RV fitting curves corresponding, from left to right, to WDJ094200.05+312920.27, WDJ113100.20+493826.27, and WDJ113941.32004009.78. WDJ094200.05+312920.27: 15 valid exposures. The phase coverages of the rank-2 period (0.2920 days) and the rank-4 period (0.5783 days) are better compared to the other three periods. WDJ113100.20+493826.27: nine valid exposures, with the best-fit period being 0.0229 days (approximately 33 minutes). However, due to the limitations of the exposure time (500–1400s), the reliability of this period is low. Other period plots have higher R² values but suffer from low phase coverage. WDJ113941.32-004009.78: nine exposures. The phase coverages of the rank-3 period (0.0357 days) and the rank-4 period (0.0274 days) are relatively good, but their accuracy is affected by the exposure time. The phase coverages of the other three periods are low. Therefore, these three DWD candidates all require additional observations to determine more accurate periods.