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The borehole thermal resistance is a significant design indicator for the ground heat exchanger (GHE) and careful design procedure is required for this indicator to decrease the length of GHE and capital investments. In this study, a modified two-dimension numerical model with the resistance model is first applied to analyze the effects of parameters including the borehole radius, pipe-pipe distance, pipe radius, soil thermal conductivity and grout thermal conductivity on the borehole thermal resistance. To implement the analysis, an L27 (35) is established. Then, the Taguchi method is carried out to obtain the optimal scenarios of parameters combination. Results using the optimal parameters set reveal that the maximum borehole thermal resistance decreased value and rate can be up to 0.146 m.K/W and 81.56%. The analysis of variance technique is applied lastly to analyze the relative significance of different parameters. The results indicate that the borehole radius, grout thermal conductivity, and pipe radius are important driving parameters in determining the borehole thermal resistance, while the pipe-pipe distance and ground thermal conductivity almost play no role in it.

To evaluate the efficacy of pulsatile gonadotropin-releasing hormone (GnRH) therapy in male patients with pituitary stalk interruption syndrome (PSIS).Fourteen male PSIS patients, who had received subcutaneous pulsatile GnRH therapy for at least four weeks at Peking Union Medical College Hospital from April 2014 to September 2015, were included in the study. Serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone level, testicular volume and sperm in ejaculation were measured. After treatment for four weeks, subjects with serum LH≥1.24 U/L were classified as"good response group", and others were classified as"poor response group".All patients were born by breech delivery and presented with absent pubertal development. Laboratory findings showed combined pituitary hormone deficiency in all patients. Pituitary stalk interruption syndrome was diagnosed based on MRI findings. Totally 11 out of 14 patients showed good response to pulsatile GnRH therapy. Their LH level increased from 0.32 (0.15, 0.61) U/L to 4.34(2.52, 7.39)U/L(P0.001), FSH from 0.84 (0.30, 1.50) U/L to 7.12 (4.53, 10.09) U/L(P0.001); serum testosterone level from 0 (0, 0.45) nmol/L to 2.46 (0.56, 11.45) nmol/L (P=0.004) and testicular volume from 2.0 (2.0, 4.0) ml to 4.0 (3.0, 6.0) ml (P=0.005). Sperm was detected in seminal samples after treatment for 8 weeks in two patients and for 12 weeks in one patients. Three out of 14 patients showed poor response to pulsatile GnRH therapy.Pulsatile GnRH therapy can effectively establish the pituitary-testicular axis function for most patients with pituitary stalk interruption syndrome, indicating enough reserve of gonadotrophs in the pituitary.

To evaluate the hypothalamic-pituitary-testicular axis (HPTA) function and spermatogenesis in male patients with X-linked adrenal hypoplasia congenita (AHC) due to DAX-1 gene mutation.Twenty-four adult male patients from Peking Union Medical College Hospital between November 2007 and December 2014 were included.Their DAX-1 gene mutations were confirmed by polymerase chain reaction (PCR) and clinical features, hormone level and semen assay were collected.All patients presented with adrenal deficiency symptom.21 patients (87.5%) showed the symptoms before the age of 10 years old.The average testicular volume was 2.0 (2.0, 3.8) ml at the baseline in 24 patients.Three patients had cryptorchidism.Serum testosterone level increased from 0.1 (0, 0.5) nmol/L to 13.5 (7.6, 15.4) nmol/L (n=16) after human chorionic gonadotropin (HCG) stimulation.23 out of 24 patients were diagnosed as hypogonadotropic hypogonadism (HH) and only one patient was diagnosed as azoospermia with normal gonadotropin and testosterone level.Combined gonadotropin therapy was administered in seven patients and their serum testosterone level reached 15.3(8.4, 25.3) nmol/L, but no obvious testicular enlargement was observed [(4.0±2.9) vs (4.9±3.3) ml , P=0.270] and seminal analysis revealed persistent azoospermia.Another patient showed response to pulsatile GnRH therapy.Luteinizing hormone(LH) level increased from 1.0 U/L to 9.3 U/L, and follicle stimulating hormone(FSH) level increased from 3.0 U/L to 13.5 U/L.Serum testosterone level increased from 0 nmol/L to 10.0 nmol/L, but testicular volume maintained 3 ml after treatment for two months.Male patients with DAX-1 gene mutations presented with primary defect in spermatogenesis and hypogonadotropic hypogonadism.Their Leydig cell function was almost normal, while Sertoli cell and seminiferous tubule function were seriously damaged.

Fe3O4 magnetic nanoparticles being used as seeding materials, Ag+ ions on the Fe3O4 magnetic nanoparticles reduced to the metal form by tartaric acid using heated treatment. Thus, Fe3O4/Ag composite core-shell magnetic nanoparticles were synthesized. The products were characterized by transmission electron microscope (TEM) and x-ray diffraction (XRD). Both TEM and XRD results showed that the Ag nanoparticles were well distributed on the surface of Fe3O4 magnetic nanoparticles. The size for Fe3O4/Ag composite magnetic nanoparticles which were spherical shape was ≃40 nm. Furthermore, the magnetic properties of samples were characterized on a vibrating sample magnetometer. Under optimal conditions, Fe3O4/Ag composite nanoparticles showed higher magnetism than pure Fe3O4 nanoparticles.

This paper presents an effective numerical method for the transient analysis of lossy transmission lines. With the discretization of the spatial variation of voltages and currents along the transmission lines while remaining the temporal derivatives unchanged, a semi- discrete model is derived from the telegrapher's equations. The time- step integration method is utilized to derive the recursive scheme of time advancing. A large time step can be used in the computation, meanwhile, its accuracy is guaranteed. Numerical examples are presented to demonstrate the stability and accuracy of the proposed method.

A superhard cubic boron nitride (c-BN), which is now an industrially important material used in preference to diamond especially for cutting and lapping steel products, has so far been synthesized by heating a starting powder of hexagonal boron nitride (h-BN) under a high pressure at a high temperature. In the present study we have mechanically milled h-BN starting material to introduce lattice defects prior to its conversion to c-BN. The synthesis of c-BN has then been facilitated prominently owing to a mechanochemical effect; under 7.7 GPa the formation of c-BN starts at 1250°C with the pre-milled h-BN powders, and at 1450°C with non-milled powders. High resolution transmission electron microscopy has clarified that a variety of defects form in h-BN during milling. The h-BN changes to w-BN by compression in the c direction, and a slight tilt at the interface between (0002)h and (0002)w partially compensates for the lattice misfit between the basal planes of both phases. Characteristic stacking ...

1. 1. Differential thermal analysis (DTA) of squeeze-cast TiO2/Al bulk indicates that an exothermic reaction occurs after the aluminium melts. A high temperature combustion synthesis process was achieved to produce a fully dense Al3Ti + α-Al2O3+ Al in situ composite. 2. 2. Very fine-scale dispersion of the Al3Ti and α-Al2O3 reinforcing phases, ranging from 0.4 to 1.0μm, was obtained in the Al matrix. The Al3Ti phase, some containing Al2Ti precipitates, form in the shape of block and whisker. The nanometer scale α-Al2O3 particles are found near the Al3Ti phase and in the Al matrix, and, occasionally, within the Al3Ti phase. 3. 3. Analysis of the microstructural evolution indicates that the in situ processing involves two steps: (1) a reaction process between the molten aluminium and TiO2 to produce alumina particulates and liquid Ti. (2) a subsequent solidification process of remained Al and Ti displaced from the reaction with decreasing temperature to produce Al + Al3Ti blocks and then the smaller Al3Ti precipitates form as the solidcools.

The nature of the interface, the orientation relationship of β-SiC whisker (β-SiCw)-Al combination, and the misfit dislocation structures at the β-SiCw-Al interfaces in a β-SiCw-Al composite have been observed by a high-resolution transmission electron microscopy (HRTEM). It was shown that quite a good bonding between the whisker and the aluminium was achieved due largely to the lattice match between SiC and aluminium at the interfaces. The orientation relationship between the whisker and the aluminium was {002}SiC∥{111}Al; 〈110〉SiC∥〈110〉Al. The interface was clean, faceted and semicoherent. The misfit dislocation cores were located in the whisker side away from the β-SiCw-Al interfaces.

A modified method of numerical inversion of a Laplace transform is presented for time response analysis of nonuniform transmission lines. It is more accurate and efficient than the traditional one, because of the stepping algorithm which it contains. >

To compare the laparoscopic approach with laparotomy in the treatment of ectopic pregnancy. The aim of this study was to evaluate the efficiency of laparoscopic surgery for ectopic pregnancies in China.A retrospective analysis involving 142 patients with ectopic pregnancies was done. Seventy-two of the 142 patients were treated laparoscopically.In the laparoscopic group, the operating time and post-hospital stay were significantly shorter but the total cost was higher compared with the laparotomy group.Although the laparoscopic surgery for ectopic pregnancies is a new approach and it is not widely practiced in China; it has more advantages than open surgery and it has been well accepted by the surgeons and patients. It is a safe and feasible approach, but the rate of laparoscopic approach for ectopic pregnancy is still low in China when compared with the developed countries.

A method for analysis of the time response of nonuniform multiconductor transmission lines is presented. The lines which can be analysed may be arbitrarily loaded, and may have frequency-dependent losses. Accurate and stable results are obtained.