted cubic spline analysis found a threshold distance of about 300 m, where had the lowest risk of VHD, aortic regurgitation (AR), MR, TR. Our results found a positive association between traffic-related air pollution and VHD especially in female.

This paper discusses the application of audio signal parameters extraction and analysis technology in multimedia vocal music teaching, and studies the vocal music teaching technology based on voice recognition. In the process of voice recognition, MFCC parameters and speech frame energy constitute a combination of feature parameters as feature parameters, and the improved DTW is taken as pattern matching algorithm of evaluation criteria. Matlab is used to simulate the algorithm used in the system to determine the reliability of its performance, and the running test of the system is realized successfully. The experimental results show that the system realizes the real-time modification and playback of acoustic wave waveform and pitch on the computer, which improves the intuitive and interactive vocal music teaching.

Three tetraphenylethylene-based fluorescent single crystals (TPE-AA-1, 2, 3) were formed from different solvents. Three different self-assembly modes were adopted due to the solvent effect. One HOFs (hydrogen-bonded organic frameworks) structure with characteristic porosity was obtained from acetonitrile/acetic acid as solvents. TPE-AA-3 show the best detection performance for nitro explosives.

By considering the intensity fluctuation mechanism of the fundamental laser, the rate-equation-based model for the CW mode-locking intra-cavity OPO (IOPO) is developed, which includes the behavior of the fundamental laser, the signal and idle light. In the derived model, the OPO nonlinear conversion is considered as a loss for the fundamental laser and thus the mode-locked signal or idle profile originates from the mode-locked fundamental laser. In experiment, the CW mode-locked Nd3+: GdVO4/KTA IOPO with semiconductor saturable absorber mirror (SESAM) is realized. The near-infrared signal light is obtained, which are generated from the IOPO pumped by CW mode-locked fundamental laser. The signal and fundamental spectra are experimentally measured, and then the wavelength of the idle light is estimated to be 3.31 μm. The theoretical values from the rate equations agree with the experimental results well. The developed model explains the behavior of the mode-locked IOPO, which is helpful to system optimization.

A 2.5nm-thickness molybdenum diselenide (MoSe

The stability of solid electrolyte interphase (SEI) layers is critical for developing lithium (Li) metal batteries. However, the fabrication of stable SEI layers is plagued by un-controlled structures, properties, and functions. Here a controllable design of an ordered LiF-rich and lithiophilic hybrid Janus interphase (LiF-HJI) is reported using organic fluorination reagent as a functional SEI precursor. The LiF-HJI with a lower crystalline LiF layer and an upper Li organosulfide layer provides high interfacial energy with the Li metal and strong Li-ion affinity, allows homogenous Li-ion distribution, fast and uniform Li-ion transport, and excellent mechanical and passivation properties, enabling stable Li metal anodes under harsh conditions, such as high deposition capacities (6 mA h cm-2 ), current densities (10 mA cm-2 ), and rates (5 C). Stable LiF-HJI@Li greatly improves cycling stability and capacity retention (80.1% after 300 cycles) of Li||LiNi0.8 Co0.1 Mn0.1 O2 cells at a commercial-level areal capacity (≈4.2 mA h cm-2 ). Even under a lean-electrolyte condition of 3 g Ah-1 , 80% capacity retention can be maintained after 100 cycles, demonstrating excellent cycling performance under such harsh conditions.

Compared with the traditional synchronous generator power supply, the main characteristics of gridconnected new energy units are: firstly, because the units are connected to the grid through power electronic devices, there is no inertia or weak inertia on the grid dynamics, and basically do not respond to the changes of the grid; secondly, in order to obtain the maximum power, the grid-connected new energy units generally operate in the maximum power tracking state, so there is no active power reserve. Reactive power and voltage support for power grid can be achieved by controlling the grid-side inverters of grid-connected new energy units, while frequency support for power grid is difficult to achieve due to the operation characteristics of the units. Because of the characteristics of new energy units, gridconnected units do not respond to the changes of active power of power grid and do not have the ability of frequency control. Therefore, it is necessary to study the frequency characteristics and frequency modulation parameters optimization of the high proportion of new energy in the power grid at the transmitter end.

By applying a prepared 3 nm-thick tungsten diselenide (WSe2) saturable absorber to an electro-optic (EO) modulated fundamental-light laser, an active and passive Q-switched intra-cavity optical parametric oscillator (IOPO) has been experimentally realized. Benefiting from the saturable absorption property of WSe2, the output characteristics of Q-switched IOPO with signal-light oscillating are obviously improved, including the 93.7%-increased peak power, 54.6%-compressed pulse width, 30.1%-improved conversion efficiency, 60.1%-improved pulse-train stability, 17.8%-improved beam quality, and 27.4%-shortened linewidth. With the values of absorption parameters calculated from the measured nonlinear-transmittance curve of WSe2, the rate equations for dual-loss Q-switched IOPO with WSe2 saturable absorber and electro-optic modulator are numerically solved. The theoretical values correspond to the experimental data well.

ObjectivesTo analyse differences in regional distribution and inequality in health-resource allocation at the hospital and primary health centre (PHC) levels in Shanghai over 7 years.DesignA longitudinal survey using 2010–2016 data, which were collected for analysis.SettingThe study was conducted at the hospital and PHC levels in Shanghai, China.Outcome measuresTen health-resource indicators were used to measure health-resource distribution at the hospital and PHC levels. In addition, the Theil Index was calculated to measure inequality in health-resource allocation.ResultsAll quantities of healthcare resources per 1000 people in hospitals and PHCs increased across Shanghai districts from 2010 to 2016. Relative to suburban districts, the central districts had higher ratios, both in terms of doctors and equipment, and had faster growth in the doctor indicator and slower growth in the equipment indicator in hospitals and PHCs. The Theil Indices of all health-resource allocation in hospitals had higher values compared with those in PHCs every year from 2010 to 2016; furthermore, the Theil Indices of the indicators, except for technicians and doctors in hospitals, all exhibited downward time trends in hospitals and PHCs.ConclusionsIncreased healthcare resources and reduced inequality of health-resource allocation in Shanghai during the 7 years indicated that measures taken by the Shanghai government to deepen the new round of healthcare reform in China since 2009 had been successful. Meanwhile there still existed regional difference between urban and rural areas and inequality across different medical institutions. To solve these problems, we prescribe increased wages, improved working conditions, and more open access to career development for doctors and nurses; reduced investments in redundant equipment in hospitals; and other incentives for balancing the health workforce between hospitals and PHCs.

A 2.5 nm-thickness tungsten disulfide (WS2) saturable absorber (SA) was successfully fabricated by the electron beam evaporation (EBE) combined with post vulcanization. By applying the prepared WS2 SA to an acousto-optic (AO) Q-switched fundamental laser, a dual-loss-modulated Q-switched intracavity optical parametric oscillator (IOPO) has been experimentally realized. Because of the participation of WS2 SA, the problem of output decline was alleviated when the pump power was between 8.6 W and 10.8 W. The pulse width could be maximally compressed by 73% in WS2 SA based active-passive Q-switched IOPO with 10 kHz pulse-repetition rate, and the shortest pulse width in experiment was 1.098 ns. Benefiting from the pulse compression, the maximum pulse peak power in dual-loss-modulated Q-switched IOPO was 427% higher than that in AO active Q-switched IOPO. The application of WS2 SA also contributed to the stability of signal pulse train whose root mean square error (RMS) was efficiently lowered from 0.01776 to 0.00954. The nonlinear conversion efficiency was improved by approximate 38.2% in the dual-loss-modulated Q-switched IOPO.

Intestinal lipomas are rare nonepithelial tumors that are typically small in size and detected incidentally. Colonic intussusception is an uncommon complication of colonic lipoma. A 56 y old woman visited our emergency room with sudden onset of intermittent abdominal cramps. A CT scan showed a 5.0 cm, nodular, homogenous, hypodense structure in the hepatic flexure of the colon as the lead point of an intussusception. The hypodense structure was suggestive of a colonic lipoma, and the tumor was suspected to be the cause of the intestinal intussusception. Laparoscopic exploration was performed, and the pathology demonstrated a mature submucosal colonic lipoma. In addition to the case report, we discuss the role of imaging modalities in diagnosing neoplasms and for assessing the clinical behavior of lipomas when symptomatic.

A 2.5nm-thickness molybdenum diselenide (MoSe2) saturable absorber (SA) is prepared by electron beam evaporation (EBE) method. Applying the prepared MoSe2 SA to an acousto-optic (AO) Q-switched fundamental laser, a dual-loss-modulated intra-cavity optical parametric oscillator (IOPO) has been experimentally realized. The signal-pulse train from this IOPO has 0.0053 standard deviation (SD) of pulse amplitude. When the MoSe2 SA is applied to IOPO, the signal pulse is compressed by maximum 68%, the peak power increases by 274%, and the nonlinear conversion increases by 12.6%. To solve the established rate equation of IOPO, the ground-state and excited-state absorption cross section of MoSe2 are rationally estimated to be 1.04×10−18cm−2 and 6.25×10−19cm−2 from the measured transmittance curve, and the excited-state lifetime is 275.6µs. The numerical solution of the equations fits the experimental data well.

A new method was developed for determination of ketamine (KT) in urine and plasma samples by derivatization and gas chromatography-mass spectrometry. In this article, KT was first derivatized with sodium nitrite to volatile N-nitrosamines under acidic condition. Then the derivative had been identified by the mass spectra. The derivatization conditions including the amount of hydrochloric acid, the amount of sodium nitrite, reaction temperature, reaction time and the extraction reagents were optimized. Calibration curves were linear in the range of 0.04-20 μg mL(-1) for KT, and the limit of detection (LOD) and limit of quantitation (LOQ) were 0.01 μg mL(-1) and 0.04 μg mL(-1), respectively. The results of recovery indicated that the method had good precision and reproducibility. Compared with existing derivatization methods, this method provided a rapid, convenient, effective and low-cost way for gas chromatography method of KT quantification.

The combination of molecularly imprinted polymer with high performance liquid chromatography has been developed to determine cyromazine and its metabolic melamine in some samples. However, the potential risk of template leakage used in molecularly imprinted polymer is a major disadvantage. To solve this problem, 2-(4,6-diamino-1,3,5-triazin-2-ylamino) ethanethiol disulfide, a molecule that shares the similar imprinting sites with cyromazine and melamine, was selected as pseudo template to prepare molecularly imprinted polymer. Methacrylic acid, ethylene glycol dimethyl acrylate and toluene were selected as functional monomer, crosslinker and porogen, respectively. The molecular recognition property and binding capability of cyromazine and melamine were evaluated by adsorption test and Scatchard analysis. The results showed that the molecularly imprinted polymer based on pseudo template had more excellent affinity and selectivity for cyromazine and melamine. The resulting molecularly imprinted polymer was used as a solid-phase extraction material to enrich cyromazine and melamine in egg and milk samples for high performance liquid chromatography analysis. The solid-phase extraction process was carefully optimized. It was found that when different concentration of cyromazine and melamine standards were spiked into samples, satisfactory recovery rate of cyromazine and melamine were obtained as 85.6-98.8% with relative standard deviation

An intracavity optical parametric oscillator (IOPO) pumped by a continuous-wave (CW) mode-locked laser is experimentally realized. The fundamental cavity and optical parametric oscillator cavity are designed to satisfy synchronous pumping. The output characteristics of signal and idle light are measured. Because of higher fundamental photon intensity in IOPO, the threshold of IOPO is lower than that of an extra-cavity optical parametric oscillator. The spectroscopy of signal light is obtained and the wavelength of idle light can be estimated to be 3.298 μm from noncritical phase matching. Based on the intensity fluctuation mechanism of fundamental locking, the dynamical model for IOPO pumped by a CW mode-locked laser is developed. The simulated results for the temporal shape of three lights are calculated from the derived rate equations. Because of dispersion, the signal pulse width of the theory is smaller than that of the experiment with the same pump energy.

Kinetics of oxidation of dl-pipecolinate by bis(hydrogenperiodato)argentate(III) complex anion, [Ag(HIO6)2]5−, has been studied in aqueous alkaline medium in the temperature range of 25–40 °C. The oxidation kinetics is first order in the silver(III) and pipecolinate concentrations. The observed second-order rate constant, decreasing with increasing [periodate] is virtually independent of [OH−]. α-Aminoadipate as the major oxidation product of pipecolinate has been identified by chromatographic analysis. A reaction mechanism is proposed that involves a pre-equilibrium between [Ag(HIO6)2]5− and [Ag(HIO6)(H2O)(OH)]2−, a mono-periodate coordinated silver(III) complex. Both Ag(III) complexes are reduced in parallel by pipecolinate in rate-determining steps (described by k 1 for the former Ag(III) species and k 2 for the latter). The determined rate constants and their associated activation parameters are k 1 (25 °C) = 0.40 ± 0.02 M−1 s−1, ∆H 1 ≠ = 53 ± 2 kJ mol−1, ∆S 1 ≠ = −74 ± 5 J K−1 mol−1 and k 2 (25 °C) = 0.64 ± 0.02 M−1 s−1, ∆H 2 ≠ = 41 ± 2 kJ mol−1, ∆S 2 ≠ = −110 ± 5 J K−1 mol−1. The time-resolved spectra, a positive dependence of the rate constants on ionic strength of the reaction medium, and the consistency of pre-equilibrium constants derived from different reaction systems support the proposed reaction mechanism.

In this paper, a novel closed-loop DC voltage regulation strategy of DC micro-grid is proposed, which includes tertiary control, secondary control and primary control. The tertiary control is in charge of economical dispatch. It assigns the scheduled power to all the voltage controllers. The primary control and secondary control are real time operation control. The secondary control provides the voltage set point for the primary control through distributed cooperative mechanism to maintain the micro-grid average voltage as the reference value and help fine proportional load sharing which is assigned by the tertiary control. The primary control, implementing a droop mechanism, regulates the output voltage of individual converters. The simulation results validate the effectiveness of the proposed strategy.

Aiming at the multi peak phenomenon in the output power characteristic curve of photovoltaic (PV) array under partially-shaded conditions, this paper addresses a new global maximum power point tracking (GMPPT) method based on sliding mode control (SMC). First, the output power characteristic curve of the PV array is scanned and the global maximum power point (GMPP) is stored at the same times. The SMC is introduced in this process, which greatly reduces the scanning time. Then the SMC based MPPT (SMC-MPPT) method is adopted to quickly stabilize the the operating point of the PV array at the GMPP, reducing the power fluctuations during steady-state operation. Simulation results validate that the proposed method can track the GMPP with good dynamic response performance under partially shaded conditions, reducing the power loss of the whole tracking process.

Aiming at the multiple peaks phenomenon on the power-voltage characteristic curve of photovoltaic (PV) array under partially shaded conditions, this paper proposes a fast global maximum power point tracking method based on sliding mode control (SMC). First, according to the operating characteristics of PV arrays, a reduced scanning range is adopted to avoid large power fluctuations and the optimal scanning direction of global maximum power point (GMPP) is determined to avoid the repeating scanning of the PV curve, both of which reduce the scanning time greatly. Second, during the scanning and tracking process, SMC is introduced to move the operating point quickly to the reference value, which improves the scanning speed further. Finally, when the operating point is close to the GMPP, the control mode is switched from the SMC based tracking control to the SMC based maximum power point tracking control, which quickly stabilizes the operating point of the PV array at the GMPP, reducing the power ripple during steady-state operation. Furthermore, the proposed method is independent of PV parameters, due to the new open circuit voltage detection method proposed in this paper, which does not occupy extra time. Simulation and experimental results validate that the proposed method can guarantee accurate convergence to the GMPP with fast tracking process and low energy loss under partially shaded conditions.

The Sulige is the largest discovered gas field in China. The reservoir is characterized by low porosity, low permeability and strong heterogeneity. Meanwhile single sand body is superimposed each other and the composite sand bodies are contiguous, whereas the distribution of gas reservoirs is dispersed. Consequently, traditional method for sand body prediction is difficult to meet the need for gas reservoir prediction that is the one of key problems of reservoir prediction in Sulige area. P-wave seismic technology has played an important role in exploration and development of Sulige gas field. But with the expanding edge of exploration and the fineness of development, using PP seismic data alone has shortcoming for the prediction of effective thin reservoir and spatial distribution of gas and water reservoirs. Beginning with the first full digital 3D3C seismic data acquisition in Sulige area in 2003, it gradually sets up a work flow and related methods of using multicomponent seismic data to identify gas reservoir. In this paper, we present a practical application of using 3D3C seismic data. Considering the feature of tight gas reservoir in Sulige area, characteristics of rock physics parameters being sensitive to gas reservoir are set up on the basis of rock physics analysis. Through the co-analysis of seismic modeling and joint PP/PS pre-stack inversion, elastic parameters including P-impedance, S-impedance and Vp/Vs ratio etc are got from joint PP/PS pre-stack inversion. Finally, the methods of elastic parameters crossplot and facies/fluid probability analysis are employed to interpret the inversion result, thus improving the accuracy of gas reservoir prediction.

The combination of molecularly imprinted polymer with high performance liquid chromatography has been developed to determine cyromazine and its metabolic melamine in some samples. However, the potential risk of template leakage used in molecularly imprinted polymer is a major disadvantage. To solve this problem, 2-(4,6-diamino-1,3,5-triazin-2-ylamino) ethanethiol disulfide, a molecule that shares the similar imprinting sites with cyromazine and melamine, was selected as pseudo template to prepare molecularly imprinted polymer. Methacrylic acid, ethylene glycol dimethyl acrylate and toluene were selected as functional monomer, crosslinker and porogen, respectively. The molecular recognition property and binding capability of cyromazine and melamine were evaluated by adsorption test and Scatchard analysis. The results showed that the molecularly imprinted polymer based on pseudo template had more excellent affinity and selectivity for cyromazine and melamine. The resulting molecularly imprinted polymer was used as a solid-phase extraction material to enrich cyromazine and melamine in egg and milk samples for high performance liquid chromatography analysis. The solid-phase extraction process was carefully optimized. It was found that when different concentration of cyromazine and melamine standards were spiked into samples, satisfactory recovery rate of cyromazine and melamine were obtained as 85.6-98.8% with relative standard deviation5.5%.

Wind farm group integrated system consists of many Large-Scale a single wind farm, which will have a total capacity of 1,000MW (and above). Reactive- power fluctuation of Wind farm group will seriously worse the voltage in limited area nearby .However, Reactive power optimization is limited to the regulation of reactive power of a single wind farm mostly, that cannot satisfy the demand of voltage regulating for local power system. Using the voltage level of PCC and integrated substation as a target function, this paper applies an efficient method based on genetic algorithm to extract reactive power compensation point and optimize reactive power compensation capacity of STATCOM. Taking wind power system within Inner Mongolia Huitengxile district power network as an example, the simulation results show that this method is valid to prevent voltage collapse.

Medium voltage distribution network is the basis for the development of urban distribution network. With the power load increasing, 20kV instead of 10kV voltage level will become the main future development direction for distribution network. The load forecasting is an important aspect of distribution network planning, whose model based on exponential smoothing method which is simple created, less data storage required. It can quickly calculate a new predicted value by the recent observations, which is applicable to the load forecast for the near future. By the load forecasting to a newly industrial park for 20kV distribution network, this paper preliminary studies based on the exponential smoothing method in distribution network planning application.