Publications by authors named "Lilong Xu"

7 Publications

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Visualization Experimental Study on Well Spacing Optimization of SAGD with a Combination of Vertical and Horizontal Wells.

ACS Omega 2021 Nov 27;6(44):30050-30060. Epub 2021 Oct 27.

Shandong Ruiheng Xingyu Petroleum Technology Development Co., Ltd, Qingdao 266500, China.

For oil sand reservoirs, the steam-assisted gravity drainage (SAGD) technique is one of the most efficient thermal recovery technologies. However, the high oil viscosity and the severe heat loss seriously affect the production effect of SAGD in developing thin oil sand reservoirs by the traditional SAGD technology. Therefore, it is essential to improve the SAGD technology to enhance the recovery of the thin oil sand reservoir. In this paper, SAGD with a combination of vertical and horizontal well (VH-SAGD) technology was adopted, and the influence of different well spacings (horizontal distance between vertical steam injection wells and horizontal production wells) on the development of steam chambers was investigated. By the similarity criterion, the experimental parameters were obtained. After that, an improved 2D visualization physical model was designed with 9 × 9 high-precision thermocouples installed inside the device to monitor the real-time temperature. This experimental physical model can not only accurately capture the temperature distribution but also display the continuous change process of the chamber inside the model by the visible window. Finally, different well spacing cases (10, 15, and 20 cm) were tested to observe the development of the steam chamber and analyze the production data. Both the temperature distribution and visual window showed that the steam chamber has four obvious stages, and reasonable well spacing can promote the development of the steam chamber. When the well spacing is relatively small, the unswept area of the cold oil on both sides is large, and the area of the steam chamber overlaps more. When the well spacing is relatively moderate, the steam chamber is the most complete and the recovery factor is the highest. When the well spacing is relatively large, although the unswept area of the cold oil on both sides is small, the middle cold oil area is larger than the previous two groups. Therefore, the best well spacing for oil sand reservoirs of about 15 m thickness is 15-20 m, where the VH-SAGD method has a better displacement effect and higher oil recovery. The experimental conclusions can provide theoretical support for the production of thin oil sand reservoirs.
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http://dx.doi.org/10.1021/acsomega.1c04737DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8582263PMC
November 2021

Aging Effect on Mandarin Chinese Vowel and Tone Identification in Six-Talker Babble.

Am J Audiol 2021 Sep 19;30(3):616-630. Epub 2021 Jul 19.

School of Foreign Languages, Tongji University, Shanghai, China.

Purpose The purpose of this study was to measure Mandarin Chinese vowel-plus-tone identification in quiet and noise for younger and older listeners. Method Two types of noise served as the masker, namely, six-talker babble and babble-modulated noise, at two signal-to-noise ratios (SNRs) of -4 and -8 dB. Fourteen listeners from both age groups were recruited, and three sets of data analyses were conducted: the identification of vowel plus tone, the identification of vowel, and the identification of tone. Results Younger listeners outperformed older listeners in all listening conditions, whereas the younger-older listener difference became greater in noise than in quiet, indicating a more detrimental effect of noise for older listeners than for younger listeners. In addition, vowel identification showed slightly better scores than tone identification in noise, suggesting that noise appeared to affect tone perception more negatively than vowel perception in Mandarin Chinese. At -4 dB SNR, there was a significantly greater amount of informational masking (IM) and a greater amount of energetic masking (EM) for older listeners than for younger listeners. At -8 dB SNR, there was a greater amount of EM for older listeners than for younger listeners but with no group difference in the amount of IM. Conclusion These results suggest that older listeners received a more negative impact of noise for Mandarin Chinese phonemic and tone recognition and had a larger amount of IM or EM from competing speech noise than younger listeners, depending on the SNR.
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http://dx.doi.org/10.1044/2021_AJA-20-00139DOI Listing
September 2021

Alterations in diaphragmatic function assessed by ultrasonography in mechanically ventilated patients with sepsis.

J Clin Ultrasound 2019 May 22;47(4):206-211. Epub 2019 Jan 22.

Department of Critical Care Medicine, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.

Purpose: To assess alteration of diaphragmatic function by ultrasonography in a population of mechanically ventilated patients with or without sepsis.

Methods: We performed a prospective, 6-month, single-center, observational cohort study. Mechanically ventilated septic and nonseptic patients were studied within 24 hours following intubation and before the moment of ventilator liberation. Diaphragm thickness and contractile activity (quantified by diaphragmatic thickening fraction, DTF) were measured by ultrasonography at the zone of apposition. Intraobserver and interobserver reproducibility were measured.

Results: Fifty-two critically ill patients were included, 28 with sepsis and 24 without sepsis. Upon initiation of ventilation, DTF was lower in septic than that in nonseptic patients (P = 0.03). No difference was observed between septic and nonseptic patients for diaphragm thickness. Mean 188 ± 111 hours after the first measurement, both diaphragm thickness and DTF decreased significantly compared with first measurements in septic and nonseptic patients, all P < 0.001. Diaphragm thickness decreased by 9.1 ± 10.7% in nonseptic and by 16.0 ± 13.5% in septic patients, P = 0.049. DTF decreased by 15.2 ± 21.3% in nonseptic and by 30.7 ± 22.0% in septic patients, P = 0.013.

Conclusions: Mechanically ventilated patients with sepsis were associated with an earlier and more severe diaphragm dysfunction compared with patients without sepsis.
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http://dx.doi.org/10.1002/jcu.22690DOI Listing
May 2019

Aging Effect on Categorical Perception of Mandarin Tones 2 and 3 and Thresholds of Pitch Contour Discrimination.

Am J Audiol 2017 Mar;26(1):18-26

Department of Communication Sciences and Disorders, University of Texas at Austin.

Purpose: The purpose of the study was to examine the aging effect on the categorical perception of Mandarin Chinese Tone 2 (rising F0 pitch contour) and Tone 3 (falling-then-rising F0 pitch contour) as well as on the thresholds of pitch contour discrimination.

Method: Three experiments of Mandarin tone perception were conducted for younger and older listeners with Mandarin Chinese as the native language. The first 2 experiments were in the categorical perception paradigm: tone identification and tone discrimination for a series of stimuli, the F0 contour of which systematically varied from Tone 2 to Tone 3. In the third experiment, the just-noticeable differences of pitch contour discrimination were measured for both groups.

Results: In the measures of categorical perception, older listeners showed significantly shallower slopes in the tone identification function and significantly smaller peakedness in the tone discrimination function compared with younger listeners. Moreover, the thresholds of pitch contour discrimination were significantly higher for older listeners than for younger listeners.

Conclusion: These results suggest that aging reduced the categoricality of Mandarin tone perception and worsened the psychoacoustic capacity to discriminate pitch contour changes, thereby possibly leading to older listeners' difficulty in identifying Tones 2 and 3.
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http://dx.doi.org/10.1044/2016_AJA-16-0020DOI Listing
March 2017

[The value of thyroglobulin measurement in fine-needle aspiration for diagnosis of suspicious lymph nodes in patients with thyroid carcinoma after thyroidectomy].

Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2016 May;51(5):378-82

Department of Diagnostic Ultrasound, Sir Run Run Shaw Hospital of Zhejiang University College of Medicine & Sir Run Run Shaw Institute of Clinical Medicine of Zhejiang University, Hangzhou 310016, China.

Objective: To investigate the value of thyroglobulin measurement in ultrasound guided fine-needle aspiration(FNA-Tg)for detecting neck node metastasis in patients with papillary thyroid carcinoma(PTC)after thyroidectomy.

Methods: A total of 128 suspicious metastatic lymph nodes in 112 patients were retrospectively analyzed. Postoperative pathologic results were taken as the gold standard. The values of FNA and FNA-Tg combined FNA in the diagnosis of metastatic lymph nodes were compared with different ultrasonic features.

Results: The sensitivity, specificity and accuracy of single FNA for the diagnosis of neck node metastasis were 67.5%, 98.0% and 79.7% respectively, and those of FNA-Tg combined FNA were 87.0%, 100.0% and 92.2% respectively. Compared with single FNA, the sensitivity and accuracy of FNA-Tg combined FNA were increased significantly(χ(2)=8.319, P=0.004; χ(2)=8.275, P=0.004). When the ultrasonographic characteristics met any one of five indicators for neck node metastasis, the sensitivity, specificity and accuracy of single FNA for the diagnosis of neck node metastasis were 38.1%, 95.7% and 68.2% respectively, and those of FNA-Tg combined FNA were 71.0%, 100.0% and 86.4% respectively. Compared with single FNA, the sensitivity and accuracy of FNA-Tg combined FNA were increased significantly(χ(2)=4.709, P=0.030; χ(2)=4.141, P=0.042). When the ultrasonographic characteristics met any two of five indicators for neck node metastasis, the sensitivity, specificity and accuracy of single FNA for the diagnosis of neck node metastasis were 55.0%, 100.0% and 73.5% respectively, and those of FNA-Tg combined FNA were 90.0%, 100.0% and 94.1% respectively. Compared with single FNA, the sensitivity and accuracy of FNA-Tg combined FNA were increased significantly(χ(2)=6.140, P=0.013; χ(2)=5.314, P=0.021). The ultrasonographic characteristics met any three, four or five of five indicators or did not meet any of the indicators, there was no significant difference in the value of the diagnosis of metastatic lymph nodes between single FNA and FNA-Tg combined FNA(P>0.05).

Conclusions: The combination of FNA with FNA-Tg could be helpful in diagnosis of lymph node metastasis. When the suspicious lymph nodes had one or two ultrasound characteristics for neck node metastasis, FNA-Tg could raise the sensitivity and accuracy of FNA, and FNA-Tg could not significantly improve in the diagnosis of FNA when presenting with no or with more than 2 ultrasonographic features.
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http://dx.doi.org/10.3760/cma.j.issn.1673-0860.2016.05.012DOI Listing
May 2016

Aging effect on Mandarin Chinese vowel and tone identification.

J Acoust Soc Am 2015 Oct;138(4):EL411-6

Department of Communication Sciences and Disorders, University of Texas at Austin, Austin, Texas 78712, USA

Mandarin Chinese speech sounds (vowels × tones) were presented to younger and older Chinese-native speakers with normal hearing. For the identification of vowel-plus-tone, vowel-only, and tone-only, younger listeners significantly outperformed older listeners. The tone 3 identification scores correlated significantly with the age of older listeners. Moreover, for older listeners, the identification rate of vowel-plus-tone was significantly lower than that of vowel-only and tone-only, whereas for younger listeners, there was no difference among the three identification scores. Therefore, aging negatively affected Mandarin vowel and tone perception, especially when listeners needed to process both phonemic and tonal information.
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http://dx.doi.org/10.1121/1.4933234DOI Listing
October 2015

[Application value of contrast-enhanced ultrasonography for assessing the high-risk population of hepatic malignant tumor].

Zhonghua Zhong Liu Za Zhi 2015 Jul;37(7):545-8

Department of Diagnostic Ultrasound, Sir Run Run Shaw Hospital of Zhejiang University College of Medicine & Sir Run Run Shaw Institute of Clinical Medicine of Zhejiang University, Hangzhou 310016, China.

Objective: To investigate the clinical value of contrast-enhanced ultrasonography (CEUS) in assessing the high-risk population of hepatic malignant tumor (HMT).

Methods: Three hundred patients with high-risk of HMT were enrolled and examined by CEUS. The clinical data of these patients were collected. A comparative analysis was performed to assess the ability of CEUS for detecting and characterizing lesions in the liver. Kappa test was used for assessing the intra-and inter-observer reliability of CEUS.

Results: In 87 enrolled patients with 119 malignant lesions detected by contrast-enhanced MRI, 112 lesions were detected by CEUS and 95 lesions were detected by unenhanced ultrasonography (US). The detection rate of CEUS for HMT was significant higher than that of US (94.1% vs. 79.8%; P < 0.01). More HMT lesions were detected by CEUS than by US in 17.2% patients. One hundred and seventy-seven patients with 215 lesions were confirmed by pathological diagnosis or long-time follow-up. There were 118 malignant and 97 benign lesions. The accuracy of CEUS for differential diagnosis of the liver lesions was 91.6% (197/215), significantly higher than that by US (59.1%, 127/215) (P < 0.01). CEUS improved the accuracy for 35.0% (62/177) patients. For 96 patients with 105 lesions detected for the first time, the agreement of diagnosis by CEUS was 92.4% (97/105). The reliability of CEUS was high (Kappainter = 0.866; Kappaintra = 0.934).

Conclusions: CEUS improves the detection rate and diagnostic accuracy rate of the HMT high-risk population, with a high agreement for diagnosing the new lesions. CEUS may be considered as a first-line method to assess the high-risk population of HMT conveniently, accurately and reliably.
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July 2015
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