Biography:

In the past X. Jia has collaborated on articles with M. Elimelech and Z.Z. Liang. One of their most recent publications is Distributed study of air temperature inside a dry-expansion evaporator. Which was published in journal Applied Thermal Engineering.

More information about X. Jia research including statistics on their citations can be found on their Copernicus Academic profile page.

X. Jia's Articles: (36)

Distributed study of air temperature inside a dry-expansion evaporator

AbstractA distributed steady and transient model is presented for studying air temperature distribution inside dry-expansion evaporators. The evaporating two-phase flow inside coils is described by a drift-flux flow. The model is capable of predicting distributions of refrigerant velocity, void fraction, temperature, tube wall temperature, air temperature and humidity, in both position and time domains. Comparison between the prediction and experimental measurements on a commercial evaporator is satisfactory for both steady and transient responses. The results indicate that an even air temperature distribution off the evaporator may be obtained by controlling liquid dry-out point at the two ends of the coil.

Synthesis of diamond with high nitrogen concentration from powder catalyst-C-additive NaN3 by HPHT

AbstractDiamond crystals with high nitrogen concentration, 1000–2000 ppm, have been successfully synthesized from the system of powder catalyst (Fe–Ni)–C-additive NaN3 in a cubic anvil high-pressure and high-temperature apparatus. The synthetic diamond crystals are cubo-octahedral or octahedral shape with a green or dark green color. The FTIR spectra of the diamond synthesized indicate that its nitrogen concentration increases with an increase of the NaN3 additive. Furthermore, such additive increase also leads to an increase in the minimum temperature and pressure for graphite/diamond conversion. We found iron nitride in the sample synthesized with high content of NaN3. We believe its presence is an indication that Fe content in the Fe–Ni alloy is reduced and the characteristics of catalyst are changed, leading to the increase of the minimum temperature and pressure for graphite/diamond conversion.

Giant improved thermoelectric properties in PbTe by HPHT at room temperature

AbstractWe report a large increase in the thermoelectric properties of n-type lead telluride compounds synthesized by applying pressure tuning and temperature tuning simultaneously. The value of the thermoelectric figure of merit, ZT for PbTe measured at ambient temperature and pressure, 0.87, has been achieved. This value is nearly 20 times larger than that of PbTe synthesized at the ambient pressure, and approximately equal to that of Bi2Te3. It is suggested that this method has potential application in obtaining good quality thermoelectric materials.

Abnormal regional homogeneity in Parkinson's disease: a resting state fMRI study

Highlights•Functional changes were found in PD patients independent of structural atrophy.•Both increased and decreased ReHo were observed in motor network regions in PD.•Increased ReHo was detected in visual association cortex for PD patients.

Effects of radial motion on interchange injections at Saturn

Highlights•Method of identifying flow channel features based on recent radial transport.•Inward transport of energetic charged particles limited by flow channel properties.•Use data model comparisons to infer flow channel properties at Saturn.

Priority communicationContainerless processing using floating zone technique on the ground

AbstractAn experiment of containerless processing was carried out by a modified floating zone technique on the ground condition using a Ba(B0.9Al0.1)2O4 as a source material. In this technique, a pair of Pt tubes with different diameters was used at the upper and the lower positions, and a molten zone was formed between the two Pt tubes. Melting started from the source material near the Pt tubes and ended at the center of the molten zone. Crystallization of the molten Ba(B0.9Al0.1)2O4 started from the center of the side surface of the molten zone when the supercooling was more than 250°C.

Checking into China's cow hotels: Have policies following the milk scandal changed the structure of the dairy sector?

AbstractChina's milk scandal is well known for causing the nation's largest food safety crisis and for its effect on thousands of children. Less, however, is known about the effect on the other victim: China's small dairy farmers. Although small backyard producers were not the ones that added melamine to the milk supply, the incomes of dairy farmers fell sharply after the crisis. In response, one of the actions taken by the government was to encourage small dairy producers to check into production complexes that were supposed to supply services, new technologies, and provide for easy/bulk procurement of the milk produced by the cows of the farmers. Because both farmers and their cows were living (and working) away from home, in the rest of the paper we call these complexes cow hotels. In this paper we examine the dynamics of China's dairy production structure before and after the milk scandal. In particular, we seek to gain a better understanding about how China's policies have been successful in encouraging farmers to move from the backyard into cow hotels. We also seek to find if larger or smaller farmers respond differently to these policy measures. Using data from a sample of farmers from dairy-producing villages in Greater Beijing, our empirical analysis finds that 1 yr after the milk scandal, the dairy production structure changed substantially. Approximately one quarter (26%) of the sample checked into cow hotels after the milk scandal, increasing from 2% before the crisis. Our results also demonstrate that the increase in cow hotel production can largely be attributed to China's dairy policies. Finally, our results suggest that the effects of government policy differ across farm sizes; China's dairy policies are more likely to persuade larger farms to join cow hotels. Apparently, larger farms benefit more when they join cow hotels. Overall, these results suggest that during the first year after the crisis, the government policies were effective in moving some of the backyard farmers into cow hotels (although 60% farmers remained backyard producing).

Annealing effects on mechanical properties and microstructure of F82H irradiated at ⩽60 °C with 800 MeV protons

AbstractMartensitic steel F82H was irradiated with 800 MeV protons up to 7.8 dpa at low temperatures ⩽60 °C. Tensile tests have been performed at 22, 160, 250, 350 and 400 °C. The microstructure of specimens with doses of 6–7.8 dpa after annealing 20 min and 2 h at 160, 250, 350 and 400 °C has been studied. The tensile results show that the yield of irradiated specimens decreases gradually with increasing test temperature. The ductility starts to recover at about 300 °C and is substantially recovered at 400 °C. The recovery depends on irradiation dose. The TEM results indicate that the number density of dislocation loops induced by irradiation decreases with annealing temperature, while the mean size of loops increases only slightly at 400 °C. A part of dislocation loops transferred into network dislocations and resulted in increase of network dislocation density. However, the total dislocation density (including loops) decreases gradually with annealing temperature.

Tensile tests and TEM investigations on LiSoR-2 to -4

AbstractMartensitic steel T91 will be used for the liquid lead bismuth eutectic (LBE) container of the MEGAPIE target. The irradiation assisted LBE corrosion and embrittlement effects on the behaviours of T91 steel have been studied by performing the LiSoR experiments, where T91 steel was irradiated with 72 MeV protons to doses up to 0.2 dpa at temperatures above 300 °C in flowing LBE with or without mechanical stress. Tensile tests on the T91 steel after irradiation demonstrated that the irradiation assisted LBE embrittlement was not evident at such a low irradiation dose. The irradiation produced small defect clusters and dislocation loops were observed in the inner tensile-stressed specimens (ITS-specimens) of LiSoR-3 and LiSoR-4. The main features of the dislocation structure in the ITS-specimen of LiSoR-2 and the test-section tubes (TS-tubes) were dislocation tangles and dislocation networks, and small defect clusters and dislocation loops were hardly observed due to the high irradiation temperatures. The TEM observations support the results of the tensile tests.

A subchronic toxicity study of elemental Nano-Se in Sprague-Dawley rats

AbstractThe subchronic toxicity of Nano-Se was compared with selenite and high-selenium protein in rats. Groups of Sprague-Dawley rats (12 males and 12 females per group) were fed diets containing Nano-Se, selenite and high-selenium protein at concentrations of 0, 2, 3, 4 and 5 ppm Se, respectively, for 13 weeks. Clinical observations were made and body weight and food consumption were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for hematology and clinical chemistry determination. Histopathological examination was performed on selected tissues. At the two higher doses (4 and 5 ppm Se), significant abnormal changes were found in body weight, hematology, clinical chemistry, relative organ weights and histopathology parameters. However, the toxicity was more pronounced in the selenite and high-selenium protein groups than the Nano-Se group. At the dose of 3 ppm Se, significant growth inhibition and degeneration of liver cells were found in the selenite and high-selenium protein groups. No changes attributable to administration of Nano-Se at the dose of 3 ppm Se were found. Taken together, the no-observed-adverse-effect level (NOAEL) of Nano-Se in male and female rats was considered to be 3 ppm Se, equivalent to 0.22 mg/kg bw/day for males and 0.33 mg/kg bw/day for females. On the other hand, the NOAELs of selenite and high-selenium protein in males and females were considered to be 2 ppm Se, equivalent to 0.14 mg/kg bw/day for males and 0.20 mg/kg bw/day for females. In addition, studies have shown that Nano-Se has a similar bioavailability in rat, and much less acute toxicity in mice compared with selenite. In conclusion, Nano-Se is less toxic than selenite and high-selenium protein in the 13-week rat study.

The etching process of boron nitride by alkali and alkaline earth fluorides under high pressure and high temperature

Highlights•Appropriate etch processes of hBN and cBN under HPHT are proposed.•The degree of the crystallization of hBN was decreased.•A special cBN growth mechanism with a triangular unit is proposed.•Plate-shape cBN crystals with large ratio of length to thickness were obtained.•A strategy provides useful guidance for controlling the cBN morphology.

Validation of a digital packing algorithm in predicting powder packing densities

AbstractDigiPac is a particle packing algorithm based on a digital approach to represent particle shape, packing space and particle movements. It is capable of packing particles of arbitrary shapes and sizes in a container of arbitrary geometry. A number of case studies have been performed to validate this digital approach, some of which are reported in this paper to show that with DigiPac shape factors used by many traditional models for predicting packing density become redundant. It also demonstrates that for polydisperse mixtures of non-spherical particles, a single size distribution measured using conventional means (e.g. light scattering) is inadequate for the purpose of predicting packing properties.

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