t Research and development of safe and effective control technology of hard roof is an inevitable trend at present. Directional hydraulic fracturing technology is expected to become a safe and effective way to control...t Research and development of safe and effective control technology of hard roof is an inevitable trend at present. Directional hydraulic fracturing technology is expected to become a safe and effective way to control and manage hard roof. In order to make hard roof fracture in a directional way, a hydraulic fracture field test has been conducted in the third panel district of Tashan Coal Mine in Datong. First, two hydraulic fracturing drilling holes and four observing drilling holes were arranged in the roof, followed by a wedge-shaped ring slot in each hydraulic fracturing drilling hole. The hydraulic fracturing holes were then sealed and, hydraulic fracturing was conducted. The results show that the hard roof is fractured directionally by the hydraulic fracturing function of the two fracturing drilling holes; the sudden drop, or the overall downward trend of hydraulic pressure from hydraulic monitoring is the proof that the rock in the hard roof has been fractured. The required hydraulic pressure to fracture the hard roof in Tashan coal mine, consisting of carboniferous sandstone layer, is 50.09 MPa, and the fracturing radius of a single drilling hole is not less than 10.5 m. The wedge-shaped ring slot made in the bottom of the hydraulic fracturing drilling hole plays a guiding role for crack propagation. After the hydraulic fracturing drill hole is cracked, the propagation of the resulting hydraulic crack, affected mainly by the regional stress field, will turn to other directions.展开更多
Dynamic hip/compression screw （DHS/ DCS） is one of the most commonly performed surgeries in orthopaedic practice. Sliding barrel plate over the DHS/DCS lag screw is one of t.he very crucial and at times uncomfor- ta...Dynamic hip/compression screw （DHS/ DCS） is one of the most commonly performed surgeries in orthopaedic practice. Sliding barrel plate over the DHS/DCS lag screw is one of t.he very crucial and at times uncomfor- table and time consuming steps of DHS/DCS surgery espe- cially when it comes to inexperienced surgeons and residents. Also in developing countries where not all stan- dard instrumentation is always available, this crucial step becomes more time consuming. Here we present a case re- port of 58-year-old male patient with intertrochanteric fracture, in which we used a new device for insertion of barrel plate over DHS/DCS lag screw and found that a small DHS/DCS lag screw extension （sliding jig of barrel plate） can be very helpful to slide barrel plate over the DHS/DCS lag screw.展开更多
The general steam-injection pressing is mainly used for produce particleboards and medium density fiberboard. However, it is difficult to produce soft fiberboard with desired strength. However, the closing steam-injec...The general steam-injection pressing is mainly used for produce particleboards and medium density fiberboard. However, it is difficult to produce soft fiberboard with desired strength. However, the closing steam-injection pressing that based on the steam-injection pressing could. The wooden frame sealing up the slab could prevent the steam from emitting when the steam injected into the slab. The caloric released by steam condensation make the slab reach high temperature level for a short period. This method is very appropriate for making thick panels in theory, especially for the soft fiberboard. It makes a great leap forward on the hot pressing process that for wood-based panels. Moreover, it will be a meaningful technological breakthrough in developing new products and improving wood utilization.展开更多
基金Supported by the National Natural Science Foundation of China （51274194, 51004104） the Program for New Century Excellent Talents in University （NCET- 12-0958）
文摘t Research and development of safe and effective control technology of hard roof is an inevitable trend at present. Directional hydraulic fracturing technology is expected to become a safe and effective way to control and manage hard roof. In order to make hard roof fracture in a directional way, a hydraulic fracture field test has been conducted in the third panel district of Tashan Coal Mine in Datong. First, two hydraulic fracturing drilling holes and four observing drilling holes were arranged in the roof, followed by a wedge-shaped ring slot in each hydraulic fracturing drilling hole. The hydraulic fracturing holes were then sealed and, hydraulic fracturing was conducted. The results show that the hard roof is fractured directionally by the hydraulic fracturing function of the two fracturing drilling holes; the sudden drop, or the overall downward trend of hydraulic pressure from hydraulic monitoring is the proof that the rock in the hard roof has been fractured. The required hydraulic pressure to fracture the hard roof in Tashan coal mine, consisting of carboniferous sandstone layer, is 50.09 MPa, and the fracturing radius of a single drilling hole is not less than 10.5 m. The wedge-shaped ring slot made in the bottom of the hydraulic fracturing drilling hole plays a guiding role for crack propagation. After the hydraulic fracturing drill hole is cracked, the propagation of the resulting hydraulic crack, affected mainly by the regional stress field, will turn to other directions.
文摘Dynamic hip/compression screw （DHS/ DCS） is one of the most commonly performed surgeries in orthopaedic practice. Sliding barrel plate over the DHS/DCS lag screw is one of t.he very crucial and at times uncomfor- table and time consuming steps of DHS/DCS surgery espe- cially when it comes to inexperienced surgeons and residents. Also in developing countries where not all stan- dard instrumentation is always available, this crucial step becomes more time consuming. Here we present a case re- port of 58-year-old male patient with intertrochanteric fracture, in which we used a new device for insertion of barrel plate over DHS/DCS lag screw and found that a small DHS/DCS lag screw extension （sliding jig of barrel plate） can be very helpful to slide barrel plate over the DHS/DCS lag screw.
基金special research of nonprofit industry "Reseach on the Energy-saving and Sound Insulation Wall of PrefabricatedWooden Frame and Structural Materials"(No.200704013)
文摘The general steam-injection pressing is mainly used for produce particleboards and medium density fiberboard. However, it is difficult to produce soft fiberboard with desired strength. However, the closing steam-injection pressing that based on the steam-injection pressing could. The wooden frame sealing up the slab could prevent the steam from emitting when the steam injected into the slab. The caloric released by steam condensation make the slab reach high temperature level for a short period. This method is very appropriate for making thick panels in theory, especially for the soft fiberboard. It makes a great leap forward on the hot pressing process that for wood-based panels. Moreover, it will be a meaningful technological breakthrough in developing new products and improving wood utilization.
